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SSLproxy/ssl.c
Daniel Roethlisberger fa425e08d4 Fix PURIFY and warn when not seeding the RNG
2012-04-23 00:51:02 +02:00

1630 lines
42 KiB
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/*
* SSLsplit - transparent and scalable SSL/TLS interception
* Copyright (c) 2009-2012, Daniel Roethlisberger <daniel@roe.ch>
* All rights reserved.
* http://www.roe.ch/SSLsplit
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "ssl.h"
#include "log.h"
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <limits.h>
#include <openssl/crypto.h>
#include <openssl/engine.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#ifndef OPENSSL_NO_DH
#include <openssl/dh.h>
#endif /* !OPENSSL_NO_DH */
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/ocsp.h>
/*
* Collection of helper functions on top of the OpenSSL API.
*/
/*
* Print OpenSSL version and build-time configuration to standard error and
* return.
*/
void
ssl_openssl_version(void)
{
fprintf(stderr, "compiled against %s (%lx)\n",
OPENSSL_VERSION_TEXT,
(long unsigned int)OPENSSL_VERSION_NUMBER);
fprintf(stderr, "rtlinked against %s (%lx)\n",
SSLeay_version(SSLEAY_VERSION),
SSLeay());
#ifndef OPENSSL_NO_TLSEXT
fprintf(stderr, "TLS Server Name Indication (SNI) supported\n");
#else /* OPENSSL_NO_TLSEXT */
fprintf(stderr, "TLS Server Name Indication (SNI) not supported\n");
#endif /* OPENSSL_NO_TLSEXT */
#ifdef OPENSSL_THREADS
#ifndef OPENSSL_NO_THREADID
fprintf(stderr, "OpenSSL is thread-safe with THREADID\n");
#else /* OPENSSL_NO_THREADID */
fprintf(stderr, "OpenSSL is thread-safe without THREADID\n");
#endif /* OPENSSL_NO_THREADID */
#else /* !OPENSSL_THREADS */
fprintf(stderr, "OpenSSL is not thread-safe\n");
#endif /* !OPENSSL_THREADS */
fprintf(stderr, "SSL/TLS algorithm availability:");
#ifndef OPENSSL_NO_RSA
fprintf(stderr, " RSA");
#else /* OPENSSL_NO_RSA */
fprintf(stderr, " !RSA");
#endif /* OPENSSL_NO_RSA */
#ifndef OPENSSL_NO_DSA
fprintf(stderr, " DSA");
#else /* OPENSSL_NO_DSA */
fprintf(stderr, " !DSA");
#endif /* OPENSSL_NO_DSA */
#ifndef OPENSSL_NO_ECDSA
fprintf(stderr, " ECDSA");
#else /* OPENSSL_NO_ECDSA */
fprintf(stderr, " !ECDSA");
#endif /* OPENSSL_NO_ECDSA */
#ifndef OPENSSL_NO_DH
fprintf(stderr, " DH");
#else /* OPENSSL_NO_DH */
fprintf(stderr, " !DH");
#endif /* OPENSSL_NO_DH */
#ifndef OPENSSL_NO_ECDH
fprintf(stderr, " ECDH");
#else /* OPENSSL_NO_ECDH */
fprintf(stderr, " !ECDH");
#endif /* OPENSSL_NO_ECDH */
fprintf(stderr, "\n");
fprintf(stderr, "OpenSSL option availability:");
#ifdef SSL_OP_NO_COMPRESSION
fprintf(stderr, " SSL_OP_NO_COMPRESSION");
#else /* !SSL_OP_NO_COMPRESSION */
fprintf(stderr, " !SSL_OP_NO_COMPRESSION");
#endif /* SSL_OP_NO_COMPRESSION */
#ifdef SSL_OP_NO_TICKET
fprintf(stderr, " SSL_OP_NO_TICKET");
#else /* !SSL_OP_NO_TICKET */
fprintf(stderr, " !SSL_OP_NO_TICKET");
#endif /* SSL_OP_NO_TICKET */
#ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
fprintf(stderr, " SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION");
#else /* !SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION */
fprintf(stderr, " !SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION");
#endif /* !SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION */
#ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
fprintf(stderr, " SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS");
#else /* !SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS */
fprintf(stderr, " !SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS");
#endif /* !SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS */
#ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
fprintf(stderr, " SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION");
#else /* !SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION */
fprintf(stderr, " !SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION");
#endif /* !SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION */
#ifdef SSL_OP_TLS_ROLLBACK_BUG
fprintf(stderr, " SSL_OP_TLS_ROLLBACK_BUG");
#else /* !SSL_OP_TLS_ROLLBACK_BUG */
fprintf(stderr, " !SSL_OP_TLS_ROLLBACK_BUG");
#endif /* !SSL_OP_TLS_ROLLBACK_BUG */
fprintf(stderr, "\n");
}
/*
* 1 if OpenSSL has been initialized, 0 if not. When calling a _load()
* function the first time, OpenSSL will automatically be initialized.
* Not protected by a mutex and thus not thread-safe.
*/
static int ssl_initialized = 0;
#ifdef OPENSSL_THREADS
struct CRYPTO_dynlock_value {
pthread_mutex_t mutex;
};
static pthread_mutex_t *ssl_mutex;
static int ssl_mutex_num;
/*
* OpenSSL thread-safety locking callback, #1.
*/
static void
ssl_thr_locking_cb(int mode, int type, UNUSED const char *file,
UNUSED int line) {
if (type < ssl_mutex_num) {
if (mode & CRYPTO_LOCK)
pthread_mutex_lock(&ssl_mutex[type]);
else
pthread_mutex_unlock(&ssl_mutex[type]);
}
}
/*
* OpenSSL thread-safety locking callback, #2.
*/
static struct CRYPTO_dynlock_value *
ssl_thr_dyn_create_cb(UNUSED const char *file, UNUSED int line)
{
struct CRYPTO_dynlock_value *dl;
if ((dl = malloc(sizeof(struct CRYPTO_dynlock_value)))) {
pthread_mutex_init(&dl->mutex, NULL);
}
return dl;
}
/*
* OpenSSL thread-safety locking callback, #3.
*/
static void
ssl_thr_dyn_lock_cb(int mode, struct CRYPTO_dynlock_value *dl,
UNUSED const char *file, UNUSED int line)
{
if (mode & CRYPTO_LOCK) {
pthread_mutex_lock(&dl->mutex);
} else {
pthread_mutex_unlock(&dl->mutex);
}
}
/*
* OpenSSL thread-safety locking callback, #4.
*/
static void
ssl_thr_dyn_destroy_cb(struct CRYPTO_dynlock_value *dl,
UNUSED const char *file, UNUSED int line)
{
pthread_mutex_destroy(&dl->mutex);
free(dl);
}
#ifdef OPENSSL_NO_THREADID
/*
* OpenSSL thread-safety thread ID callback, legacy version.
