| From | Andi Kleen <> | Subject | [PATCH] [110/275] NFSD: memory corruption due to writing beyond the stat array | Date | Wed, 30 Mar 2011 14:05:49 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Konstantin Khorenko <khorenko@parallels.com>
commit 3aa6e0aa8ab3e64bbfba092c64d42fd1d006b124 upstream.
If nfsd fails to find an exported via NFS file in the readahead cache, it should increment corresponding nfsdstats counter (ra_depth[10]), but due to a bug it may instead write to ra_depth[11], corrupting the following field.
In a kernel with NFSDv4 compiled in the corruption takes the form of an increment of a counter of the number of NFSv4 operation 0's received; since there is no operation 0, this is harmless.
In a kernel with NFSDv4 disabled it corrupts whatever happens to be in the memory beyond nfsdstats.
Signed-off-by: Konstantin Khorenko <khorenko@openvz.org> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- fs/nfsd/vfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.35.y/fs/nfsd/vfs.c =================================================================== --- linux-2.6.35.y.orig/fs/nfsd/vfs.c 2011-03-29 22:51:24.834087726 -0700 +++ linux-2.6.35.y/fs/nfsd/vfs.c 2011-03-29 23:03:00.482287829 -0700 @@ -819,7 +819,7 @@ if (ra->p_count == 0) frap = rap; } - depth = nfsdstats.ra_size*11/10; + depth = nfsdstats.ra_size; if (!frap) { spin_unlock(&rab->pb_lock); return NULL;
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