From: Ollie Wild <[email protected]>
Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly
from the old mm into the new mm.
We create the new mm before the binfmt code runs, and place the new stack
at the very top of the address space. Once the binfmt code runs and figures
out where the stack should be, we move it downwards.
It is a bit peculiar in that we have one task with two mm's, one of which is
inactive.
Signed-off-by: Ollie Wild <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
---
Changes:
- reverted the UML changes, those were no longer needed
- reworked the no-MMU stuff to reduce #ifdef clutter and enhance compilability
- removed move_page_tables_up() since it turned out to be unused
- sprinkled comments
arch/ia64/ia32/binfmt_elf32.c | 65 +---
arch/x86_64/ia32/ia32_aout.c | 2
arch/x86_64/ia32/ia32_binfmt.c | 58 ---
fs/binfmt_elf.c | 28 +
fs/binfmt_elf_fdpic.c | 8
fs/binfmt_misc.c | 4
fs/binfmt_script.c | 4
fs/compat.c | 128 +++-----
fs/exec.c | 606 +++++++++++++++++++++++++----------------
include/linux/binfmts.h | 18 -
include/linux/mm.h | 9
kernel/auditsc.c | 2
mm/mmap.c | 61 ++--
mm/mprotect.c | 2
mm/mremap.c | 2
15 files changed, 541 insertions(+), 456 deletions(-)
Index: linux-2.6-2/arch/x86_64/ia32/ia32_binfmt.c
===================================================================
--- linux-2.6-2.orig/arch/x86_64/ia32/ia32_binfmt.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/arch/x86_64/ia32/ia32_binfmt.c 2007-06-13 11:52:46.000000000 +0200
@@ -233,9 +233,6 @@ do { \
#define load_elf_binary load_elf32_binary
#define ELF_PLAT_INIT(r, load_addr) elf32_init(r)
-#define setup_arg_pages(bprm, stack_top, exec_stack) \
- ia32_setup_arg_pages(bprm, stack_top, exec_stack)
-int ia32_setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_top, int executable_stack);
#undef start_thread
#define start_thread(regs,new_rip,new_rsp) do { \
@@ -287,61 +284,6 @@ static void elf32_init(struct pt_regs *r
me->thread.es = __USER_DS;
}
-int ia32_setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_top,
- int executable_stack)
-{
- unsigned long stack_base;
- struct vm_area_struct *mpnt;
- struct mm_struct *mm = current->mm;
- int i, ret;
-
- stack_base = stack_top - MAX_ARG_PAGES * PAGE_SIZE;
- mm->arg_start = bprm->p + stack_base;
-
- bprm->p += stack_base;
- if (bprm->loader)
- bprm->loader += stack_base;
- bprm->exec += stack_base;
-
- mpnt = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
- if (!mpnt)
- return -ENOMEM;
-
- down_write(&mm->mmap_sem);
- {
- mpnt->vm_mm = mm;
- mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
- mpnt->vm_end = stack_top;
- if (executable_stack == EXSTACK_ENABLE_X)
- mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
- else if (executable_stack == EXSTACK_DISABLE_X)
- mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
- else
- mpnt->vm_flags = VM_STACK_FLAGS;
- mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC) ?
- PAGE_COPY_EXEC : PAGE_COPY;
- if ((ret = insert_vm_struct(mm, mpnt))) {
- up_write(&mm->mmap_sem);
- kmem_cache_free(vm_area_cachep, mpnt);
- return ret;
- }
- mm->stack_vm = mm->total_vm = vma_pages(mpnt);
- }
-
- for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
- struct page *page = bprm->page[i];
- if (page) {
- bprm->page[i] = NULL;
- install_arg_page(mpnt, page, stack_base);
- }
- stack_base += PAGE_SIZE;
- }
- up_write(&mm->mmap_sem);
-
- return 0;
-}
-EXPORT_SYMBOL(ia32_setup_arg_pages);
-
#ifdef CONFIG_SYSCTL
/* Register vsyscall32 into the ABI table */
#include <linux/sysctl.h>
Index: linux-2.6-2/fs/binfmt_elf.c
===================================================================
--- linux-2.6-2.orig/fs/binfmt_elf.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/fs/binfmt_elf.c 2007-06-13 11:52:46.000000000 +0200
@@ -148,6 +148,7 @@ create_elf_tables(struct linux_binprm *b
elf_addr_t *elf_info;
int ei_index = 0;
struct task_struct *tsk = current;
+ struct vm_area_struct *vma;
/*
* If this architecture has a platform capability string, copy it
@@ -234,6 +235,15 @@ create_elf_tables(struct linux_binprm *b
sp = (elf_addr_t __user *)bprm->p;
#endif
+
+ /*
+ * Grow the stack manually; some architectures have a limit on how
+ * far ahead a user-space access may be in order to grow the stack.
+ */
+ vma = find_extend_vma(current->mm, bprm->p);
+ if (!vma)
+ return -EFAULT;
+
/* Now, let's put argc (and argv, envp if appropriate) on the stack */
if (__put_user(argc, sp++))
return -EFAULT;
@@ -254,8 +264,8 @@ create_elf_tables(struct linux_binprm *b
size_t len;
if (__put_user((elf_addr_t)p, argv++))
return -EFAULT;
- len = strnlen_user((void __user *)p, PAGE_SIZE*MAX_ARG_PAGES);
- if (!len || len > PAGE_SIZE*MAX_ARG_PAGES)
+ len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
+ if (!len || len > MAX_ARG_STRLEN)
return 0;
p += len;
}
@@ -266,8 +276,8 @@ create_elf_tables(struct linux_binprm *b
size_t len;
if (__put_user((elf_addr_t)p, envp++))
return -EFAULT;
- len = strnlen_user((void __user *)p, PAGE_SIZE*MAX_ARG_PAGES);
- if (!len || len > PAGE_SIZE*MAX_ARG_PAGES)
+ len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
+ if (!len || len > MAX_ARG_STRLEN)
return 0;
p += len;
}
@@ -826,10 +836,6 @@ static int load_elf_binary(struct linux_
}
/* OK, This is the point of no return */
- current->mm->start_data = 0;
- current->mm->end_data = 0;
- current->mm->end_code = 0;
- current->mm->mmap = NULL;
current->flags &= ~PF_FORKNOEXEC;
current->mm->def_flags = def_flags;
@@ -1051,9 +1057,13 @@ static int load_elf_binary(struct linux_
compute_creds(bprm);
current->flags &= ~PF_FORKNOEXEC;
- create_elf_tables(bprm, &loc->elf_ex,
+ retval = create_elf_tables(bprm, &loc->elf_ex,
(interpreter_type == INTERPRETER_AOUT),
load_addr, interp_load_addr);
+ if (retval < 0) {
+ send_sig(SIGKILL, current, 0);
+ goto out;
+ }
/* N.B. passed_fileno might not be initialized? */
if (interpreter_type == INTERPRETER_AOUT)
current->mm->arg_start += strlen(passed_fileno) + 1;
Index: linux-2.6-2/fs/binfmt_elf_fdpic.c
===================================================================
--- linux-2.6-2.orig/fs/binfmt_elf_fdpic.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/fs/binfmt_elf_fdpic.c 2007-06-13 11:52:46.000000000 +0200
@@ -621,8 +621,8 @@ static int create_elf_fdpic_tables(struc
p = (char __user *) current->mm->arg_start;
for (loop = bprm->argc; loop > 0; loop--) {
__put_user((elf_caddr_t) p, argv++);
- len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
- if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
+ len = strnlen_user(p, MAX_ARG_STRLEN);
+ if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
@@ -633,8 +633,8 @@ static int create_elf_fdpic_tables(struc
current->mm->env_start = (unsigned long) p;
for (loop = bprm->envc; loop > 0; loop--) {
__put_user((elf_caddr_t)(unsigned long) p, envp++);
- len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
- if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
+ len = strnlen_user(p, MAX_ARG_STRLEN);
+ if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
Index: linux-2.6-2/fs/binfmt_misc.c
===================================================================
--- linux-2.6-2.orig/fs/binfmt_misc.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/fs/binfmt_misc.c 2007-06-13 11:52:46.000000000 +0200
@@ -126,7 +126,9 @@ static int load_misc_binary(struct linux
goto _ret;
if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) {
- remove_arg_zero(bprm);
+ retval = remove_arg_zero(bprm);
+ if (retval)
+ goto _ret;
}
if (fmt->flags & MISC_FMT_OPEN_BINARY) {
Index: linux-2.6-2/fs/binfmt_script.c
===================================================================
--- linux-2.6-2.orig/fs/binfmt_script.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/fs/binfmt_script.c 2007-06-13 11:52:46.000000000 +0200
@@ -67,7 +67,9 @@ static int load_script(struct linux_binp
* This is done in reverse order, because of how the
* user environment and arguments are stored.
