This is a note to let you know that I've just added the patch titled
NFSD: Fix exposure in nfsd4_decode_bitmap()
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-fix-exposure-in-nfsd4_decode_bitmap.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d7404ded8a62e52b77aab13b6224dbcbf027cb24
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Sun Nov 14 15:16:04 2021 -0500
NFSD: Fix exposure in nfsd4_decode_bitmap()
[ Upstream commit c0019b7db1d7ac62c711cda6b357a659d46428fe ]
rtm@xxxxxxxxxxxxx reports:
> nfsd4_decode_bitmap4() will write beyond bmval[bmlen-1] if the RPC
> directs it to do so. This can cause nfsd4_decode_state_protect4_a()
> to write client-supplied data beyond the end of
> nfsd4_exchange_id.spo_must_allow[] when called by
> nfsd4_decode_exchange_id().
Rewrite the loops so nfsd4_decode_bitmap() cannot iterate beyond
@bmlen.
Reported by: rtm@xxxxxxxxxxxxx
Fixes: d1c263a031e8 ("NFSD: Replace READ* macros in nfsd4_decode_fattr()")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index ba2ed12df2060..d9758232a398c 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -288,11 +288,8 @@ nfsd4_decode_bitmap4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen)
p = xdr_inline_decode(argp->xdr, count << 2);
if (!p)
return nfserr_bad_xdr;
- i = 0;
- while (i < count)
- bmval[i++] = be32_to_cpup(p++);
- while (i < bmlen)
- bmval[i++] = 0;
+ for (i = 0; i < bmlen; i++)
+ bmval[i] = (i < count) ? be32_to_cpup(p++) : 0;
return nfs_ok;
}
