path: root/net
diff options
authorTomáš Trnka <>2016-05-20 16:41:10 +0200
committerJ. Bruce Fields <>2016-05-23 10:58:21 -0400
commitc0cb8bf3a8e4bd82e640862cdd8891400405cb89 (patch)
tree5d4fcca1617d852d01c00f910a8d842741e05892 /net
parentd96b9c9398fcddca7f2386cff44a6788edfe7db1 (diff)
sunrpc: fix stripping of padded MIC tokens
The length of the GSS MIC token need not be a multiple of four bytes. It is then padded by XDR to a multiple of 4 B, but unwrap_integ_data() would previously only trim mic.len + 4 B. The remaining up to three bytes would then trigger a check in nfs4svc_decode_compoundargs(), leading to a "garbage args" error and mount failure: nfs4svc_decode_compoundargs: compound not properly padded! nfsd: failed to decode arguments! This would prevent older clients using the pre-RFC 4121 MIC format (37-byte MIC including a 9-byte OID) from mounting exports from v3.9+ servers using krb5i. The trimming was introduced by commit 4c190e2f913f ("sunrpc: trim off trailing checksum before returning decrypted or integrity authenticated buffer"). Fixes: 4c190e2f913f "unrpc: trim off trailing checksum..." Signed-off-by: Tomáš Trnka <> Cc: Acked-by: Jeff Layton <> Signed-off-by: J. Bruce Fields <>
Diffstat (limited to 'net')
1 files changed, 2 insertions, 2 deletions
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 22886097d8ee..e085f5ae1548 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -856,8 +856,8 @@ unwrap_integ_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct g
goto out;
if (svc_getnl(&buf->head[0]) != seq)
goto out;
- /* trim off the mic at the end before returning */
- xdr_buf_trim(buf, mic.len + 4);
+ /* trim off the mic and padding at the end before returning */
+ xdr_buf_trim(buf, round_up_to_quad(mic.len) + 4);
stat = 0;