nfsd4: stricter cred comparison for setclientid/exchange_id

The typical setclientid or exchange_id will probably be performed with a
credential that maps to either root or nobody, so comparing just uid's
is unlikely to be useful.  So, use everything else we can get our hands
on.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 21 insertions, 1 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 37bafb290c11..6dc0cfb37541 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1201,11 +1201,31 @@ same_clid(clientid_t *cl1, clientid_t *cl2)
         return (cl1->cl_boot == cl2->cl_boot) && (cl1->cl_id == cl2->cl_id);
 }
 
+static bool groups_equal(struct group_info *g1, struct group_info *g2)
+{
+        int i;
+
+        if (g1->ngroups != g2->ngroups)
+                return false;
+        for (i=0; i<g1->ngroups; i++)
+                if (GROUP_AT(g1, i) != GROUP_AT(g2, i))
+                        return false;
+        return true;
+}
+
 /* XXX what about NGROUP */
 static int
 same_creds(struct svc_cred *cr1, struct svc_cred *cr2)
 {
-        return cr1->cr_uid == cr2->cr_uid;
+        if ((cr1->cr_uid != cr2->cr_uid)
+                || (cr1->cr_gid != cr2->cr_gid)
+                || !groups_equal(cr1->cr_group_info, cr2->cr_group_info))
+                return false;
+        if (cr1->cr_principal == cr2->cr_principal)
+                return true;
+        if (!cr1->cr_principal || !cr2->cr_principal)
+                return false;
+        return 0 == strcmp(cr1->cr_principal, cr1->cr_principal);
 }
 
 static void gen_clid(struct nfs4_client *clp)