2020-09-18 13:26:54

by Arnd Bergmann

Subject: [PATCH 0/4] syscalls: remove compat_alloc_user_space callers

Going through compat_alloc_user_space() to convert indirect system call
arguments tends to add complexity compared to handling the native and
compat logic in the same code.

I have patches for all other uses of compat_alloc_user_space() as well,
and would expect that we can subsequently remove the interface itself.

Arnd

Arnd Bergmann (4):
x86: add __X32_COND_SYSCALL() macro
kexec: remove compat_sys_kexec_load syscall
mm: remove compat_sys_move_pages
mm: remove compat numa syscalls

arch/arm64/include/asm/unistd32.h | 12 +-
arch/mips/kernel/syscalls/syscall_n32.tbl | 12 +-
arch/mips/kernel/syscalls/syscall_o32.tbl | 12 +-
arch/parisc/kernel/syscalls/syscall.tbl | 10 +-
arch/powerpc/kernel/syscalls/syscall.tbl | 12 +-
arch/s390/kernel/syscalls/syscall.tbl | 12 +-
arch/sparc/kernel/syscalls/syscall.tbl | 12 +-
arch/x86/entry/syscalls/syscall_32.tbl | 6 +-
arch/x86/entry/syscalls/syscall_64.tbl | 4 +-
arch/x86/include/asm/syscall_wrapper.h | 5 +
include/linux/compat.h | 26 ---
include/uapi/asm-generic/unistd.h | 12 +-
kernel/kexec.c | 77 +++------
kernel/sys_ni.c | 5 -
mm/mempolicy.c | 193 +++++-----------------
mm/migrate.c | 45 +++--
16 files changed, 143 insertions(+), 312 deletions(-)

--
2.27.0

2020-09-18 13:27:00

by Arnd Bergmann

Subject: [PATCH 2/4] kexec: remove compat_sys_kexec_load syscall

The compat version of sys_kexec_load() uses compat_alloc_user_space to
convert the user-provided arguments into the native format.

Move the conversion into the regular implementation with
an in_compat_syscall() check to simplify it and avoid the
compat_alloc_user_space() call.

Signed-off-by: Arnd Bergmann <[email protected]>
---
arch/arm64/include/asm/unistd32.h | 2 +-
arch/mips/kernel/syscalls/syscall_n32.tbl | 2 +-
arch/mips/kernel/syscalls/syscall_o32.tbl | 2 +-
arch/parisc/kernel/syscalls/syscall.tbl | 2 +-
arch/powerpc/kernel/syscalls/syscall.tbl | 2 +-
arch/s390/kernel/syscalls/syscall.tbl | 2 +-
arch/sparc/kernel/syscalls/syscall.tbl | 2 +-
arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
arch/x86/entry/syscalls/syscall_64.tbl | 2 +-
include/linux/compat.h | 6 --
include/uapi/asm-generic/unistd.h | 2 +-
kernel/kexec.c | 75 ++++++-----------------
12 files changed, 29 insertions(+), 72 deletions(-)

diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 734860ac7cf9..b6517df74037 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -705,7 +705,7 @@ __SYSCALL(__NR_getcpu, sys_getcpu)
#define __NR_epoll_pwait 346
__SYSCALL(__NR_epoll_pwait, compat_sys_epoll_pwait)
#define __NR_kexec_load 347
-__SYSCALL(__NR_kexec_load, compat_sys_kexec_load)
+__SYSCALL(__NR_kexec_load, sys_kexec_load)
#define __NR_utimensat 348
__SYSCALL(__NR_utimensat, sys_utimensat_time32)
#define __NR_signalfd 349
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index f9df9edb67a4..ad157aab4c09 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -282,7 +282,7 @@
271 n32 move_pages compat_sys_move_pages
272 n32 set_robust_list compat_sys_set_robust_list
273 n32 get_robust_list compat_sys_get_robust_list
-274 n32 kexec_load compat_sys_kexec_load
+274 n32 kexec_load sys_kexec_load
275 n32 getcpu sys_getcpu
276 n32 epoll_pwait compat_sys_epoll_pwait
277 n32 ioprio_set sys_ioprio_set
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 195b43cf27c8..57baf6c8008f 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -322,7 +322,7 @@
308 o32 move_pages sys_move_pages compat_sys_move_pages
309 o32 set_robust_list sys_set_robust_list compat_sys_set_robust_list
310 o32 get_robust_list sys_get_robust_list compat_sys_get_robust_list
-311 o32 kexec_load sys_kexec_load compat_sys_kexec_load
+311 o32 kexec_load sys_kexec_load
312 o32 getcpu sys_getcpu
313 o32 epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
314 o32 ioprio_set sys_ioprio_set
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index def64d221cd4..778bf166d7bd 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -336,7 +336,7 @@
297 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
298 common statfs64 sys_statfs64 compat_sys_statfs64
299 common fstatfs64 sys_fstatfs64 compat_sys_fstatfs64
-300 common kexec_load sys_kexec_load compat_sys_kexec_load
+300 common kexec_load sys_kexec_load
301 32 utimensat sys_utimensat_time32
301 64 utimensat sys_utimensat
302 common signalfd sys_signalfd compat_sys_signalfd
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index c2d737ff2e7b..f128ba8b9a71 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -350,7 +350,7 @@
265 64 mq_timedreceive sys_mq_timedreceive
266 nospu mq_notify sys_mq_notify compat_sys_mq_notify
267 nospu mq_getsetattr sys_mq_getsetattr compat_sys_mq_getsetattr
-268 nospu kexec_load sys_kexec_load compat_sys_kexec_load
+268 nospu kexec_load sys_kexec_load
269 nospu add_key sys_add_key
270 nospu request_key sys_request_key
271 nospu keyctl sys_keyctl compat_sys_keyctl
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 10456bc936fb..d45952058be2 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -283,7 +283,7 @@
274 common mq_timedreceive sys_mq_timedreceive sys_mq_timedreceive_time32
275 common mq_notify sys_mq_notify compat_sys_mq_notify
276 common mq_getsetattr sys_mq_getsetattr compat_sys_mq_getsetattr
-277 common kexec_load sys_kexec_load compat_sys_kexec_load
+277 common kexec_load sys_kexec_load sys_kexec_load
278 common add_key sys_add_key sys_add_key
279 common request_key sys_request_key sys_request_key
280 common keyctl sys_keyctl compat_sys_keyctl
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 4af114e84f20..a46edcdd950d 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -369,7 +369,7 @@
303 common mbind sys_mbind compat_sys_mbind
304 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
305 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
-306 common kexec_load sys_kexec_load compat_sys_kexec_load
+306 common kexec_load sys_kexec_load sys_kexec_load
307 common move_pages sys_move_pages compat_sys_move_pages
308 common getcpu sys_getcpu
309 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 3db3d8823dc8..7e4140b78aad 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -294,7 +294,7 @@
280 i386 mq_timedreceive sys_mq_timedreceive_time32
281 i386 mq_notify sys_mq_notify compat_sys_mq_notify
282 i386 mq_getsetattr sys_mq_getsetattr compat_sys_mq_getsetattr
-283 i386 kexec_load sys_kexec_load compat_sys_kexec_load
+283 i386 kexec_load sys_kexec_load sys_kexec_load
284 i386 waitid sys_waitid compat_sys_waitid
# 285 sys_setaltroot
286 i386 add_key sys_add_key
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index f30d6ae9a688..9986f5f08278 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -384,7 +384,7 @@
525 x32 sigaltstack compat_sys_sigaltstack
526 x32 timer_create compat_sys_timer_create
527 x32 mq_notify compat_sys_mq_notify
-528 x32 kexec_load compat_sys_kexec_load
+528 x32 kexec_load sys_kexec_load
529 x32 waitid compat_sys_waitid
530 x32 set_robust_list compat_sys_set_robust_list
531 x32 get_robust_list compat_sys_get_robust_list
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 3d96a841bd49..a7a5a0ff59ef 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -643,12 +643,6 @@ asmlinkage long compat_sys_setitimer(int which,
struct old_itimerval32 __user *in,
struct old_itimerval32 __user *out);

-/* kernel/kexec.c */
-asmlinkage long compat_sys_kexec_load(compat_ulong_t entry,
- compat_ulong_t nr_segments,
- struct compat_kexec_segment __user *,
- compat_ulong_t flags);
-
/* kernel/posix-timers.c */
asmlinkage long compat_sys_timer_create(clockid_t which_clock,
struct compat_sigevent __user *timer_event_spec,
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 995b36c2ea7d..83f1fc7fd3d7 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -342,7 +342,7 @@ __SC_COMP(__NR_setitimer, sys_setitimer, compat_sys_setitimer)

/* kernel/kexec.c */
#define __NR_kexec_load 104
-__SC_COMP(__NR_kexec_load, sys_kexec_load, compat_sys_kexec_load)
+__SYSCALL(__NR_kexec_load, sys_kexec_load)

/* kernel/module.c */
#define __NR_init_module 105
diff --git a/kernel/kexec.c b/kernel/kexec.c
index f977786fe498..1ef7d3dc906f 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -29,7 +29,25 @@ static int copy_user_segment_list(struct kimage *image,
/* Read in the segments */
image->nr_segments = nr_segments;
segment_bytes = nr_segments * sizeof(*segments);
- ret = copy_from_user(image->segment, segments, segment_bytes);
+ if (in_compat_syscall()) {
+ struct compat_kexec_segment __user *cs = (void __user *)segments;
+ struct compat_kexec_segment segment;
+ int i;
+ for (i=0; i< nr_segments; i++) {
+ copy_from_user(&segment, &cs[i], sizeof(segment));
+ if (ret)
+ break;
+
+ image->segment[i] = (struct kexec_segment) {
+ .buf = compat_ptr(segment.buf),
+ .bufsz = segment.bufsz,
+ .mem = segment.mem,
+ .memsz = segment.memsz,
+ };
+ }
+ } else {
+ ret = copy_from_user(image->segment, segments, segment_bytes);
+ }
if (ret)
ret = -EFAULT;

@@ -264,58 +282,3 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,

return result;
}
-
-#ifdef CONFIG_COMPAT
-COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
- compat_ulong_t, nr_segments,
- struct compat_kexec_segment __user *, segments,
- compat_ulong_t, flags)
-{
- struct compat_kexec_segment in;
- struct kexec_segment out, __user *ksegments;
- unsigned long i, result;
-
- result = kexec_load_check(nr_segments, flags);
- if (result)
- return result;
-
- /* Don't allow clients that don't understand the native
- * architecture to do anything.
- */
- if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
- return -EINVAL;
-
- ksegments = compat_alloc_user_space(nr_segments * sizeof(out));
- for (i = 0; i < nr_segments; i++) {
- result = copy_from_user(&in, &segments[i], sizeof(in));
- if (result)
- return -EFAULT;
-
- out.buf = compat_ptr(in.buf);
- out.bufsz = in.bufsz;
- out.mem = in.mem;
- out.memsz = in.memsz;
-
- result = copy_to_user(&ksegments[i], &out, sizeof(out));
- if (result)
- return -EFAULT;
- }
-
- /* Because we write directly to the reserved memory
- * region when loading crash kernels we need a mutex here to
- * prevent multiple crash kernels from attempting to load
- * simultaneously, and to prevent a crash kernel from loading
- * over the top of a in use crash kernel.
- *
- * KISS: always take the mutex.
- */
- if (!mutex_trylock(&kexec_mutex))
- return -EBUSY;
-
- result = do_kexec_load(entry, nr_segments, ksegments, flags);
-
- mutex_unlock(&kexec_mutex);
-
- return result;
-}
-#endif
--
2.27.0

2020-09-18 13:27:07

by Arnd Bergmann

Subject: [PATCH 3/4] mm: remove compat_sys_move_pages

The compat move_pages() implementation uses compat_alloc_user_space()
for converting the pointer array. Moving the compat handling into
the function itself is a bit simpler and lets us avoid the
compat_alloc_user_space() call.

