5.10-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit c0019b7db1d7ac62c711cda6b357a659d46428fe ]
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: d1c263a031e8 ("NFSD: Replace READ* macros in nfsd4_decode_fattr()") Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfs4xdr.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)
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; }