*/
static unsigned long
ssl_thr_id_cb(void) {
return (unsigned long) pthread_self();
}
#else /* !OPENSSL_NO_THREADID */
/*
* OpenSSL thread-safety thread ID callback, up-to-date version.
*/
static void
ssl_thr_id_cb(CRYPTO_THREADID *id)
{
CRYPTO_THREADID_set_numeric(id, (unsigned long) pthread_self());
}
#endif /* !OPENSSL_NO_THREADID */
#endif /* OPENSSL_THREADS */
/*
* Initialize OpenSSL and verify the random number generator works.
* Returns -1 on failure, 0 on success.
*/
int
ssl_init(void)
{
#ifndef PURIFY
int fd;
#endif /* !PURIFY */
char buf[256];
if (ssl_initialized)
return 0;
/* general initialization */
SSL_library_init();
#ifdef PURIFY
CRYPTO_malloc_init();
CRYPTO_mem_ctrl(CRYPTO_MEM_CHECK_ON);
#endif /* PURIFY */
SSL_load_error_strings();
OpenSSL_add_all_algorithms();
/* thread-safety */
#ifdef OPENSSL_THREADS
ssl_mutex_num = CRYPTO_num_locks();
ssl_mutex = malloc(ssl_mutex_num * sizeof(*ssl_mutex));
for (int i = 0; i < ssl_mutex_num; i++) {
pthread_mutex_init(&ssl_mutex[i], NULL);
}
CRYPTO_set_locking_callback(ssl_thr_locking_cb);
CRYPTO_set_dynlock_create_callback(ssl_thr_dyn_create_cb);
CRYPTO_set_dynlock_lock_callback(ssl_thr_dyn_lock_cb);
CRYPTO_set_dynlock_destroy_callback(ssl_thr_dyn_destroy_cb);
#ifdef OPENSSL_NO_THREADID
CRYPTO_set_id_callback(ssl_thr_id_cb);
#else /* !OPENSSL_NO_THREADID */
CRYPTO_THREADID_set_callback(ssl_thr_id_cb);
#endif /* !OPENSSL_NO_THREADID */
#endif /* OPENSSL_THREADS */
/* randomness */
#ifndef PURIFY
if ((fd = open("/dev/urandom", O_RDONLY)) == -1) {
log_err_printf("Error opening /dev/urandom for reading: %s\n",
strerror(errno));
return -1;
}
while (!RAND_status()) {
if (read(fd, buf, sizeof(buf)) == -1) {
log_err_printf("Error reading from /dev/urandom: %s\n",
strerror(errno));
close(fd);
return -1;
}
RAND_seed(buf, sizeof(buf));
}
close(fd);
if (!RAND_poll()) {
log_err_printf("RAND_poll() failed.\n");
return -1;
}
#else /* PURIFY */
log_err_printf("Warning: not seeding OpenSSL RAND due to PURITY!\n");
memset(buf, 0, sizeof(buf));
while (!RAND_status()) {
RAND_seed(buf, sizeof(buf));
}
#endif /* PURIFY */
#ifdef USE_FOOTPRINT_HACKS
/* HACK: disable compression by zeroing the global comp algo stack.
* This lowers the per-connection memory footprint by ~500k. */
STACK_OF(SSL_COMP)* comp_methods = SSL_COMP_get_compression_methods();
sk_SSL_COMP_zero(comp_methods);
#endif /* USE_FOOTPRINT_HACKS */
ssl_initialized = 1;
return 0;
}
/*
* Deinitialize OpenSSL and free as much memory as possible.
* Some 10k-100k will still remain resident no matter what.
*/
void
ssl_fini(void)
{
if (!ssl_initialized)
return;
ERR_remove_state(0); /* current thread */
#ifdef OPENSSL_THREADS
CRYPTO_set_locking_callback(NULL);
CRYPTO_set_dynlock_create_callback(NULL);
CRYPTO_set_dynlock_lock_callback(NULL);
CRYPTO_set_dynlock_destroy_callback(NULL);
#ifdef OPENSSL_NO_THREADID
CRYPTO_set_id_callback(NULL);
#else /* !OPENSSL_NO_THREADID */
CRYPTO_THREADID_set_callback(NULL);
#endif /* !OPENSSL_NO_THREADID */
for (int i = 0; i < ssl_mutex_num; i++) {
pthread_mutex_destroy(&ssl_mutex[i]);
}
free(ssl_mutex);
#endif
ENGINE_cleanup();
CONF_modules_finish();
CONF_modules_unload(1);
CONF_modules_free();
EVP_cleanup();
ERR_free_strings();
CRYPTO_cleanup_all_ex_data();
}
#ifndef OPENSSL_NO_DH
static unsigned char dh_g[] = { 0x02 };
static unsigned char dh512_p[] = {
0xAB, 0xC0, 0x34, 0x16, 0x95, 0x8B, 0x57, 0xE5, 0x5C, 0xB3, 0x4E, 0x6E,
0x16, 0x0B, 0x35, 0xC5, 0x6A, 0xCC, 0x4F, 0xD3, 0xE5, 0x46, 0xE2, 0x23,
0x6A, 0x5B, 0xBB, 0x5D, 0x3D, 0x52, 0xEA, 0xCE, 0x4F, 0x7D, 0xCA, 0xFF,
0xB4, 0x8B, 0xC9, 0x78, 0xDC, 0xA0, 0xFC, 0xBE, 0xF3, 0xB5, 0xE6, 0x61,
0xA6, 0x6D, 0x58, 0xFC, 0xA0, 0x0F, 0xF7, 0x9B, 0x97, 0xE6, 0xC7, 0xE8,
0x1F, 0xCD, 0x16, 0x73 };
static unsigned char dh1024_p[] = {
0x99, 0x28, 0x34, 0x48, 0x9E, 0xB7, 0xD1, 0x4F, 0x0D, 0x17, 0x09, 0x97,
0xB9, 0x9B, 0x20, 0xFE, 0xE5, 0x65, 0xE0, 0xE2, 0x56, 0x37, 0x80, 0xA2,
