userns: Convert group_info values from gid_t to kgid_t.

As a first step to converting struct cred to be all kuid_t and kgid_t
values convert the group values stored in group_info to always be
kgid_t values.   Unless user namespaces are used this change should
have no effect.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

1 files changed, 14 insertions, 4 deletions

diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 521d8f7dc833..71ec8530ec8c 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -14,6 +14,7 @@
 #include <net/sock.h>
 #include <net/ipv6.h>
 #include <linux/kernel.h>
+#include <linux/user_namespace.h>
 #define RPCDBG_FACILITY RPCDBG_AUTH
 
 #include <linux/sunrpc/clnt.h>
@@ -530,11 +531,15 @@ static int unix_gid_parse(struct cache_detail *cd,
 
         for (i = 0 ; i < gids ; i++) {
                 int gid;
+                kgid_t kgid;
                 rv = get_int(&mesg, &gid);
                 err = -EINVAL;
                 if (rv)
                         goto out;
-                GROUP_AT(ug.gi, i) = gid;
+                kgid = make_kgid(&init_user_ns, gid);
+                if (!gid_valid(kgid))
+                        goto out;
+                GROUP_AT(ug.gi, i) = kgid;
         }
 
         ugp = unix_gid_lookup(cd, uid);
@@ -563,6 +568,7 @@ static int unix_gid_show(struct seq_file *m,
                          struct cache_detail *cd,
                          struct cache_head *h)
 {
+        struct user_namespace *user_ns = current_user_ns();
         struct unix_gid *ug;
         int i;
         int glen;
@@ -580,7 +586,7 @@ static int unix_gid_show(struct seq_file *m,
 
         seq_printf(m, "%u %d:", ug->uid, glen);
         for (i = 0; i < glen; i++)
-                seq_printf(m, " %d", GROUP_AT(ug->gi, i));
+                seq_printf(m, " %d", from_kgid_munged(user_ns, GROUP_AT(ug->gi, i)));
         seq_printf(m, "\n");
         return 0;
 }
@@ -831,8 +837,12 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
         cred->cr_group_info = groups_alloc(slen);
         if (cred->cr_group_info == NULL)
                 return SVC_CLOSE;
-        for (i = 0; i < slen; i++)
-                GROUP_AT(cred->cr_group_info, i) = svc_getnl(argv);
+        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) {
                 *authp = rpc_autherr_badverf;
                 return SVC_DENIED;