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-rwxr-xr-xres/res_crypto.c633
1 files changed, 633 insertions, 0 deletions
diff --git a/res/res_crypto.c b/res/res_crypto.c
new file mode 100755
index 000000000..8aa4e9d6e
--- /dev/null
+++ b/res/res_crypto.c
@@ -0,0 +1,633 @@
+/*
+ * Asterisk -- A telephony toolkit for Linux.
+ *
+ * Provide Cryptographic Signature capability
+ *
+ * Copyright (C) 1999, Mark Spencer
+ *
+ * Mark Spencer <markster@linux-support.net>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License
+ */
+
+#include <asterisk/file.h>
+#include <asterisk/channel.h>
+#include <asterisk/logger.h>
+#include <asterisk/say.h>
+#include <asterisk/module.h>
+#include <asterisk/options.h>
+#include <asterisk/crypto.h>
+#include <asterisk/md5.h>
+#include <asterisk/cli.h>
+#include <asterisk/io.h>
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <dirent.h>
+#include <string.h>
+#include <errno.h>
+#include "../asterisk.h"
+
+/*
+ * Asterisk uses RSA keys with SHA-1 message digests for its
+ * digital signatures. The choice of RSA is due to its higher
+ * throughput on verification, and the choice of SHA-1 based
+ * on the recently discovered collisions in MD5's compression
+ * algorithm and recommendations of avoiding MD5 in new schemes
+ * from various industry experts.
+ *
+ * We use OpenSSL to provide our crypto routines, although we never
+ * actually use full-up SSL
+ *
+ */
+
+/*
+ * XXX This module is not very thread-safe. It is for everyday stuff
+ * like reading keys and stuff, but there are all kinds of weird
+ * races with people running reload and key init at the same time
+ * for example
+ *
+ * XXXX
+ */
+
+static char base64[64];
+static char b2a[256];
+
+static pthread_mutex_t keylock = PTHREAD_MUTEX_INITIALIZER;
+
+#define KEY_NEEDS_PASSCODE (1 << 16)
+
+struct ast_key {
+ /* Name of entity */
+ char name[80];
+ /* File name */
+ char fn[256];
+ /* Key type (AST_KEY_PUB or AST_KEY_PRIV, along with flags from above) */
+ int ktype;
+ /* RSA structure (if successfully loaded) */
+ RSA *rsa;
+ /* Whether we should be deleted */
+ int delme;
+ /* FD for input (or -1 if no input allowed, or -2 if we needed input) */
+ int infd;
+ /* FD for output */
+ int outfd;
+ /* Last MD5 Digest */
+ unsigned char digest[16];
+ struct ast_key *next;
+};
+
+static struct ast_key *keys = NULL;
+
+static int fdprint(int fd, char *s)
+{
+ return write(fd, s, strlen(s) + 1);
+}
+
+static int pw_cb(char *buf, int size, int rwflag, void *userdata)
+{
+ struct ast_key *key = (struct ast_key *)userdata;
+ char prompt[256];
+ int res;
+ int tmp;
+ if (key->infd > -1) {
+ snprintf(prompt, sizeof(prompt), ">>>> passcode for %s key '%s': ",
+ key->ktype == AST_KEY_PRIVATE ? "PRIVATE" : "PUBLIC", key->name);
+ write(key->outfd, prompt, strlen(prompt));
+ memset(buf, 0, sizeof(buf));
+ tmp = ast_hide_password(key->infd);
+ memset(buf, 0, size);
+ res = read(key->infd, buf, size);
+ ast_restore_tty(key->infd, tmp);
+ if (buf[strlen(buf) -1] == '\n')
+ buf[strlen(buf) - 1] = '\0';
