On Wed, Mar 28, 2018 at 09:00:14AM +0100, M A Young wrote: > On Tue, 27 Mar 2018, Eric Biggers wrote: > > > Hi Michael, > > > > On Tue, Mar 27, 2018 at 11:06:14PM +0100, Michael Young wrote: > > > NFS mounts stopped working on one of my computers after a kernel update > > > from > > > 4.15.3 to 4.15.4. I traced the problem to the commit > > > [46e8d06e423c4f35eac7a8b677b713b3ec9b0684] crypto: hash - prevent using > > > keyed hashes without setting key > > > and a later kernel with this patch reverted works normally. > > > > > > The problem seems to be related to kerberos as the mount fails when the > > > keytab is present, but works if I rename the keytab file. This is true > > > even > > > though the mount is with sec=sys . The mount should also work with > > > sec=krb5 > > > but that also fails in the same way. When the mount fails there are errors > > > in dmesg like > > > [ 1232.522816] gss_marshal: gss_get_mic FAILED (851968) > > > [ 1232.522819] RPC: couldn't encode RPC header, exit EIO > > > [ 1232.522856] gss_marshal: gss_get_mic FAILED (851968) > > > [ 1232.522857] RPC: couldn't encode RPC header, exit EIO > > > [ 1232.522863] NFS: nfs4_discover_server_trunking unhandled error -5. > > > Exiting with error EIO > > > [ 1232.525039] gss_marshal: gss_get_mic FAILED (851968) > > > [ 1232.525042] RPC: couldn't encode RPC header, exit EIO > > > > > > Michael Young > > > > Thanks for the bug report. I think the error is coming from > > net/sunrpc/auth_gss/gss_krb5_crypto.c. There are two potential problems I > > see. > > The first one, which is definitely a bug, is that make_checksum_hmac_md5() > > allocates an HMAC transform and request, then does these crypto API calls: > > > > crypto_ahash_init() > > crypto_ahash_setkey() > > crypto_ahash_digest() > > > > This is wrong because it makes no sense to init() the HMAC request before > > the > > key has been set, and doubly so when it's calling digest() which is > > shorthand > > for init() + update() + final(). So I think it just needs to be removed. > > You > > can test the following patch: > > > > diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c > > b/net/sunrpc/auth_gss/gss_krb5_crypto.c > > index 12649c9fedab..8654494b4d0a 100644 > > --- a/net/sunrpc/auth_gss/gss_krb5_crypto.c > > +++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c > > @@ -237,9 +237,6 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char > > *header, int hdrlen, > > > > ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, > > NULL); > > > > - err = crypto_ahash_init(req); > > - if (err) > > - goto out; > > err = crypto_ahash_setkey(hmac_md5, cksumkey, > > kctx->gk5e->keylength); > > if (err) > > goto out; > > > > If that's not it, it's also possible that the error is coming from the > > crypto_ahash_init() in make_checksum(). That can only happen if 'cksumkey' > > is > > NULL and the hash algorithm is keyed, which implies a logical error as it > > doesn't make sense to use a keyed hash algorithm without the key. The > > callers > > do check kctx->gk5e->keyed_cksum which I'd hope would prevent this, though > > perhaps kctx->cksum can be NULL. > > > > Eric > > The patch fixes the problem. > > Michael Young
Okay, thanks for testing! I'll send a formal patch. Eric
