userns: Convert audit to work with user namespaces enabled

- Explicitly format uids gids in audit messges in the initial user
  namespace. This is safe because auditd is restrected to be in
  the initial user namespace.

- Convert audit_sig_uid into a kuid_t.

- Enable building the audit code and user namespaces at the same time.

The net result is that the audit subsystem now uses kuid_t and kgid_t whenever
possible making it almost impossible to confuse a raw uid_t with a kuid_t
preventing bugs.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

3 files changed, 34 insertions, 23 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index 44a4b13c9f00..511488a7bc71 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -105,7 +105,7 @@ static int	audit_backlog_wait_time = 60 * HZ;
 static int      audit_backlog_wait_overflow = 0;
 
 /* The identity of the user shutting down the audit system. */
-uid_t           audit_sig_uid = -1;
+kuid_t          audit_sig_uid = INVALID_UID;
 pid_t           audit_sig_pid = -1;
 u32             audit_sig_sid = 0;
 
@@ -853,7 +853,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                                 security_release_secctx(ctx, len);
                         return -ENOMEM;
                 }
-                sig_data->uid = audit_sig_uid;
+                sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
                 sig_data->pid = audit_sig_pid;
                 if (audit_sig_sid) {
                         memcpy(sig_data->ctx, ctx, len);
diff --git a/kernel/audit.h b/kernel/audit.h
index 4b428bb41ea3..9eb3d79482b6 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -146,7 +146,7 @@ extern void audit_kill_trees(struct list_head *);
 extern char *audit_unpack_string(void **, size_t *, size_t);
 
 extern pid_t audit_sig_pid;
-extern uid_t audit_sig_uid;
+extern kuid_t audit_sig_uid;
 extern u32 audit_sig_sid;
 
 #ifdef CONFIG_AUDITSYSCALL
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 26fdfc092e35..ff4798fcb488 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -150,7 +150,7 @@ struct audit_aux_data_pids {
         struct audit_aux_data   d;
         pid_t                   target_pid[AUDIT_AUX_PIDS];
         kuid_t                  target_auid[AUDIT_AUX_PIDS];
-        uid_t                   target_uid[AUDIT_AUX_PIDS];
+        kuid_t                  target_uid[AUDIT_AUX_PIDS];
         unsigned int            target_sessionid[AUDIT_AUX_PIDS];
         u32                     target_sid[AUDIT_AUX_PIDS];
         char                    target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
@@ -208,14 +208,14 @@ struct audit_context {
         size_t sockaddr_len;
                                 /* Save things to print about task_struct */
         pid_t               pid, ppid;
-        uid_t               uid, euid, suid, fsuid;
-        gid_t               gid, egid, sgid, fsgid;
+        kuid_t              uid, euid, suid, fsuid;
+        kgid_t              gid, egid, sgid, fsgid;
         unsigned long       personality;
         int                 arch;
 
         pid_t               target_pid;
         kuid_t              target_auid;
-        uid_t               target_uid;
+        kuid_t              target_uid;
         unsigned int        target_sessionid;
         u32                 target_sid;
         char                target_comm[TASK_COMM_LEN];
@@ -231,8 +231,8 @@ struct audit_context {
                         long args[6];
                 } socketcall;
                 struct {
-                        uid_t                   uid;
-                        gid_t                   gid;
+                        kuid_t                  uid;
+                        kgid_t                  gid;
                         umode_t                 mode;
                         u32                     osid;
                         int                     has_perm;
@@ -1176,7 +1176,7 @@ static void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk
 }
 
 static int audit_log_pid_context(struct audit_context *context, pid_t pid,
-                                 kuid_t auid, uid_t uid, unsigned int sessionid,
+                                 kuid_t auid, kuid_t uid, unsigned int sessionid,
                                  u32 sid, char *comm)
 {
         struct audit_buffer *ab;
@@ -1190,7 +1190,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 
         audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
                          from_kuid(&init_user_ns, auid),
-                         uid, sessionid);
+                         from_kuid(&init_user_ns, uid), sessionid);
         if (security_secid_to_secctx(sid, &ctx, &len)) {
                 audit_log_format(ab, " obj=(none)");
                 rc = 1;
@@ -1440,7 +1440,9 @@ static void show_special(struct audit_context *context, int *call_panic)
                 u32 osid = context->ipc.osid;
 
