The member auxv in prctl_mm_map structure which be shared with
userspace is pointer type, but the kernel supporting COMPAT didn't
handle it. This patch fix the compat handling for prctl syscall.
Signed-off-by: Li Bin <[email protected]>
---
kernel/sys.c | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/kernel/sys.c b/kernel/sys.c
index ad69218..d4259938 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1969,6 +1969,26 @@ static int validate_prctl_map(struct prctl_mm_map *prctl_map)
}
#ifdef CONFIG_CHECKPOINT_RESTORE
+
+#ifdef CONFIG_COMPAT
+struct compat_prctl_mm_map {
+ __u64 start_code; /* code section bounds */
+ __u64 end_code;
+ __u64 start_data; /* data section bounds */
+ __u64 end_data;
+ __u64 start_brk; /* heap for brk() syscall */
+ __u64 brk;
+ __u64 start_stack; /* stack starts at */
+ __u64 arg_start; /* command line arguments bounds */
+ __u64 arg_end;
+ __u64 env_start; /* environment variables bounds */
+ __u64 env_end;
+ compat_uptr_t auxv; /* auxiliary vector */
+ __u32 auxv_size; /* vector size */
+ __u32 exe_fd; /* /proc/$pid/exe link file */
+};
+#endif
+
static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size)
{
struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, };
@@ -1986,6 +2006,28 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data
if (data_size != sizeof(prctl_map))
return -EINVAL;
+#ifdef CONFIG_COMPAT
+ if (in_compat_syscall()) {
+ struct compat_prctl_mm_map prctl_map32;
+ if (copy_from_user(&prctl_map32, addr, sizeof(prctl_map32)))
+ return -EFAULT;
+
+ prctl_map.start_code = prctl_map32.start_code;
+ prctl_map.end_code = prctl_map32.end_code;
+ prctl_map.start_data = prctl_map32.start_data;
+ prctl_map.end_data = prctl_map32.end_data;
+ prctl_map.start_brk = prctl_map32.start_brk;
+ prctl_map.brk = prctl_map32.brk;
+ prctl_map.start_stack = prctl_map32.start_stack;
+ prctl_map.arg_start = prctl_map32.arg_start;
+ prctl_map.arg_end = prctl_map32.arg_end;
+ prctl_map.env_start = prctl_map32.env_start;
+ prctl_map.env_end = prctl_map32.env_end;
+ prctl_map.auxv = compat_ptr(prctl_map32.auxv);
+ prctl_map.auxv_size = prctl_map32.auxv_size;
+ prctl_map.exe_fd = prctl_map32.exe_fd;
+ } else
+#endif
if (copy_from_user(&prctl_map, addr, sizeof(prctl_map)))
return -EFAULT;
--
1.7.12.4
> On Apr 18, 2018, at 9:06 PM, Li Bin <[email protected]> wrote:
>
> The member auxv in prctl_mm_map structure which be shared with
> userspace is pointer type, but the kernel supporting COMPAT didn't
> handle it. This patch fix the compat handling for prctl syscall.
>
> Signed-off-by: Li Bin <[email protected]>
> ---
> kernel/sys.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/kernel/sys.c b/kernel/sys.c
> index ad69218..d4259938 100644
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -1969,6 +1969,26 @@ static int validate_prctl_map(struct prctl_mm_map *prctl_map)
> }
>
> #ifdef CONFIG_CHECKPOINT_RESTORE
> +
> +#ifdef CONFIG_COMPAT
> +struct compat_prctl_mm_map {
> + __u64 start_code; /* code section bounds */
> + __u64 end_code;
> + __u64 start_data; /* data section bounds */
> + __u64 end_data;
> + __u64 start_brk; /* heap for brk() syscall */
> + __u64 brk;
> + __u64 start_stack; /* stack starts at */
> + __u64 arg_start; /* command line arguments bounds */
> + __u64 arg_end;
> + __u64 env_start; /* environment variables bounds */
> + __u64 env_end;
> + compat_uptr_t auxv; /* auxiliary vector */
> + __u32 auxv_size; /* vector size */
> + __u32 exe_fd; /* /proc/$pid/exe link file */
> +};
> +#endif
> +
> static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size)
> {
> struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, };
> @@ -1986,6 +2006,28 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data
> if (data_size != sizeof(prctl_map))
> return -EINVAL;
>
> +#ifdef CONFIG_COMPAT
> + if (in_compat_syscall()) {
> + struct compat_prctl_mm_map prctl_map32;
> + if (copy_from_user(&prctl_map32, addr, sizeof(prctl_map32)))
> + return -EFAULT;
> +
> + prctl_map.start_code = prctl_map32.start_code;
> + prctl_map.end_code = prctl_map32.end_code;
> + prctl_map.start_data = prctl_map32.start_data;
> + prctl_map.end_data = prctl_map32.end_data;
> + prctl_map.start_brk = prctl_map32.start_brk;
> + prctl_map.brk = prctl_map32.brk;
> + prctl_map.start_stack = prctl_map32.start_stack;
> + prctl_map.arg_start = prctl_map32.arg_start;
> + prctl_map.arg_end = prctl_map32.arg_end;
> + prctl_map.env_start = prctl_map32.env_start;
> + prctl_map.env_end = prctl_map32.env_end;
> + prctl_map.auxv = compat_ptr(prctl_map32.auxv);
> + prctl_map.auxv_size = prctl_map32.auxv_size;
> + prctl_map.exe_fd = prctl_map32.exe_fd;
> + } else
> +#endif
> if (copy_from_user(&prctl_map, addr, sizeof(prctl_map)))
> return -EFAULT;
>
> --
> 1.7.12.4
>
> On Apr 18, 2018, at 9:06 PM, Li Bin <[email protected]> wrote:
>
> The member auxv in prctl_mm_map structure which be shared with
> userspace is pointer type, but the kernel supporting COMPAT didn't
> handle it. This patch fix the compat handling for prctl syscall.
I would propose an alternative fix: change the type to u64. As far as
I know, this thing is only used by CRIU, and CRIU doesn’t work (AFAIK)
on native 32-bit anyway. Do you know of some reason that this
wouldn't work?
在 2018/4/19 10:25, Andy Lutomirski 写道:
>> On Apr 18, 2018, at 9:06 PM, Li Bin <[email protected]> wrote:
>>
>> The member auxv in prctl_mm_map structure which be shared with
>> userspace is pointer type, but the kernel supporting COMPAT didn't
>> handle it. This patch fix the compat handling for prctl syscall.
>
> I would propose an alternative fix: change the type to u64. As far as
But we also need to modify the sys/prctl.h in Glibc, right?
> I know, this thing is only used by CRIU, and CRIU doesn’t work (AFAIK)
> on native 32-bit anyway. Do you know of some reason that this
> wouldn't work?
>
> .
>
2018-04-19 3:25 GMT+01:00 Andy Lutomirski <[email protected]>:
>> On Apr 18, 2018, at 9:06 PM, Li Bin <[email protected]> wrote:
>>
>> The member auxv in prctl_mm_map structure which be shared with
>> userspace is pointer type, but the kernel supporting COMPAT didn't
>> handle it. This patch fix the compat handling for prctl syscall.
>
> I would propose an alternative fix: change the type to u64. As far as
> I know, this thing is only used by CRIU, and CRIU doesn’t work (AFAIK)
> on native 32-bit anyway.
Yeah, it's right - CRIU doesn't work on native 32-bit and no support planned.
Thanks,
Dmitry