+ return strlen(buf);
+ } else {
+ /* Note that we were at least called */
+ key->infd = -2;
+ }
+ return -1;
+}
+
+struct ast_key *ast_key_get(char *kname, int ktype)
+{
+ struct ast_key *key;
+ ast_pthread_mutex_lock(&keylock);
+ key = keys;
+ while(key) {
+ if (!strcmp(kname, key->name) &&
+ (ktype == key->ktype))
+ break;
+ key = key->next;
+ }
+ ast_pthread_mutex_unlock(&keylock);
+ return key;
+}
+
+static struct ast_key *try_load_key (char *dir, char *fname, int ifd, int ofd, int *not2)
+{
+ int ktype = 0;
+ char *c = NULL;
+ char ffname[256];
+ char digest[16];
+ FILE *f;
+ struct MD5Context md5;
+ struct ast_key *key;
+ static int notice = 0;
+ int found = 0;
+
+ /* Make sure its name is a public or private key */
+
+ if ((c = strstr(fname, ".pub")) && !strcmp(c, ".pub")) {
+ ktype = AST_KEY_PUBLIC;
+ } else if ((c = strstr(fname, ".key")) && !strcmp(c, ".key")) {
+ ktype = AST_KEY_PRIVATE;
+ } else
+ return NULL;
+
+ /* Get actual filename */
+ snprintf(ffname, sizeof(ffname), "%s/%s", dir, fname);
+
+ ast_pthread_mutex_lock(&keylock);
+ key = keys;
+ while(key) {
+ /* Look for an existing version already */
+ if (!strcasecmp(key->fn, ffname))
+ break;
+ key = key->next;
+ }
+ ast_pthread_mutex_unlock(&keylock);
+
+ /* Open file */
+ f = fopen(ffname, "r");
+ if (!f) {
+ ast_log(LOG_WARNING, "Unable to open key file %s: %s\n", ffname, strerror(errno));
+ return NULL;
+ }
+ MD5Init(&md5);
+ while(!feof(f)) {
+ /* Calculate a "whatever" quality md5sum of the key */
+ char buf[256];
+ fgets(buf, sizeof(buf), f);
+ if (!feof(f)) {
+ MD5Update(&md5, buf, strlen(buf));
+ }
+ }
+ MD5Final(digest, &md5);
+ if (key) {
+ /* If the MD5 sum is the same, and it isn't awaiting a passcode
+ then this is far enough */
+ if (!memcmp(digest, key->digest, 16) &&
+ !(key->ktype & KEY_NEEDS_PASSCODE)) {
+ fclose(f);
+ key->delme = 0;
+ return NULL;
+ } else {
+ /* Preserve keytype */
+ ktype = key->ktype;
+ /* Recycle the same structure */
+ found++;
+ }
+ }
+
+ /* Make fname just be the normal name now */
+ *c = '\0';
+ if (!key) {
+ key = (struct ast_key *)malloc(sizeof(struct ast_key));
+ if (!key) {
+ ast_log(LOG_WARNING, "Out of memory\n");
+ fclose(f);
+ return NULL;
+ }
+ memset(key, 0, sizeof(struct ast_key));
+ }
+ /* At this point we have a key structure (old or new). Time to
+ fill it with what we know */
+ /* Gotta lock if this one already exists */
+ if (found)
+ ast_pthread_mutex_lock(&keylock);
+ /* First the filename */
+ strncpy(key->fn, ffname, sizeof(key->fn));
+ /* Then the name */
+ strncpy(key->name, fname, sizeof(key->name));
+ key->ktype = ktype;
+ /* Yes, assume we're going to be deleted */
+ key->delme = 1;
+ /* Keep the key type */
+ memcpy(key->digest, digest, 16);
+ /* Can I/O takes the FD we're given */
+ key->infd = ifd;
+ key->outfd = ofd;
+ /* Reset the file back to the beginning */
+ rewind(f);
+ /* Now load the key with the right method */
+ if (ktype == AST_KEY_PUBLIC)
+ key->rsa = PEM_read_RSA_PUBKEY(f, NULL, pw_cb, key);
+ else
