Fix utils directory breakage.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@393675 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 202 insertions, 0 deletions

diff --git a/main/crypt.c b/main/crypt.c
new file mode 100644
index 000000000..5e5df02cd
--- /dev/null
+++ b/main/crypt.c
@@ -0,0 +1,202 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2012 - 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ *
+ * \brief Asterisk wrapper for crypt(3)
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+/*** MODULEINFO
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include <unistd.h>
+#if defined(HAVE_CRYPT_R)
+#include <crypt.h>
+#endif
+
+#include "asterisk/utils.h"
+
+/*!
+ * \brief Max length of a salt string.
+ *
+ * $[1,5,6]$[a–zA–Z0–9./]{1,16}$, plus null terminator
+ */
+#define MAX_SALT_LEN 21
+
+static char salt_chars[] =
+	"abcdefghijklmnopqrstuvwxyz"
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	"0123456789"
+	"./";
+
+/*! Randomly select a character for a salt string */
+static char gen_salt_char(void)
+{
+	int which = ast_random_double() * 64;
+	return salt_chars[which];
+}
+
+/*!
+ * \brief Generates a salt to try with crypt.
+ *
+ * If given an empty string, will generate a salt for the most secure algorithm
+ * to try with crypt(). If given a previously generated salt, the algorithm will
+ * be lowered by one level of security.
+ *
+ * \param[out] current_salt Output string in which to generate the salt.
+ *                          This can be an empty string, or the results of a
+ *                          prior gen_salt call.
+ * \param max_len Length of \a current_salt.
+ * \return 0 on success.
+ * \return Non-zero on error.
+ */
+static int gen_salt(char *current_salt, size_t maxlen)
+{
+	int i;
+
+	if (maxlen < MAX_SALT_LEN || current_salt == NULL) {
+		return -1;
+	}
+
+	switch (current_salt[0]) {
+	case '\0':
+		/* Initial generation; $6$ = SHA-512 */
+		*current_salt++ = '$';
+		*current_salt++ = '6';
+		*current_salt++ = '$';
+		for (i = 0; i < 16; ++i) {
+			*current_salt++ = gen_salt_char();
+		}
+		*current_salt++ = '$';
+		*current_salt++ = '\0';
+		return 0;
+	case '$':
+		switch (current_salt[1]) {
+		case '6':
+			/* Downgrade to SHA-256 */
+			current_salt[1] = '5';
+			return 0;
+		case '5':
+			/* Downgrade to MD5 */
+			current_salt[1] = '1';
+			return 0;
+		case '1':
+			/* Downgrade to traditional crypt */
+			*current_salt++ = gen_salt_char();
+			*current_salt++ = gen_salt_char();
+			*current_salt++ = '\0';
+			return 0;
+		default:
+			/* Unrecognized algorithm */
+			return -1;
+		}
+	default:
+		/* Was already as insecure as it gets */
+		return -1;
+	}
+
+}
+
+#if defined(HAVE_CRYPT_R)
+
+char *ast_crypt(const char *key, const char *salt)
+{
+	struct crypt_data data = {};
+	const char *crypted = crypt_r(key, salt, &data);
+
+	/* Crypt may return success even if it doesn't recognize the salt. But
+	 * in those cases it always mangles the salt in some way.
+	 */
+	if (!crypted || !ast_begins_with(crypted, salt)) {
+		return NULL;
+	}
+
+	return ast_strdup(crypted);
+}
+
+int ast_crypt_validate(const char *key, const char *expected)
+{
+	struct crypt_data data = {};
+	return strcmp(expected, crypt_r(key, expected, &data)) == 0;
+}
+
+#elif defined(HAVE_CRYPT)
+
+/* crypt is not reentrant. A global mutex is neither ideal nor perfect, but good
+ * enough if crypt_r support is unavailable
+ */
+AST_MUTEX_DEFINE_STATIC(crypt_mutex);
+
+char *ast_crypt(const char *key, const char *salt)
+{
+	const char *crypted;
+	SCOPED_MUTEX(lock, &crypt_mutex);
+
+	crypted = crypt(key, salt);
+
+	/* Crypt may return success even if it doesn't recognize the salt. But
+	 * in those cases it always mangles the salt in some way.
+	 */
+	if (!crypted || !ast_begins_with(crypted, salt)) {
+		return NULL;
+	}
+
+	return ast_strdup(crypted);
+}
+
+int ast_crypt_validate(const char *key, const char *expected)
+{
+	SCOPED_MUTEX(lock, &crypt_mutex);
+	return strcmp(expected, crypt(key, expected)) == 0;
+}
+
+#else /* No crypt support */
+
+char *ast_crypt(const char *key, const char *salt)
+{
+	ast_log(LOG_WARNING,
+		"crypt() support not available; cannot encrypt password\n");
+	return NULL;
+}
+
+int ast_crypt_validate(const char *key, const char *expected)
+{
+	ast_log(LOG_WARNING,
+		"crypt() support not available; cannot validate password\n");
+	return 0;
+}
+
+#endif  /* No crypt support */
+
+char *ast_crypt_encrypt(const char *key)
+{
+	char salt[MAX_SALT_LEN] = {};
+	while (gen_salt(salt, sizeof(salt)) == 0) {
+		char *crypted = ast_crypt(key, salt);
+		if (crypted) {
+			return crypted;
+		}
+	}
+	return NULL;
+}