Signed-off-by: Arnd Bergmann <[email protected]>
---
arch/arm64/include/asm/unistd32.h | 2 +-
arch/mips/kernel/syscalls/syscall_n32.tbl | 2 +-
arch/mips/kernel/syscalls/syscall_o32.tbl | 2 +-
arch/parisc/kernel/syscalls/syscall.tbl | 2 +-
arch/powerpc/kernel/syscalls/syscall.tbl | 2 +-
arch/s390/kernel/syscalls/syscall.tbl | 2 +-
arch/sparc/kernel/syscalls/syscall.tbl | 2 +-
arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
arch/x86/entry/syscalls/syscall_64.tbl | 2 +-
include/linux/compat.h | 5 ---
include/uapi/asm-generic/unistd.h | 2 +-
kernel/sys_ni.c | 1 -
mm/migrate.c | 45 +++++++++++------------
13 files changed, 32 insertions(+), 39 deletions(-)

diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index b6517df74037..af793775ba98 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -699,7 +699,7 @@ __SYSCALL(__NR_tee, sys_tee)
#define __NR_vmsplice 343
__SYSCALL(__NR_vmsplice, compat_sys_vmsplice)
#define __NR_move_pages 344
-__SYSCALL(__NR_move_pages, compat_sys_move_pages)
+__SYSCALL(__NR_move_pages, sys_move_pages)
#define __NR_getcpu 345
__SYSCALL(__NR_getcpu, sys_getcpu)
#define __NR_epoll_pwait 346
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index ad157aab4c09..7fa1ca45e44c 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -279,7 +279,7 @@
268 n32 sync_file_range sys_sync_file_range
269 n32 tee sys_tee
270 n32 vmsplice compat_sys_vmsplice
-271 n32 move_pages compat_sys_move_pages
+271 n32 move_pages sys_move_pages
272 n32 set_robust_list compat_sys_set_robust_list
273 n32 get_robust_list compat_sys_get_robust_list
274 n32 kexec_load sys_kexec_load
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 57baf6c8008f..194c7fbeedf7 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -319,7 +319,7 @@
305 o32 sync_file_range sys_sync_file_range sys32_sync_file_range
306 o32 tee sys_tee
307 o32 vmsplice sys_vmsplice compat_sys_vmsplice
-308 o32 move_pages sys_move_pages compat_sys_move_pages
+308 o32 move_pages sys_move_pages
309 o32 set_robust_list sys_set_robust_list compat_sys_set_robust_list
310 o32 get_robust_list sys_get_robust_list compat_sys_get_robust_list
311 o32 kexec_load sys_kexec_load
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 778bf166d7bd..5c17edaffe70 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -331,7 +331,7 @@
292 64 sync_file_range sys_sync_file_range
293 common tee sys_tee
294 common vmsplice sys_vmsplice compat_sys_vmsplice
-295 common move_pages sys_move_pages compat_sys_move_pages
+295 common move_pages sys_move_pages
296 common getcpu sys_getcpu
297 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
298 common statfs64 sys_statfs64 compat_sys_statfs64
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index f128ba8b9a71..04fb42d7b377 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -389,7 +389,7 @@
298 common faccessat sys_faccessat
299 common get_robust_list sys_get_robust_list compat_sys_get_robust_list
300 common set_robust_list sys_set_robust_list compat_sys_set_robust_list
-301 common move_pages sys_move_pages compat_sys_move_pages
+301 common move_pages sys_move_pages
302 common getcpu sys_getcpu
303 nospu epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
304 32 utimensat sys_utimensat_time32
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index d45952058be2..3197965d45e9 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -317,7 +317,7 @@
307 common sync_file_range sys_sync_file_range compat_sys_s390_sync_file_range
308 common tee sys_tee sys_tee
309 common vmsplice sys_vmsplice compat_sys_vmsplice
-310 common move_pages sys_move_pages compat_sys_move_pages
+310 common move_pages sys_move_pages
311 common getcpu sys_getcpu sys_getcpu
312 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
313 common utimes sys_utimes sys_utimes_time32
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index a46edcdd950d..e36ac364e61a 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -370,7 +370,7 @@
304 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
305 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
306 common kexec_load sys_kexec_load sys_kexec_load
-307 common move_pages sys_move_pages compat_sys_move_pages
+307 common move_pages sys_move_pages
308 common getcpu sys_getcpu
309 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
310 32 utimensat sys_utimensat_time32
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 7e4140b78aad..b3263b8b2eae 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -328,7 +328,7 @@
314 i386 sync_file_range sys_ia32_sync_file_range
315 i386 tee sys_tee
316 i386 vmsplice sys_vmsplice compat_sys_vmsplice
-317 i386 move_pages sys_move_pages compat_sys_move_pages
+317 i386 move_pages sys_move_pages
318 i386 getcpu sys_getcpu
319 i386 epoll_pwait sys_epoll_pwait
320 i386 utimensat sys_utimensat_time32
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 9986f5f08278..4a997a0cbf47 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -389,7 +389,7 @@
530 x32 set_robust_list compat_sys_set_robust_list
531 x32 get_robust_list compat_sys_get_robust_list
532 x32 vmsplice compat_sys_vmsplice
-533 x32 move_pages compat_sys_move_pages
+533 x32 move_pages sys_move_pages
534 x32 preadv compat_sys_preadv64
535 x32 pwritev compat_sys_pwritev64
536 x32 rt_tgsigqueueinfo compat_sys_rt_tgsigqueueinfo
diff --git a/include/linux/compat.h b/include/linux/compat.h
index a7a5a0ff59ef..db1d7ac2c9e0 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -763,11 +763,6 @@ asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,
const compat_ulong_t __user *new_nodes);
-asmlinkage long compat_sys_move_pages(pid_t pid, compat_ulong_t nr_pages,
- __u32 __user *pages,
- const int __user *nodes,
- int __user *status,
- int flags);

asmlinkage long compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid,
compat_pid_t pid, int sig,
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 83f1fc7fd3d7..4da51702fb21 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -681,7 +681,7 @@ __SC_COMP(__NR_set_mempolicy, sys_set_mempolicy, compat_sys_set_mempolicy)
#define __NR_migrate_pages 238
__SC_COMP(__NR_migrate_pages, sys_migrate_pages, compat_sys_migrate_pages)
#define __NR_move_pages 239
-__SC_COMP(__NR_move_pages, sys_move_pages, compat_sys_move_pages)
+__SYSCALL(__NR_move_pages, sys_move_pages)
#endif

#define __NR_rt_tgsigqueueinfo 240
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index c925d1e1777e..783a24ceee88 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -290,7 +290,6 @@ COND_SYSCALL_COMPAT(set_mempolicy);
COND_SYSCALL(migrate_pages);
COND_SYSCALL_COMPAT(migrate_pages);
COND_SYSCALL(move_pages);
-COND_SYSCALL_COMPAT(move_pages);

COND_SYSCALL(perf_event_open);
COND_SYSCALL(accept4);
diff --git a/mm/migrate.c b/mm/migrate.c
index 34a842a8eb6a..e9dfbde5f12c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1835,6 +1835,27 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
mmap_read_unlock(mm);
}

+static int put_pages_array(const void __user *chunk_pages[],
+ const void __user * __user *pages,
+ unsigned long chunk_nr)
+{
+ compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages;
+ compat_uptr_t p;
+ int i;
+
+ if (!in_compat_syscall())
+ return copy_from_user(chunk_pages, pages,
+ chunk_nr * sizeof(*chunk_pages));
+
+ for (i = 0; i < chunk_nr; i++) {
+ if (get_user(p, pages32 + i))
+ return -EFAULT;
+ chunk_pages[i] = compat_ptr(p);
+ }
+
+ return 0;
+}
+
/*
* Determine the nodes of a user array of pages and store it in
* a user array of status.
@@ -1854,7 +1875,7 @@ static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages,
if (chunk_nr > DO_PAGES_STAT_CHUNK_NR)
chunk_nr = DO_PAGES_STAT_CHUNK_NR;

- if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages)))
+ if (put_pages_array(chunk_pages, pages, chunk_nr))
break;

do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);
@@ -1943,28 +1964,6 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
return kernel_move_pages(pid, nr_pages, pages, nodes, status, flags);
}

-#ifdef CONFIG_COMPAT
-COMPAT_SYSCALL_DEFINE6(move_pages, pid_t, pid, compat_ulong_t, nr_pages,
- compat_uptr_t __user *, pages32,
- const int __user *, nodes,
- int __user *, status,
- int, flags)
-{
- const void __user * __user *pages;
- int i;
-
- pages = compat_alloc_user_space(nr_pages * sizeof(void *));
- for (i = 0; i < nr_pages; i++) {
- compat_uptr_t p;
-
- if (get_user(p, pages32 + i) ||
- put_user(compat_ptr(p), pages + i))
- return -EFAULT;
- }
- return kernel_move_pages(pid, nr_pages, pages, nodes, status, flags);
-}
-#endif /* CONFIG_COMPAT */
-
#ifdef CONFIG_NUMA_BALANCING
/*
* Returns true if this is a safe migration target node for misplaced NUMA
--
2.27.0

2020-09-18 13:27:16

by Arnd Bergmann

Subject: [PATCH 4/4] mm: remove compat numa syscalls

The compat implementations for mbind, get_mempolicy, set_mempolicy
and migrate_pages are just there to handle the subtly different
layout of bitmaps on 32-bit hosts.

The compat implementation however lacks some of the checks that
are present in the native one, in particular for checking that
the extra bits are all zero when user space has a larger mask
size than the kernel. Worse, those extra bits do not get cleared
when copying in or out of the kernel, which can lead to incorrect
data as well.

Unify the implementation to handle the compat bitmap layout directly
in the get_nodes() and copy_nodes_to_user() helpers. Splitting out
the get_bitmap() helper from get_nodes() also helps readability of the
native case.

On x86, two additional problems are addressed by this: compat tasks can
pass a bitmap at the end of a mapping, causing a fault when reading
across the page boundary for a 64-bit word. x32 tasks might also run
into problems with get_mempolicy corrupting data when an odd number of
32-bit words gets passed.

On parisc the migrate_pages() system call apparently had the wrong
calling convention, as big-endian architectures expect the words
inside of a bitmap to be swapped. This is not a problem though
since parisc has no NUMA support.

