Messages in this thread Patch in this message | | | From | Paul Gortmaker <> | Subject | [34-longterm 090/247] NFSD: memory corruption due to writing beyond the stat array | Date | Thu, 23 Jun 2011 13:32:38 -0400 |
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From: Konstantin Khorenko <khorenko@parallels.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
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: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/nfsd/vfs.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 4eb9baa..054b50b 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -819,7 +819,7 @@ 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; -- 1.7.4.4
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