3.4-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Linus Torvalds <torva...@linux-foundation.org>

[ Upstream commit 83f1b4ba917db5dc5a061a44b3403ddb6e783494 ]

Commit 257b5358b32f ("scm: Capture the full credentials of the scm
sender") changed the credentials passing code to pass in the effective
uid/gid instead of the real uid/gid.

Obviously this doesn't matter most of the time (since normally they are
the same), but it results in differences for suid binaries when the wrong
uid/gid ends up being used.

This just undoes that (presumably unintentional) part of the commit.

Reported-by: Andy Lutomirski <l...@amacapital.net>
Cc: Eric W. Biederman <ebied...@xmission.com>
Cc: Serge E. Hallyn <se...@hallyn.com>
Cc: David S. Miller <da...@davemloft.net>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Acked-by: "Eric W. Biederman" <ebied...@xmission.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 include/linux/socket.h |    3 ++-
 include/net/scm.h      |    2 +-
 net/core/sock.c        |   14 ++++++++++----
 3 files changed, 13 insertions(+), 6 deletions(-)

--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -316,7 +316,8 @@ struct ucred {
 /* IPX options */
 #define IPX_TYPE       1
 
-extern void cred_to_ucred(struct pid *pid, const struct cred *cred, struct 
ucred *ucred);
+extern void cred_to_ucred(struct pid *pid, const struct cred *cred, struct 
ucred *ucred,
+                         bool use_effective);
 
 extern int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
 extern int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -50,7 +50,7 @@ static __inline__ void scm_set_cred(stru
 {
        scm->pid  = get_pid(pid);
        scm->cred = cred ? get_cred(cred) : NULL;
-       cred_to_ucred(pid, cred, &scm->creds);
+       cred_to_ucred(pid, cred, &scm->creds, false);
 }
 
 static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -815,15 +815,20 @@ EXPORT_SYMBOL(sock_setsockopt);
 
 
 void cred_to_ucred(struct pid *pid, const struct cred *cred,
-                  struct ucred *ucred)
+                  struct ucred *ucred, bool use_effective)
 {
        ucred->pid = pid_vnr(pid);
        ucred->uid = ucred->gid = -1;
        if (cred) {
                struct user_namespace *current_ns = current_user_ns();
 
-               ucred->uid = user_ns_map_uid(current_ns, cred, cred->euid);
-               ucred->gid = user_ns_map_gid(current_ns, cred, cred->egid);
+               if (use_effective) {
+                       ucred->uid = user_ns_map_uid(current_ns, cred, 
cred->euid);
+                       ucred->gid = user_ns_map_gid(current_ns, cred, 
cred->egid);
+               } else {
+                       ucred->uid = user_ns_map_uid(current_ns, cred, 
cred->uid);
+                       ucred->gid = user_ns_map_gid(current_ns, cred, 
cred->gid);
+               }
        }
 }
 EXPORT_SYMBOL_GPL(cred_to_ucred);
@@ -984,7 +989,8 @@ int sock_getsockopt(struct socket *sock,
                struct ucred peercred;
                if (len > sizeof(peercred))
                        len = sizeof(peercred);
-               cred_to_ucred(sk->sk_peer_pid, sk->sk_peer_cred, &peercred);
+               cred_to_ucred(sk->sk_peer_pid, sk->sk_peer_cred,
+                             &peercred, true);
                if (copy_to_user(optval, &peercred, len))
                        return -EFAULT;
                goto lenout;


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to