New upstream version 4.15.1

lib/env.c

@@ -0,0 +1,248 @@
+/*
+ * SPDX-FileCopyrightText: 1989 - 1992, Julianne Frances Haugh
+ * SPDX-FileCopyrightText: 1996 - 1999, Marek Michałkiewicz
+ * SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
+ * SPDX-FileCopyrightText: 2008 - 2009, Nicolas François
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#ident "$Id$"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "alloc.h"
+#include "prototypes.h"
+#include "defines.h"
+#include "shadowlog.h"
+#include "string/sprintf.h"
+
+
+/*
+ * NEWENVP_STEP must be a power of two.  This is the number
+ * of (char *) pointers to allocate at a time, to avoid using
+ * realloc() too often.
+ */
+#define NEWENVP_STEP 16
+size_t newenvc = 0;
+/*@null@*/char **newenvp = NULL;
+
+static const char *const forbid[] = {
+	"_RLD_=",
+	"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=",
+	NULL
+};
+
+/* these are allowed, but with no slashes inside
+   (to work around security problems in GNU gettext) */
+static const char *const noslash[] = {
+	"LANG=",
+	"LANGUAGE=",
+	"LC_",			/* anything with the LC_ prefix */
+	NULL
+};
+
+/*
+ * initenv() must be called once before using addenv().
+ */
+void initenv (void)
+{
+	newenvp = XMALLOC(NEWENVP_STEP, char *);
+	*newenvp = NULL;
+}
+
+
+void addenv (const char *string, /*@null@*/const char *value)
+{
+	char    *cp, *newstring;
+	size_t  i, n;
+
+	if (NULL != value) {
+		xasprintf(&newstring, "%s=%s", string, value);
+	} else {
+		newstring = xstrdup (string);
+	}
+
+	/*
+	 * Search for a '=' character within the string and if none is found
+	 * just ignore the whole string.
+	 */
+
+	cp = strchr (newstring, '=');
+	if (NULL == cp) {
+		free(newstring);
+		return;
+	}
+
+	n = (size_t) (cp - newstring);
+
+	/*
+	 * If this environment variable is already set, change its value.
+	 */
+	for (i = 0; i < newenvc; i++) {
+		if (   (strncmp (newstring, newenvp[i], n) == 0)
+		    && (('=' == newenvp[i][n]) || ('\0' == newenvp[i][n]))) {
+			break;
+		}
+	}
+
+	if (i < newenvc) {
+		free(newenvp[i]);
+		newenvp[i] = newstring;
+		return;
+	}
+
+	/*
+	 * Otherwise, save the new environment variable
+	 */
+	newenvp[newenvc++] = newstring;
+
+	/*
+	 * And extend the environment if needed.
+	 */
+
+	/*
+	 * Check whether newenvc is a multiple of NEWENVP_STEP.
+	 * If so we have to resize the vector.
+	 * the expression (newenvc & (NEWENVP_STEP - 1)) == 0
+	 * is equal to    (newenvc %  NEWENVP_STEP) == 0
+	 * as long as NEWENVP_STEP is a power of 2.
+	 */
+
+	if ((newenvc & (NEWENVP_STEP - 1)) == 0) {
+		bool  update_environ;
+		char  **__newenvp;
+
+		/*
+		 * If the resize operation succeeds we can
+		 * happily go on, else print a message.
+		 */
+		update_environ = (environ == newenvp);
+
+		__newenvp = REALLOC(newenvp, newenvc + NEWENVP_STEP, char *);
+
+		if (NULL != __newenvp) {
+			/*
+			 * If this is our current environment, update
+			 * environ so that it doesn't point to some
+			 * free memory area (realloc() could move it).
+			 */
+			if (update_environ)
+				environ = __newenvp;
+			newenvp = __newenvp;
+		} else {
+			(void) fputs (_("Environment overflow\n"), log_get_logfd());
+			newenvc--;
+			free (newenvp[newenvc]);
+		}
+	}
+
+	/*
+	 * The last entry of newenvp must be NULL
+	 */
+
+	newenvp[newenvc] = NULL;
+}
+
+
+/*
+ * set_env - copy command line arguments into the environment
+ */
+void set_env (int argc, char *const *argv)
+{
+	int   noname = 1;
+	char  variable[1024];
+	char  *cp;
+
+	for (; argc > 0; argc--, argv++) {
+		if (strlen (*argv) >= sizeof variable) {
+			continue;	/* ignore long entries */
+		}
+
+		cp = strchr (*argv, '=');
+		if (NULL == cp) {
+			assert(SNPRINTF(variable, "L%d", noname) != -1);
+			noname++;
+			addenv (variable, *argv);
+		} else {
+			const char *const *p;
+
+			for (p = forbid; NULL != *p; p++) {
+				if (strncmp (*argv, *p, strlen (*p)) == 0) {
+					break;
+				}
+			}
+
+			if (NULL != *p) {
+				stpcpy(mempcpy(variable, *argv, (size_t)(cp - *argv)), "");
+				printf (_("You may not change $%s\n"),
+					variable);
+				continue;
+			}
+
+			addenv (*argv, NULL);
+		}
+	}
+}
+
+/*
+ * sanitize_env - remove some nasty environment variables
+ * If you fall into a total paranoia, you should call this
+ * function for any root-setuid program or anything the user
+ * might change the environment with. 99% useless as almost
+ * all modern Unixes will handle setuid executables properly,
+ * but... I feel better with that silly precaution. -j.
+ */
+
+void sanitize_env (void)
+{
+	char **envp = environ;
+	const char *const *bad;
+	char **cur;
+	char **move;
+
+	for (cur = envp; NULL != *cur; cur++) {
+		for (bad = forbid; NULL != *bad; bad++) {
+			if (strncmp (*cur, *bad, strlen (*bad)) == 0) {
+				for (move = cur; NULL != *move; move++) {
+					*move = *(move + 1);
+				}
+				cur--;
+				break;
+			}
+		}
+	}
+
+	for (cur = envp; NULL != *cur; cur++) {
+		for (bad = noslash; NULL != *bad; bad++) {
+			if (strncmp (*cur, *bad, strlen (*bad)) != 0) {
+				continue;
+			}
+			if (strchr (*cur, '/') == NULL) {
+				continue;	/* OK */
+			}
+			for (move = cur; NULL != *move; move++) {
+				*move = *(move + 1);
+			}
+			cur--;
+			break;
+		}
+	}
+}
+