Merge tag 'selinux-pr-20190612' of git://git.kernel.org/pub/scm/linux…

…/kernel/git/pcmoore/selinux

Pull selinux fixes from Paul Moore:
 "Three patches for v5.2.

  One fixes a problem where we weren't correctly logging raw SELinux
  labels, the other two fix problems where we weren't properly checking
  calls to kmemdup()"

* tag 'selinux-pr-20190612' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: fix a missing-check bug in selinux_sb_eat_lsm_opts()
  selinux: fix a missing-check bug in selinux_add_mnt_opt( )
  selinux: log raw contexts as untrusted strings

security/selinux/avc.c

@@ -739,14 +739,20 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
 	rc = security_sid_to_context_inval(sad->state, sad->ssid, &scontext,
 					   &scontext_len);
 	if (!rc && scontext) {
-		audit_log_format(ab, " srawcon=%s", scontext);
+		if (scontext_len && scontext[scontext_len - 1] == '\0')
+			scontext_len--;
+		audit_log_format(ab, " srawcon=");
+		audit_log_n_untrustedstring(ab, scontext, scontext_len);
 		kfree(scontext);
 	}
 
 	rc = security_sid_to_context_inval(sad->state, sad->tsid, &scontext,
 					   &scontext_len);
 	if (!rc && scontext) {
-		audit_log_format(ab, " trawcon=%s", scontext);
+		if (scontext_len && scontext[scontext_len - 1] == '\0')
+			scontext_len--;
+		audit_log_format(ab, " trawcon=");
+		audit_log_n_untrustedstring(ab, scontext, scontext_len);
 		kfree(scontext);
 	}
 }

security/selinux/hooks.c

@@ -1052,15 +1052,24 @@ static int selinux_add_mnt_opt(const char *option, const char *val, int len,
 	if (token == Opt_error)
 		return -EINVAL;
 
-	if (token != Opt_seclabel)
+	if (token != Opt_seclabel) {
 		val = kmemdup_nul(val, len, GFP_KERNEL);
+		if (!val) {
+			rc = -ENOMEM;
+			goto free_opt;
+		}
+	}
 	rc = selinux_add_opt(token, val, mnt_opts);
 	if (unlikely(rc)) {
 		kfree(val);
-		if (*mnt_opts) {
-			selinux_free_mnt_opts(*mnt_opts);
-			*mnt_opts = NULL;
-		}
+		goto free_opt;
+	}
+	return rc;
+
+free_opt:
+	if (*mnt_opts) {
+		selinux_free_mnt_opts(*mnt_opts);
+		*mnt_opts = NULL;
 	}
 	return rc;
 }
@@ -2616,10 +2625,11 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
 	char *from = options;
 	char *to = options;
 	bool first = true;
+	int rc;
 
 	while (1) {
 		int len = opt_len(from);
-		int token, rc;
+		int token;
 		char *arg = NULL;
 
 		token = match_opt_prefix(from, len, &arg);
@@ -2635,15 +2645,15 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
 						*q++ = c;
 				}
 				arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
+				if (!arg) {
+					rc = -ENOMEM;
+					goto free_opt;
+				}
 			}
 			rc = selinux_add_opt(token, arg, mnt_opts);
 			if (unlikely(rc)) {
 				kfree(arg);
-				if (*mnt_opts) {
-					selinux_free_mnt_opts(*mnt_opts);
-					*mnt_opts = NULL;
-				}
-				return rc;
+				goto free_opt;
 			}
 		} else {
 			if (!first) {	// copy with preceding comma
@@ -2661,6 +2671,13 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
 	}
 	*to = '\0';
 	return 0;
+
+free_opt:
+	if (*mnt_opts) {
+		selinux_free_mnt_opts(*mnt_opts);
+		*mnt_opts = NULL;
+	}
+	return rc;
 }
 
 static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)