+ key->rsa = PEM_read_RSAPrivateKey(f, NULL, pw_cb, key);
+ fclose(f);
+ if (key->rsa) {
+ /* Key loaded okay */
+ key->ktype &= ~KEY_NEEDS_PASSCODE;
+ if (option_verbose > 2)
+ ast_verbose(VERBOSE_PREFIX_3 "Loaded %s key '%s'\n", key->ktype == AST_KEY_PUBLIC ? "PUBLIC" : "PRIVATE", key->name);
+ if (option_debug)
+ ast_log(LOG_DEBUG, "Key '%s' loaded OK\n", key->name);
+ key->delme = 0;
+ } else if (key->infd != -2) {
+ ast_log(LOG_WARNING, "Key load %s '%s' failed\n",key->ktype == AST_KEY_PUBLIC ? "PUBLIC" : "PRIVATE", key->name);
+ if (ofd > -1) {
+ ERR_print_errors_fp(stderr);
+ } else
+ ERR_print_errors_fp(stderr);
+ } else {
+ ast_log(LOG_NOTICE, "Key '%s' needs passcode.\n", key->name);
+ key->ktype |= KEY_NEEDS_PASSCODE;
+ if (!notice) {
+ if (!option_initcrypto)
+ ast_log(LOG_NOTICE, "Add the '-i' flag to the asterisk command line if you want to automatically initialize passcodes at launch.\n");
+ notice++;
+ }
+ /* Keep it anyway */
+ key->delme = 0;
+ /* Print final notice about "init keys" when done */
+ *not2 = 1;
+ }
+ if (found)
+ ast_pthread_mutex_unlock(&keylock);
+ if (!found) {
+ ast_pthread_mutex_lock(&keylock);
+ key->next = keys;
+ keys = key;
+ ast_pthread_mutex_unlock(&keylock);
+ }
+ return key;
+}
+
+#if 0
+
+static void dump(unsigned char *src, int len)
+{
+ int x;
+ for (x=0;x<len;x++)
+ printf("%02x", *(src++));
+ printf("\n");
+}
+
+static char *binary(int y, int len)
+{
+ static char res[80];
+ int x;
+ memset(res, 0, sizeof(res));
+ for (x=0;x<len;x++) {
+ if (y & (1 << x))
+ res[(len - x - 1)] = '1';
+ else
+ res[(len - x - 1)] = '0';
+ }
+ return res;
+}
+
+#endif
+
+static int base64decode(unsigned char *dst, char *src, int max)
+{
+ int cnt = 0;
+ unsigned int byte = 0;
+ unsigned int bits = 0;
+ int incnt = 0;
+#if 0
+ unsigned char *odst = dst;
+#endif
+ while(*src && (cnt < max)) {
+ /* Shift in 6 bits of input */
+ byte <<= 6;
+ byte |= (b2a[(int)(*src)]) & 0x3f;
+ bits += 6;
+#if 0
+ printf("Add: %c %s\n", *src, binary(b2a[(int)(*src)] & 0x3f, 6));
+#endif
+ src++;
+ incnt++;
+ /* If we have at least 8 bits left over, take that character
+ off the top */
+ if (bits >= 8) {
+ bits -= 8;
+ *dst = (byte >> bits) & 0xff;
+#if 0
+ printf("Remove: %02x %s\n", *dst, binary(*dst, 8));
+#endif
+ dst++;
+ cnt++;
+ }
+ }
+#if 0
+ dump(odst, cnt);
+#endif
+ /* Dont worry about left over bits, they're extra anyway */
+ return cnt;
+}
+
+static int base64encode(char *dst, unsigned char *src, int srclen, int max)
+{
+ int cnt = 0;
+ unsigned int byte = 0;
+ int bits = 0;
+ int index;
+ int cntin = 0;
+#if 0
+ char *odst = dst;
+ dump(src, srclen);
+#endif
+ /* Reserve one bit for end */
+ max--;
+ while((cntin < srclen) && (cnt < max)) {
+ byte <<= 8;
+#if 0
+ printf("Add: %02x %s\n", *src, binary(*src, 8));
+#endif
+ byte |= *(src++);
+ bits += 8;
+ cntin++;
+ while((bits >= 6) && (cnt < max)) {
+ bits -= 6;
+ /* We want only the top */
+ index = (byte >> bits) & 0x3f;
+ *dst = base64[index];
+#if 0
+ printf("Remove: %c %s\n", *dst, binary(index, 6));
+#endif
+ dst++;
+ cnt++;
