| From 114279be2120a916e8a04feeb2ac976a10016f2f Mon Sep 17 00:00:00 2001 |
| From: Oleg Nesterov <oleg@redhat.com> |
| Date: Tue, 30 Nov 2010 20:56:02 +0100 |
| Subject: exec: copy-and-paste the fixes into compat_do_execve() paths |
| |
| From: Oleg Nesterov <oleg@redhat.com> |
| |
| commit 114279be2120a916e8a04feeb2ac976a10016f2f upstream. |
| |
| Note: this patch targets 2.6.37 and tries to be as simple as possible. |
| That is why it adds more copy-and-paste horror into fs/compat.c and |
| uglifies fs/exec.c, this will be cleanuped later. |
| |
| compat_copy_strings() plays with bprm->vma/mm directly and thus has |
| two problems: it lacks the RLIMIT_STACK check and argv/envp memory |
| is not visible to oom killer. |
| |
| Export acct_arg_size() and get_arg_page(), change compat_copy_strings() |
| to use get_arg_page(), change compat_do_execve() to do acct_arg_size(0) |
| as do_execve() does. |
| |
| Add the fatal_signal_pending/cond_resched checks into compat_count() and |
| compat_copy_strings(), this matches the code in fs/exec.c and certainly |
| makes sense. |
| |
| Signed-off-by: Oleg Nesterov <oleg@redhat.com> |
| Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Andi Kleen <ak@linux.intel.com> |
| Cc: Moritz Muehlenhoff <jmm@debian.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| fs/compat.c | 28 +++++++++++++++------------- |
| fs/exec.c | 8 ++++---- |
| include/linux/binfmts.h | 4 ++++ |
| 3 files changed, 23 insertions(+), 17 deletions(-) |
| |
| --- a/fs/compat.c |
| +++ b/fs/compat.c |
| @@ -1351,6 +1351,10 @@ static int compat_count(compat_uptr_t __ |
| argv++; |
| if (i++ >= max) |
| return -E2BIG; |
| + |
| + if (fatal_signal_pending(current)) |
| + return -ERESTARTNOHAND; |
| + cond_resched(); |
| } |
| } |
| return i; |
| @@ -1392,6 +1396,12 @@ static int compat_copy_strings(int argc, |
| while (len > 0) { |
| int offset, bytes_to_copy; |
| |
| + if (fatal_signal_pending(current)) { |
| + ret = -ERESTARTNOHAND; |
| + goto out; |
| + } |
| + cond_resched(); |
| + |
| offset = pos % PAGE_SIZE; |
| if (offset == 0) |
| offset = PAGE_SIZE; |
| @@ -1408,18 +1418,8 @@ static int compat_copy_strings(int argc, |
| 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. */ |
| + page = get_arg_page(bprm, pos, 1); |
| + if (!page) { |
| ret = -E2BIG; |
| goto out; |
| } |
| @@ -1540,8 +1540,10 @@ int compat_do_execve(char * filename, |
| return retval; |
| |
| out: |
| - if (bprm->mm) |
| + if (bprm->mm) { |
| + acct_arg_size(bprm, 0); |
| mmput(bprm->mm); |
| + } |
| |
| out_file: |
| if (bprm->file) { |
| --- a/fs/exec.c |
| +++ b/fs/exec.c |
| @@ -158,7 +158,7 @@ out: |
| |
| #ifdef CONFIG_MMU |
| |
| -static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
| +void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
| { |
| struct mm_struct *mm = current->mm; |
| long diff = (long)(pages - bprm->vma_pages); |
| @@ -173,7 +173,7 @@ static void acct_arg_size(struct linux_b |
| up_write(&mm->mmap_sem); |
| } |
| |
| -static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| +struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| int write) |
| { |
| struct page *page; |
| @@ -290,11 +290,11 @@ static bool valid_arg_len(struct linux_b |
| |
| #else |
| |
| -static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
| +void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
| { |
| } |
| |
| -static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| +struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| int write) |
| { |
| struct page *page; |
| --- a/include/linux/binfmts.h |
| +++ b/include/linux/binfmts.h |
| @@ -60,6 +60,10 @@ struct linux_binprm{ |
| unsigned long loader, exec; |
| }; |
| |
| +extern void acct_arg_size(struct linux_binprm *bprm, unsigned long pages); |
| +extern struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| + int write); |
| + |
| #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0 |
| #define BINPRM_FLAGS_ENFORCE_NONDUMP (1 << BINPRM_FLAGS_ENFORCE_NONDUMP_BIT) |
| |