Signed-off-by: Arnd Bergmann <[email protected]>
---
arch/arm64/include/asm/unistd32.h | 8 +-
arch/mips/kernel/syscalls/syscall_n32.tbl | 8 +-
arch/mips/kernel/syscalls/syscall_o32.tbl | 8 +-
arch/parisc/kernel/syscalls/syscall.tbl | 6 +-
arch/powerpc/kernel/syscalls/syscall.tbl | 8 +-
arch/s390/kernel/syscalls/syscall.tbl | 8 +-
arch/sparc/kernel/syscalls/syscall.tbl | 8 +-
arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
include/linux/compat.h | 15 --
include/uapi/asm-generic/unistd.h | 8 +-
kernel/kexec.c | 6 +-
kernel/sys_ni.c | 4 -
mm/mempolicy.c | 193 +++++-----------------
13 files changed, 79 insertions(+), 203 deletions(-)

diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index af793775ba98..31479f7120a0 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -649,11 +649,11 @@ __SYSCALL(__NR_inotify_add_watch, sys_inotify_add_watch)
#define __NR_inotify_rm_watch 318
__SYSCALL(__NR_inotify_rm_watch, sys_inotify_rm_watch)
#define __NR_mbind 319
-__SYSCALL(__NR_mbind, compat_sys_mbind)
+__SYSCALL(__NR_mbind, sys_mbind)
#define __NR_get_mempolicy 320
-__SYSCALL(__NR_get_mempolicy, compat_sys_get_mempolicy)
+__SYSCALL(__NR_get_mempolicy, sys_get_mempolicy)
#define __NR_set_mempolicy 321
-__SYSCALL(__NR_set_mempolicy, compat_sys_set_mempolicy)
+__SYSCALL(__NR_set_mempolicy, sys_set_mempolicy)
#define __NR_openat 322
__SYSCALL(__NR_openat, compat_sys_openat)
#define __NR_mkdirat 323
@@ -811,7 +811,7 @@ __SYSCALL(__NR_rseq, sys_rseq)
#define __NR_io_pgetevents 399
__SYSCALL(__NR_io_pgetevents, compat_sys_io_pgetevents)
#define __NR_migrate_pages 400
-__SYSCALL(__NR_migrate_pages, compat_sys_migrate_pages)
+__SYSCALL(__NR_migrate_pages, sys_migrate_pages)
#define __NR_kexec_file_load 401
__SYSCALL(__NR_kexec_file_load, sys_kexec_file_load)
/* 402 is unused */
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 7fa1ca45e44c..15fda882d07e 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -239,9 +239,9 @@
228 n32 clock_nanosleep sys_clock_nanosleep_time32
229 n32 tgkill sys_tgkill
230 n32 utimes sys_utimes_time32
-231 n32 mbind compat_sys_mbind
-232 n32 get_mempolicy compat_sys_get_mempolicy
-233 n32 set_mempolicy compat_sys_set_mempolicy
+231 n32 mbind sys_mbind
+232 n32 get_mempolicy sys_get_mempolicy
+233 n32 set_mempolicy sys_set_mempolicy
234 n32 mq_open compat_sys_mq_open
235 n32 mq_unlink sys_mq_unlink
236 n32 mq_timedsend sys_mq_timedsend_time32
@@ -258,7 +258,7 @@
247 n32 inotify_init sys_inotify_init
248 n32 inotify_add_watch sys_inotify_add_watch
249 n32 inotify_rm_watch sys_inotify_rm_watch
-250 n32 migrate_pages compat_sys_migrate_pages
+250 n32 migrate_pages sys_migrate_pages
251 n32 openat sys_openat
252 n32 mkdirat sys_mkdirat
253 n32 mknodat sys_mknodat
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 194c7fbeedf7..6591388a9d88 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -279,9 +279,9 @@
265 o32 clock_nanosleep sys_clock_nanosleep_time32
266 o32 tgkill sys_tgkill
267 o32 utimes sys_utimes_time32
-268 o32 mbind sys_mbind compat_sys_mbind
-269 o32 get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
-270 o32 set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
+268 o32 mbind sys_mbind
+269 o32 get_mempolicy sys_get_mempolicy
+270 o32 set_mempolicy sys_set_mempolicy
271 o32 mq_open sys_mq_open compat_sys_mq_open
272 o32 mq_unlink sys_mq_unlink
273 o32 mq_timedsend sys_mq_timedsend_time32
@@ -298,7 +298,7 @@
284 o32 inotify_init sys_inotify_init
285 o32 inotify_add_watch sys_inotify_add_watch
286 o32 inotify_rm_watch sys_inotify_rm_watch
-287 o32 migrate_pages sys_migrate_pages compat_sys_migrate_pages
+287 o32 migrate_pages sys_migrate_pages
288 o32 openat sys_openat compat_sys_openat
289 o32 mkdirat sys_mkdirat
290 o32 mknodat sys_mknodat
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 5c17edaffe70..30f3c0146abf 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -292,9 +292,9 @@
258 32 clock_nanosleep sys_clock_nanosleep_time32
258 64 clock_nanosleep sys_clock_nanosleep
259 common tgkill sys_tgkill
-260 common mbind sys_mbind compat_sys_mbind
-261 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
-262 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
+260 common mbind sys_mbind
+261 common get_mempolicy sys_get_mempolicy
+262 common set_mempolicy sys_set_mempolicy
# 263 was vserver
264 common add_key sys_add_key
265 common request_key sys_request_key
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 04fb42d7b377..4f5216320721 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -338,10 +338,10 @@
256 64 sys_debug_setcontext sys_ni_syscall
256 spu sys_debug_setcontext sys_ni_syscall
# 257 reserved for vserver
-258 nospu migrate_pages sys_migrate_pages compat_sys_migrate_pages
-259 nospu mbind sys_mbind compat_sys_mbind
-260 nospu get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
-261 nospu set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
+258 nospu migrate_pages sys_migrate_pages
+259 nospu mbind sys_mbind
+260 nospu get_mempolicy sys_get_mempolicy
+261 nospu set_mempolicy sys_set_mempolicy
262 nospu mq_open sys_mq_open compat_sys_mq_open
263 nospu mq_unlink sys_mq_unlink
264 32 mq_timedsend sys_mq_timedsend_time32
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 3197965d45e9..70c0b830d14f 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -274,9 +274,9 @@
265 common statfs64 sys_statfs64 compat_sys_statfs64
266 common fstatfs64 sys_fstatfs64 compat_sys_fstatfs64
267 common remap_file_pages sys_remap_file_pages sys_remap_file_pages
-268 common mbind sys_mbind compat_sys_mbind
-269 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
-270 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
+268 common mbind sys_mbind sys_mbind
+269 common get_mempolicy sys_get_mempolicy sys_get_mempolicy
+270 common set_mempolicy sys_set_mempolicy sys_set_mempolicy
271 common mq_open sys_mq_open compat_sys_mq_open
272 common mq_unlink sys_mq_unlink sys_mq_unlink
273 common mq_timedsend sys_mq_timedsend sys_mq_timedsend_time32
@@ -293,7 +293,7 @@
284 common inotify_init sys_inotify_init sys_inotify_init
285 common inotify_add_watch sys_inotify_add_watch sys_inotify_add_watch
286 common inotify_rm_watch sys_inotify_rm_watch sys_inotify_rm_watch
-287 common migrate_pages sys_migrate_pages compat_sys_migrate_pages
+287 common migrate_pages sys_migrate_pages sys_migrate_pages
288 common openat sys_openat compat_sys_openat
289 common mkdirat sys_mkdirat sys_mkdirat
290 common mknodat sys_mknodat sys_mknodat
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index e36ac364e61a..50ff839a2661 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -365,10 +365,10 @@
299 common unshare sys_unshare
300 common set_robust_list sys_set_robust_list compat_sys_set_robust_list
301 common get_robust_list sys_get_robust_list compat_sys_get_robust_list
-302 common migrate_pages sys_migrate_pages compat_sys_migrate_pages
-303 common mbind sys_mbind compat_sys_mbind
-304 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
-305 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
+302 common migrate_pages sys_migrate_pages
+303 common mbind sys_mbind
+304 common get_mempolicy sys_get_mempolicy
+305 common set_mempolicy sys_set_mempolicy
306 common kexec_load sys_kexec_load sys_kexec_load
307 common move_pages sys_move_pages
308 common getcpu sys_getcpu
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index b3263b8b2eae..d07c3fbd4697 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -286,7 +286,7 @@
272 i386 fadvise64_64 sys_ia32_fadvise64_64
273 i386 vserver
274 i386 mbind sys_mbind
-275 i386 get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
+275 i386 get_mempolicy sys_get_mempolicy
276 i386 set_mempolicy sys_set_mempolicy
277 i386 mq_open sys_mq_open compat_sys_mq_open
278 i386 mq_unlink sys_mq_unlink
diff --git a/include/linux/compat.h b/include/linux/compat.h
index db1d7ac2c9e0..be06367b336c 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -749,21 +749,6 @@ asmlinkage long compat_sys_execve(const char __user *filename, const compat_uptr
/* mm/fadvise.c: No generic prototype for fadvise64_64 */

/* mm/, CONFIG_MMU only */
-asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
- compat_ulong_t mode,
- compat_ulong_t __user *nmask,
- compat_ulong_t maxnode, compat_ulong_t flags);
-asmlinkage long compat_sys_get_mempolicy(int __user *policy,
- compat_ulong_t __user *nmask,
- compat_ulong_t maxnode,
- compat_ulong_t addr,
- compat_ulong_t flags);
-asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
- compat_ulong_t maxnode);
-asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
- compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,
- const compat_ulong_t __user *new_nodes);
-
asmlinkage long compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid,
compat_pid_t pid, int sig,
struct compat_siginfo __user *uinfo);
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 4da51702fb21..4e31f9b68a8f 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -673,13 +673,13 @@ __SYSCALL(__NR_madvise, sys_madvise)
#define __NR_remap_file_pages 234
__SYSCALL(__NR_remap_file_pages, sys_remap_file_pages)
#define __NR_mbind 235
-__SC_COMP(__NR_mbind, sys_mbind, compat_sys_mbind)
+__SYSCALL(__NR_mbind, sys_mbind)
#define __NR_get_mempolicy 236
-__SC_COMP(__NR_get_mempolicy, sys_get_mempolicy, compat_sys_get_mempolicy)
+__SYSCALL(__NR_get_mempolicy, sys_get_mempolicy)
#define __NR_set_mempolicy 237
-__SC_COMP(__NR_set_mempolicy, sys_set_mempolicy, compat_sys_set_mempolicy)
+__SYSCALL(__NR_set_mempolicy, sys_set_mempolicy)
#define __NR_migrate_pages 238
-__SC_COMP(__NR_migrate_pages, sys_migrate_pages, compat_sys_migrate_pages)
+__SYSCALL(__NR_migrate_pages, sys_migrate_pages)
#define __NR_move_pages 239
__SYSCALL(__NR_move_pages, sys_move_pages)
#endif
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 1ef7d3dc906f..0fecf2370be1 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -30,11 +30,13 @@ static int copy_user_segment_list(struct kimage *image,
image->nr_segments = nr_segments;
segment_bytes = nr_segments * sizeof(*segments);
if (in_compat_syscall()) {
- struct compat_kexec_segment __user *cs = (void __user *)segments;
+ struct compat_kexec_segment __user *cs;
struct compat_kexec_segment segment;
int i;
+
+ cs = (struct compat_kexec_segment __user *)segments;
for (i=0; i< nr_segments; i++) {
- copy_from_user(&segment, &cs[i], sizeof(segment));
+ ret = copy_from_user(&segment, &cs[i], sizeof(segment));
if (ret)
break;

diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 783a24ceee88..0850111f888e 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -282,13 +282,9 @@ COND_SYSCALL(mincore);
COND_SYSCALL(madvise);
COND_SYSCALL(remap_file_pages);
COND_SYSCALL(mbind);
-COND_SYSCALL_COMPAT(mbind);
COND_SYSCALL(get_mempolicy);
-COND_SYSCALL_COMPAT(get_mempolicy);
COND_SYSCALL(set_mempolicy);
-COND_SYSCALL_COMPAT(set_mempolicy);
COND_SYSCALL(migrate_pages);
-COND_SYSCALL_COMPAT(migrate_pages);
COND_SYSCALL(move_pages);

COND_SYSCALL(perf_event_open);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index eddbe4e56c73..2e1b90143b2c 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1374,16 +1374,30 @@ static long do_mbind(unsigned long start, unsigned long len,
/*
* User space interface with variable sized bitmaps for nodelists.
*/
+static int get_bitmap(unsigned long *mask, const unsigned long __user *nmask,
+ unsigned long maxnode)
+{
+ unsigned long nlongs = BITS_TO_LONGS(maxnode);
+ int ret;
+
+ if (in_compat_syscall())
+ ret = compat_get_bitmap(mask, (void __user *)nmask, maxnode);
+ else
+ ret = copy_from_user(mask, nmask, nlongs*sizeof(unsigned long));
+
+ if (ret)
+ return -EFAULT;
+
+ if (maxnode % BITS_PER_LONG)
+ mask[nlongs-1] &= (1UL << (maxnode % BITS_PER_LONG)) - 1;
+
+ return 0;
+}