0x9F, 0x2C, 0x2D, 0x87, 0x10, 0x58, 0x39, 0xAD, 0xF3, 0xC5, 0xA9, 0x08,
0x24, 0xC7, 0xAA, 0xA9, 0x29, 0x3A, 0x13, 0xDF, 0x4E, 0x0A, 0x6D, 0x11,
0x39, 0xB1, 0x1C, 0x3F, 0xFE, 0xFE, 0x0A, 0x5E, 0xAD, 0x2E, 0x5C, 0x10,
0x97, 0x38, 0xAC, 0xE8, 0xEB, 0xAA, 0x4A, 0xA1, 0xC0, 0x5C, 0x1D, 0x27,
0x65, 0x9C, 0xC8, 0x53, 0xAC, 0x35, 0xDD, 0x84, 0x1F, 0x47, 0x0E, 0x04,
0xF1, 0x90, 0x61, 0x62, 0x2E, 0x29, 0x2C, 0xC6, 0x28, 0x91, 0x6D, 0xF0,
0xE2, 0x5E, 0xCE, 0x60, 0x3E, 0xF7, 0xF8, 0x37, 0x99, 0x4D, 0x9F, 0xFB,
0x68, 0xEC, 0x7F, 0x9D, 0x32, 0x74, 0xD1, 0xAA, 0xD4, 0x4C, 0xF5, 0xCD,
0xC2, 0xD7, 0xD7, 0xAC, 0xDA, 0x69, 0xF5, 0x2B };
#if 0
static unsigned char dh2048_p[] = {
0xAB, 0x88, 0x97, 0xCA, 0xF1, 0xE1, 0x60, 0x39, 0xFA, 0xB1, 0xA8, 0x7D,
0xB3, 0x7A, 0x38, 0x08, 0xF0, 0x7A, 0x3D, 0x21, 0xC4, 0xE6, 0xB8, 0x32,
0x3D, 0xAB, 0x0F, 0xE7, 0x8C, 0xA1, 0x59, 0x47, 0xB2, 0x0A, 0x7A, 0x3A,
0x20, 0x2A, 0x1B, 0xD4, 0xBA, 0xFC, 0x4C, 0xC5, 0xEE, 0xA2, 0xB9, 0xB9,
0x65, 0x47, 0xCC, 0x13, 0x99, 0xD7, 0xA6, 0xCA, 0xFF, 0x23, 0x05, 0x91,
0xAB, 0x5C, 0x82, 0xB8, 0xB4, 0xFD, 0xB1, 0x2E, 0x5B, 0x0F, 0x8E, 0x03,
0x3C, 0x23, 0xD6, 0x6A, 0xE2, 0x83, 0x95, 0xD2, 0x8E, 0xEB, 0xDF, 0x3A,
0xAF, 0x89, 0xF0, 0xA0, 0x14, 0x09, 0x12, 0xF6, 0x54, 0x54, 0x93, 0xF4,
0xD4, 0x41, 0x56, 0x7A, 0x0E, 0x56, 0x20, 0x1F, 0x1D, 0xBA, 0x3F, 0x07,
0xD2, 0x89, 0x1B, 0x40, 0xD0, 0x1C, 0x08, 0xDF, 0x00, 0x7F, 0x34, 0xF4,
0x28, 0x4E, 0xF7, 0x53, 0x8D, 0x4A, 0x00, 0xC3, 0xC0, 0x89, 0x9E, 0x63,
0x96, 0xE9, 0x52, 0xDF, 0xA5, 0x2C, 0x00, 0x4E, 0xB0, 0x82, 0x6A, 0x10,
0x28, 0x8D, 0xB9, 0xE7, 0x7A, 0xCB, 0xC3, 0xD6, 0xC1, 0xC0, 0x4D, 0x91,
0xC4, 0x6F, 0xD3, 0x99, 0xD1, 0x86, 0x71, 0x67, 0x0A, 0xA1, 0xFC, 0xF4,
0x7D, 0x40, 0x88, 0x8D, 0xAC, 0xCB, 0xBC, 0xEA, 0x17, 0x85, 0x0B, 0xC6,
0x12, 0x3E, 0x4A, 0xB9, 0x60, 0x74, 0x93, 0x54, 0x14, 0x39, 0x10, 0xBF,
0x21, 0xB0, 0x8B, 0xB1, 0x55, 0x3F, 0xBB, 0x6A, 0x1F, 0x42, 0x82, 0x0A,
0x40, 0x3A, 0x15, 0xCD, 0xD3, 0x79, 0xD0, 0x02, 0xA4, 0xF5, 0x79, 0x78,
0x03, 0xBD, 0x47, 0xCC, 0xD5, 0x08, 0x6A, 0x46, 0xAE, 0x36, 0xE4, 0xCD,
0xB1, 0x17, 0x48, 0x30, 0xB4, 0x02, 0xBC, 0x50, 0x68, 0xE3, 0xA2, 0x76,
0xD0, 0x5C, 0xB9, 0xE6, 0xBE, 0x4C, 0xFD, 0x50, 0xEF, 0xD0, 0x3F, 0x39,
0x4F, 0x53, 0x16, 0x3B };
#endif
/*
* OpenSSL temporary DH callback which loads DH parameters from static memory.
*/
DH *
ssl_tmp_dh_callback(UNUSED SSL *s, UNUSED int is_export, int keylength)
{
DH *dh;
if (!(dh = DH_new()))
return NULL;
if (keylength <= 512) {
dh->p = BN_bin2bn(dh512_p, sizeof(dh512_p), NULL);
} else /* if (keylength <= 1024) */ {
dh->p = BN_bin2bn(dh1024_p, sizeof(dh1024_p), NULL);
} /* else {
dh->p = BN_bin2bn(dh2048_p, sizeof(dh2048_p), NULL);
} */
dh->g = BN_bin2bn(dh_g, sizeof(dh_g), NULL);
if (!dh->p || !dh->g) {
DH_free(dh);
return NULL;
}
return(dh);
}
/*
* Load DH parameters from a PEM file.
* Not thread-safe.
*/
DH *
ssl_dh_load(const char *filename)
{
DH *dh;
FILE *fh;
if (ssl_init() == -1)
return NULL;
if (!(fh = fopen(filename, "r"))) {
return NULL;
}
dh = PEM_read_DHparams(fh, NULL, NULL, NULL);
fclose(fh);
return dh;
}
#endif /* !OPENSSL_NO_DH */
#ifndef OPENSSL_NO_ECDH
/*
* Load an Elliptic Curve by name. If curvename is NULL, a default curve is
* loaded.
*/
EC_KEY *
ssl_ecdh_by_name(const char *curvename)
{
int nid;
if (!curvename)
curvename = SSL_EC_KEY_CURVE_DEFAULT;
if ((nid = OBJ_sn2nid(curvename)) == NID_undef) {
return NULL;
}
return EC_KEY_new_by_curve_name(nid);
}
#endif /* !OPENSSL_NO_ECDH */
/*
* Add a X509v3 extension to a certificate and handle errors.
* Returns -1 on errors, 0 on success.
*/
int
ssl_x509_v3ext_add(X509V3_CTX *ctx, X509 *crt, char *k, char *v)
{
X509_EXTENSION *ext;
if (!(ext = X509V3_EXT_conf(NULL, ctx, k, v))) {
return -1;
}
if (X509_add_ext(crt, ext, -1) != 1) {
X509_EXTENSION_free(ext);
return -1;
}
X509_EXTENSION_free(ext);
return 0;
}
/*
* Copy a X509v3 extension from one certificate to another.
