3.2.44-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
commit 83f1b4ba917db5dc5a061a44b3403ddb6e783494 upstream.
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 <luto@xxxxxxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Serge E. Hallyn <serge@xxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.2: scm_set_cred() does user namespace conversion
of euid/egid using cred_to_ucred(). Add and use cred_real_to_ucred() to
do the same thing for real uid/gid.]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
include/net/scm.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- 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_real_to_ucred(pid, cred, &scm->creds);
}
static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -761,6 +761,20 @@ void cred_to_ucred(struct pid *pid, cons
}
EXPORT_SYMBOL_GPL(cred_to_ucred);
+void cred_real_to_ucred(struct pid *pid, const struct cred *cred,
+ struct ucred *ucred)
+{
+ 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->uid);
+ ucred->gid = user_ns_map_gid(current_ns, cred, cred->gid);
+ }
+}
+EXPORT_SYMBOL_GPL(cred_real_to_ucred);
+
int sock_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -317,6 +317,7 @@ struct ucred {
#define IPX_TYPE 1
extern void cred_to_ucred(struct pid *pid, const struct cred *cred, struct ucred *ucred);
+extern void cred_real_to_ucred(struct pid *pid, const struct cred *cred, struct ucred *ucred);
extern int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
extern int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
--
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