4 files changed, 16 insertions, 35 deletions

diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index 0a996a3517ed..a8836e8445cc 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -29,7 +29,8 @@ struct unix_address {
 
 struct unix_skb_parms {
         struct pid              *pid;           /* Skb credentials      */
-        const struct cred       *cred;
+        kuid_t                  uid;
+        kgid_t                  gid;
         struct scm_fp_list      *fp;            /* Passed files         */
 #ifdef CONFIG_SECURITY_NETWORK
         u32                     secid;          /* Security ID          */
diff --git a/include/net/scm.h b/include/net/scm.h
index 975cca01048b..5a4c6a9eb122 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -26,7 +26,6 @@ struct scm_fp_list {
 
 struct scm_cookie {
         struct pid              *pid;           /* Skb credentials */
-        const struct cred       *cred;
         struct scm_fp_list      *fp;            /* Passed files         */
         struct scm_creds        creds;          /* Skb credentials      */
 #ifdef CONFIG_SECURITY_NETWORK
@@ -51,23 +50,18 @@ static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_co
 #endif /* CONFIG_SECURITY_NETWORK */
 
 static __inline__ void scm_set_cred(struct scm_cookie *scm,
-                                    struct pid *pid, const struct cred *cred)
+                                    struct pid *pid, kuid_t uid, kgid_t gid)
 {
         scm->pid  = get_pid(pid);
-        scm->cred = cred ? get_cred(cred) : NULL;
         scm->creds.pid = pid_vnr(pid);
-        scm->creds.uid = cred ? cred->euid : INVALID_UID;
-        scm->creds.gid = cred ? cred->egid : INVALID_GID;
+        scm->creds.uid = uid;
+        scm->creds.gid = gid;
 }
 
 static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
 {
         put_pid(scm->pid);
         scm->pid  = NULL;
-
-        if (scm->cred)
-                put_cred(scm->cred);
-        scm->cred = NULL;
 }
 
 static __inline__ void scm_destroy(struct scm_cookie *scm)
@@ -81,8 +75,10 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
                                struct scm_cookie *scm, bool forcecreds)
 {
         memset(scm, 0, sizeof(*scm));
+        scm->creds.uid = INVALID_UID;
+        scm->creds.gid = INVALID_GID;
         if (forcecreds)
-                scm_set_cred(scm, task_tgid(current), current_cred());
+                scm_set_cred(scm, task_tgid(current), current_euid(), current_egid());
         unix_get_peersec_dgram(sock, scm);
         if (msg->msg_controllen <= 0)
                 return 0;
diff --git a/net/core/scm.c b/net/core/scm.c
index 2dc6cdaaae8a..83b2b383c865 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -187,22 +187,6 @@ int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
 
                         p->creds.uid = uid;
                         p->creds.gid = gid;
-
-                        if (!p->cred ||
-                            !uid_eq(p->cred->euid, uid) ||
-                            !gid_eq(p->cred->egid, gid)) {
-                                struct cred *cred;
-                                err = -ENOMEM;
-                                cred = prepare_creds();
-                                if (!cred)
-                                        goto error;
-
-                                cred->uid = cred->euid = uid;
-                                cred->gid = cred->egid = gid;
-                                if (p->cred)
-                                        put_cred(p->cred);
-                                p->cred = cred;
-                        }
                         break;
                 }
                 default:
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 824eaf2c3afa..5ca1631de7ef 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1340,7 +1340,6 @@ static void unix_destruct_scm(struct sk_buff *skb)
         struct scm_cookie scm;
         memset(&scm, 0, sizeof(scm));
         scm.pid  = UNIXCB(skb).pid;
-        scm.cred = UNIXCB(skb).cred;
         if (UNIXCB(skb).fp)
                 unix_detach_fds(&scm, skb);
 
@@ -1391,8 +1390,8 @@ static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool sen
         int err = 0;
 
         UNIXCB(skb).pid  = get_pid(scm->pid);
-        if (scm->cred)
-                UNIXCB(skb).cred = get_cred(scm->cred);
+        UNIXCB(skb).uid = scm->creds.uid;
+        UNIXCB(skb).gid = scm->creds.gid;
         UNIXCB(skb).fp = NULL;
         if (scm->fp && send_fds)
                 err = unix_attach_fds(scm, skb);
@@ -1409,13 +1408,13 @@ static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool sen
 static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
                             const struct sock *other)
 {
-        if (UNIXCB(skb).cred)
+        if (UNIXCB(skb).pid)
                 return;
         if (test_bit(SOCK_PASSCRED, &sock->flags) ||
             !other->sk_socket ||
             test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
                 UNIXCB(skb).pid  = get_pid(task_tgid(current));
-                UNIXCB(skb).cred = get_current_cred();
+                current_euid_egid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
         }
 }
 
@@ -1819,7 +1818,7 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
                 siocb->scm = &tmp_scm;
                 memset(&tmp_scm, 0, sizeof(tmp_scm));
         }
-        scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
+        scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
         unix_set_secdata(siocb->scm, skb);
 
         if (!(flags & MSG_PEEK)) {
@@ -1991,11 +1990,12 @@ again:
                 if (check_creds) {
                         /* Never glue messages from different writers */
                         if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
-                            (UNIXCB(skb).cred != siocb->scm->cred))
+                            !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) ||
+                            !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid))
                                 break;
                 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
                         /* Copy credentials */
-                        scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
+                        scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
                         check_creds = 1;
                 }