*/
- remove_arg_zero(bprm);
+ retval = remove_arg_zero(bprm);
+ if (retval)
+ return retval;
retval = copy_strings_kernel(1, &bprm->interp, bprm);
if (retval < 0) return retval;
bprm->argc++;
Index: linux-2.6-2/fs/compat.c
===================================================================
--- linux-2.6-2.orig/fs/compat.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/fs/compat.c 2007-06-13 11:52:46.000000000 +0200
@@ -1257,6 +1257,7 @@ static int compat_copy_strings(int argc,
{
struct page *kmapped_page = NULL;
char *kaddr = NULL;
+ unsigned long kpos = 0;
int ret;
while (argc-- > 0) {
@@ -1265,92 +1266,84 @@ static int compat_copy_strings(int argc,
unsigned long pos;
if (get_user(str, argv+argc) ||
- !(len = strnlen_user(compat_ptr(str), bprm->p))) {
+ !(len = strnlen_user(compat_ptr(str), MAX_ARG_STRLEN))) {
ret = -EFAULT;
goto out;
}
- if (bprm->p < len) {
+ if (len > MAX_ARG_STRLEN) {
ret = -E2BIG;
goto out;
}
- bprm->p -= len;
- /* XXX: add architecture specific overflow check here. */
+ /* We're going to work our way backwords. */
pos = bprm->p;
+ str += len;
+ bprm->p -= len;
while (len > 0) {
- int i, new, err;
int offset, bytes_to_copy;
- struct page *page;
offset = pos % PAGE_SIZE;
- i = pos/PAGE_SIZE;
- page = bprm->page[i];
- new = 0;
- if (!page) {
- page = alloc_page(GFP_HIGHUSER);
- bprm->page[i] = page;
- if (!page) {
- ret = -ENOMEM;
+ if (offset == 0)
+ offset = PAGE_SIZE;
+
+ bytes_to_copy = offset;
+ if (bytes_to_copy > len)
+ bytes_to_copy = len;
+
+ offset -= bytes_to_copy;
+ pos -= bytes_to_copy;
+ str -= bytes_to_copy;
+ len -= bytes_to_copy;
+
+ if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
+ struct page *page;
+
+#ifdef CONFIG_STACK_GROWSUP
+ ret = expand_stack_downwards(bprm->vma, pos);
+ if (ret < 0) {
+ /* We've exceed the stack rlimit. */
+ ret = -E2BIG;
+ goto out;
+ }
+#endif
+ ret = get_user_pages(current, bprm->mm, pos,
+ 1, 1, 1, &page, NULL);
+ if (ret <= 0) {
+ /* We've exceed the stack rlimit. */
+ ret = -E2BIG;
goto out;
}
- new = 1;
- }
- if (page != kmapped_page) {
- if (kmapped_page)
+ if (kmapped_page) {
+ flush_kernel_dcache_page(kmapped_page);
kunmap(kmapped_page);
+ put_page(kmapped_page);
+ }
kmapped_page = page;
kaddr = kmap(kmapped_page);
+ kpos = pos & PAGE_MASK;
+ flush_cache_page(bprm->vma, kpos,
+ page_to_pfn(kmapped_page));
}
- if (new && offset)
- memset(kaddr, 0, offset);
- bytes_to_copy = PAGE_SIZE - offset;
- if (bytes_to_copy > len) {
- bytes_to_copy = len;
- if (new)
- memset(kaddr+offset+len, 0,
- PAGE_SIZE-offset-len);
- }
- err = copy_from_user(kaddr+offset, compat_ptr(str),
- bytes_to_copy);
- if (err) {
+ if (copy_from_user(kaddr+offset, compat_ptr(str),
+ bytes_to_copy)) {
ret = -EFAULT;
goto out;
}
-
- pos += bytes_to_copy;
- str += bytes_to_copy;
- len -= bytes_to_copy;
}
}
ret = 0;
out:
- if (kmapped_page)
+ if (kmapped_page) {
+ flush_kernel_dcache_page(kmapped_page);
kunmap(kmapped_page);
- return ret;
-}
-
-#ifdef CONFIG_MMU
-
-#define free_arg_pages(bprm) do { } while (0)
-
-#else
-
-static inline void free_arg_pages(struct linux_binprm *bprm)
-{
- int i;
-
- for (i = 0; i < MAX_ARG_PAGES; i++) {
- if (bprm->page[i])
- __free_page(bprm->page[i]);
- bprm->page[i] = NULL;
+ put_page(kmapped_page);
}
+ return ret;
}
-#endif /* CONFIG_MMU */
-
/*
* compat_do_execve() is mostly a copy of do_execve(), with the exception
* that it processes 32 bit argv and envp pointers.
