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| author | Tomáš Trnka <ttrnka@mail.muni.cz> | 2016-05-20 16:41:10 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-06-07 17:21:58 -0700 |
| commit | 89bd18288361ac9f737e1b805c6524fa513a50e9 (patch) | |
| tree | 60c227dd182cfe1037ed90bca4d490dbb6c00b1b /net | |
| parent | aa77dea436de2eb3be817b96e573ca3ef856d7c3 (diff) | |
| download | lwn-89bd18288361ac9f737e1b805c6524fa513a50e9.tar.gz lwn-89bd18288361ac9f737e1b805c6524fa513a50e9.zip | |
sunrpc: fix stripping of padded MIC tokens
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 <ttrnka@mail.muni.cz>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sunrpc/auth_gss/svcauth_gss.c | 4 |
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 0f73f4507746..ae9b1fe46f8f 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); |