* If the extension is not present in the original certificate,
* the extension will not be added to the destination certificate.
* Returns 1 if ext was copied, 0 if not present in origcrt, -1 on error.
*/
int
ssl_x509_v3ext_copy_by_nid(X509 *crt, X509 *origcrt, int nid)
{
X509_EXTENSION *ext;
int pos;
pos = X509_get_ext_by_NID(origcrt, nid, -1);
if (pos == -1)
return 0;
ext = X509_get_ext(origcrt, pos);
if (!ext)
return -1;
if (X509_add_ext(crt, ext, -1) != 1)
return -1;
return 1;
}
/*
* Best effort randomness generator.
* Not for real life cryptography applications.
* Returns 0 on success, -1 on failure.
*/
int
ssl_rand(void *p, size_t sz)
{
int rv;
rv = RAND_pseudo_bytes((unsigned char*)p, sz);
if (rv == -1) {
rv = RAND_bytes((unsigned char*)p, sz);
if (rv != 1)
return -1;
}
return 0;
}
/*
* Copy the serial number from src certificate to dst certificate
* and modify it by a random offset.
* If reading the serial fails for some reason, generate a new
* random serial and store it in the dst certificate.
* Using the same serial is not a good idea since some SSL stacks
* check for duplicate certificate serials.
* Returns 0 on success, -1 on error.
*/
int
ssl_x509_serial_copyrand(X509 *dstcrt, X509 *srccrt)
{
ASN1_INTEGER *srcptr, *dstptr;
BIGNUM *bnserial;
unsigned int rand;
int rv;
#ifndef PURIFY
rv = ssl_rand(&rand, sizeof(rand));
#else /* PURIFY */
rand = 0xF001;
rv = 0;
#endif /* PURIFY */
dstptr = X509_get_serialNumber(dstcrt);
srcptr = X509_get_serialNumber(srccrt);
if ((rv == -1) || !dstptr || !srcptr)
return -1;
bnserial = ASN1_INTEGER_to_BN(srcptr, NULL);
if (!bnserial) {
/* random 32-bit serial */
ASN1_INTEGER_set(dstptr, rand);
} else {
/* original serial plus random 32-bit offset */
BN_add_word(bnserial, rand);
BN_to_ASN1_INTEGER(bnserial, dstptr);
BN_free(bnserial);
}
return 0;
}
/*
* Create a fake X509v3 certificate, signed by the provided CA,
* based on the original certificate retrieved from the real server.
* The returned certificate is created using X509_new() and thus must
* be freed by the caller using X509_free().
* The optional argument extraname is added to subjectAltNames if provided.
*/
X509 *
ssl_x509_forge(X509 *cacrt, EVP_PKEY *cakey, X509 *origcrt,
const char *extraname, EVP_PKEY *key)
{
X509_NAME *subject, *issuer;
GENERAL_NAMES *names;
GENERAL_NAME *gn;
X509 *crt;
subject = X509_get_subject_name(origcrt);
issuer = X509_get_subject_name(cacrt);
if (!subject || !issuer)
return NULL;
crt = X509_new();
if (!crt)
return NULL;
if (!X509_set_version(crt, 0x02) ||
!X509_set_subject_name(crt, subject) ||
!X509_set_issuer_name(crt, issuer) ||
ssl_x509_serial_copyrand(crt, origcrt) == -1 ||
!X509_gmtime_adj(X509_get_notBefore(crt), (long)-60*60*24) ||
!X509_gmtime_adj(X509_get_notAfter(crt), (long)60*60*24*364) ||
!X509_set_pubkey(crt, key))
goto errout;
/* add standard v3 extensions; cf. RFC 2459 */
X509V3_CTX ctx;
X509V3_set_ctx(&ctx, cacrt, crt, NULL, NULL, 0);
if (ssl_x509_v3ext_add(&ctx, crt, "basicConstraints",
"CA:FALSE") == -1 ||
ssl_x509_v3ext_add(&ctx, crt, "keyUsage",
"digitalSignature,"
"keyEncipherment") == -1 ||
ssl_x509_v3ext_add(&ctx, crt, "extendedKeyUsage",
"serverAuth") == -1 ||
ssl_x509_v3ext_add(&ctx, crt, "subjectKeyIdentifier",
"hash") == -1 ||
ssl_x509_v3ext_add(&ctx, crt, "authorityKeyIdentifier",
"keyid,issuer:always") == -1)
goto errout;
if (!extraname) {
/* no extraname provided: copy original subjectAltName ext */
if (ssl_x509_v3ext_copy_by_nid(crt, origcrt,
NID_subject_alt_name) == -1)
goto errout;
} else {
names = X509_get_ext_d2i(origcrt, NID_subject_alt_name, 0, 0);
if (!names) {
/* no subjectAltName present: add new one */
char *cfval;
if (asprintf(&cfval, "DNS:%s", extraname) == -1)
goto errout;
if (ssl_x509_v3ext_add(&ctx, crt, "subjectAltName",
cfval) == -1) {
free(cfval);
goto errout;
}
free(cfval);
} else {
/* add extraname to original subjectAltName
* and add it to the new certificate */
gn = GENERAL_NAME_new();
if (!gn)
goto errout2;
gn->type = GEN_DNS;
gn->d.dNSName = M_ASN1_IA5STRING_new();
if (!gn->d.dNSName)
goto errout3;
ASN1_STRING_set(gn->d.dNSName,
(unsigned char *)extraname,
strlen(extraname));
sk_GENERAL_NAME_push(names, gn);
X509_EXTENSION *ext = X509V3_EXT_i2d(
NID_subject_alt_name, 0, names);
if (!X509_add_ext(crt, ext, -1)) {
if (ext) {
X509_EXTENSION_free(ext);
}
goto errout3;
}
X509_EXTENSION_free(ext);
sk_GENERAL_NAME_pop_free(names, GENERAL_NAME_free);
}
}
#ifdef DEBUG_CERTIFICATE
ssl_x509_v3ext_add(&ctx, crt, "nsComment", "Generated by " PNAME);
#endif /* DEBUG_CERTIFICATE */
const EVP_MD *md;
switch (EVP_PKEY_type(cakey->type)) {
#ifndef OPENSSL_NO_RSA
case EVP_PKEY_RSA:
md = EVP_sha1();
break;
#endif /* !OPENSSL_NO_RSA */
#ifndef OPENSSL_NO_DSA
case EVP_PKEY_DSA:
md = EVP_dss1();
break;
#endif /* !OPENSSL_NO_DSA */
#ifndef OPENSSL_NO_ECDSA
case EVP_PKEY_EC:
md = EVP_ecdsa();
break;
#endif /* !OPENSSL_NO_ECDSA */
default:
goto errout;
}
if (!X509_sign(crt, cakey, md))
goto errout;
return crt;
errout3:
GENERAL_NAME_free(gn);
errout2:
sk_GENERAL_NAME_pop_free(names, GENERAL_NAME_free);
errout:
X509_free(crt);
return NULL;
}
/*
* Load a X509 certificate chain from a PEM file.
