skeud

commit: ede0807dcc155cd71d80c51ddfe8978e7032007e
parent 285c64f0fdcb2f69022291aceb74b5ea9b822725
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Mon, 11 Sep 2023 08:44:35 +0200

su: Assemble shell command in an array

Diffstat:
M
su.c
32
++++++++++++++++++++------------

1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/su.c b/su.c
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2022 Haelwenn (lanodan) Monnier <contact+skeud@hacktivis.me>
+// SPDX-FileCopyrightText: 2022-2023 Haelwenn (lanodan) Monnier <contact+skeud@hacktivis.me>
 // SPDX-License-Identifier: MPL-2.0
 
 #define _POSIX_C_SOURCE 200809L
@@ -33,7 +33,7 @@ main(int argc, char *argv[])
 	char *username       = "root";
 	struct passwd *pwent = NULL;
 	char *shell          = NULL;
-	char *command        = NULL;
+	char *opt_cmd        = NULL;
 
 	if(geteuid() != 0)
 	{
@@ -46,8 +46,8 @@ main(int argc, char *argv[])
 	{
 		switch(c)
 		{
-		case 'c': // command
-			command = optarg;
+		case 'c': // opt_cmd
+			opt_cmd = optarg;
 			break;
 		case 'l': // login-mode
 			opt_l = true;
@@ -230,18 +230,26 @@ main(int argc, char *argv[])
 	setenv("SHELL", shell, 1);
 	setenv("IFS", " \t\n", 1);
 
-	errno   = 0;
-	int ret = 0;
-	if(command != NULL)
+	int cmd_argc              = 1;
+	char *cmd_argv[2 + 1 + 2] = {shell, NULL};
+
+	if(opt_l)
 	{
-		/* flawfinder: ignore CWE-78 */
-		ret = execlp(shell, shell, "-l", "-c", command, NULL);
+		cmd_argv[cmd_argc++] = "-l";
 	}
-	else
+
+	if(opt_cmd != NULL)
 	{
-		/* flawfinder: ignore CWE-78 */
-		ret = execlp(shell, shell, "-l", NULL);
+		cmd_argv[cmd_argc++] = "-c";
+		cmd_argv[cmd_argc++] = opt_cmd;
 	}
+
+	/* Just to be sure it's null-terminated */
+	cmd_argv[cmd_argc + 1] = NULL;
+
+	errno = 0;
+	/* flawfinder: ignore CWE-78 */
+	int ret = execvp(shell, cmd_argv);
 	if(ret < 0)
 	{
 		if(errno == ENOENT)