/* Copy a node mask from user space. */
static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
unsigned long maxnode)
{
- unsigned long k;
- unsigned long t;
- unsigned long nlongs;
- unsigned long endmask;
-
--maxnode;
nodes_clear(*nodes);
if (maxnode == 0 || !nmask)
@@ -1391,49 +1405,29 @@ static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
return -EINVAL;

- nlongs = BITS_TO_LONGS(maxnode);
- if ((maxnode % BITS_PER_LONG) == 0)
- endmask = ~0UL;
- else
- endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
-
/*
* When the user specified more nodes than supported just check
- * if the non supported part is all zero.
- *
- * If maxnode have more longs than MAX_NUMNODES, check
- * the bits in that area first. And then go through to
- * check the rest bits which equal or bigger than MAX_NUMNODES.
- * Otherwise, just check bits [MAX_NUMNODES, maxnode).
+ * if the non supported part is all zero, one word at a time,
+ * starting at the end.
*/
- if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) {
- for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) {
- if (get_user(t, nmask + k))
- return -EFAULT;
- if (k == nlongs - 1) {
- if (t & endmask)
- return -EINVAL;
- } else if (t)
- return -EINVAL;
- }
- nlongs = BITS_TO_LONGS(MAX_NUMNODES);
- endmask = ~0UL;
- }
-
- if (maxnode > MAX_NUMNODES && MAX_NUMNODES % BITS_PER_LONG != 0) {
- unsigned long valid_mask = endmask;
+ while (maxnode > MAX_NUMNODES) {
+ unsigned long bits = min_t(unsigned long, maxnode, BITS_PER_LONG);
+ unsigned long t;

- valid_mask &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
- if (get_user(t, nmask + nlongs - 1))
+ if (get_bitmap(&t, &nmask[maxnode / BITS_PER_LONG], bits))
return -EFAULT;
- if (t & valid_mask)
+
+ if (maxnode - bits >= MAX_NUMNODES) {
+ maxnode -= bits;
+ } else {
+ maxnode = MAX_NUMNODES;
+ t &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1);
+ }
+ if (t)
return -EINVAL;
}

- if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long)))
- return -EFAULT;
- nodes_addr(*nodes)[nlongs-1] &= endmask;
- return 0;
+ return get_bitmap(nodes_addr(*nodes), nmask, maxnode);
}

/* Copy a kernel node mask to user space */
@@ -1442,6 +1436,10 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
{
unsigned long copy = ALIGN(maxnode-1, 64) / 8;
unsigned int nbytes = BITS_TO_LONGS(nr_node_ids) * sizeof(long);
+ bool compat = in_compat_syscall();
+
+ if (compat)
+ nbytes = BITS_TO_COMPAT_LONGS(nr_node_ids) * sizeof(compat_long_t);

if (copy > nbytes) {
if (copy > PAGE_SIZE)
@@ -1450,6 +1448,11 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
return -EFAULT;
copy = nbytes;
}
+
+ if (compat)
+ return compat_put_bitmap((compat_ulong_t __user *)mask,
+ nodes_addr(*nodes), maxnode);
+
return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
}

@@ -1641,116 +1644,6 @@ SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
return kernel_get_mempolicy(policy, nmask, maxnode, addr, flags);
}

-#ifdef CONFIG_COMPAT
-
-COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
- compat_ulong_t __user *, nmask,
- compat_ulong_t, maxnode,
- compat_ulong_t, addr, compat_ulong_t, flags)
-{
- long err;
- unsigned long __user *nm = NULL;
- unsigned long nr_bits, alloc_size;
- DECLARE_BITMAP(bm, MAX_NUMNODES);
-
- nr_bits = min_t(unsigned long, maxnode-1, nr_node_ids);
- alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
-
- if (nmask)
- nm = compat_alloc_user_space(alloc_size);
-
- err = kernel_get_mempolicy(policy, nm, nr_bits+1, addr, flags);
-
- if (!err && nmask) {
- unsigned long copy_size;
- copy_size = min_t(unsigned long, sizeof(bm), alloc_size);
- err = copy_from_user(bm, nm, copy_size);
- /* ensure entire bitmap is zeroed */
- err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8);
- err |= compat_put_bitmap(nmask, bm, nr_bits);
- }
-
- return err;
-}
-
-COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
- compat_ulong_t, maxnode)
-{
- unsigned long __user *nm = NULL;
- unsigned long nr_bits, alloc_size;
- DECLARE_BITMAP(bm, MAX_NUMNODES);
-
- nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
- alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
-
- if (nmask) {
- if (compat_get_bitmap(bm, nmask, nr_bits))
- return -EFAULT;
- nm = compat_alloc_user_space(alloc_size);
- if (copy_to_user(nm, bm, alloc_size))
- return -EFAULT;
- }
-
- return kernel_set_mempolicy(mode, nm, nr_bits+1);
-}
-
-COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
- compat_ulong_t, mode, compat_ulong_t __user *, nmask,
- compat_ulong_t, maxnode, compat_ulong_t, flags)
-{
- unsigned long __user *nm = NULL;
- unsigned long nr_bits, alloc_size;
- nodemask_t bm;
-
- nr_bits = min_t(unsigned long, maxnode-1, MAX_NUMNODES);
- alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
-
- if (nmask) {
- if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
- return -EFAULT;
- nm = compat_alloc_user_space(alloc_size);
- if (copy_to_user(nm, nodes_addr(bm), alloc_size))
- return -EFAULT;
- }
-
- return kernel_mbind(start, len, mode, nm, nr_bits+1, flags);
-}
-
-COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
- compat_ulong_t, maxnode,
- const compat_ulong_t __user *, old_nodes,
- const compat_ulong_t __user *, new_nodes)
-{
- unsigned long __user *old = NULL;
- unsigned long __user *new = NULL;
- nodemask_t tmp_mask;
- unsigned long nr_bits;
- unsigned long size;
-
- nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
- size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
- if (old_nodes) {
- if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
- return -EFAULT;
- old = compat_alloc_user_space(new_nodes ? size * 2 : size);
- if (new_nodes)
- new = old + size / sizeof(unsigned long);
- if (copy_to_user(old, nodes_addr(tmp_mask), size))
- return -EFAULT;
- }
- if (new_nodes) {
- if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
- return -EFAULT;
- if (new == NULL)
- new = compat_alloc_user_space(size);
- if (copy_to_user(new, nodes_addr(tmp_mask), size))
- return -EFAULT;
- }
- return kernel_migrate_pages(pid, nr_bits + 1, old, new);
-}
-
-#endif /* CONFIG_COMPAT */
-
bool vma_migratable(struct vm_area_struct *vma)
{
if (vma->vm_flags & (VM_IO | VM_PFNMAP))
--
2.27.0

2020-09-18 13:29:03

by Arnd Bergmann

Subject: [PATCH 1/4] x86: add __X32_COND_SYSCALL() macro

sys_move_pages() is an optional syscall, and once we remove
the compat version of it in favor of the native one with an
in_compat_syscall() check, the x32 syscall table refers to
a __x32_sys_move_pages symbol that may not exist when the
syscall is disabled.

Change the COND_SYSCALL() definition on x86 to also include
the redirection for x32.

Signed-off-by: Arnd Bergmann <[email protected]>
---
arch/x86/include/asm/syscall_wrapper.h | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index a84333adeef2..5eacd35a7f97 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -171,12 +171,16 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
__SYS_STUBx(x32, compat_sys##name, \
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))

+#define __X32_COND_SYSCALL(name) \
+ __COND_SYSCALL(x32, sys_##name)
+
#define __X32_COMPAT_COND_SYSCALL(name) \
__COND_SYSCALL(x32, compat_sys_##name)

#define __X32_COMPAT_SYS_NI(name) \
__SYS_NI(x32, compat_sys_##name)
#else /* CONFIG_X86_X32 */
+#define __X32_COND_SYSCALL(name)
#define __X32_COMPAT_SYS_STUB0(name)
#define __X32_COMPAT_SYS_STUBx(x, name, ...)
#define __X32_COMPAT_COND_SYSCALL(name)
@@ -253,6 +257,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
static long __do_sys_##sname(const struct pt_regs *__unused)

#define COND_SYSCALL(name) \
+ __X32_COND_SYSCALL(name) \
__X64_COND_SYSCALL(name) \
__IA32_COND_SYSCALL(name)

--
2.27.0

2020-09-19 05:37:11

by Christoph Hellwig

Subject: Re: [PATCH 1/4] x86: add __X32_COND_SYSCALL() macro

On Fri, Sep 18, 2020 at 03:24:36PM +0200, Arnd Bergmann wrote:
> sys_move_pages() is an optional syscall, and once we remove
> the compat version of it in favor of the native one with an
> in_compat_syscall() check, the x32 syscall table refers to
> a __x32_sys_move_pages symbol that may not exist when the
> syscall is disabled.
>
> Change the COND_SYSCALL() definition on x86 to also include
> the redirection for x32.
>
> Signed-off-by: Arnd Bergmann <[email protected]>

Adding the x86 maintainers and Brian Gerst. Brian proposed another
problem to the mess that most of the compat syscall handlers used by
x32 here:

https://lkml.org/lkml/2020/6/16/664

hpa didn't particularly like it, but with your and my pending series
we'll soon use more native than compat syscalls for x32, so something
will need to change..

> ---
> arch/x86/include/asm/syscall_wrapper.h | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
> index a84333adeef2..5eacd35a7f97 100644
> --- a/arch/x86/include/asm/syscall_wrapper.h
> +++ b/arch/x86/include/asm/syscall_wrapper.h
> @@ -171,12 +171,16 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
> __SYS_STUBx(x32, compat_sys##name, \
> SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
>
> +#define __X32_COND_SYSCALL(name) \
> + __COND_SYSCALL(x32, sys_##name)
> +
> #define __X32_COMPAT_COND_SYSCALL(name) \
> __COND_SYSCALL(x32, compat_sys_##name)
>
> #define __X32_COMPAT_SYS_NI(name) \
> __SYS_NI(x32, compat_sys_##name)
> #else /* CONFIG_X86_X32 */
> +#define __X32_COND_SYSCALL(name)
> #define __X32_COMPAT_SYS_STUB0(name)
> #define __X32_COMPAT_SYS_STUBx(x, name, ...)
> #define __X32_COMPAT_COND_SYSCALL(name)
> @@ -253,6 +257,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
> static long __do_sys_##sname(const struct pt_regs *__unused)
>
> #define COND_SYSCALL(name) \
> + __X32_COND_SYSCALL(name) \
> __X64_COND_SYSCALL(name) \
> __IA32_COND_SYSCALL(name)
>
> --
> 2.27.0
>
---end quoted text---