* Returns the first certificate in *crt and all subsequent certificates in
* *chain. If crt is NULL, the first certificate is prepended to *chain
* instead of returned separately. If *chain is NULL, a new stack of X509*
* is created in *chain, else the certs are pushed onto an existing stack.
* Returns -1 on error.
* Not thread-safe.
*
* By accessing (SSLCTX*)->extra_certs directly, we depend on OpenSSL
* internals in this function.
*
* XXX try to reimplement this with exposed BIO/ASN.1 functionality
* in order to get rid of the ->extra_certs direct access.
*/
int
ssl_x509chain_load(X509 **crt, STACK_OF(X509) **chain, const char *filename)
{
X509 *tmpcrt;
SSL_CTX *tmpctx;
SSL *tmpssl;
int rv;
if (ssl_init() == -1)
return -1;
tmpctx = SSL_CTX_new(SSLv23_server_method());
if (!tmpctx)
goto leave1;
rv = SSL_CTX_use_certificate_chain_file(tmpctx, filename);
if (rv != 1)
goto leave2;
tmpssl = SSL_new(tmpctx);
if (rv != 1 || !tmpssl)
goto leave2;
tmpcrt = SSL_get_certificate(tmpssl);
if (!tmpcrt)
goto leave3;
if (!*chain) {
*chain = sk_X509_new_null();
if (!*chain)
goto leave3;
}
if (crt) {
*crt = tmpcrt;
} else {
sk_X509_push(*chain, tmpcrt);
}
ssl_x509_refcount_inc(tmpcrt);
for (int i = 0; i < sk_X509_num(tmpctx->extra_certs); i++) {
tmpcrt = sk_X509_value(tmpctx->extra_certs, i);
ssl_x509_refcount_inc(tmpcrt);
sk_X509_push(*chain, tmpcrt);
}
SSL_free(tmpssl);
SSL_CTX_free(tmpctx);
return 0;
leave3:
SSL_free(tmpssl);
leave2:
SSL_CTX_free(tmpctx);
leave1:
return -1;
}
/*
* Use a X509 certificate chain for an SSL context.
* Copies the certificate stack to the SSL_CTX internal data structures
* and increases reference counts accordingly.
*/
void
ssl_x509chain_use(SSL_CTX *sslctx, X509 *crt, STACK_OF(X509) *chain)
{
SSL_CTX_use_certificate(sslctx, crt);
for (int i = 0; i < sk_X509_num(chain); i++) {
X509 *tmpcrt;
tmpcrt = sk_X509_value(chain, i);
ssl_x509_refcount_inc(tmpcrt);
sk_X509_push(sslctx->extra_certs, tmpcrt);
SSL_CTX_add_extra_chain_cert(sslctx, tmpcrt);
}
}
/*
* Load a X509 certificate from a PEM file.
* Returned X509 must be freed using X509_free() by the caller.
* Not thread-safe.
*/
X509 *
ssl_x509_load(const char *filename)
{
X509 *crt = NULL;
SSL_CTX *tmpctx;
SSL *tmpssl;
int rv;
if (ssl_init() == -1)
return NULL;
tmpctx = SSL_CTX_new(SSLv23_server_method());
if (!tmpctx)
goto leave1;
rv = SSL_CTX_use_certificate_file(tmpctx, filename, SSL_FILETYPE_PEM);
tmpssl = SSL_new(tmpctx);
if (rv != 1 || !tmpssl)
goto leave2;
crt = SSL_get_certificate(tmpssl);
if (crt)
ssl_x509_refcount_inc(crt);
SSL_free(tmpssl);
leave2:
SSL_CTX_free(tmpctx);
leave1:
return crt;
}
/*
* Load a private key from a PEM file.
* Returned EVP_PKEY must be freed using EVP_PKEY_free() by the caller.
* Not thread-safe.
*/
EVP_PKEY *
ssl_key_load(const char *filename)
{
EVP_PKEY *key = NULL;
SSL_CTX *tmpctx;
SSL *tmpssl;
int rv;
if (ssl_init() == -1)
return NULL;
tmpctx = SSL_CTX_new(SSLv23_server_method());
if (!tmpctx)
goto leave1;
rv = SSL_CTX_use_PrivateKey_file(tmpctx, filename, SSL_FILETYPE_PEM);
tmpssl = SSL_new(tmpctx);
if (rv != 1 || !tmpssl)
goto leave2;
key = SSL_get_privatekey(tmpssl);
if (key)
ssl_key_refcount_inc(key);
SSL_free(tmpssl);
leave2:
SSL_CTX_free(tmpctx);
leave1:
return key;
}
/*
* Generate a new RSA key.
* Returned EVP_PKEY must be freed using EVP_PKEY_free() by the caller.
*/
EVP_PKEY *
ssl_key_genrsa(const int keysize)
{
EVP_PKEY * pkey;
RSA * rsa;
rsa = RSA_generate_key(keysize, 3, NULL, NULL);
if (!rsa)
return NULL;
pkey = EVP_PKEY_new();
EVP_PKEY_assign_RSA(pkey, rsa);
return pkey;
}
/*
* Returns the one-line representation of the subject DN in a newly allocated
* string which must be freed by the caller.
*/
char *
ssl_x509_subject(X509 *crt)
{
return X509_NAME_oneline(X509_get_subject_name(crt), NULL, 0);
}
/*
* Parse the common name from the subject distinguished name.
* Returns string allocated using malloc(), caller must free().
* Returns NULL on errors.
*/
char *
ssl_x509_subject_cn(X509 *crt, size_t *sz)
{
X509_NAME *ptr;
char *cn;
ptr = X509_get_subject_name(crt);
if (!ptr)
return NULL;
*sz = X509_NAME_get_text_by_NID(ptr, NID_commonName, NULL, 0) + 1;
if ((sz == 0) || !(cn = malloc(*sz)))
return NULL;
X509_NAME_get_text_by_NID(ptr, NID_commonName, cn, *sz);
return cn;
}
/*
* Write the SHA1 fingerprint of certificate to fpr as SSL_X509_FPRSZ (20)
* bytes long binary buffer.
* Returns -1 on error, 0 on success.
*/
int
ssl_x509_fingerprint_sha1(X509 *crt, unsigned char *fpr)
{
unsigned int sz = SSL_X509_FPRSZ;
return X509_digest(crt, EVP_sha1(), fpr, &sz) ? 0 : -1;
}
#ifndef OPENSSL_NO_DH
/*
* Increment the reference count of DH parameters in a thread-safe
* manner.
