From 5fbe9702a191169cc259de7010c766e8a4c222f6 Mon Sep 17 00:00:00 2001
From: Jakob Kaivo <jkk@ung.org>
Date: Mon, 1 Feb 2021 12:36:27 -0500
Subject: set PATH to reasonable default before executing SUID wrapper

---
 privexec/privexec.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/privexec/privexec.c b/privexec/privexec.c
index 4e3816c..11b14da 100644
--- a/privexec/privexec.c
+++ b/privexec/privexec.c
@@ -1,9 +1,16 @@
 #define _POSIX_C_SOURCE 200809L
+#include <limits.h>
 #include <spawn.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <sys/wait.h>
+#include <string.h>
 #include <unistd.h>
 
+#ifndef ARG_MAX
+#define ARG_MAX _POSIX_ARG_MAX
+#endif
+
 #ifndef PATH_CHECK
 #define PATH_CHECK	"/usr/local/lib/privexec/check"
 #endif
@@ -12,6 +19,10 @@
 #define PATH_EXEC	"/usr/local/lib/privexec/exec"
 #endif
 
+#ifndef DEFAULT_PATH
+#define DEFAULT_PATH	"/bin:/usr/bin"
+#endif
+
 static int exec_with_privileges(char *argv[])
 {
 	argv[0] = PATH_EXEC;
@@ -64,6 +75,12 @@ int main(int argc, char *argv[])
 	}
 
 	if (check_privileges(argv) == 0) {
+		char path[ARG_MAX];
+		if (confstr(_CS_PATH, path, sizeof(path)) < 1) {
+			strcpy(path, DEFAULT_PATH);
+		}
+		setenv("PATH", path, 1);
+
 		return exec_with_privileges(argv);
 	}
 
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