diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2011-04-14 20:19:36 +0200 |
|---|---|---|
| committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2011-04-17 16:16:01 -0400 |
| commit | 0130382485c1330f40a8f5090f1ea70c6baa20e6 (patch) | |
| tree | 26f3887fa00257a5dc31f3f0067c18b9c97aa63f /include | |
| parent | 9e7e10466fee07044f7357055eb203642647ec39 (diff) | |
exec: make argv/envp memory visible to oom-killer
commit 3c77f845722158206a7209c45ccddc264d19319c upstream.
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.
Compared to upstream:
before 2.6.36 kernel, oom-killer's badness() takes
mm->total_vm into account and nothing else. So
acct_arg_size() has to play with this counter too.
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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 c809e286d213..39798c65c238 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]; |