diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2010-11-30 22:55:34 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-12-01 04:56:37 +0300 |
| commit | 3c77f845722158206a7209c45ccddc264d19319c (patch) | |
| tree | 9eace97a8b88eb68b7d5d3127041b14c202421ae /include | |
| parent | 37a09f07459753e7c98d4e21f1c61e8756923f81 (diff) | |
| download | linux-3c77f845722158206a7209c45ccddc264d19319c.tar.xz | |
exec: make argv/envp memory visible to oom-killer
Brad Spengler published a local memory-allocation DoS that
evades the OOM-killer (though not the virtual memory RLIMIT):
http://www.grsecurity.net/~spender/64bit_dos.c
execve()->copy_strings() can allocate a lot of memory, but
this is not visible to oom-killer, nobody can see the nascent
bprm->mm and take it into account.
With this patch get_arg_page() increments current's MM_ANONPAGES
counter every time we allocate the new page for argv/envp. When
do_execve() succeds or fails, we change this counter back.
Technically this is not 100% correct, we can't know if the new
page is swapped out and turn MM_ANONPAGES into MM_SWAPENTS, but
I don't think this really matters and everything becomes correct
once exec changes ->mm or fails.
Reported-by: Brad Spengler <spender@grsecurity.net>
Reviewed-and-discussed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/binfmts.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index a065612fc928..7c87796d20da 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -29,6 +29,7 @@ struct linux_binprm{ char buf[BINPRM_BUF_SIZE]; #ifdef CONFIG_MMU struct vm_area_struct *vma; + unsigned long vma_pages; #else # define MAX_ARG_PAGES 32 struct page *page[MAX_ARG_PAGES]; |