*/
void
ssl_dh_refcount_inc(DH *dh)
{
#ifdef OPENSSL_THREADS
CRYPTO_add(&dh->references, 1, CRYPTO_LOCK_DH);
#else /* !OPENSSL_THREADS */
dh->references++;
#endif /* !OPENSSL_THREADS */
}
#endif /* !OPENSSL_NO_DH */
/*
* Increment the reference count of an X509 certificate in a thread-safe
* manner.
*/
void
ssl_key_refcount_inc(EVP_PKEY *key)
{
#ifdef OPENSSL_THREADS
CRYPTO_add(&key->references, 1, CRYPTO_LOCK_EVP_PKEY);
#else /* !OPENSSL_THREADS */
key->references++;
#endif /* !OPENSSL_THREADS */
}
/*
* Increment the reference count of an X509 certificate in a thread-safe
* manner. This differs from X509_dup() in that it does not create new,
* full copy of the certificate, but only increases the reference count.
*/
void
ssl_x509_refcount_inc(X509 *crt)
{
#ifdef OPENSSL_THREADS
CRYPTO_add(&crt->references, 1, CRYPTO_LOCK_X509);
#else /* !OPENSSL_THREADS */
crt->references++;
#endif /* !OPENSSL_THREADS */
}
/*
* Match a URL/URI hostname against a single certificate DNS name
* using RFC 6125 rules (6.4.3 Checking of Wildcard Certificates):
*
* 1. The client SHOULD NOT attempt to match a presented identifier in
* which the wildcard character comprises a label other than the
* left-most label (e.g., do not match bar.*.example.net).
*
* 2. If the wildcard character is the only character of the left-most
* label in the presented identifier, the client SHOULD NOT compare
* against anything but the left-most label of the reference
* identifier (e.g., *.example.com would match foo.example.com but
* not bar.foo.example.com or example.com).
*
* 3. The client MAY match a presented identifier in which the wildcard
* character is not the only character of the label (e.g.,
* baz*.example.net and *baz.example.net and b*z.example.net would
* be taken to match baz1.example.net and foobaz.example.net and
* buzz.example.net, respectively). However, the client SHOULD NOT
* attempt to match a presented identifier where the wildcard
* character is embedded within an A-label or U-label [IDNA-DEFS] of
* an internationalized domain name [IDNA-PROTO].
*
* The optional partial matching in rule 3 is not implemented.
* Returns 1 on match, 0 on no match.
*/
int
ssl_dnsname_match(const char *certname, size_t certnamesz,
const char *hostname, size_t hostnamesz)
{
if (hostnamesz < certnamesz)
return 0;
if ((hostnamesz == certnamesz) &&
!memcmp(certname, hostname, certnamesz))
return 1;
if (!memcmp(certname, "xn--", 4))
return 0;
if ((certnamesz == 1) && (certname[0] == '*') &&
!memchr(hostname, '.', hostnamesz))
return 1;
if ((certnamesz > 2) && (certname[0] == '*') && (certname[1] == '.') &&
!memcmp(&certname[1],
&hostname[hostnamesz - (certnamesz - 1)],
certnamesz - 1) &&
(memchr(hostname, '.', hostnamesz) ==
&hostname[hostnamesz - (certnamesz - 1)]))
return 1;
return 0;
}
/*
* Transform a NULL-terminated hostname into a matching wildcard hostname,
* e.g. "test.example.org" -> "*.example.org".
* Returns string which must be free()'d by the caller, or NULL on error.
*/
char *
ssl_wildcardify(const char *hostname)
{
char *dot, *wildcarded;
size_t dotsz;
if (!(dot = strchr(hostname, '.')))
return strdup("*");
dotsz = strlen(dot);
if (!(wildcarded = malloc(dotsz + 2)))
return NULL;
wildcarded[0] = '*';
strncpy(wildcarded + 1, dot, dotsz);
wildcarded[dotsz + 1] = '\0';
return wildcarded;
}
/*
* Match DNS name against certificate subject CN and subjectAltNames DNS names.
* Returns 1 if any name matches, 0 if none matches.
*/
int
ssl_x509_names_match(X509 *crt, const char *dnsname)
{
GENERAL_NAMES *altnames;
char *cn;
size_t cnsz, dnsnamesz;
dnsnamesz = strlen(dnsname);
cn = ssl_x509_subject_cn(crt, &cnsz);
if (cn && ssl_dnsname_match(cn, cnsz, dnsname, dnsnamesz)) {
free(cn);
return 1;
}
if (cn) {
free(cn);
}
altnames = X509_get_ext_d2i(crt, NID_subject_alt_name, 0, 0);
if (!altnames)
return 0;
for (int i = 0; i < sk_GENERAL_NAME_num(altnames); i++) {
GENERAL_NAME *gn = sk_GENERAL_NAME_value(altnames, i);
if (gn->type == GEN_DNS) {
unsigned char *altname;
int altnamesz;
ASN1_STRING_to_UTF8(&altname, gn->d.dNSName);
altnamesz = ASN1_STRING_length(gn->d.dNSName);
if (altnamesz < 0)
break;
if (ssl_dnsname_match((char *)altname,
(size_t)altnamesz,
dnsname, dnsnamesz)) {
OPENSSL_free((char*)altname);
GENERAL_NAMES_free(altnames);
return 1;
}
OPENSSL_free((char*)altname);
}
}
GENERAL_NAMES_free(altnames);
return 0;
}
/*
* Returns a NULL terminated array of pointers to all common names found
* in the Subject DN CN and subjectAltNames extension (DNSName only).
* Caller must free returned buffer and all pointers within.
* Embedded NULL characters in hostnames are replaced with '!'.
*/
char **
ssl_x509_names(X509 *crt)
{
GENERAL_NAMES *altnames;
char *cn;
size_t cnsz;
char **res, **p;
size_t count;
cn = ssl_x509_subject_cn(crt, &cnsz);
altnames = X509_get_ext_d2i(crt, NID_subject_alt_name, NULL, NULL);
count = (altnames ? sk_GENERAL_NAME_num(altnames) : 0) + (cn ? 2 : 1);
res = malloc(count * sizeof(char*));
if (!res)
return NULL;
p = res;
if (cn)
*(p++) = cn;
if (!altnames) {
*p = NULL;
return res;
}
for (int i = 0; i < sk_GENERAL_NAME_num(altnames); i++) {
GENERAL_NAME *gn = sk_GENERAL_NAME_value(altnames, i);
if (gn->type == GEN_DNS) {
unsigned char *altname;
int altnamesz;
ASN1_STRING_to_UTF8(&altname, gn->d.dNSName);
if (!altname)
break;
altnamesz = ASN1_STRING_length(gn->d.dNSName);
if (altnamesz < 0) {
OPENSSL_free((char*)altname);
break;
}
*p = malloc(altnamesz + 1);
if (!*p) {
OPENSSL_free((char*)altname);
GENERAL_NAMES_free(altnames);
for (p = res; *p; p++)
free(*p);
free(res);
return NULL;
}
for (int j = 0; j < altnamesz; j++) {
(*p)[j] = altname[j] ? altname[j] : '!';
}
(*p)[altnamesz] = '\0';
OPENSSL_free((char*)altname);
p++;
}
}
*p = NULL;
GENERAL_NAMES_free(altnames);
return res;
}
/*
* Returns a printable representation of a certificate's common names found
* in the Subject DN CN and subjectAltNames extension, separated by slashes.