                 audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
-                         context->ipc.uid, context->ipc.gid, context->ipc.mode);
+                                 from_kuid(&init_user_ns, context->ipc.uid),
+                                 from_kgid(&init_user_ns, context->ipc.gid),
+                                 context->ipc.mode);
                 if (osid) {
                         char *ctx = NULL;
                         u32 len;
@@ -1553,8 +1555,8 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
                                  MAJOR(n->dev),
                                  MINOR(n->dev),
                                  n->mode,
-                                 n->uid,
-                                 n->gid,
+                                 from_kuid(&init_user_ns, n->uid),
+                                 from_kgid(&init_user_ns, n->gid),
                                  MAJOR(n->rdev),
                                  MINOR(n->rdev));
         }
@@ -1632,10 +1634,15 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
                   context->ppid,
                   context->pid,
                   from_kuid(&init_user_ns, tsk->loginuid),
-                  context->uid,
-                  context->gid,
-                  context->euid, context->suid, context->fsuid,
-                  context->egid, context->sgid, context->fsgid, tty,
+                  from_kuid(&init_user_ns, context->uid),
+                  from_kgid(&init_user_ns, context->gid),
+                  from_kuid(&init_user_ns, context->euid),
+                  from_kuid(&init_user_ns, context->suid),
+                  from_kuid(&init_user_ns, context->fsuid),
+                  from_kgid(&init_user_ns, context->egid),
+                  from_kgid(&init_user_ns, context->sgid),
+                  from_kgid(&init_user_ns, context->fsgid),
+                  tty,
                   tsk->sessionid);
 
 
@@ -2315,7 +2322,8 @@ int audit_set_loginuid(kuid_t loginuid)
                         audit_log_format(ab, "login pid=%d uid=%u "
                                 "old auid=%u new auid=%u"
                                 " old ses=%u new ses=%u",
-                                task->pid, task_uid(task),
+                                task->pid,
+                                from_kuid(&init_user_ns, task_uid(task)),
                                 from_kuid(&init_user_ns, task->loginuid),
                                 from_kuid(&init_user_ns, loginuid),
                                 task->sessionid, sessionid);
@@ -2540,7 +2548,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
         struct audit_aux_data_pids *axp;
         struct task_struct *tsk = current;
         struct audit_context *ctx = tsk->audit_context;
-        uid_t uid = current_uid(), t_uid = task_uid(t);
+        kuid_t uid = current_uid(), t_uid = task_uid(t);
 
         if (audit_pid && t->tgid == audit_pid) {
                 if (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1 || sig == SIGUSR2) {
@@ -2666,8 +2674,8 @@ void __audit_mmap_fd(int fd, int flags)
 
 static void audit_log_abend(struct audit_buffer *ab, char *reason, long signr)
 {
-        uid_t auid, uid;
-        gid_t gid;
+        kuid_t auid, uid;
+        kgid_t gid;
         unsigned int sessionid;
 
         auid = audit_get_loginuid(current);
@@ -2675,7 +2683,10 @@ static void audit_log_abend(struct audit_buffer *ab, char *reason, long signr)
         current_uid_gid(&uid, &gid);
 
         audit_log_format(ab, "auid=%u uid=%u gid=%u ses=%u",
-                         auid, uid, gid, sessionid);
+                         from_kuid(&init_user_ns, auid),
+                         from_kuid(&init_user_ns, uid),
+                         from_kgid(&init_user_ns, gid),
+                         sessionid);
         audit_log_task_context(ab);
         audit_log_format(ab, " pid=%d comm=", current->pid);
         audit_log_untrustedstring(ab, current->comm);