Commit 3aa6e0aa authored Feb 01, 2011 by Konstantin Khorenko Committed by J. Bruce Fields Feb 14, 2011

NFSD: memory corruption due to writing beyond the stat array



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>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

parent 0af3f814

fs/nfsd/vfs.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -808,7 +808,7 @@ nfsd_get_raparms(dev_t dev, ino_t ino)
		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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