2020-09-19 05:38:48

by Christoph Hellwig

Subject: Re: [PATCH 2/4] kexec: remove compat_sys_kexec_load syscall

On Fri, Sep 18, 2020 at 03:24:37PM +0200, Arnd Bergmann wrote:
> The compat version of sys_kexec_load() uses compat_alloc_user_space to
> convert the user-provided arguments into the native format.
>
> Move the conversion into the regular implementation with
> an in_compat_syscall() check to simplify it and avoid the
> compat_alloc_user_space() call.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> arch/arm64/include/asm/unistd32.h | 2 +-
> arch/mips/kernel/syscalls/syscall_n32.tbl | 2 +-
> arch/mips/kernel/syscalls/syscall_o32.tbl | 2 +-
> arch/parisc/kernel/syscalls/syscall.tbl | 2 +-
> arch/powerpc/kernel/syscalls/syscall.tbl | 2 +-
> arch/s390/kernel/syscalls/syscall.tbl | 2 +-
> arch/sparc/kernel/syscalls/syscall.tbl | 2 +-
> arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
> arch/x86/entry/syscalls/syscall_64.tbl | 2 +-
> include/linux/compat.h | 6 --
> include/uapi/asm-generic/unistd.h | 2 +-
> kernel/kexec.c | 75 ++++++-----------------
> 12 files changed, 29 insertions(+), 72 deletions(-)
>
> diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
> index 734860ac7cf9..b6517df74037 100644
> --- a/arch/arm64/include/asm/unistd32.h
> +++ b/arch/arm64/include/asm/unistd32.h
> @@ -705,7 +705,7 @@ __SYSCALL(__NR_getcpu, sys_getcpu)
> #define __NR_epoll_pwait 346
> __SYSCALL(__NR_epoll_pwait, compat_sys_epoll_pwait)
> #define __NR_kexec_load 347
> -__SYSCALL(__NR_kexec_load, compat_sys_kexec_load)
> +__SYSCALL(__NR_kexec_load, sys_kexec_load)
> #define __NR_utimensat 348
> __SYSCALL(__NR_utimensat, sys_utimensat_time32)
> #define __NR_signalfd 349
> diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
> index f9df9edb67a4..ad157aab4c09 100644
> --- a/arch/mips/kernel/syscalls/syscall_n32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
> @@ -282,7 +282,7 @@
> 271 n32 move_pages compat_sys_move_pages
> 272 n32 set_robust_list compat_sys_set_robust_list
> 273 n32 get_robust_list compat_sys_get_robust_list
> -274 n32 kexec_load compat_sys_kexec_load
> +274 n32 kexec_load sys_kexec_load
> 275 n32 getcpu sys_getcpu
> 276 n32 epoll_pwait compat_sys_epoll_pwait
> 277 n32 ioprio_set sys_ioprio_set
> diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
> index 195b43cf27c8..57baf6c8008f 100644
> --- a/arch/mips/kernel/syscalls/syscall_o32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
> @@ -322,7 +322,7 @@
> 308 o32 move_pages sys_move_pages compat_sys_move_pages
> 309 o32 set_robust_list sys_set_robust_list compat_sys_set_robust_list
> 310 o32 get_robust_list sys_get_robust_list compat_sys_get_robust_list
> -311 o32 kexec_load sys_kexec_load compat_sys_kexec_load
> +311 o32 kexec_load sys_kexec_load
> 312 o32 getcpu sys_getcpu
> 313 o32 epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
> 314 o32 ioprio_set sys_ioprio_set
> diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
> index def64d221cd4..778bf166d7bd 100644
> --- a/arch/parisc/kernel/syscalls/syscall.tbl
> +++ b/arch/parisc/kernel/syscalls/syscall.tbl
> @@ -336,7 +336,7 @@
> 297 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
> 298 common statfs64 sys_statfs64 compat_sys_statfs64
> 299 common fstatfs64 sys_fstatfs64 compat_sys_fstatfs64
> -300 common kexec_load sys_kexec_load compat_sys_kexec_load
> +300 common kexec_load sys_kexec_load
> 301 32 utimensat sys_utimensat_time32
> 301 64 utimensat sys_utimensat
> 302 common signalfd sys_signalfd compat_sys_signalfd
> diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
> index c2d737ff2e7b..f128ba8b9a71 100644
> --- a/arch/powerpc/kernel/syscalls/syscall.tbl
> +++ b/arch/powerpc/kernel/syscalls/syscall.tbl
> @@ -350,7 +350,7 @@
> 265 64 mq_timedreceive sys_mq_timedreceive
> 266 nospu mq_notify sys_mq_notify compat_sys_mq_notify
> 267 nospu mq_getsetattr sys_mq_getsetattr compat_sys_mq_getsetattr
> -268 nospu kexec_load sys_kexec_load compat_sys_kexec_load
> +268 nospu kexec_load sys_kexec_load
> 269 nospu add_key sys_add_key
> 270 nospu request_key sys_request_key
> 271 nospu keyctl sys_keyctl compat_sys_keyctl
> diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
> index 10456bc936fb..d45952058be2 100644
> --- a/arch/s390/kernel/syscalls/syscall.tbl
> +++ b/arch/s390/kernel/syscalls/syscall.tbl
> @@ -283,7 +283,7 @@
> 274 common mq_timedreceive sys_mq_timedreceive sys_mq_timedreceive_time32
> 275 common mq_notify sys_mq_notify compat_sys_mq_notify
> 276 common mq_getsetattr sys_mq_getsetattr compat_sys_mq_getsetattr
> -277 common kexec_load sys_kexec_load compat_sys_kexec_load
> +277 common kexec_load sys_kexec_load sys_kexec_load
> 278 common add_key sys_add_key sys_add_key
> 279 common request_key sys_request_key sys_request_key
> 280 common keyctl sys_keyctl compat_sys_keyctl
> diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
> index 4af114e84f20..a46edcdd950d 100644
> --- a/arch/sparc/kernel/syscalls/syscall.tbl
> +++ b/arch/sparc/kernel/syscalls/syscall.tbl
> @@ -369,7 +369,7 @@
> 303 common mbind sys_mbind compat_sys_mbind
> 304 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
> 305 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
> -306 common kexec_load sys_kexec_load compat_sys_kexec_load
> +306 common kexec_load sys_kexec_load sys_kexec_load
> 307 common move_pages sys_move_pages compat_sys_move_pages
> 308 common getcpu sys_getcpu
> 309 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
> index 3db3d8823dc8..7e4140b78aad 100644
> --- a/arch/x86/entry/syscalls/syscall_32.tbl
> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
> @@ -294,7 +294,7 @@
> 280 i386 mq_timedreceive sys_mq_timedreceive_time32
> 281 i386 mq_notify sys_mq_notify compat_sys_mq_notify
> 282 i386 mq_getsetattr sys_mq_getsetattr compat_sys_mq_getsetattr
> -283 i386 kexec_load sys_kexec_load compat_sys_kexec_load
> +283 i386 kexec_load sys_kexec_load sys_kexec_load
> 284 i386 waitid sys_waitid compat_sys_waitid
> # 285 sys_setaltroot
> 286 i386 add_key sys_add_key
> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
> index f30d6ae9a688..9986f5f08278 100644
> --- a/arch/x86/entry/syscalls/syscall_64.tbl
> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
> @@ -384,7 +384,7 @@
> 525 x32 sigaltstack compat_sys_sigaltstack
> 526 x32 timer_create compat_sys_timer_create
> 527 x32 mq_notify compat_sys_mq_notify
> -528 x32 kexec_load compat_sys_kexec_load
> +528 x32 kexec_load sys_kexec_load
> 529 x32 waitid compat_sys_waitid
> 530 x32 set_robust_list compat_sys_set_robust_list
> 531 x32 get_robust_list compat_sys_get_robust_list
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index 3d96a841bd49..a7a5a0ff59ef 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -643,12 +643,6 @@ asmlinkage long compat_sys_setitimer(int which,
> struct old_itimerval32 __user *in,
> struct old_itimerval32 __user *out);
>
> -/* kernel/kexec.c */
> -asmlinkage long compat_sys_kexec_load(compat_ulong_t entry,
> - compat_ulong_t nr_segments,
> - struct compat_kexec_segment __user *,
> - compat_ulong_t flags);
> -
> /* kernel/posix-timers.c */
> asmlinkage long compat_sys_timer_create(clockid_t which_clock,
> struct compat_sigevent __user *timer_event_spec,
> diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> index 995b36c2ea7d..83f1fc7fd3d7 100644
> --- a/include/uapi/asm-generic/unistd.h
> +++ b/include/uapi/asm-generic/unistd.h
> @@ -342,7 +342,7 @@ __SC_COMP(__NR_setitimer, sys_setitimer, compat_sys_setitimer)
>
> /* kernel/kexec.c */
> #define __NR_kexec_load 104
> -__SC_COMP(__NR_kexec_load, sys_kexec_load, compat_sys_kexec_load)
> +__SYSCALL(__NR_kexec_load, sys_kexec_load)
>
> /* kernel/module.c */
> #define __NR_init_module 105
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index f977786fe498..1ef7d3dc906f 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -29,7 +29,25 @@ static int copy_user_segment_list(struct kimage *image,
> /* Read in the segments */
> image->nr_segments = nr_segments;
> segment_bytes = nr_segments * sizeof(*segments);
> - ret = copy_from_user(image->segment, segments, segment_bytes);
> + if (in_compat_syscall()) {
> + struct compat_kexec_segment __user *cs = (void __user *)segments;
> + struct compat_kexec_segment segment;
> + int i;
> + for (i=0; i< nr_segments; i++) {

Missing empty line after the variable declarations and really strange
indentation.

> + copy_from_user(&segment, &cs[i], sizeof(segment));

Missing return value check.

> + if (ret)
> + break;
> +
> + image->segment[i] = (struct kexec_segment) {
> + .buf = compat_ptr(segment.buf),
> + .bufsz = segment.bufsz,
> + .mem = segment.mem,
> + .memsz = segment.memsz,
> + };
> + }

I'd split the whole compat handling into a helper, and I'd probably
use the unsafe_get/put user to optimize it a little more.

> + } else {
> + ret = copy_from_user(image->segment, segments, segment_bytes);
> + }
> if (ret)
> ret = -EFAULT;

Why not just

if (copy_from_user(image->segment, segments, segment_bytes))
ret = -EFAULT;

?