* Caller must free returned buffer.
* Embedded NULL characters in hostnames are replaced with '!'.
*/
char *
ssl_x509_names_to_str(X509 *crt)
{
char **names;
size_t sz;
char *buf, *next;
names = ssl_x509_names(crt);
if (!names)
return NULL;
sz = 0;
for (char **p = names; *p; p++) {
sz += strlen(*p) + 1;
}
if (!(buf = malloc(sz)))
goto out;
next = buf;
for (char **p = names; *p; p++) {
char *src = *p;
while (*src) {
*next++ = *src++;
}
*next++ = '/';
}
*--next = '\0';
out:
for (char **p = names; *p; p++)
free(*p);
free(names);
return buf;
}
/*
* Returns a zero-terminated buffer containing the ASN1 IA5 string.
* Returned buffer must be free()'d by caller.
*/
static char *
ssl_ia5string_strdup(ASN1_IA5STRING *ia5)
{
char *str;
if (!ia5 || !ia5->length)
return NULL;
str = malloc(ia5->length + 1);
if (!str)
return NULL;
memcpy(str, ia5->data, ia5->length);
str[ia5->length] = 0;
return str;
}
/*
* Returns a NULL terminated array of pointers to copies of Authority
* Information Access (AIA) URLs of a given type contained in the certificate.
* Caller must free returned buffer and all pointers within.
*/
char **
ssl_x509_aias(X509 *crt, const int type)
{
AUTHORITY_INFO_ACCESS *aias;
char **res;
int count, i, j;
aias = X509_get_ext_d2i(crt, NID_info_access, NULL, NULL);
if (!aias || !(count = sk_ACCESS_DESCRIPTION_num(aias)))
return NULL;
res = malloc((count + 1) * sizeof(char *));
if (!res) {
sk_ACCESS_DESCRIPTION_pop_free(aias, ACCESS_DESCRIPTION_free);
return NULL;
}
for (i = 0, j = 0; i < count; i++) {
ACCESS_DESCRIPTION *aia;
aia = sk_ACCESS_DESCRIPTION_value(aias, i);
if (aia &&
OBJ_obj2nid(aia->method) == type &&
aia->location->type == GEN_URI) {
res[j] = ssl_ia5string_strdup(aia->location->d.ia5);
if (res[j])
j++;
}
}
res[j] = '\0';
sk_ACCESS_DESCRIPTION_pop_free(aias, ACCESS_DESCRIPTION_free);
return res;
}
/*
* Returns a NULL terminated array of pointers to copies of Authority
* Information Access (AIA) URLs of type OCSP contained in the certificate.
* Caller must free returned buffer and all pointers within.
*/
char **
ssl_x509_ocsps(X509 *crt)
{
return ssl_x509_aias(crt, NID_ad_OCSP);
}
/*
* Check whether the certificate is valid based on current time.
* Return 1 if valid, 0 otherwise.
*/
int
ssl_x509_is_valid(X509 *crt)
{
if (X509_cmp_current_time(X509_get_notAfter(crt)) <= 0)
return 0;
if (X509_cmp_current_time(X509_get_notBefore(crt)) > 0)
return 0;
return 1;
}
/*
* Print X509 certificate data to a newly allocated string.
* Caller must free returned string.
* Returns NULL on errors.
*/
char *
ssl_x509_to_str(X509 *crt)
{
BIO *bio;
char *p, *ret;
size_t sz;
bio = BIO_new(BIO_s_mem());
if (!bio)
return NULL;
X509_print(bio, crt);
sz = BIO_get_mem_data(bio, &p);
if (!(ret = malloc(sz + 1))) {
BIO_free(bio);
return NULL;
}
memcpy(ret, p, sz);
ret[sz] = '\0';
BIO_free(bio);
return ret;
}
/*
* Convert X509 certificate to PEM format in a newly allocated string.
* Caller must free returned string.
* Returns NULL on errors.
*/
char *
ssl_x509_to_pem(X509 *crt)
{
BIO *bio;
char *p, *ret;
size_t sz;
bio = BIO_new(BIO_s_mem());
if (!bio)
return NULL;
PEM_write_bio_X509(bio, crt);
sz = BIO_get_mem_data(bio, &p);
if (!(ret = malloc(sz + 1))) {
BIO_free(bio);
return NULL;
}
memcpy(ret, p, sz);
ret[sz] = '\0';
BIO_free(bio);
return ret;
}
/*
* Print SSL_SESSION data to a newly allocated string.
* Caller must free returned string.
* Returns NULL on errors.
*/
char *
ssl_session_to_str(SSL_SESSION *sess)
{
BIO *bio;
char *p, *ret;
size_t sz;
bio = BIO_new(BIO_s_mem());
if (!bio)
return NULL;
SSL_SESSION_print(bio, sess);
sz = BIO_get_mem_data(bio, &p);
if (!(ret = malloc(sz + 1))) {
BIO_free(bio);
return NULL;
}
memcpy(ret, p, sz);
ret[sz] = '\0';
BIO_free(bio);
return ret;
}
/*
* Returns non-zero if the session timeout has not expired yet,
* zero if the session has expired or an error occured.
*/
int
ssl_session_is_valid(SSL_SESSION *sess)
{
time_t curtimet;
long curtime, timeout;
curtimet = time(NULL);
if (curtimet == (time_t)-1)
return 0;
curtime = curtimet;
if ((curtime < 0) || ((time_t)curtime != curtimet))
return 0;
timeout = SSL_SESSION_get_timeout(sess);
if (curtime > LONG_MAX - timeout)
return 0;
return (SSL_SESSION_get_time(sess) < curtime + timeout);
}
/*
* Returns 1 if buf contains a DER encoded OCSP request which can be parsed.
* Returns 0 otherwise.