+ }
+ }
+ if (bits && (cnt < max)) {
+ /* Add one last character for the remaining bits,
+ padding the rest with 0 */
+ byte <<= (6 - bits);
+ index = (byte) & 0x3f;
+ *(dst++) = base64[index];
+ cnt++;
+ }
+ *dst = '\0';
+ return cnt;
+}
+
+int ast_sign(struct ast_key *key, char *msg, char *sig)
+{
+ unsigned char digest[20];
+ unsigned char dsig[128];
+ int siglen = sizeof(dsig);
+ int res;
+
+ if (key->ktype != AST_KEY_PRIVATE) {
+ ast_log(LOG_WARNING, "Cannot sign with a private key\n");
+ return -1;
+ }
+
+ /* Calculate digest of message */
+ SHA1((unsigned char *)msg, strlen(msg), digest);
+
+ /* Verify signature */
+ res = RSA_sign(NID_sha1, digest, sizeof(digest), dsig, &siglen, key->rsa);
+
+ if (!res) {
+ ast_log(LOG_WARNING, "RSA Signature (key %s) failed\n", key->name);
+ return -1;
+ }
+
+ if (siglen != sizeof(dsig)) {
+ ast_log(LOG_WARNING, "Unexpected signature length %d, expecting %d\n", siglen, sizeof(dsig));
+ return -1;
+ }
+
+ /* Success -- encode (256 bytes max as documented) */
+ base64encode(sig, dsig, siglen, 256);
+ return 0;
+
+}
+
+int ast_check_signature(struct ast_key *key, char *msg, char *sig)
+{
+ unsigned char digest[20];
+ unsigned char dsig[128];
+ int res;
+
+ if (key->ktype != AST_KEY_PUBLIC) {
+ /* Okay, so of course you really *can* but for our purposes
+ we're going to say you can't */
+ ast_log(LOG_WARNING, "Cannot check message signature with a private key\n");
+ return -1;
+ }
+
+ /* Decode signature */
+ res = base64decode(dsig, sig, sizeof(dsig));
+ if (res != sizeof(dsig)) {
+ ast_log(LOG_WARNING, "Signature improper length (expect %d, got %d)\n", sizeof(dsig), res);
+ return -1;
+ }
+
+ /* Calculate digest of message */
+ SHA1((unsigned char *)msg, strlen(msg), digest);
+
+ /* Verify signature */
+ res = RSA_verify(NID_sha1, digest, sizeof(digest), dsig, sizeof(dsig), key->rsa);
+
+ if (!res) {
+ ast_log(LOG_DEBUG, "Key failed verification\n");
+ return -1;
+ }
+ /* Pass */
+ return 0;
+}
+
+static void crypto_load(int ifd, int ofd)
+{
+ struct ast_key *key, *nkey, *last;
+ DIR *dir;
+ struct dirent *ent;
+ int note = 0;
+ /* Mark all keys for deletion */
+ ast_pthread_mutex_lock(&keylock);
+ key = keys;
+ while(key) {
+ key->delme = 1;
+ key = key->next;
+ }
+ ast_pthread_mutex_unlock(&keylock);
+ /* Load new keys */
+ dir = opendir(AST_KEY_DIR);
+ if (dir) {
+ while((ent = readdir(dir))) {
+ try_load_key(AST_KEY_DIR, ent->d_name, ifd, ofd, &note);
+ }
+ closedir(dir);
+ } else
+ ast_log(LOG_WARNING, "Unable to open key directory '%s'\n", AST_KEY_DIR);
+ if (note) {
+ ast_log(LOG_NOTICE, "Please run the command 'init keys' to enter the passcodes for the keys\n");
+ }
+ ast_pthread_mutex_lock(&keylock);
+ key = keys;
+ last = NULL;
+ while(key) {
+ nkey = key->next;
+ if (key->delme) {
+ ast_log(LOG_DEBUG, "Deleting key %s type %d\n", key->name, key->ktype);
+ /* Do the delete */
+ if (last)
+ last->next = nkey;
+ else
+ keys = nkey;
+ if (key->rsa)
+ RSA_free(key->rsa);
+ free(key);
+ } else
+ last = key;
+ key = nkey;
+ }
