svcrpc: fix failures to handle -1 uid's and gid's

As of f025adf191924e3a75ce80e130afcd2485b53bb8 "sunrpc: Properly decode
kuids and kgids in RPC_AUTH_UNIX credentials" any rpc containing a -1
(0xffff) uid or gid would fail with a badcred error.

Reported symptoms were xmbc clients failing on upgrade of the NFS
server; examination of the network trace showed them sending -1 as the
gid.

Reported-by: Julian Sikorski <belegdol@gmail.com>
Tested-by: Julian Sikorski <belegdol@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index c3f9e1ef7f531857f432993896d13d0ae8442876..06bdf5a1082c850030650fc3957f47ef75ebda8a 100644 (file)
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -810,11 +810,15 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
                goto badcred;
        argv->iov_base = (void*)((__be32*)argv->iov_base + slen);       /* skip machname */
        argv->iov_len -= slen*4;
-
+       /*
+        * Note: we skip uid_valid()/gid_valid() checks here for
+        * backwards compatibility with clients that use -1 id's.
+        * Instead, -1 uid or gid is later mapped to the
+        * (export-specific) anonymous id by nfsd_setuser.
+        * Supplementary gid's will be left alone.
+        */
        cred->cr_uid = make_kuid(&init_user_ns, svc_getnl(argv)); /* uid */
        cred->cr_gid = make_kgid(&init_user_ns, svc_getnl(argv)); /* gid */
-       if (!uid_valid(cred->cr_uid) || !gid_valid(cred->cr_gid))
-               goto badcred;
        slen = svc_getnl(argv);                 /* gids length */
        if (slen > 16 || (len -= (slen + 2)*4) < 0)
                goto badcred;
@@ -823,8 +827,6 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
                return SVC_CLOSE;
        for (i = 0; i < slen; i++) {
                kgid_t kgid = make_kgid(&init_user_ns, svc_getnl(argv));
-               if (!gid_valid(kgid))
-                       goto badcred;
                GROUP_AT(cred->cr_group_info, i) = kgid;
        }
        if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) {