1 files changed, 140 insertions, 0 deletions
diff --git a/lib/env.c b/lib/env.c
new file mode 100644
index 0000000..91c935c
--- /dev/null
+++ b/lib/env.c
@@ -0,0 +1,140 @@
+/*
+ * environ[] array cleanup code and getenv() wappers
+ *
+ * No copyright is claimed.  This code is in the public domain; do with
+ * it what you wish.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef HAVE_SYS_PRCTL_H
+#include <sys/prctl.h>
+#else
+#define PR_GET_DUMPABLE 3
+#endif
+#if (!defined(HAVE_PRCTL) && defined(linux))
+#include <sys/syscall.h>
+#endif
+#include <unistd.h>
+#include <sys/types.h>
+
+#include "env.h"
+
+#ifndef HAVE_ENVIRON_DECL
+extern char **environ;
+#endif
+
+static char * const forbid[] = {
+        "BASH_ENV=",    /* GNU creeping featurism strikes again... */
+        "ENV=",
+        "HOME=",
+        "IFS=",
+        "KRB_CONF=",
+        "LD_",          /* anything with the LD_ prefix */
+        "LIBPATH=",
+        "MAIL=",
+        "NLSPATH=",
+        "PATH=",
+        "SHELL=",
+        "SHLIB_PATH=",
+        (char *) 0
+};
+
+/* these are allowed, but with no slashes inside
+   (to work around security problems in GNU gettext) */
+static char * const noslash[] = {
+        "LANG=",
+        "LANGUAGE=",
+        "LC_",          /* anything with the LC_ prefix */
+        (char *) 0
+};
+
+void
+sanitize_env(void)
+{
+        char **envp = environ;
+        char * const *bad;
+        char **cur;
+        int last = 0;
+
+        for (cur = envp; *cur; cur++)
+                last++;
+
+        for (cur = envp; *cur; cur++) {
+                for (bad = forbid; *bad; bad++) {
+                        if (strncmp(*cur, *bad, strlen(*bad)) == 0) {
+                                last = remote_entry(envp, cur - envp, last);
+                                cur--;
+                                break;
+                        }
+                }
+        }
+
+        for (cur = envp; *cur; cur++) {
+                for (bad = noslash; *bad; bad++) {
+                        if (strncmp(*cur, *bad, strlen(*bad)) != 0)
+                                continue;
+                        if (!strchr(*cur, '/'))
+                                continue;  /* OK */
+                        last = remote_entry(envp, cur - envp, last);
+                        cur--;
+                        break;
+                }
+        }
+}
+
+
+char *safe_getenv(const char *arg)
+{
+	uid_t ruid = getuid();
+
+	if (ruid != 0 || (ruid != geteuid()) || (getgid() != getegid()))
+		return NULL;
+#ifdef HAVE_PRCTL
+	if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
+		return NULL;
+#else
+#if (defined(linux) && defined(SYS_prctl))
+	if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
+		return NULL;
+#endif
+#endif
+#ifdef HAVE_SECURE_GETENV
+return secure_getenv(arg);
+#elif HAVE___SECURE_GETENV
+	return __secure_getenv(arg);
+#else
+	return getenv(arg);
+#endif
+}
+
+#ifdef TEST_PROGRAM
+int main(void)
+{
+	char *const *bad;
+	char copy[32];
+	char *p;
+	int retval = EXIT_SUCCESS;
+
+	for (bad = forbid; *bad; bad++) {
+		strcpy(copy, *bad);
+		p = strchr(copy, '=');
+		if (p)
+			*p = '\0';
+		setenv(copy, copy, 1);
+	}
+	sanitize_env();
+	for (bad = forbid; *bad; bad++) {
+		strcpy(copy, *bad);
+		p = strchr(copy, '=');
+		if (p)
+			*p = '\0';
+		p = getenv(copy);
+		if (p) {
+			warnx("%s was not removed", copy);
+			retval = EXIT_FAILURE;
+		}
+	}
+	return retval;
+}
+#endif