@@ -1363,7 +1356,6 @@ int compat_do_execve(char * filename,
struct linux_binprm *bprm;
struct file *file;
int retval;
- int i;
retval = -ENOMEM;
bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
@@ -1377,24 +1369,19 @@ int compat_do_execve(char * filename,
sched_exec();
- bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
bprm->file = file;
bprm->filename = filename;
bprm->interp = filename;
- bprm->mm = mm_alloc();
- retval = -ENOMEM;
- if (!bprm->mm)
- goto out_file;
- retval = init_new_context(current, bprm->mm);
- if (retval < 0)
- goto out_mm;
+ retval = bprm_mm_init(bprm);
+ if (retval)
+ goto out_file;
- bprm->argc = compat_count(argv, bprm->p / sizeof(compat_uptr_t));
+ bprm->argc = compat_count(argv, MAX_ARG_STRINGS);
if ((retval = bprm->argc) < 0)
goto out_mm;
- bprm->envc = compat_count(envp, bprm->p / sizeof(compat_uptr_t));
+ bprm->envc = compat_count(envp, MAX_ARG_STRINGS);
if ((retval = bprm->envc) < 0)
goto out_mm;
@@ -1421,8 +1408,6 @@ int compat_do_execve(char * filename,
retval = search_binary_handler(bprm, regs);
if (retval >= 0) {
- free_arg_pages(bprm);
-
/* execve success */
security_bprm_free(bprm);
acct_update_integrals(current);
@@ -1431,19 +1416,12 @@ int compat_do_execve(char * filename,
}
out:
- /* Something went wrong, return the inode and free the argument pages*/
- for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
- struct page * page = bprm->page[i];
- if (page)
- __free_page(page);
- }
-
if (bprm->security)
security_bprm_free(bprm);
out_mm:
if (bprm->mm)
- mmdrop(bprm->mm);
+ mmput(bprm->mm);
out_file:
if (bprm->file) {
Index: linux-2.6-2/fs/exec.c
===================================================================
--- linux-2.6-2.orig/fs/exec.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/fs/exec.c 2007-06-13 11:52:46.000000000 +0200
@@ -54,6 +54,7 @@
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
+#include <asm/tlb.h>
#ifdef CONFIG_KMOD
#include <linux/kmod.h>
@@ -178,6 +179,191 @@ exit:
goto out;
}
+#ifdef CONFIG_MMU
+
+static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
+ int write)
+{
+ struct page *page;
+ int ret;
+
+#ifdef CONFIG_STACK_GROWSUP
+ if (write) {
+ ret = expand_stack_downwards(bprm->vma, pos);
+ if (ret < 0)
+ return NULL;
+ }
+#endif
+ ret = get_user_pages(current, bprm->mm, pos,
+ 1, write, 1, &page, NULL);
+ if (ret <= 0)
+ return NULL;
+
+ return page;
+}
+
+static void put_arg_page(struct page *page)
+{
+ put_page(page);
+}
+
+static void free_arg_page(struct linux_binprm *bprm, int i)
+{
+}
+
+static void free_arg_pages(struct linux_binprm *bprm)
+{
+}
+
+static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
+ struct page *page)
+{
+ flush_cache_page(bprm->vma, pos, page_to_pfn(page));
+}
+
+static int __bprm_mm_init(struct linux_binprm *bprm)
+{
+ int err = -ENOMEM;
+ struct vm_area_struct *vma = NULL;
+ struct mm_struct *mm = bprm->mm;
+
+ bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+ if (!vma)
+ goto err;
+
+ down_write(&mm->mmap_sem);
+ vma->vm_mm = mm;
+
+ /*
+ * Place the stack at the largest stack address the architecture
+ * supports. Later, we'll move this to an appropriate place. We don't
+ * use STACK_TOP because that can depend on attributes which aren't
+ * configured yet.
+ */
+ vma->vm_end = STACK_TOP_MAX;
+ vma->vm_start = vma->vm_end - PAGE_SIZE;
+
+ vma->vm_flags = VM_STACK_FLAGS;
+ vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
+ err = insert_vm_struct(mm, vma);
+ if (err) {
+ up_write(&mm->mmap_sem);
+ goto err;
+ }
+
+ mm->stack_vm = mm->total_vm = 1;
+ up_write(&mm->mmap_sem);
+
+ bprm->p = vma->vm_end - sizeof(void *);
+
+ return 0;
+
+err:
+ if (vma) {
+ bprm->vma = NULL;
+ kmem_cache_free(vm_area_cachep, vma);
+ }
+
+ return err;
+}
+
+static bool valid_arg_len(struct linux_binprm *bprm, long len)
+{
+ return len <= MAX_ARG_STRLEN;
+}
+
+#else
+
+static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
+ int write)
+{
+ struct page *page;
+
+ page = bprm->page[pos / PAGE_SIZE];
+ if (!page && write) {
+ page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
+ if (!page)
+ return NULL;
+ bprm->page[pos / PAGE_SIZE] = page;
+ }
+
+ return page;
+}
+
+static void put_arg_page(struct page *page)
+{
+}
+
+static void free_arg_page(struct linux_binprm *bprm, int i)
+{
+ if (bprm->page[i]) {
+ __free_page(bprm->page[i]);
+ bprm->page[i] = NULL;
+ }
+}
+
+static void free_arg_pages(struct linux_binprm *bprm)
+{
+ int i;
+
+ for (i = 0; i < MAX_ARG_PAGES; i++)
+ free_arg_page(bprm, i);
+}
+
+static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
+ struct page *page)
+{
+}
+
+static int __bprm_mm_init(struct linux_binprm *bprm)
+{
+ bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
+ return 0;
+}
+
+static bool valid_arg_len(struct linux_binprm *bprm, long len)
+{
+ return len <= bprm->p;
+}
+
+#endif /* CONFIG_MMU */
+
+/*
+ * Create a new mm_struct and populate it with a temporary stack
+ * vm_area_struct. We don't have enough context at this point to set the stack
+ * flags, permissions, and offset, so we use temporary values. We'll update
+ * them later in setup_arg_pages().
+ */
+int bprm_mm_init(struct linux_binprm *bprm)
+{
+ int err;
+ struct mm_struct *mm = NULL;
+
+ bprm->mm = mm = mm_alloc();
+ err = -ENOMEM;
+ if (!mm)
+ goto err;
+
+ err = init_new_context(current, mm);
+ if (err)
+ goto err;
+
+ err = __bprm_mm_init(bprm);
+ if (err)
+ goto err;
+
+ return 0;
+
+err:
+ if (mm) {
+ bprm->mm = NULL;
+ mmdrop(mm);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(bprm_mm_init);
+
/*
* count() counts the number of strings in array ARGV.
*/
@@ -203,15 +389,16 @@ static int count(char __user * __user *
}
/*
- * 'copy_strings()' copies argument/environment strings from user
- * memory to free pages in kernel mem. These are in a format ready
- * to be put directly into the top of new user memory.
+ * 'copy_strings()' copies argument/environment strings from the old
+ * processes's memory to the new process's stack. The call to get_user_pages()
+ * ensures the destination page is created and not swapped out.