2020-09-19 05:40:39

by Christoph Hellwig

Subject: Re: [PATCH 3/4] mm: remove compat_sys_move_pages

On Fri, Sep 18, 2020 at 03:24:38PM +0200, Arnd Bergmann wrote:
> The compat move_pages() implementation uses compat_alloc_user_space()
> for converting the pointer array. Moving the compat handling into
> the function itself is a bit simpler and lets us avoid the
> compat_alloc_user_space() call.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> arch/arm64/include/asm/unistd32.h | 2 +-
> arch/mips/kernel/syscalls/syscall_n32.tbl | 2 +-
> arch/mips/kernel/syscalls/syscall_o32.tbl | 2 +-
> arch/parisc/kernel/syscalls/syscall.tbl | 2 +-
> arch/powerpc/kernel/syscalls/syscall.tbl | 2 +-
> arch/s390/kernel/syscalls/syscall.tbl | 2 +-
> arch/sparc/kernel/syscalls/syscall.tbl | 2 +-
> arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
> arch/x86/entry/syscalls/syscall_64.tbl | 2 +-
> include/linux/compat.h | 5 ---
> include/uapi/asm-generic/unistd.h | 2 +-
> kernel/sys_ni.c | 1 -
> mm/migrate.c | 45 +++++++++++------------
> 13 files changed, 32 insertions(+), 39 deletions(-)
>
> diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
> index b6517df74037..af793775ba98 100644
> --- a/arch/arm64/include/asm/unistd32.h
> +++ b/arch/arm64/include/asm/unistd32.h
> @@ -699,7 +699,7 @@ __SYSCALL(__NR_tee, sys_tee)
> #define __NR_vmsplice 343
> __SYSCALL(__NR_vmsplice, compat_sys_vmsplice)
> #define __NR_move_pages 344
> -__SYSCALL(__NR_move_pages, compat_sys_move_pages)
> +__SYSCALL(__NR_move_pages, sys_move_pages)
> #define __NR_getcpu 345
> __SYSCALL(__NR_getcpu, sys_getcpu)
> #define __NR_epoll_pwait 346
> diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
> index ad157aab4c09..7fa1ca45e44c 100644
> --- a/arch/mips/kernel/syscalls/syscall_n32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
> @@ -279,7 +279,7 @@
> 268 n32 sync_file_range sys_sync_file_range
> 269 n32 tee sys_tee
> 270 n32 vmsplice compat_sys_vmsplice
> -271 n32 move_pages compat_sys_move_pages
> +271 n32 move_pages sys_move_pages
> 272 n32 set_robust_list compat_sys_set_robust_list
> 273 n32 get_robust_list compat_sys_get_robust_list
> 274 n32 kexec_load sys_kexec_load
> diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
> index 57baf6c8008f..194c7fbeedf7 100644
> --- a/arch/mips/kernel/syscalls/syscall_o32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
> @@ -319,7 +319,7 @@
> 305 o32 sync_file_range sys_sync_file_range sys32_sync_file_range
> 306 o32 tee sys_tee
> 307 o32 vmsplice sys_vmsplice compat_sys_vmsplice
> -308 o32 move_pages sys_move_pages compat_sys_move_pages
> +308 o32 move_pages sys_move_pages
> 309 o32 set_robust_list sys_set_robust_list compat_sys_set_robust_list
> 310 o32 get_robust_list sys_get_robust_list compat_sys_get_robust_list
> 311 o32 kexec_load sys_kexec_load
> diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
> index 778bf166d7bd..5c17edaffe70 100644
> --- a/arch/parisc/kernel/syscalls/syscall.tbl
> +++ b/arch/parisc/kernel/syscalls/syscall.tbl
> @@ -331,7 +331,7 @@
> 292 64 sync_file_range sys_sync_file_range
> 293 common tee sys_tee
> 294 common vmsplice sys_vmsplice compat_sys_vmsplice
> -295 common move_pages sys_move_pages compat_sys_move_pages
> +295 common move_pages sys_move_pages
> 296 common getcpu sys_getcpu
> 297 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
> 298 common statfs64 sys_statfs64 compat_sys_statfs64
> diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
> index f128ba8b9a71..04fb42d7b377 100644
> --- a/arch/powerpc/kernel/syscalls/syscall.tbl
> +++ b/arch/powerpc/kernel/syscalls/syscall.tbl
> @@ -389,7 +389,7 @@
> 298 common faccessat sys_faccessat
> 299 common get_robust_list sys_get_robust_list compat_sys_get_robust_list
> 300 common set_robust_list sys_set_robust_list compat_sys_set_robust_list
> -301 common move_pages sys_move_pages compat_sys_move_pages
> +301 common move_pages sys_move_pages
> 302 common getcpu sys_getcpu
> 303 nospu epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
> 304 32 utimensat sys_utimensat_time32
> diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
> index d45952058be2..3197965d45e9 100644
> --- a/arch/s390/kernel/syscalls/syscall.tbl
> +++ b/arch/s390/kernel/syscalls/syscall.tbl
> @@ -317,7 +317,7 @@
> 307 common sync_file_range sys_sync_file_range compat_sys_s390_sync_file_range
> 308 common tee sys_tee sys_tee
> 309 common vmsplice sys_vmsplice compat_sys_vmsplice
> -310 common move_pages sys_move_pages compat_sys_move_pages
> +310 common move_pages sys_move_pages
> 311 common getcpu sys_getcpu sys_getcpu
> 312 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
> 313 common utimes sys_utimes sys_utimes_time32
> diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
> index a46edcdd950d..e36ac364e61a 100644
> --- a/arch/sparc/kernel/syscalls/syscall.tbl
> +++ b/arch/sparc/kernel/syscalls/syscall.tbl
> @@ -370,7 +370,7 @@
> 304 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
> 305 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
> 306 common kexec_load sys_kexec_load sys_kexec_load
> -307 common move_pages sys_move_pages compat_sys_move_pages
> +307 common move_pages sys_move_pages
> 308 common getcpu sys_getcpu
> 309 common epoll_pwait sys_epoll_pwait compat_sys_epoll_pwait
> 310 32 utimensat sys_utimensat_time32
> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
> index 7e4140b78aad..b3263b8b2eae 100644
> --- a/arch/x86/entry/syscalls/syscall_32.tbl
> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
> @@ -328,7 +328,7 @@
> 314 i386 sync_file_range sys_ia32_sync_file_range
> 315 i386 tee sys_tee
> 316 i386 vmsplice sys_vmsplice compat_sys_vmsplice
> -317 i386 move_pages sys_move_pages compat_sys_move_pages
> +317 i386 move_pages sys_move_pages
> 318 i386 getcpu sys_getcpu
> 319 i386 epoll_pwait sys_epoll_pwait
> 320 i386 utimensat sys_utimensat_time32
> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
> index 9986f5f08278..4a997a0cbf47 100644
> --- a/arch/x86/entry/syscalls/syscall_64.tbl
> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
> @@ -389,7 +389,7 @@
> 530 x32 set_robust_list compat_sys_set_robust_list
> 531 x32 get_robust_list compat_sys_get_robust_list
> 532 x32 vmsplice compat_sys_vmsplice
> -533 x32 move_pages compat_sys_move_pages
> +533 x32 move_pages sys_move_pages
> 534 x32 preadv compat_sys_preadv64
> 535 x32 pwritev compat_sys_pwritev64
> 536 x32 rt_tgsigqueueinfo compat_sys_rt_tgsigqueueinfo
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index a7a5a0ff59ef..db1d7ac2c9e0 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -763,11 +763,6 @@ asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
> asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
> compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,
> const compat_ulong_t __user *new_nodes);
> -asmlinkage long compat_sys_move_pages(pid_t pid, compat_ulong_t nr_pages,
> - __u32 __user *pages,
> - const int __user *nodes,
> - int __user *status,
> - int flags);
>
> asmlinkage long compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid,
> compat_pid_t pid, int sig,
> diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> index 83f1fc7fd3d7..4da51702fb21 100644
> --- a/include/uapi/asm-generic/unistd.h
> +++ b/include/uapi/asm-generic/unistd.h
> @@ -681,7 +681,7 @@ __SC_COMP(__NR_set_mempolicy, sys_set_mempolicy, compat_sys_set_mempolicy)
> #define __NR_migrate_pages 238
> __SC_COMP(__NR_migrate_pages, sys_migrate_pages, compat_sys_migrate_pages)
> #define __NR_move_pages 239
> -__SC_COMP(__NR_move_pages, sys_move_pages, compat_sys_move_pages)
> +__SYSCALL(__NR_move_pages, sys_move_pages)
> #endif
>
> #define __NR_rt_tgsigqueueinfo 240
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index c925d1e1777e..783a24ceee88 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -290,7 +290,6 @@ COND_SYSCALL_COMPAT(set_mempolicy);
> COND_SYSCALL(migrate_pages);
> COND_SYSCALL_COMPAT(migrate_pages);
> COND_SYSCALL(move_pages);
> -COND_SYSCALL_COMPAT(move_pages);
>
> COND_SYSCALL(perf_event_open);
> COND_SYSCALL(accept4);
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 34a842a8eb6a..e9dfbde5f12c 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1835,6 +1835,27 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
> mmap_read_unlock(mm);
> }
>
> +static int put_pages_array(const void __user *chunk_pages[],
> + const void __user * __user *pages,
> + unsigned long chunk_nr)
> +{
> + compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages;
> + compat_uptr_t p;
> + int i;
> +
> + if (!in_compat_syscall())
> + return copy_from_user(chunk_pages, pages,
> + chunk_nr * sizeof(*chunk_pages));
> +
> + for (i = 0; i < chunk_nr; i++) {
> + if (get_user(p, pages32 + i))
> + return -EFAULT;
> + chunk_pages[i] = compat_ptr(p);
> + }
> +
> + return 0;

I'd just keep the native version inline and have the compat one in
a helper, but that is just a minor detail.

