SUNRPC: Fix the server AUTH_UNIX userspace mappings

gid_parse() is part of a downcall, so uids and gids should be assumed
encoded using the current user namespace.
svcauth_unix_accept() is, on the other hand, decoding uids and gids from
the wire, so we assume those are encoded to match the user namespace of
the server process.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index fb9041b92f72..f92ef79c8ea5 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -500,7 +500,7 @@ static int unix_gid_parse(struct cache_detail *cd,
         rv = get_int(&mesg, &id);
         if (rv)
                 return -EINVAL;
-        uid = make_kuid(&init_user_ns, id);
+        uid = make_kuid(current_user_ns(), id);
         ug.uid = uid;
 
         expiry = get_expiry(&mesg);
@@ -522,7 +522,7 @@ static int unix_gid_parse(struct cache_detail *cd,
                 err = -EINVAL;
                 if (rv)
                         goto out;
-                kgid = make_kgid(&init_user_ns, gid);
+                kgid = make_kgid(current_user_ns(), gid);
                 if (!gid_valid(kgid))
                         goto out;
                 ug.gi->gid[i] = kgid;
@@ -555,7 +555,7 @@ static int unix_gid_show(struct seq_file *m,
                          struct cache_detail *cd,
                          struct cache_head *h)
 {
-        struct user_namespace *user_ns = &init_user_ns;
+        struct user_namespace *user_ns = m->file->f_cred->user_ns;
         struct unix_gid *ug;
         int i;
         int glen;
@@ -796,6 +796,7 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
         struct kvec     *argv = &rqstp->rq_arg.head[0];
         struct kvec     *resv = &rqstp->rq_res.head[0];
         struct svc_cred *cred = &rqstp->rq_cred;
+        struct user_namespace *userns;
         u32             slen, i;
         int             len   = argv->iov_len;
 
@@ -816,8 +817,10 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
          * (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 */
+        userns = (rqstp->rq_xprt && rqstp->rq_xprt->xpt_cred) ?
+                rqstp->rq_xprt->xpt_cred->user_ns : &init_user_ns;
+        cred->cr_uid = make_kuid(userns, svc_getnl(argv)); /* uid */
+        cred->cr_gid = make_kgid(userns, svc_getnl(argv)); /* gid */
         slen = svc_getnl(argv);                 /* gids length */
         if (slen > UNX_NGROUPS || (len -= (slen + 2)*4) < 0)
                 goto badcred;
@@ -825,7 +828,7 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
         if (cred->cr_group_info == NULL)
                 return SVC_CLOSE;
         for (i = 0; i < slen; i++) {
-                kgid_t kgid = make_kgid(&init_user_ns, svc_getnl(argv));
+                kgid_t kgid = make_kgid(userns, svc_getnl(argv));
                 cred->cr_group_info->gid[i] = kgid;
         }
         groups_sort(cred->cr_group_info);