*/
static int copy_strings(int argc, char __user * __user * argv,
struct linux_binprm *bprm)
{
struct page *kmapped_page = NULL;
char *kaddr = NULL;
+ unsigned long kpos = 0;
int ret;
while (argc-- > 0) {
@@ -220,69 +407,69 @@ static int copy_strings(int argc, char _
unsigned long pos;
if (get_user(str, argv+argc) ||
- !(len = strnlen_user(str, bprm->p))) {
+ !(len = strnlen_user(str, MAX_ARG_STRLEN))) {
ret = -EFAULT;
goto out;
}
- if (bprm->p < len) {
+ if (!valid_arg_len(bprm, len)) {
ret = -E2BIG;
goto out;
}
- bprm->p -= len;
- /* XXX: add architecture specific overflow check here. */
+ /* We're going to work our way backwords. */
pos = bprm->p;
+ str += len;
+ bprm->p -= len;
while (len > 0) {
- int i, new, err;
int offset, bytes_to_copy;
- struct page *page;
offset = pos % PAGE_SIZE;
- i = pos/PAGE_SIZE;
- page = bprm->page[i];
- new = 0;
- if (!page) {
- page = alloc_page(GFP_HIGHUSER);
- bprm->page[i] = page;
+ if (offset == 0)
+ offset = PAGE_SIZE;
+
+ bytes_to_copy = offset;
+ if (bytes_to_copy > len)
+ bytes_to_copy = len;
+
+ offset -= bytes_to_copy;
+ pos -= bytes_to_copy;
+ str -= bytes_to_copy;
+ len -= bytes_to_copy;
+
+ if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
+ struct page *page;
+
+ page = get_arg_page(bprm, pos, 1);
if (!page) {
- ret = -ENOMEM;
+ ret = -E2BIG;
goto out;
}
- new = 1;
- }
- if (page != kmapped_page) {
- if (kmapped_page)
+ if (kmapped_page) {
+ flush_kernel_dcache_page(kmapped_page);
kunmap(kmapped_page);
+ put_arg_page(kmapped_page);
+ }
kmapped_page = page;
kaddr = kmap(kmapped_page);
+ kpos = pos & PAGE_MASK;
+ flush_arg_page(bprm, kpos, kmapped_page);
}
- if (new && offset)
- memset(kaddr, 0, offset);
- bytes_to_copy = PAGE_SIZE - offset;
- if (bytes_to_copy > len) {
- bytes_to_copy = len;
- if (new)
- memset(kaddr+offset+len, 0,
- PAGE_SIZE-offset-len);
- }
- err = copy_from_user(kaddr+offset, str, bytes_to_copy);
- if (err) {
+ if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
ret = -EFAULT;
goto out;
}
-
- pos += bytes_to_copy;
- str += bytes_to_copy;
- len -= bytes_to_copy;
}
}
ret = 0;
out:
- if (kmapped_page)
+ if (kmapped_page) {
+ flush_kernel_dcache_page(kmapped_page);
kunmap(kmapped_page);
+ put_arg_page(kmapped_page);
+ }
return ret;
}
@@ -298,181 +485,172 @@ int copy_strings_kernel(int argc,char **
set_fs(oldfs);
return r;
}
-
EXPORT_SYMBOL(copy_strings_kernel);
#ifdef CONFIG_MMU
+
/*
- * This routine is used to map in a page into an address space: needed by
- * execve() for the initial stack and environment pages.
+ * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
+ * the binfmt code determines where the new stack should reside, we shift it to
+ * its final location. The process proceeds as follows:
*
- * vma->vm_mm->mmap_sem is held for writing.
+ * 1) Use shift to calculate the new vma endpoints.
+ * 2) Extend vma to cover both the old and new ranges. This ensures the
+ * arguments passed to subsequent functions are consistent.
+ * 3) Move vma's page tables to the new range.
+ * 4) Free up any cleared pgd range.
+ * 5) Shrink the vma to cover only the new range.
*/
-void install_arg_page(struct vm_area_struct *vma,
- struct page *page, unsigned long address)
+static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
{
struct mm_struct *mm = vma->vm_mm;
- pte_t * pte;
- spinlock_t *ptl;
+ unsigned long old_start = vma->vm_start;
+ unsigned long old_end = vma->vm_end;
+ unsigned long length = old_end - old_start;
+ unsigned long new_start = old_start - shift;
+ unsigned long new_end = old_end - shift;
+ struct mmu_gather *tlb;
- if (unlikely(anon_vma_prepare(vma)))
- goto out;
+ BUG_ON(new_start > new_end);
- flush_dcache_page(page);
- pte = get_locked_pte(mm, address, &ptl);
- if (!pte)
- goto out;
- if (!pte_none(*pte)) {
- pte_unmap_unlock(pte, ptl);
- goto out;
+ /*
+ * ensure there are no vmas between where we want to go
+ * and where we are
+ */
+ if (vma != find_vma(mm, new_start))
+ return -EFAULT;
+
+ /*
+ * cover the whole range: [new_start, old_end)
+ */
+ vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL);
+
+ /*
+ * move the page tables downwards, on failure we rely on
+ * process cleanup to remove whatever mess we made.
+ */
+ if (length != move_page_tables(vma, old_start,
+ vma, new_start, length))
+ return -ENOMEM;
+
+ lru_add_drain();
+ tlb = tlb_gather_mmu(mm, 0);
+ if (new_end > old_start) {
+ /*
+ * when the old and new regions overlap clear from new_end.
+ */
+ free_pgd_range(&tlb, new_end, old_end, new_end,
+ vma->vm_next ? vma->vm_next->vm_start : 0);
+ } else {
+ /*
+ * otherwise, clean from old_start; this is done to not touch
+ * the address space in [new_end, old_start) some architectures
+ * have constraints on va-space that make this illegal (IA64) -
+ * for the others its just a little faster.
+ */
+ free_pgd_range(&tlb, old_start, old_end, new_end,
+ vma->vm_next ? vma->vm_next->vm_start : 0);
}
- inc_mm_counter(mm, anon_rss);
- lru_cache_add_active(page);
- set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
- page, vma->vm_page_prot))));
- page_add_new_anon_rmap(page, vma, address);
- pte_unmap_unlock(pte, ptl);
+ tlb_finish_mmu(tlb, new_end, old_end);
- /* no need for flush_tlb */
- return;
-out:
- __free_page(page);
- force_sig(SIGKILL, current);
+ /*
+ * shrink the vma to just the new range.
+ */
+ vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
+
+ return 0;
}
#define EXTRA_STACK_VM_PAGES 20 /* random */
+/*
+ * Finalizes the stack vm_area_struct. The flags and permissions are updated,
+ * the stack is optionally relocated, and some extra space is added.
+ */
int setup_arg_pages(struct linux_binprm *bprm,
unsigned long stack_top,
int executable_stack)
{
- unsigned long stack_base;
- struct vm_area_struct *mpnt;
+ unsigned long ret;
+ unsigned long stack_shift;
struct mm_struct *mm = current->mm;
- int i, ret;
- long arg_size;
+ struct vm_area_struct *vma = bprm->vma;
+ struct vm_area_struct *prev = NULL;
+ unsigned long vm_flags;
+ unsigned long stack_base;
#ifdef CONFIG_STACK_GROWSUP
- /* Move the argument and environment strings to the bottom of the
- * stack space.
