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authorOleg Nesterov <oleg@redhat.com>2010-11-30 20:55:34 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2010-11-30 17:56:37 -0800
commit3c77f845722158206a7209c45ccddc264d19319c (patch)
tree9eace97a8b88eb68b7d5d3127041b14c202421ae /include
parent37a09f07459753e7c98d4e21f1c61e8756923f81 (diff)
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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.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index a065612fc92..7c87796d20d 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];