Commit c0019b7d authored by Chuck Lever's avatar Chuck Lever Committed by J. Bruce Fields
Browse files

NFSD: Fix exposure in nfsd4_decode_bitmap() 



rtm@csail.mit.edu 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@csail.mit.edu
Fixes: d1c263a0 ("NFSD: Replace READ* macros in nfsd4_decode_fattr()")
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 80479eb8

fs/nfsd/nfs4xdr.c

+2 −5
Original line number Diff line number Diff line
@@ -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;

}