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authorChuck Lever <chuck.lever@oracle.com>2021-11-14 15:16:04 -0500
committerJ. Bruce Fields <bfields@redhat.com>2021-11-15 15:33:10 -0500
commitc0019b7db1d7ac62c711cda6b357a659d46428fe (patch)
tree89686f8c5bb9f59109ca919a3539c89c31d06b22 /fs/nfsd
parent80479eb862102f9513e93fcf726c78cc0be2e3b2 (diff)
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: 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>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/nfs4xdr.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 9b609aac47e1..5bdfaa43c99d 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;
}