- */
- int offset, j;
- char *to, *from;
-
- /* Start by shifting all the pages down */
- i = 0;
- for (j = 0; j < MAX_ARG_PAGES; j++) {
- struct page *page = bprm->page[j];
- if (!page)
- continue;
- bprm->page[i++] = page;
- }
-
- /* Now move them within their pages */
- offset = bprm->p % PAGE_SIZE;
- to = kmap(bprm->page[0]);
- for (j = 1; j < i; j++) {
- memmove(to, to + offset, PAGE_SIZE - offset);
- from = kmap(bprm->page[j]);
- memcpy(to + PAGE_SIZE - offset, from, offset);
- kunmap(bprm->page[j - 1]);
- to = from;
- }
- memmove(to, to + offset, PAGE_SIZE - offset);
- kunmap(bprm->page[j - 1]);
-
/* Limit stack size to 1GB */
stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
if (stack_base > (1 << 30))
stack_base = 1 << 30;
- stack_base = PAGE_ALIGN(stack_top - stack_base);
- /* Adjust bprm->p to point to the end of the strings. */
- bprm->p = stack_base + PAGE_SIZE * i - offset;
+ /* Make sure we didn't let the argument array grow too large. */
+ if (vma->vm_end - vma->vm_start > stack_base)
+ return -ENOMEM;
- mm->arg_start = stack_base;
- arg_size = i << PAGE_SHIFT;
+ stack_base = PAGE_ALIGN(stack_top - stack_base);
- /* zero pages that were copied above */
- while (i < MAX_ARG_PAGES)
- bprm->page[i++] = NULL;
+ stack_shift = vma->vm_start - stack_base;
+ mm->arg_start = bprm->p - stack_shift;
+ bprm->p = vma->vm_end - stack_shift;
#else
- stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
- stack_base = PAGE_ALIGN(stack_base);
- bprm->p += stack_base;
+ stack_top = arch_align_stack(stack_top);
+ stack_top = PAGE_ALIGN(stack_top);
+ stack_shift = vma->vm_end - stack_top;
+
+ bprm->p -= stack_shift;
mm->arg_start = bprm->p;
- arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
#endif
- arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
-
if (bprm->loader)
- bprm->loader += stack_base;
- bprm->exec += stack_base;
-
- mpnt = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
- if (!mpnt)
- return -ENOMEM;
+ bprm->loader -= stack_shift;
+ bprm->exec -= stack_shift;
down_write(&mm->mmap_sem);
- {
- mpnt->vm_mm = mm;
-#ifdef CONFIG_STACK_GROWSUP
- mpnt->vm_start = stack_base;
- mpnt->vm_end = stack_base + arg_size;
-#else
- mpnt->vm_end = stack_top;
- mpnt->vm_start = mpnt->vm_end - arg_size;
-#endif
- /* Adjust stack execute permissions; explicitly enable
- * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
- * and leave alone (arch default) otherwise. */
- if (unlikely(executable_stack == EXSTACK_ENABLE_X))
- mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
- else if (executable_stack == EXSTACK_DISABLE_X)
- mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
- else
- mpnt->vm_flags = VM_STACK_FLAGS;
- mpnt->vm_flags |= mm->def_flags;
- mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
- if ((ret = insert_vm_struct(mm, mpnt))) {
+ vm_flags = vma->vm_flags;
+
+ /*
+ * Adjust stack execute permissions; explicitly enable for
+ * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
+ * (arch default) otherwise.
+ */
+ if (unlikely(executable_stack == EXSTACK_ENABLE_X))
+ vm_flags |= VM_EXEC;
+ else if (executable_stack == EXSTACK_DISABLE_X)
+ vm_flags &= ~VM_EXEC;
+ vm_flags |= mm->def_flags;
+
+ ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
+ vm_flags);
+ if (ret)
+ goto out_unlock;
+ BUG_ON(prev != vma);
+
+ /* Move stack pages down in memory. */
+ if (stack_shift) {
+ ret = shift_arg_pages(vma, stack_shift);
+ if (ret) {
up_write(&mm->mmap_sem);
- kmem_cache_free(vm_area_cachep, mpnt);
return ret;
}
- mm->stack_vm = mm->total_vm = vma_pages(mpnt);
}
- for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
- struct page *page = bprm->page[i];
- if (page) {
- bprm->page[i] = NULL;
- install_arg_page(mpnt, page, stack_base);
- }
- stack_base += PAGE_SIZE;
- }
+#ifdef CONFIG_STACK_GROWSUP
+ stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+#else
+ stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+#endif
+ ret = expand_stack(vma, stack_base);
+ if (ret)
+ ret = -EFAULT;
+
+out_unlock:
up_write(&mm->mmap_sem);
-
return 0;
}
-
EXPORT_SYMBOL(setup_arg_pages);
-#define free_arg_pages(bprm) do { } while (0)
-
-#else
-
-static inline void free_arg_pages(struct linux_binprm *bprm)
-{
- int i;
-
- for (i = 0; i < MAX_ARG_PAGES; i++) {
- if (bprm->page[i])
- __free_page(bprm->page[i]);
- bprm->page[i] = NULL;
- }
-}
-
#endif /* CONFIG_MMU */
struct file *open_exec(const char *name)
@@ -1000,43 +1178,42 @@ EXPORT_SYMBOL(compute_creds);
* points to; chop off the first by relocating brpm->p to right after
* the first '\0' encountered.
*/
-void remove_arg_zero(struct linux_binprm *bprm)
+int remove_arg_zero(struct linux_binprm *bprm)
{
- if (bprm->argc) {
- char ch;
+ int ret = 0;
+ unsigned long offset;
+ char *kaddr;
+ struct page *page;
- do {
- unsigned long offset;
- unsigned long index;
- char *kaddr;
- struct page *page;
-
- offset = bprm->p & ~PAGE_MASK;
- index = bprm->p >> PAGE_SHIFT;
-
- page = bprm->page[index];
- kaddr = kmap_atomic(page, KM_USER0);
-
- /* run through page until we reach end or find NUL */
- do {
- ch = *(kaddr + offset);
-
- /* discard that character... */
- bprm->p++;
- offset++;
- } while (offset < PAGE_SIZE && ch != '\0');
-
- kunmap_atomic(kaddr, KM_USER0);
-
- /* free the old page */
- if (offset == PAGE_SIZE) {
- __free_page(page);
- bprm->page[index] = NULL;
- }
- } while (ch != '\0');
+ if (!bprm->argc)
+ return 0;
- bprm->argc--;
- }
+ do {
+ offset = bprm->p & ~PAGE_MASK;
+ page = get_arg_page(bprm, bprm->p, 0);
+ if (!page) {
+ ret = -EFAULT;
+ goto out;
+ }
+ kaddr = kmap_atomic(page, KM_USER0);
+
+ for (; offset < PAGE_SIZE && kaddr[offset];
+ offset++, bprm->p++)
+ ;
+
+ kunmap_atomic(kaddr, KM_USER0);
+ put_arg_page(page);
+
+ if (offset == PAGE_SIZE)
+ free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
+ } while (offset == PAGE_SIZE);
+
+ bprm->p++;
+ bprm->argc--;
+ ret = 0;
+
+out:
+ return ret;
}
EXPORT_SYMBOL(remove_arg_zero);
@@ -1062,7 +1239,7 @@ int search_binary_handler(struct linux_b
fput(bprm->file);
bprm->file = NULL;
- loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
+ loader = bprm->vma->vm_end - sizeof(void *);
file = open_exec("/sbin/loader");
retval = PTR_ERR(file);
@@ -1156,7 +1333,6 @@ int do_execve(char * filename,
struct file *file;
unsigned long env_p;
int retval;
- int i;
retval = -ENOMEM;
bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
@@ -1170,25 +1346,19 @@ int do_execve(char * filename,
sched_exec();
- bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
-
bprm->file = file;
bprm->filename = filename;
bprm->interp = filename;
- bprm->mm = mm_alloc();
- retval = -ENOMEM;
- if (!bprm->mm)
- goto out_file;
- retval = init_new_context(current, bprm->mm);
- if (retval < 0)
- goto out_mm;
+ retval = bprm_mm_init(bprm);
+ if (retval)
+ goto out_file;
- bprm->argc = count(argv, bprm->p / sizeof(void *));
+ bprm->argc = count(argv, MAX_ARG_STRINGS);
if ((retval = bprm->argc) < 0)
goto out_mm;
- bprm->envc = count(envp, bprm->p / sizeof(void *));
+ bprm->envc = count(envp, MAX_ARG_STRINGS);
if ((retval = bprm->envc) < 0)
goto out_mm;
@@ -1217,9 +1387,8 @@ int do_execve(char * filename,
retval = search_binary_handler(bprm,regs);
if (retval >= 0) {
- free_arg_pages(bprm);
-
/* execve success */
+ free_arg_pages(bprm);
security_bprm_free(bprm);
acct_update_integrals(current);
kfree(bprm);
@@ -1227,26 +1396,19 @@ int do_execve(char * filename,
}
out:
- /* Something went wrong, return the inode and free the argument pages*/
- for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
- struct page * page = bprm->page[i];
- if (page)
- __free_page(page);
- }
-
+ free_arg_pages(bprm);
if (bprm->security)
security_bprm_free(bprm);
out_mm:
if (bprm->mm)
- mmdrop(bprm->mm);
+ mmput (bprm->mm);
out_file:
if (bprm->file) {
allow_write_access(bprm->file);
fput(bprm->file);
}
-
out_kfree:
kfree(bprm);
Index: linux-2.6-2/include/linux/binfmts.h
===================================================================
--- linux-2.6-2.orig/include/linux/binfmts.h 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/include/linux/binfmts.h 2007-06-13 11:52:46.000000000 +0200
@@ -6,11 +6,13 @@
struct pt_regs;
/*
- * MAX_ARG_PAGES defines the number of pages allocated for arguments
- * and envelope for the new program. 32 should suffice, this gives
- * a maximum env+arg of 128kB w/4KB pages!
