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authorEric Sandeen <sandeen@redhat.com>2006-12-06 20:33:06 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-07 08:39:23 -0800
commit5d1854e15ee979f8e27330f0d3ce5e2703afa1dc (patch)
tree8aff9641966020284218f2cdd75fd3b7bfc2babc
parent4af2bfc1202041006a0f01d0591a975f6c573f09 (diff)
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[PATCH] reject corrupt swapfiles earlier
The fsfuzzer found this; with a corrupt small swapfile that claims to have many pages: [root]# file swap.741.img swap.741.img: Linux/i386 swap file (new style) 1 (4K pages) size 1040191487 pages [root]# ls -l swap.741.img -rw-r--r-- 1 root root 16777216 Nov 22 05:18 swap.741.img sys_swapon() will try to vmalloc all those pages, and -then- check to see if the file is actually that large: if (!(p->swap_map = vmalloc(maxpages * sizeof(short)))) { <snip> if (swapfilesize && maxpages > swapfilesize) { printk(KERN_WARNING "Swap area shorter than signature indicates\n"); It seems to me that it would make more sense to move this test up before the vmalloc, with the other checks, to avoid the OOM-killer in this situation... Signed-off-by: Eric Sandeen <sandeen@redhat.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--mm/swapfile.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 8e206cea0f5..f315131db00 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1552,6 +1552,11 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
error = -EINVAL;
if (!maxpages)
goto bad_swap;
+ if (swapfilesize && maxpages > swapfilesize) {
+ printk(KERN_WARNING
+ "Swap area shorter than signature indicates\n");
+ goto bad_swap;
+ }
if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode))
goto bad_swap;
if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)
@@ -1579,12 +1584,6 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
goto bad_swap;
}
- if (swapfilesize && maxpages > swapfilesize) {
- printk(KERN_WARNING
- "Swap area shorter than signature indicates\n");
- error = -EINVAL;
- goto bad_swap;
- }
if (nr_good_pages) {
p->swap_map[0] = SWAP_MAP_BAD;
p->max = maxpages;