+ ast_pthread_mutex_unlock(&keylock);
+}
+
+static void md52sum(char *sum, unsigned char *md5)
+{
+ int x;
+ for (x=0;x<16;x++)
+ sum += sprintf(sum, "%02x", *(md5++));
+}
+
+static int show_keys(int fd, int argc, char *argv[])
+{
+ struct ast_key *key;
+ char sum[16 * 2 + 1];
+
+ ast_pthread_mutex_lock(&keylock);
+ key = keys;
+ ast_cli(fd, "%-18s %-8s %-16s %-33s\n", "Key Name", "Type", "Status", "Sum");
+ while(key) {
+ md52sum(sum, key->digest);
+ ast_cli(fd, "%-18s %-8s %-16s %-33s\n", key->name,
+ (key->ktype & 0xf) == AST_KEY_PUBLIC ? "PUBLIC" : "PRIVATE",
+ key->ktype & KEY_NEEDS_PASSCODE ? "[Needs Passcode]" : "[Loaded]", sum);
+
+ key = key->next;
+ }
+ ast_pthread_mutex_unlock(&keylock);
+ return RESULT_SUCCESS;
+}
+
+static int init_keys(int fd, int argc, char *argv[])
+{
+ struct ast_key *key;
+ int ign;
+ char *kn;
+ char tmp[256];
+
+ key = keys;
+ while(key) {
+ /* Reload keys that need pass codes now */
+ if (key->ktype & KEY_NEEDS_PASSCODE) {
+ kn = key->fn + strlen(AST_KEY_DIR) + 1;
+ strncpy(tmp, kn, sizeof(tmp));
+ try_load_key(AST_KEY_DIR, tmp, fd, fd, &ign);
+ }
+ key = key->next;
+ }
+ return RESULT_SUCCESS;
+}
+
+static char show_key_usage[] =
+"Usage: show keys\n"
+" Displays information about RSA keys known by Asterisk\n";
+
+static char init_keys_usage[] =
+"Usage: init keys\n"
+" Initializes private keys (by reading in pass code from the user)\n";
+
+static struct ast_cli_entry cli_show_keys =
+{ { "show", "keys", NULL }, show_keys, "Displays RSA key information", show_key_usage };
+
+static struct ast_cli_entry cli_init_keys =
+{ { "init", "keys", NULL }, init_keys, "Initialize RSA key passcodes", init_keys_usage };
+
+static void base64_init(void)
+{
+ int x;
+ memset(b2a, -1, sizeof(b2a));
+ /* Initialize base-64 Conversion table */
+ for (x=0;x<26;x++) {
+ /* A-Z */
+ base64[x] = 'A' + x;
+ b2a['A' + x] = x;
+ /* a-z */
+ base64[x + 26] = 'a' + x;
+ b2a['a' + x] = x + 26;
+ /* 0-9 */
+ if (x < 10) {
+ base64[x + 52] = '0' + x;
+ b2a['0' + x] = x + 52;
+ }
+ }
+ base64[62] = '+';
+ base64[63] = '/';
+ b2a[(int)'+'] = 62;
+ b2a[(int)'/'] = 63;
+#if 0
+ for (x=0;x<64;x++) {
+ if (b2a[(int)base64[x]] != x) {
+ fprintf(stderr, "!!! %d failed\n", x);
+ } else
+ fprintf(stderr, "--- %d passed\n", x);
+ }
+#endif
+}
+
+static int crypto_init(void)
+{
+ base64_init();
+ SSL_library_init();
+ ERR_load_crypto_strings();
+ ast_cli_register(&cli_show_keys);
+ ast_cli_register(&cli_init_keys);
+ return 0;
+}
+
+int reload(void)
+{
+ crypto_load(-1, -1);
+ return 0;
+}
+
+int load_module(void)
+{
+ crypto_init();
+ if (option_initcrypto)
+ crypto_load(STDIN_FILENO, STDOUT_FILENO);
+ else
+ crypto_load(-1, -1);
+ return 0;
+}
+
+int unload_module(void)
+{
+ /* Can't unload this once we're loaded */
+ return -1;
+}
+
+char *description(void)
+{
+ return "Cryptographic Digital Signatures";
+}
+
+int usecount(void)
+{
+ /* We should never be unloaded */
+ return 1;
+}
+
+char *key()
+{
+ return ASTERISK_GPL_KEY;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-03 16:57:24 +0000