From ed93bd2a7c53a1d131e8fe9df743bc0278221569 Mon Sep 17 00:00:00 2001 From: Tomáš Trnka Date: Fri, 20 May 2016 16:41:10 +0200 Subject: sunrpc: fix stripping of padded MIC tokens MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit c0cb8bf3a8e4bd82e640862cdd8891400405cb89 upstream. 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 Acked-by: Jeff Layton Signed-off-by: J. Bruce Fields Signed-off-by: Jiri Slaby --- net/sunrpc/auth_gss/svcauth_gss.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index e18be86dc486..9d7e6097ef5b 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -855,8 +855,8 @@ 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; out: kfree(mic.data); -- cgit v1.2.3