+ * These are the maximum length and maximum number of strings passed to the
+ * execve() system call. MAX_ARG_STRLEN is essentially random but serves to
+ * prevent the kernel from being unduly impacted by misaddressed pointers.
+ * MAX_ARG_STRINGS is chosen to fit in a signed 32-bit integer.
*/
-#define MAX_ARG_PAGES 32
+#define MAX_ARG_STRLEN (PAGE_SIZE * 32)
+#define MAX_ARG_STRINGS 0x7FFFFFFF
/* sizeof(linux_binprm->buf) */
#define BINPRM_BUF_SIZE 128
@@ -24,7 +26,12 @@ struct pt_regs;
*/
struct linux_binprm{
char buf[BINPRM_BUF_SIZE];
+#ifdef CONFIG_MMU
+ struct vm_area_struct *vma;
+#else
+# define MAX_ARG_PAGES 32
struct page *page[MAX_ARG_PAGES];
+#endif
struct mm_struct *mm;
unsigned long p; /* current top of mem */
int sh_bang;
@@ -69,7 +76,7 @@ extern int register_binfmt(struct linux_
extern int unregister_binfmt(struct linux_binfmt *);
extern int prepare_binprm(struct linux_binprm *);
-extern void remove_arg_zero(struct linux_binprm *);
+extern int __must_check remove_arg_zero(struct linux_binprm *);
extern int search_binary_handler(struct linux_binprm *,struct pt_regs *);
extern int flush_old_exec(struct linux_binprm * bprm);
@@ -86,6 +93,7 @@ extern int suid_dumpable;
extern int setup_arg_pages(struct linux_binprm * bprm,
unsigned long stack_top,
int executable_stack);
+extern int bprm_mm_init(struct linux_binprm *bprm);
extern int copy_strings_kernel(int argc,char ** argv,struct linux_binprm *bprm);
extern void compute_creds(struct linux_binprm *binprm);
extern int do_coredump(long signr, int exit_code, struct pt_regs * regs);
Index: linux-2.6-2/include/linux/mm.h
===================================================================
--- linux-2.6-2.orig/include/linux/mm.h 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/include/linux/mm.h 2007-06-13 11:52:46.000000000 +0200
@@ -815,7 +815,6 @@ static inline int handle_mm_fault(struct
extern int make_pages_present(unsigned long addr, unsigned long end);
extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
-void install_arg_page(struct vm_area_struct *, struct page *, unsigned long);
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);
@@ -832,9 +831,15 @@ int FASTCALL(set_page_dirty(struct page
int set_page_dirty_lock(struct page *page);
int clear_page_dirty_for_io(struct page *page);
+extern unsigned long move_page_tables(struct vm_area_struct *vma,
+ unsigned long old_addr, struct vm_area_struct *new_vma,
+ unsigned long new_addr, unsigned long len);
extern unsigned long do_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr);
+extern int mprotect_fixup(struct vm_area_struct *vma,
+ struct vm_area_struct **pprev, unsigned long start,
+ unsigned long end, unsigned long newflags);
/*
* A callback you can register to apply pressure to ageable caches.
@@ -1159,6 +1164,8 @@ extern int expand_stack(struct vm_area_s
#ifdef CONFIG_IA64
extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
#endif
+extern int expand_stack_downwards(struct vm_area_struct *vma,
+ unsigned long address);
/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
Index: linux-2.6-2/mm/mmap.c
===================================================================
--- linux-2.6-2.orig/mm/mmap.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/mm/mmap.c 2007-06-13 11:52:46.000000000 +0200
@@ -1581,33 +1581,11 @@ int expand_upwards(struct vm_area_struct
}
#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
-#ifdef CONFIG_STACK_GROWSUP
-int expand_stack(struct vm_area_struct *vma, unsigned long address)
-{
- return expand_upwards(vma, address);
-}
-
-struct vm_area_struct *
-find_extend_vma(struct mm_struct *mm, unsigned long addr)
-{
- struct vm_area_struct *vma, *prev;
-
- addr &= PAGE_MASK;
- vma = find_vma_prev(mm, addr, &prev);
- if (vma && (vma->vm_start <= addr))
- return vma;
- if (!prev || expand_stack(prev, addr))
- return NULL;
- if (prev->vm_flags & VM_LOCKED) {
- make_pages_present(addr, prev->vm_end);
- }
- return prev;
-}
-#else
/*
* vma is the first one with address < vma->vm_start. Have to extend vma.
*/
-int expand_stack(struct vm_area_struct *vma, unsigned long address)
+static inline int expand_downwards(struct vm_area_struct *vma,
+ unsigned long address)
{
int error;
@@ -1644,6 +1622,38 @@ int expand_stack(struct vm_area_struct *
return error;
}
+int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
+{
+ return expand_downwards(vma, address);
+}
+
+#ifdef CONFIG_STACK_GROWSUP
+int expand_stack(struct vm_area_struct *vma, unsigned long address)
+{
+ return expand_upwards(vma, address);
+}
+
+struct vm_area_struct *
+find_extend_vma(struct mm_struct *mm, unsigned long addr)
+{
+ struct vm_area_struct *vma, *prev;
+
+ addr &= PAGE_MASK;
+ vma = find_vma_prev(mm, addr, &prev);
+ if (vma && (vma->vm_start <= addr))
+ return vma;
+ if (!prev || expand_stack(prev, addr))
+ return NULL;
+ if (prev->vm_flags & VM_LOCKED)
+ make_pages_present(addr, prev->vm_end);
+ return prev;
+}
+#else
+int expand_stack(struct vm_area_struct *vma, unsigned long address)
+{
+ return expand_downwards(vma, address);
+}
+
struct vm_area_struct *
find_extend_vma(struct mm_struct * mm, unsigned long addr)
{
@@ -1661,9 +1671,8 @@ find_extend_vma(struct mm_struct * mm, u
start = vma->vm_start;
if (expand_stack(vma, addr))
return NULL;
- if (vma->vm_flags & VM_LOCKED) {
+ if (vma->vm_flags & VM_LOCKED)
make_pages_present(addr, start);
- }
return vma;
}
#endif
Index: linux-2.6-2/mm/mprotect.c
===================================================================
--- linux-2.6-2.orig/mm/mprotect.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/mm/mprotect.c 2007-06-13 11:52:46.000000000 +0200
@@ -128,7 +128,7 @@ static void change_protection(struct vm_
flush_tlb_range(vma, start, end);
}
-static int
+int
mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
unsigned long start, unsigned long end, unsigned long newflags)
{
Index: linux-2.6-2/arch/ia64/ia32/binfmt_elf32.c
===================================================================
--- linux-2.6-2.orig/arch/ia64/ia32/binfmt_elf32.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/arch/ia64/ia32/binfmt_elf32.c 2007-06-13 11:52:46.000000000 +0200
@@ -195,62 +195,27 @@ ia64_elf32_init (struct pt_regs *regs)
ia32_load_state(current);
}
+/*
+ * Undo the override of setup_arg_pages() without this ia32_setup_arg_pages()
+ * will suffer infinite self recursion.