2020-09-19 05:45:12

by Christoph Hellwig

Subject: Re: [PATCH 4/4] mm: remove compat numa syscalls

On Fri, Sep 18, 2020 at 03:24:39PM +0200, Arnd Bergmann wrote:
> The compat implementations for mbind, get_mempolicy, set_mempolicy
> and migrate_pages are just there to handle the subtly different
> layout of bitmaps on 32-bit hosts.
>
> The compat implementation however lacks some of the checks that
> are present in the native one, in particular for checking that
> the extra bits are all zero when user space has a larger mask
> size than the kernel. Worse, those extra bits do not get cleared
> when copying in or out of the kernel, which can lead to incorrect
> data as well.
>
> Unify the implementation to handle the compat bitmap layout directly
> in the get_nodes() and copy_nodes_to_user() helpers. Splitting out
> the get_bitmap() helper from get_nodes() also helps readability of the
> native case.
>
> On x86, two additional problems are addressed by this: compat tasks can
> pass a bitmap at the end of a mapping, causing a fault when reading
> across the page boundary for a 64-bit word. x32 tasks might also run
> into problems with get_mempolicy corrupting data when an odd number of
> 32-bit words gets passed.
>
> On parisc the migrate_pages() system call apparently had the wrong
> calling convention, as big-endian architectures expect the words
> inside of a bitmap to be swapped. This is not a problem though
> since parisc has no NUMA support.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> arch/arm64/include/asm/unistd32.h | 8 +-
> arch/mips/kernel/syscalls/syscall_n32.tbl | 8 +-
> arch/mips/kernel/syscalls/syscall_o32.tbl | 8 +-
> arch/parisc/kernel/syscalls/syscall.tbl | 6 +-
> arch/powerpc/kernel/syscalls/syscall.tbl | 8 +-
> arch/s390/kernel/syscalls/syscall.tbl | 8 +-
> arch/sparc/kernel/syscalls/syscall.tbl | 8 +-
> arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
> include/linux/compat.h | 15 --
> include/uapi/asm-generic/unistd.h | 8 +-
> kernel/kexec.c | 6 +-
> kernel/sys_ni.c | 4 -
> mm/mempolicy.c | 193 +++++-----------------
> 13 files changed, 79 insertions(+), 203 deletions(-)
>
> diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
> index af793775ba98..31479f7120a0 100644
> --- a/arch/arm64/include/asm/unistd32.h
> +++ b/arch/arm64/include/asm/unistd32.h
> @@ -649,11 +649,11 @@ __SYSCALL(__NR_inotify_add_watch, sys_inotify_add_watch)
> #define __NR_inotify_rm_watch 318
> __SYSCALL(__NR_inotify_rm_watch, sys_inotify_rm_watch)
> #define __NR_mbind 319
> -__SYSCALL(__NR_mbind, compat_sys_mbind)
> +__SYSCALL(__NR_mbind, sys_mbind)
> #define __NR_get_mempolicy 320
> -__SYSCALL(__NR_get_mempolicy, compat_sys_get_mempolicy)
> +__SYSCALL(__NR_get_mempolicy, sys_get_mempolicy)
> #define __NR_set_mempolicy 321
> -__SYSCALL(__NR_set_mempolicy, compat_sys_set_mempolicy)
> +__SYSCALL(__NR_set_mempolicy, sys_set_mempolicy)
> #define __NR_openat 322
> __SYSCALL(__NR_openat, compat_sys_openat)
> #define __NR_mkdirat 323
> @@ -811,7 +811,7 @@ __SYSCALL(__NR_rseq, sys_rseq)
> #define __NR_io_pgetevents 399
> __SYSCALL(__NR_io_pgetevents, compat_sys_io_pgetevents)
> #define __NR_migrate_pages 400
> -__SYSCALL(__NR_migrate_pages, compat_sys_migrate_pages)
> +__SYSCALL(__NR_migrate_pages, sys_migrate_pages)
> #define __NR_kexec_file_load 401
> __SYSCALL(__NR_kexec_file_load, sys_kexec_file_load)
> /* 402 is unused */
> diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
> index 7fa1ca45e44c..15fda882d07e 100644
> --- a/arch/mips/kernel/syscalls/syscall_n32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
> @@ -239,9 +239,9 @@
> 228 n32 clock_nanosleep sys_clock_nanosleep_time32
> 229 n32 tgkill sys_tgkill
> 230 n32 utimes sys_utimes_time32
> -231 n32 mbind compat_sys_mbind
> -232 n32 get_mempolicy compat_sys_get_mempolicy
> -233 n32 set_mempolicy compat_sys_set_mempolicy
> +231 n32 mbind sys_mbind
> +232 n32 get_mempolicy sys_get_mempolicy
> +233 n32 set_mempolicy sys_set_mempolicy
> 234 n32 mq_open compat_sys_mq_open
> 235 n32 mq_unlink sys_mq_unlink
> 236 n32 mq_timedsend sys_mq_timedsend_time32
> @@ -258,7 +258,7 @@
> 247 n32 inotify_init sys_inotify_init
> 248 n32 inotify_add_watch sys_inotify_add_watch
> 249 n32 inotify_rm_watch sys_inotify_rm_watch
> -250 n32 migrate_pages compat_sys_migrate_pages
> +250 n32 migrate_pages sys_migrate_pages
> 251 n32 openat sys_openat
> 252 n32 mkdirat sys_mkdirat
> 253 n32 mknodat sys_mknodat
> diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
> index 194c7fbeedf7..6591388a9d88 100644
> --- a/arch/mips/kernel/syscalls/syscall_o32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
> @@ -279,9 +279,9 @@
> 265 o32 clock_nanosleep sys_clock_nanosleep_time32
> 266 o32 tgkill sys_tgkill
> 267 o32 utimes sys_utimes_time32
> -268 o32 mbind sys_mbind compat_sys_mbind
> -269 o32 get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
> -270 o32 set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
> +268 o32 mbind sys_mbind
> +269 o32 get_mempolicy sys_get_mempolicy
> +270 o32 set_mempolicy sys_set_mempolicy
> 271 o32 mq_open sys_mq_open compat_sys_mq_open
> 272 o32 mq_unlink sys_mq_unlink
> 273 o32 mq_timedsend sys_mq_timedsend_time32
> @@ -298,7 +298,7 @@
> 284 o32 inotify_init sys_inotify_init
> 285 o32 inotify_add_watch sys_inotify_add_watch
> 286 o32 inotify_rm_watch sys_inotify_rm_watch
> -287 o32 migrate_pages sys_migrate_pages compat_sys_migrate_pages
> +287 o32 migrate_pages sys_migrate_pages
> 288 o32 openat sys_openat compat_sys_openat
> 289 o32 mkdirat sys_mkdirat
> 290 o32 mknodat sys_mknodat
> diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
> index 5c17edaffe70..30f3c0146abf 100644
> --- a/arch/parisc/kernel/syscalls/syscall.tbl
> +++ b/arch/parisc/kernel/syscalls/syscall.tbl
> @@ -292,9 +292,9 @@
> 258 32 clock_nanosleep sys_clock_nanosleep_time32
> 258 64 clock_nanosleep sys_clock_nanosleep
> 259 common tgkill sys_tgkill
> -260 common mbind sys_mbind compat_sys_mbind
> -261 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
> -262 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
> +260 common mbind sys_mbind
> +261 common get_mempolicy sys_get_mempolicy
> +262 common set_mempolicy sys_set_mempolicy
> # 263 was vserver
> 264 common add_key sys_add_key
> 265 common request_key sys_request_key
> diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
> index 04fb42d7b377..4f5216320721 100644
> --- a/arch/powerpc/kernel/syscalls/syscall.tbl
> +++ b/arch/powerpc/kernel/syscalls/syscall.tbl
> @@ -338,10 +338,10 @@
> 256 64 sys_debug_setcontext sys_ni_syscall
> 256 spu sys_debug_setcontext sys_ni_syscall
> # 257 reserved for vserver
> -258 nospu migrate_pages sys_migrate_pages compat_sys_migrate_pages
> -259 nospu mbind sys_mbind compat_sys_mbind
> -260 nospu get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
> -261 nospu set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
> +258 nospu migrate_pages sys_migrate_pages
> +259 nospu mbind sys_mbind
> +260 nospu get_mempolicy sys_get_mempolicy
> +261 nospu set_mempolicy sys_set_mempolicy
> 262 nospu mq_open sys_mq_open compat_sys_mq_open
> 263 nospu mq_unlink sys_mq_unlink
> 264 32 mq_timedsend sys_mq_timedsend_time32
> diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
> index 3197965d45e9..70c0b830d14f 100644
> --- a/arch/s390/kernel/syscalls/syscall.tbl
> +++ b/arch/s390/kernel/syscalls/syscall.tbl
> @@ -274,9 +274,9 @@
> 265 common statfs64 sys_statfs64 compat_sys_statfs64
> 266 common fstatfs64 sys_fstatfs64 compat_sys_fstatfs64
> 267 common remap_file_pages sys_remap_file_pages sys_remap_file_pages
> -268 common mbind sys_mbind compat_sys_mbind
> -269 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
> -270 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
> +268 common mbind sys_mbind sys_mbind
> +269 common get_mempolicy sys_get_mempolicy sys_get_mempolicy
> +270 common set_mempolicy sys_set_mempolicy sys_set_mempolicy
> 271 common mq_open sys_mq_open compat_sys_mq_open
> 272 common mq_unlink sys_mq_unlink sys_mq_unlink
> 273 common mq_timedsend sys_mq_timedsend sys_mq_timedsend_time32
> @@ -293,7 +293,7 @@
> 284 common inotify_init sys_inotify_init sys_inotify_init
> 285 common inotify_add_watch sys_inotify_add_watch sys_inotify_add_watch
> 286 common inotify_rm_watch sys_inotify_rm_watch sys_inotify_rm_watch
> -287 common migrate_pages sys_migrate_pages compat_sys_migrate_pages
> +287 common migrate_pages sys_migrate_pages sys_migrate_pages
> 288 common openat sys_openat compat_sys_openat
> 289 common mkdirat sys_mkdirat sys_mkdirat
> 290 common mknodat sys_mknodat sys_mknodat
> diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
> index e36ac364e61a..50ff839a2661 100644
> --- a/arch/sparc/kernel/syscalls/syscall.tbl
> +++ b/arch/sparc/kernel/syscalls/syscall.tbl
> @@ -365,10 +365,10 @@
> 299 common unshare sys_unshare
> 300 common set_robust_list sys_set_robust_list compat_sys_set_robust_list
> 301 common get_robust_list sys_get_robust_list compat_sys_get_robust_list
> -302 common migrate_pages sys_migrate_pages compat_sys_migrate_pages
> -303 common mbind sys_mbind compat_sys_mbind
> -304 common get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
> -305 common set_mempolicy sys_set_mempolicy compat_sys_set_mempolicy
> +302 common migrate_pages sys_migrate_pages
> +303 common mbind sys_mbind
> +304 common get_mempolicy sys_get_mempolicy
> +305 common set_mempolicy sys_set_mempolicy
> 306 common kexec_load sys_kexec_load sys_kexec_load
> 307 common move_pages sys_move_pages
> 308 common getcpu sys_getcpu
> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
> index b3263b8b2eae..d07c3fbd4697 100644
> --- a/arch/x86/entry/syscalls/syscall_32.tbl
> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
> @@ -286,7 +286,7 @@
> 272 i386 fadvise64_64 sys_ia32_fadvise64_64
> 273 i386 vserver
> 274 i386 mbind sys_mbind
> -275 i386 get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
> +275 i386 get_mempolicy sys_get_mempolicy
> 276 i386 set_mempolicy sys_set_mempolicy
> 277 i386 mq_open sys_mq_open compat_sys_mq_open
> 278 i386 mq_unlink sys_mq_unlink
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index db1d7ac2c9e0..be06367b336c 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -749,21 +749,6 @@ asmlinkage long compat_sys_execve(const char __user *filename, const compat_uptr
> /* mm/fadvise.c: No generic prototype for fadvise64_64 */
>
> /* mm/, CONFIG_MMU only */
> -asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len,
> - compat_ulong_t mode,
> - compat_ulong_t __user *nmask,
> - compat_ulong_t maxnode, compat_ulong_t flags);
> -asmlinkage long compat_sys_get_mempolicy(int __user *policy,
> - compat_ulong_t __user *nmask,
> - compat_ulong_t maxnode,
> - compat_ulong_t addr,
> - compat_ulong_t flags);
> -asmlinkage long compat_sys_set_mempolicy(int mode, compat_ulong_t __user *nmask,
> - compat_ulong_t maxnode);
> -asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
> - compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,
> - const compat_ulong_t __user *new_nodes);
> -
> asmlinkage long compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid,
> compat_pid_t pid, int sig,
> struct compat_siginfo __user *uinfo);
> diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> index 4da51702fb21..4e31f9b68a8f 100644
> --- a/include/uapi/asm-generic/unistd.h
> +++ b/include/uapi/asm-generic/unistd.h
> @@ -673,13 +673,13 @@ __SYSCALL(__NR_madvise, sys_madvise)
> #define __NR_remap_file_pages 234
> __SYSCALL(__NR_remap_file_pages, sys_remap_file_pages)
> #define __NR_mbind 235
> -__SC_COMP(__NR_mbind, sys_mbind, compat_sys_mbind)
> +__SYSCALL(__NR_mbind, sys_mbind)
> #define __NR_get_mempolicy 236
> -__SC_COMP(__NR_get_mempolicy, sys_get_mempolicy, compat_sys_get_mempolicy)
> +__SYSCALL(__NR_get_mempolicy, sys_get_mempolicy)
> #define __NR_set_mempolicy 237
> -__SC_COMP(__NR_set_mempolicy, sys_set_mempolicy, compat_sys_set_mempolicy)
> +__SYSCALL(__NR_set_mempolicy, sys_set_mempolicy)
> #define __NR_migrate_pages 238
> -__SC_COMP(__NR_migrate_pages, sys_migrate_pages, compat_sys_migrate_pages)
> +__SYSCALL(__NR_migrate_pages, sys_migrate_pages)
> #define __NR_move_pages 239
> __SYSCALL(__NR_move_pages, sys_move_pages)
> #endif
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 1ef7d3dc906f..0fecf2370be1 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -30,11 +30,13 @@ static int copy_user_segment_list(struct kimage *image,
> image->nr_segments = nr_segments;
> segment_bytes = nr_segments * sizeof(*segments);
> if (in_compat_syscall()) {
> - struct compat_kexec_segment __user *cs = (void __user *)segments;
> + struct compat_kexec_segment __user *cs;
> struct compat_kexec_segment segment;
> int i;
> +
> + cs = (struct compat_kexec_segment __user *)segments;
> for (i=0; i< nr_segments; i++) {
> - copy_from_user(&segment, &cs[i], sizeof(segment));
> + ret = copy_from_user(&segment, &cs[i], sizeof(segment));
> if (ret)
> break;
>
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index 783a24ceee88..0850111f888e 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -282,13 +282,9 @@ COND_SYSCALL(mincore);
> COND_SYSCALL(madvise);
> COND_SYSCALL(remap_file_pages);
> COND_SYSCALL(mbind);
> -COND_SYSCALL_COMPAT(mbind);
> COND_SYSCALL(get_mempolicy);
> -COND_SYSCALL_COMPAT(get_mempolicy);
> COND_SYSCALL(set_mempolicy);
> -COND_SYSCALL_COMPAT(set_mempolicy);
> COND_SYSCALL(migrate_pages);
> -COND_SYSCALL_COMPAT(migrate_pages);
> COND_SYSCALL(move_pages);
>
> COND_SYSCALL(perf_event_open);
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index eddbe4e56c73..2e1b90143b2c 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1374,16 +1374,30 @@ static long do_mbind(unsigned long start, unsigned long len,
> /*
> * User space interface with variable sized bitmaps for nodelists.
> */
> +static int get_bitmap(unsigned long *mask, const unsigned long __user *nmask,
> + unsigned long maxnode)
> +{
> + unsigned long nlongs = BITS_TO_LONGS(maxnode);
> + int ret;
> +
> + if (in_compat_syscall())
> + ret = compat_get_bitmap(mask, (void __user *)nmask, maxnode);

I'd either pass void __user all the way, or do an explicit case from
the native to the compat version in the compat handler.

