[PATCH 3/9] SUNRPC: Use the client user namespace when encoding creds

[Trond Myklebust <trondmy@xxxxxxxxx>]

When encoding AUTH_UNIX creds and AUTH_GSS upcalls, use the user namespace
of the process that created the rpc client.

Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
 net/sunrpc/auth_gss/auth_gss.c | 11 ++++++++---
 net/sunrpc/auth_unix.c         |  9 +++++----
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 3fd56c0c90ae..e3601dc6c180 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -412,7 +412,10 @@ gss_upcall_callback(struct rpc_task *task)
 
 static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg)
 {
-	uid_t uid = from_kuid(&init_user_ns, gss_msg->uid);
+	struct user_namespace *userns = gss_msg->auth->client->cl_cred ?
+		gss_msg->auth->client->cl_cred->user_ns : &init_user_ns;
+
+	uid_t uid = from_kuid_munged(userns, gss_msg->uid);
 	memcpy(gss_msg->databuf, &uid, sizeof(uid));
 	gss_msg->msg.data = gss_msg->databuf;
 	gss_msg->msg.len = sizeof(uid);
@@ -424,13 +427,15 @@ static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
 				const char *service_name,
 				const char *target_name)
 {
+	struct user_namespace *userns = gss_msg->auth->client->cl_cred ?
+		gss_msg->auth->client->cl_cred->user_ns : &init_user_ns;
 	struct gss_api_mech *mech = gss_msg->auth->mech;
 	char *p = gss_msg->databuf;
 	size_t buflen = sizeof(gss_msg->databuf);
 	int len;
 
 	len = scnprintf(p, buflen, "mech=%s uid=%d", mech->gm_name,
-			from_kuid(&init_user_ns, gss_msg->uid));
+			from_kuid_munged(userns, gss_msg->uid));
 	buflen -= len;
 	p += len;
 	gss_msg->msg.len = len;
@@ -707,7 +712,7 @@ gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 		goto err;
 	}
 
-	uid = make_kuid(&init_user_ns, id);
+	uid = make_kuid(current_user_ns(), id);
 	if (!uid_valid(uid)) {
 		err = -EINVAL;
 		goto err;
diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index d4018e5a24c5..e7df1f782b2e 100644
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -107,6 +107,8 @@ unx_marshal(struct rpc_task *task, struct xdr_stream *xdr)
 	__be32		*p, *cred_len, *gidarr_len;
 	int		i;
 	struct group_info *gi = cred->cr_cred->group_info;
+	struct user_namespace *userns = clnt->cl_cred ?
+		clnt->cl_cred->user_ns : &init_user_ns;
 
 	/* Credential */
 
@@ -122,14 +124,13 @@ unx_marshal(struct rpc_task *task, struct xdr_stream *xdr)
 	p = xdr_reserve_space(xdr, 3 * sizeof(*p));
 	if (!p)
 		goto marshal_failed;
-	*p++ = cpu_to_be32(from_kuid(&init_user_ns, cred->cr_cred->fsuid));
-	*p++ = cpu_to_be32(from_kgid(&init_user_ns, cred->cr_cred->fsgid));
+	*p++ = cpu_to_be32(from_kuid_munged(userns, cred->cr_cred->fsuid));
+	*p++ = cpu_to_be32(from_kgid_munged(userns, cred->cr_cred->fsgid));
 
 	gidarr_len = p++;
 	if (gi)
 		for (i = 0; i < UNX_NGROUPS && i < gi->ngroups; i++)
-			*p++ = cpu_to_be32(from_kgid(&init_user_ns,
-						     gi->gid[i]));
+			*p++ = cpu_to_be32(from_kgid_munged(userns, gi->gid[i]));
 	*gidarr_len = cpu_to_be32(p - gidarr_len - 1);
 	*cred_len = cpu_to_be32((p - cred_len - 1) << 2);
 	p = xdr_reserve_space(xdr, (p - gidarr_len - 1) << 2);
-- 
2.21.0