+ */
+#undef setup_arg_pages
+
int
ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
{
- unsigned long stack_base;
- struct vm_area_struct *mpnt;
- struct mm_struct *mm = current->mm;
- int i, ret;
-
- stack_base = IA32_STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE;
- mm->arg_start = bprm->p + stack_base;
-
- bprm->p += stack_base;
- if (bprm->loader)
- bprm->loader += stack_base;
- bprm->exec += stack_base;
-
- mpnt = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
- if (!mpnt)
- return -ENOMEM;
-
- down_write(¤t->mm->mmap_sem);
- {
- mpnt->vm_mm = current->mm;
- mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
- mpnt->vm_end = IA32_STACK_TOP;
- if (executable_stack == EXSTACK_ENABLE_X)
- mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
- else if (executable_stack == EXSTACK_DISABLE_X)
- mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
- else
- mpnt->vm_flags = VM_STACK_FLAGS;
- mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC)?
- PAGE_COPY_EXEC: PAGE_COPY;
- if ((ret = insert_vm_struct(current->mm, mpnt))) {
- up_write(¤t->mm->mmap_sem);
- kmem_cache_free(vm_area_cachep, mpnt);
- return ret;
- }
- current->mm->stack_vm = current->mm->total_vm = vma_pages(mpnt);
- }
+ int ret;
- for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
- struct page *page = bprm->page[i];
- if (page) {
- bprm->page[i] = NULL;
- install_arg_page(mpnt, page, stack_base);
- }
- stack_base += PAGE_SIZE;
+ ret = setup_arg_pages(bprm, IA32_STACK_TOP, executable_stack);
+ if (!ret) {
+ /*
+ * Can't do it in ia64_elf32_init(). Needs to be done before
+ * calls to elf32_map()
+ */
+ current->thread.ppl = ia32_init_pp_list();
}
- up_write(¤t->mm->mmap_sem);
- /* Can't do it in ia64_elf32_init(). Needs to be done before calls to
- elf32_map() */
- current->thread.ppl = ia32_init_pp_list();
-
- return 0;
+ return ret;
}
static void
Index: linux-2.6-2/arch/x86_64/ia32/ia32_aout.c
===================================================================
--- linux-2.6-2.orig/arch/x86_64/ia32/ia32_aout.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/arch/x86_64/ia32/ia32_aout.c 2007-06-13 11:52:46.000000000 +0200
@@ -404,7 +404,7 @@ beyond_if:
set_brk(current->mm->start_brk, current->mm->brk);
- retval = ia32_setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
+ retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
if (retval < 0) {
/* Someone check-me: is this error path enough? */
send_sig(SIGKILL, current, 0);
Index: linux-2.6-2/kernel/auditsc.c
===================================================================
--- linux-2.6-2.orig/kernel/auditsc.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/kernel/auditsc.c 2007-06-13 11:52:46.000000000 +0200
@@ -846,7 +846,7 @@ static void audit_log_execve_info(struct
return; /* execve failed, no additional info */
for (i = 0; i < axi->argc; i++, p += len) {
- len = strnlen_user(p, MAX_ARG_PAGES*PAGE_SIZE);
+ len = strnlen_user(p, MAX_ARG_STRLEN);
/*
* We just created this mm, if we can't find the strings
* we just copied into it something is _very_ wrong. Similar
Index: linux-2.6-2/mm/mremap.c
===================================================================
--- linux-2.6-2.orig/mm/mremap.c 2007-06-13 11:52:44.000000000 +0200
+++ linux-2.6-2/mm/mremap.c 2007-06-13 11:52:46.000000000 +0200
@@ -120,7 +120,7 @@ static void move_ptes(struct vm_area_str
#define LATENCY_LIMIT (64 * PAGE_SIZE)
-static unsigned long move_page_tables(struct vm_area_struct *vma,
+unsigned long move_page_tables(struct vm_area_struct *vma,
unsigned long old_addr, struct vm_area_struct *new_vma,
unsigned long new_addr, unsigned long len)
{
--
On Wed, Jun 13, Peter Zijlstra wrote:
> From: Ollie Wild <[email protected]>
>
> Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly
> from the old mm into the new mm.
> +++ linux-2.6-2/include/linux/binfmts.h 2007-06-13 11:52:46.000000000 +0200
> @@ -6,11 +6,13 @@
> struct pt_regs;
>
> /*
> - * MAX_ARG_PAGES defines the number of pages allocated for arguments
> - * and envelope for the new program. 32 should suffice, this gives
> - * a maximum env+arg of 128kB w/4KB pages!
> + * These are the maximum length and maximum number of strings passed to the
> + * execve() system call. MAX_ARG_STRLEN is essentially random but serves to
> + * prevent the kernel from being unduly impacted by misaddressed pointers.
> + * MAX_ARG_STRINGS is chosen to fit in a signed 32-bit integer.
> */
> -#define MAX_ARG_PAGES 32
> +#define MAX_ARG_STRLEN (PAGE_SIZE * 32)
> +#define MAX_ARG_STRINGS 0x7FFFFFFF
This adds a new usage of PAGE_SIZE to an exported header.
How can this be fixed for 2.6.23?
On Tue, 7 Aug 2007 21:03:57 +0200
Olaf Hering <[email protected]> wrote:
> On Wed, Jun 13, Peter Zijlstra wrote:
>
> > From: Ollie Wild <[email protected]>
> >
> > Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly
> > from the old mm into the new mm.
>
> > +++ linux-2.6-2/include/linux/binfmts.h 2007-06-13 11:52:46.000000000 +0200
> > @@ -6,11 +6,13 @@
> > struct pt_regs;
> >
> > /*
> > - * MAX_ARG_PAGES defines the number of pages allocated for arguments
> > - * and envelope for the new program. 32 should suffice, this gives
> > - * a maximum env+arg of 128kB w/4KB pages!
> > + * These are the maximum length and maximum number of strings passed to the
> > + * execve() system call. MAX_ARG_STRLEN is essentially random but serves to
> > + * prevent the kernel from being unduly impacted by misaddressed pointers.
> > + * MAX_ARG_STRINGS is chosen to fit in a signed 32-bit integer.
> > */
> > -#define MAX_ARG_PAGES 32
> > +#define MAX_ARG_STRLEN (PAGE_SIZE * 32)
> > +#define MAX_ARG_STRINGS 0x7FFFFFFF
>
> This adds a new usage of PAGE_SIZE to an exported header.