> + else
> + ret = copy_from_user(mask, nmask, nlongs*sizeof(unsigned long));

That whole BITS_TO_LONGS(b) * sizeof(unsigned long) pattern is
duplicated in various places including the checking of compat vs native
and probably want a helper that includes the in_compat_syscall() check.

2020-09-19 16:25:09

by Andy Lutomirski

Subject: Re: [PATCH 1/4] x86: add __X32_COND_SYSCALL() macro

On Fri, Sep 18, 2020 at 10:35 PM Christoph Hellwig <[email protected]> wrote:
>
> On Fri, Sep 18, 2020 at 03:24:36PM +0200, Arnd Bergmann wrote:
> > sys_move_pages() is an optional syscall, and once we remove
> > the compat version of it in favor of the native one with an
> > in_compat_syscall() check, the x32 syscall table refers to
> > a __x32_sys_move_pages symbol that may not exist when the
> > syscall is disabled.
> >
> > Change the COND_SYSCALL() definition on x86 to also include
> > the redirection for x32.
> >
> > Signed-off-by: Arnd Bergmann <[email protected]>
>
> Adding the x86 maintainers and Brian Gerst. Brian proposed another
> problem to the mess that most of the compat syscall handlers used by
> x32 here:
>
> https://lkml.org/lkml/2020/6/16/664
>
> hpa didn't particularly like it, but with your and my pending series
> we'll soon use more native than compat syscalls for x32, so something
> will need to change..

I'm fine with either solution.

2020-09-19 17:41:33

by Andy Lutomirski

Subject: Re: [PATCH 1/4] x86: add __X32_COND_SYSCALL() macro

> On Sep 19, 2020, at 10:14 AM, [email protected] wrote:
>
> On September 19, 2020 9:23:22 AM PDT, Andy Lutomirski <[email protected]> wrote:
>>> On Fri, Sep 18, 2020 at 10:35 PM Christoph Hellwig <[email protected]>
>>> wrote:
>>>
>>> On Fri, Sep 18, 2020 at 03:24:36PM +0200, Arnd Bergmann wrote:
>>>> sys_move_pages() is an optional syscall, and once we remove
>>>> the compat version of it in favor of the native one with an
>>>> in_compat_syscall() check, the x32 syscall table refers to
>>>> a __x32_sys_move_pages symbol that may not exist when the
>>>> syscall is disabled.
>>>>
>>>> Change the COND_SYSCALL() definition on x86 to also include
>>>> the redirection for x32.
>>>>
>>>> Signed-off-by: Arnd Bergmann <[email protected]>
>>>
>>> Adding the x86 maintainers and Brian Gerst. Brian proposed another
>>> problem to the mess that most of the compat syscall handlers used by
>>> x32 here:
>>>
>>> https://lkml.org/lkml/2020/6/16/664
>>>
>>> hpa didn't particularly like it, but with your and my pending series
>>> we'll soon use more native than compat syscalls for x32, so something
>>> will need to change..
>>
>> I'm fine with either solution.
>
> My main objection was naming. x64 is a widely used synonym for x86-64, and so that is confusing.
>
>

The way I deal with the syscall wrappers is that I assume the naming makes no sense whatsoever, and I go from there. With this perspective, the patches are neither an improvement nor a worsening of the current situation.

(Similarly, the last column of the tables is useless garbage. My last attempt to fix that stalled.)

2020-09-19 17:47:18

by Brian Gerst

Subject: Re: [PATCH 1/4] x86: add __X32_COND_SYSCALL() macro

An alternative to the patch I proposed earlier would be to use aliases
with the __x32_ prefix for the common syscalls.

--
Brian Gerst

On Sat, Sep 19, 2020 at 1:14 PM <[email protected]> wrote:
>
> On September 19, 2020 9:23:22 AM PDT, Andy Lutomirski <[email protected]> wrote:
> >On Fri, Sep 18, 2020 at 10:35 PM Christoph Hellwig <[email protected]>
> >wrote:
> >>
> >> On Fri, Sep 18, 2020 at 03:24:36PM +0200, Arnd Bergmann wrote:
> >> > sys_move_pages() is an optional syscall, and once we remove
> >> > the compat version of it in favor of the native one with an
> >> > in_compat_syscall() check, the x32 syscall table refers to
> >> > a __x32_sys_move_pages symbol that may not exist when the
> >> > syscall is disabled.
> >> >
> >> > Change the COND_SYSCALL() definition on x86 to also include
> >> > the redirection for x32.
> >> >
> >> > Signed-off-by: Arnd Bergmann <[email protected]>
> >>
> >> Adding the x86 maintainers and Brian Gerst. Brian proposed another
> >> problem to the mess that most of the compat syscall handlers used by
> >> x32 here:
> >>
> >> https://lkml.org/lkml/2020/6/16/664
> >>
> >> hpa didn't particularly like it, but with your and my pending series
> >> we'll soon use more native than compat syscalls for x32, so something
> >> will need to change..
> >
> >I'm fine with either solution.
>
> My main objection was naming. x64 is a widely used synonym for x86-64, and so that is confusing.
>
> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.

2020-09-19 18:18:58

by H. Peter Anvin

Subject: Re: [PATCH 1/4] x86: add __X32_COND_SYSCALL() macro

On September 19, 2020 9:23:22 AM PDT, Andy Lutomirski <[email protected]> wrote:
>On Fri, Sep 18, 2020 at 10:35 PM Christoph Hellwig <[email protected]>
>wrote:
>>
>> On Fri, Sep 18, 2020 at 03:24:36PM +0200, Arnd Bergmann wrote:
>> > sys_move_pages() is an optional syscall, and once we remove
>> > the compat version of it in favor of the native one with an
>> > in_compat_syscall() check, the x32 syscall table refers to
>> > a __x32_sys_move_pages symbol that may not exist when the
>> > syscall is disabled.
>> >
>> > Change the COND_SYSCALL() definition on x86 to also include
>> > the redirection for x32.
>> >
>> > Signed-off-by: Arnd Bergmann <[email protected]>
>>
>> Adding the x86 maintainers and Brian Gerst. Brian proposed another
>> problem to the mess that most of the compat syscall handlers used by
>> x32 here:
>>
>> https://lkml.org/lkml/2020/6/16/664
>>
>> hpa didn't particularly like it, but with your and my pending series
>> we'll soon use more native than compat syscalls for x32, so something
>> will need to change..
>
>I'm fine with either solution.

My main objection was naming. x64 is a widely used synonym for x86-64, and so that is confusing.

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

2020-09-26 15:16:28

by Arnd Bergmann

Subject: Re: [PATCH 4/4] mm: remove compat numa syscalls

On Sat, Sep 19, 2020 at 7:41 AM Christoph Hellwig <[email protected]> wrote:
> On Fri, Sep 18, 2020 at 03:24:39PM +0200, Arnd Bergmann wrote:

> > +static int get_bitmap(unsigned long *mask, const unsigned long __user *nmask,
> > + unsigned long maxnode)
> > +{
> > + unsigned long nlongs = BITS_TO_LONGS(maxnode);
> > + int ret;
> > +
> > + if (in_compat_syscall())
> > + ret = compat_get_bitmap(mask, (void __user *)nmask, maxnode);
>
> I'd either pass void __user all the way, or do an explicit case from
> the native to the compat version in the compat handler.

Changed to

if (in_compat_syscall())
ret = compat_get_bitmap(mask,
(const compat_ulong_t __user *)nmask,
maxnode);

> > + else
> > + ret = copy_from_user(mask, nmask, nlongs*sizeof(unsigned long));
>
> That whole BITS_TO_LONGS(b) * sizeof(unsigned long) pattern is
> duplicated in various places including the checking of compat vs native
> and probably want a helper that includes the in_compat_syscall() check.

I don't see what you mean here. I can see how having the helper would
simplify copy_nodes_to_user(), but not how it can be shared with the
use in get_bitmap()/get_nodes().

Arnd

2020-09-26 15:23:37

by Arnd Bergmann

Subject: Re: [PATCH 3/4] mm: remove compat_sys_move_pages

On Sat, Sep 19, 2020 at 7:38 AM Christoph Hellwig <[email protected]> wrote:
>
> I'd just keep the native version inline and have the compat one in
> a helper, but that is just a minor detail.

Folded in this change:

diff --git a/mm/migrate.c b/mm/migrate.c
index e9dfbde5f12c..d3fa3f4bf653 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1835,18 +1835,14 @@ static void do_pages_stat_array(struct
mm_struct *mm, unsigned long nr_pages,
mmap_read_unlock(mm);
}

-static int put_pages_array(const void __user *chunk_pages[],
- const void __user * __user *pages,
- unsigned long chunk_nr)
+static int put_compat_pages_array(const void __user *chunk_pages[],
+ const void __user * __user *pages,
+ unsigned long chunk_nr)
{
compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages;
compat_uptr_t p;
int i;

- if (!in_compat_syscall())
- return copy_from_user(chunk_pages, pages,
- chunk_nr * sizeof(*chunk_pages));
-
for (i = 0; i < chunk_nr; i++) {
if (get_user(p, pages32 + i))
return -EFAULT;
@@ -1875,8 +1871,15 @@ static int do_pages_stat(struct mm_struct *mm,
unsigned long nr_pages,
if (chunk_nr > DO_PAGES_STAT_CHUNK_NR)
chunk_nr = DO_PAGES_STAT_CHUNK_NR;

- if (put_pages_array(chunk_pages, pages, chunk_nr))
- break;
+ if (in_compat_syscall()) {
+ if (put_compat_pages_array(chunk_pages, pages,
+ chunk_nr))
+ break;
+ } else {
+ if (copy_from_user(chunk_pages, pages,
+ chunk_nr * sizeof(*chunk_pages)))
+ break;
+ }

do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);

It does make the separation cleaner but it's also more code, which is
why I had it in the combined function before.

Arnd

2020-09-26 21:13:04

by Arnd Bergmann

Subject: Re: [PATCH 2/4] kexec: remove compat_sys_kexec_load syscall

On Sat, Sep 19, 2020 at 7:37 AM Christoph Hellwig <[email protected]> wrote:

> > + struct compat_kexec_segment __user *cs = (void __user *)segments;
> > + struct compat_kexec_segment segment;
> > + int i;
> > + for (i=0; i< nr_segments; i++) {
>
> Missing empty line after the variable declarations and really strange
> indentation.
>
> > + copy_from_user(&segment, &cs[i], sizeof(segment));
>
> Missing return value check.
>
> > + if (ret)
> > + break;
> > +
> > + image->segment[i] = (struct kexec_segment) {
> > + .buf = compat_ptr(segment.buf),
> > + .bufsz = segment.bufsz,
> > + .mem = segment.mem,
> > + .memsz = segment.memsz,
> > + };
> > + }
>
> I'd split the whole compat handling into a helper, and I'd probably
> use the unsafe_get/put user to optimize it a little more.
>
> > + } else {
> > + ret = copy_from_user(image->segment, segments, segment_bytes);
> > + }
> > if (ret)
> > ret = -EFAULT;
>
> Why not just
>
> if (copy_from_user(image->segment, segments, segment_bytes))
> ret = -EFAULT;
>
> ?

Addressed all of these now, thanks for the suggestions!

I had already fixed the missing error handling after the kbuild bot
pointed that out. The separate function does improve the error
handling.

I ended up not using unsafe_get/put since I find the copy_from_user
based loop more readable and it should lead to smaller object code in
most cases as well. kexec is not performance critical, so readability
seems more important here.

Arnd