userns: Convert setting and getting uid and gid system calls to use kuid and kgid

Convert setregid, setgid, setreuid, setuid,
setresuid, getresuid, setresgid, getresgid, setfsuid, setfsgid,
getuid, geteuid, getgid, getegid,
waitpid, waitid, wait4.

Convert userspace uids and gids into kuids and kgids before
being placed on struct cred.  Convert struct cred kuids and
kgids into userspace uids and gids when returning them.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

kernel/exit.c

@@ -1214,7 +1214,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 	unsigned long state;
 	int retval, status, traced;
 	pid_t pid = task_pid_vnr(p);
-	uid_t uid = __task_cred(p)->uid;
+	uid_t uid = from_kuid_munged(current_user_ns(), __task_cred(p)->uid);
 	struct siginfo __user *infop;
 
 	if (!likely(wo->wo_flags & WEXITED))
@@ -1427,7 +1427,7 @@ static int wait_task_stopped(struct wait_opts *wo,
 	if (!unlikely(wo->wo_flags & WNOWAIT))
 		*p_code = 0;
 
-	uid = task_uid(p);
+	uid = from_kuid_munged(current_user_ns(), __task_cred(p)->uid);
 unlock_sig:
 	spin_unlock_irq(&p->sighand->siglock);
 	if (!exit_code)
@@ -1500,7 +1500,7 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
 	}
 	if (!unlikely(wo->wo_flags & WNOWAIT))
 		p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
-	uid = task_uid(p);
+	uid = from_kuid_munged(current_user_ns(), __task_cred(p)->uid);
 	spin_unlock_irq(&p->sighand->siglock);
 
 	pid = task_pid_vnr(p);

kernel/timer.c

@@ -1427,25 +1427,25 @@ SYSCALL_DEFINE0(getppid)
 SYSCALL_DEFINE0(getuid)
 {
 	/* Only we change this so SMP safe */
-	return current_uid();
+	return from_kuid_munged(current_user_ns(), current_uid());
 }
 
 SYSCALL_DEFINE0(geteuid)
 {
 	/* Only we change this so SMP safe */
-	return current_euid();
+	return from_kuid_munged(current_user_ns(), current_euid());
 }
 
 SYSCALL_DEFINE0(getgid)
 {
 	/* Only we change this so SMP safe */
-	return current_gid();
+	return from_kgid_munged(current_user_ns(), current_gid());
 }
 
 SYSCALL_DEFINE0(getegid)
 {
 	/* Only we change this so SMP safe */
-	return  current_egid();
+	return from_kgid_munged(current_user_ns(), current_egid());
 }
 
 #endif

kernel/uid16.c

@@ -81,14 +81,19 @@ SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
 	return ret;
 }
 
-SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruid, old_uid_t __user *, euid, old_uid_t __user *, suid)
+SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
 {
 	const struct cred *cred = current_cred();
 	int retval;
+	old_uid_t ruid, euid, suid;
 
-	if (!(retval   = put_user(high2lowuid(cred->uid),  ruid)) &&
-	    !(retval   = put_user(high2lowuid(cred->euid), euid)))
-		retval = put_user(high2lowuid(cred->suid), suid);
+	ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
+	euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
+	suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));
+
+	if (!(retval   = put_user(ruid, ruidp)) &&
+	    !(retval   = put_user(euid, euidp)))
+		retval = put_user(suid, suidp);
 
 	return retval;
 }
@@ -103,14 +108,19 @@ SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
 }
 
 
-SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgid, old_gid_t __user *, egid, old_gid_t __user *, sgid)
+SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
 {
 	const struct cred *cred = current_cred();
 	int retval;
+	old_gid_t rgid, egid, sgid;
+
+	rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
+	egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
+	sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));
 
-	if (!(retval   = put_user(high2lowgid(cred->gid),  rgid)) &&
-	    !(retval   = put_user(high2lowgid(cred->egid), egid)))
-		retval = put_user(high2lowgid(cred->sgid), sgid);
+	if (!(retval   = put_user(rgid, rgidp)) &&
+	    !(retval   = put_user(egid, egidp)))
+		retval = put_user(sgid, sgidp);
 
 	return retval;
 }
@@ -221,20 +231,20 @@ SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
 
 SYSCALL_DEFINE0(getuid16)
 {
-	return high2lowuid(current_uid());
+	return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
 }
 
 SYSCALL_DEFINE0(geteuid16)
 {
-	return high2lowuid(current_euid());
+	return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
 }
 
 SYSCALL_DEFINE0(getgid16)
 {
-	return high2lowgid(current_gid());
+	return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
 }
 
 SYSCALL_DEFINE0(getegid16)
 {
-	return high2lowgid(current_egid());
+	return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
 }