> How can this be fixed for 2.6.23?
Put #ifdef __KERNEL__ around it?
On Tue, 2007-08-07 at 12:20 -0700, Andrew Morton wrote:
> On Tue, 7 Aug 2007 21:03:57 +0200
> Olaf Hering <[email protected]> wrote:
>
> > On Wed, Jun 13, Peter Zijlstra wrote:
> >
> > > From: Ollie Wild <[email protected]>
> > >
> > > Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly
> > > from the old mm into the new mm.
> >
> > > +++ linux-2.6-2/include/linux/binfmts.h 2007-06-13 11:52:46.000000000 +0200
> > > @@ -6,11 +6,13 @@
> > > struct pt_regs;
> > >
> > > /*
> > > - * MAX_ARG_PAGES defines the number of pages allocated for arguments
> > > - * and envelope for the new program. 32 should suffice, this gives
> > > - * a maximum env+arg of 128kB w/4KB pages!
> > > + * These are the maximum length and maximum number of strings passed to the
> > > + * execve() system call. MAX_ARG_STRLEN is essentially random but serves to
> > > + * prevent the kernel from being unduly impacted by misaddressed pointers.
> > > + * MAX_ARG_STRINGS is chosen to fit in a signed 32-bit integer.
> > > */
> > > -#define MAX_ARG_PAGES 32
> > > +#define MAX_ARG_STRLEN (PAGE_SIZE * 32)
> > > +#define MAX_ARG_STRINGS 0x7FFFFFFF
> >
> > This adds a new usage of PAGE_SIZE to an exported header.
> > How can this be fixed for 2.6.23?
>
> Put #ifdef __KERNEL__ around it?
Sounds like a good idea, since its new there should not yet be anybody
using it.
If anything, someone used to use MAX_ARG_PAGES in userspace, which we
just now broke. Olaf said he'd grep a distro source base to find out :-)
On Tue, Aug 07, Andrew Morton wrote:
> > > +++ linux-2.6-2/include/linux/binfmts.h 2007-06-13 11:52:46.000000000 +0200
> > > -#define MAX_ARG_PAGES 32
> > > +#define MAX_ARG_STRLEN (PAGE_SIZE * 32)
> > > +#define MAX_ARG_STRINGS 0x7FFFFFFF
> >
> > This adds a new usage of PAGE_SIZE to an exported header.
> > How can this be fixed for 2.6.23?
>
> Put #ifdef __KERNEL__ around it?
No package uses linux/binfmts.h, will send a Kbuild patch to unexport
it.
On Wed, Jun 13, 2007 at 12:03:37PM +0200, Peter Zijlstra wrote:
> From: Ollie Wild <[email protected]>
>
> Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly
> from the old mm into the new mm.
>
[...]
> +static int __bprm_mm_init(struct linux_binprm *bprm)
> +{
[...]
> + vma->vm_flags = VM_STACK_FLAGS;
> + vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
> + err = insert_vm_struct(mm, vma);
> + if (err) {
> + up_write(&mm->mmap_sem);
> + goto err;
> + }
> +
That change causes a crash in khelper when overcommit_memory = 2
under 2.6.23-rc3.
When a khelper execs, at __bprm_mm_init() current->mm is still NULL.
insert_vm_struct() calls security_vm_enough_memory(), which calls
__vm_enough_memory(), and that's where current->mm->total_vm gets
dereferenced.
Signed-off-by: Dan Aloni <[email protected]>
diff --git a/mm/mmap.c b/mm/mmap.c
index 906ed40..6e021df 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -163,10 +163,12 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
if (!cap_sys_admin)
allowed -= allowed / 32;
allowed += total_swap_pages;
-
- /* Don't let a single process grow too big:
- leave 3% of the size of this process for other processes */
- allowed -= current->mm->total_vm / 32;
+
+ if (current->mm) {
+ /* Don't let a single process grow too big:
+ leave 3% of the size of this process for other processes */
+ allowed -= current->mm->total_vm / 32;
+ }
/*
* cast `allowed' as a signed long because vm_committed_space
--
Dan Aloni
XIV LTD, http://www.xivstorage.com
da-x (at) monatomic.org, dan (at) xiv.co.il
On Wed, 2007-08-22 at 11:48 +0300, Dan Aloni wrote:
> On Wed, Jun 13, 2007 at 12:03:37PM +0200, Peter Zijlstra wrote:
> > From: Ollie Wild <[email protected]>
> >
> > Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly
> > from the old mm into the new mm.
> >
> [...]
> > +static int __bprm_mm_init(struct linux_binprm *bprm)
> > +{
> [...]
> > + vma->vm_flags = VM_STACK_FLAGS;
> > + vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
> > + err = insert_vm_struct(mm, vma);
> > + if (err) {
> > + up_write(&mm->mmap_sem);
> > + goto err;
> > + }
> > +
>
> That change causes a crash in khelper when overcommit_memory = 2
> under 2.6.23-rc3.
>
> When a khelper execs, at __bprm_mm_init() current->mm is still NULL.
> insert_vm_struct() calls security_vm_enough_memory(), which calls
> __vm_enough_memory(), and that's where current->mm->total_vm gets
> dereferenced.
Alan proposed this patch:
http://lkml.org/lkml/2007/8/13/782
On Wed, Aug 22, 2007 at 11:48:52AM +0300, Dan Aloni wrote:
> On Wed, Jun 13, 2007 at 12:03:37PM +0200, Peter Zijlstra wrote:
> > From: Ollie Wild <[email protected]>
> >
> > Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly
> > from the old mm into the new mm.
> >
> [...]
> > +static int __bprm_mm_init(struct linux_binprm *bprm)
> > +{
> [...]
> > + vma->vm_flags = VM_STACK_FLAGS;
> > + vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
> > + err = insert_vm_struct(mm, vma);
> > + if (err) {
> > + up_write(&mm->mmap_sem);
> > + goto err;
> > + }
> > +
>
> That change causes a crash in khelper when overcommit_memory = 2
> under 2.6.23-rc3.
>
> When a khelper execs, at __bprm_mm_init() current->mm is still NULL.
> insert_vm_struct() calls security_vm_enough_memory(), which calls
> __vm_enough_memory(), and that's where current->mm->total_vm gets
> dereferenced.
>
>
> Signed-off-by: Dan Aloni <[email protected]>
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 906ed40..6e021df 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -163,10 +163,12 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
> if (!cap_sys_admin)
> allowed -= allowed / 32;
> allowed += total_swap_pages;
> -
> - /* Don't let a single process grow too big:
> - leave 3% of the size of this process for other processes */
> - allowed -= current->mm->total_vm / 32;
> +
> + if (current->mm) {
> + /* Don't let a single process grow too big:
> + leave 3% of the size of this process for other processes */
> + allowed -= current->mm->total_vm / 32;
> + }
>
> /*
> * cast `allowed' as a signed long because vm_committed_space
>
FYI: This bug has been fixed by Alan Cox: http://lkml.org/lkml/2007/8/13/782.
But thanks anyway~
On Wed, 22 Aug 2007 10:54:02 +0200 Peter Zijlstra <[email protected]> wrote:
> Alan proposed this patch:
yeah, I have a great pile of stuff queued for Linus. I'm bad. Tomorrow.