*/
int
ssl_is_ocspreq(const unsigned char *buf, size_t sz)
{
OCSP_REQUEST *req;
const unsigned char *p;
p = (const unsigned char *)buf;
req = d2i_OCSP_REQUEST(NULL, &p, sz); /* increments p */
if (!req)
return 0;
OCSP_REQUEST_free(req);
return 1;
}
#ifndef OPENSSL_NO_TLSEXT
/*
* Ugly hack to manually parse the SNI TLS extension from a clientHello buf.
* This is needed because of limitations in the OpenSSL SNI API which only
* allows to read the indicated server name at the time when we have to
* provide the server certificate. It is not possible to asynchroniously
* read the indicated server name, wait for some event to happen, and then
* later to provide the server certificate to use and continue the handshake.
*
* This function takes a buffer containing (part of) a clientHello message as
* seen on the network.
*
* If server name extension was found and parsed, returns server name buffer
* that must be free'd by the caller.
* If parsing failed for inconsistency reasons or if SNI TLS extension was
* not present in the clientHello, returns NULL.
* If not enough data was provided in buf, returns NULL and *sz is set to -1
* to indicate that a call to ssl_tls_clienthello_parse_sni() with more data
* in buf might succeed.
*
* References:
* RFC 2246: The TLS Protocol Version 1.0
* RFC 3546: Transport Layer Security (TLS) Extensions
* RFC 4346: The Transport Layer Security (TLS) Protocol Version 1.1
* RFC 4366: Transport Layer Security (TLS) Extensions
* RFC 5246: The Transport Layer Security (TLS) Protocol Version 1.2
* RFC 6066: Transport Layer Security (TLS) Extensions: Extension Definitions
*/
char *
ssl_tls_clienthello_parse_sni(const unsigned char *buf, ssize_t *sz)
{
#ifdef DEBUG_SNI_PARSER
#define DBG_printf(...) log_dbg_printf("SNI Parser: " __VA_ARGS__)
#else /* !DEBUG_SNI_PARSER */
#define DBG_printf(...)
#endif /* !DEBUG_SNI_PARSER */
const unsigned char *p = buf;
ssize_t n = *sz;
char *servername = NULL;
DBG_printf("buffer length %zd\n", n);
if (n < 1) {
*sz = -1;
goto out;
}
DBG_printf("byte 0: %02x\n", *p);
/* first byte 0x80, third byte 0x01 is SSLv2 clientHello;
* first byte 0x22, second byte 0x03 is SSLv3/TLSv1.x clientHello */
if (*p != 22) /* record type: handshake protocol */
goto out;
p++; n--;
if (n < 2) {
*sz = -1;
goto out;
}
DBG_printf("version: %02x %02x\n", p[0], p[1]);
if (p[0] != 3)
goto out;
p += 2; n -= 2;
if (n < 2) {
*sz = -1;
goto out;
}
DBG_printf("length: %02x %02x\n", p[0], p[1]);
#ifdef DEBUG_SNI_PARSER
ssize_t recordlen = p[1] + (p[0] << 8);
DBG_printf("recordlen=%zd\n", recordlen);
#endif /* DEBUG_SNI_PARSER */
p += 2; n -= 2;
if (n < 1) {
*sz = -1;
goto out;
}
DBG_printf("message type: %i\n", *p);
if (*p != 1) /* message type: ClientHello */
goto out;
p++; n--;
if (n < 3) {
*sz = -1;
goto out;
}
DBG_printf("message len: %02x %02x %02x\n", p[0], p[1], p[2]);
ssize_t msglen = p[2] + (p[1] << 8) + (p[0] << 16);
DBG_printf("msglen=%zd\n", msglen);
if (msglen < 4)
goto out;
p += 3; n -= 3;
if (n < msglen) {
*sz = -1;
goto out;
}
n = msglen; /* only parse first message */
if (n < 2)
goto out;
DBG_printf("clienthello version %02x %02x\n", p[0], p[1]);
if (p[0] != 3)
goto out;
p += 2; n -= 2;
if (n < 32)
goto out;
DBG_printf("clienthello random %02x %02x %02x %02x ...\n",
p[0], p[1], p[2], p[3]);
DBG_printf("compare localtime: %08x\n", (unsigned int)time(NULL));
p += 32; n -= 32;
if (n < 1)
goto out;
DBG_printf("clienthello sidlen %02x\n", *p);
ssize_t sidlen = *p; /* session id length, 0..32 */
p += 1; n -= 1;
if (n < sidlen)
goto out;
p += sidlen; n -= sidlen;
if (n < 2)
goto out;
DBG_printf("clienthello cipher suites length %02x %02x\n", p[0], p[1]);
ssize_t suiteslen = p[1] + (p[0] << 8);
p += 2; n -= 2;
if (n < suiteslen) {
DBG_printf("n < suiteslen (%zd, %zd)\n", n, suiteslen);
goto out;
}
p += suiteslen;
n -= suiteslen;
if (n < 1)
goto out;
DBG_printf("clienthello compress methods length %02x\n", *p);
ssize_t compslen = *p;
p++; n--;
if (n < compslen)
goto out;
p += compslen;
n -= compslen;
/* begin of extensions */
if (n < 2)
goto out;
DBG_printf("tlsexts length %02x %02x\n", p[0], p[1]);
ssize_t tlsextslen = p[1] + (p[0] << 8);
DBG_printf("tlsextslen %zd\n", tlsextslen);
p += 2;
n -= 2;
if (n < tlsextslen)
goto out;
n = tlsextslen; /* only parse extensions, ignore trailing bits */
while (n > 0) {
if (n < 4)
goto out;
DBG_printf("tlsext type %02x %02x len %02x %02x\n",
p[0], p[1], p[2], p[3]);
unsigned short exttype = p[1] + (p[0] << 8);
ssize_t extlen = p[3] + (p[2] << 8);
p += 4;
n -= 4;
if (n < extlen)
goto out;
switch (exttype) {
case 0:
{
ssize_t extn = extlen;
const unsigned char *extp = p;
if (extn < 2)
goto out;
DBG_printf("list length %02x %02x\n",
extp[0], extp[1]);
ssize_t namelistlen = extp[1] + (extp[0] << 8);
DBG_printf("namelistlen = %zd\n", namelistlen);
extp += 2;
extn -= 2;
if (namelistlen != extn)
goto out;
while (extn > 0) {
if (extn < 3)
goto out;
DBG_printf("ServerName type %02x"
" len %02x %02x\n",
extp[0], extp[1], extp[2]);
unsigned char sntype = extp[0];
ssize_t snlen = extp[2] + (extp[1]<<8);
extp += 3;
extn -= 3;
if (snlen > extn)
goto out;
if (snlen > TLSEXT_MAXLEN_host_name)
goto out;
if (sntype == 0) {
servername = malloc(snlen + 1);
memcpy(servername, extp, snlen);
servername[snlen] = '\0';
/* deliberately not checking
* for malformed hostnames
* containing invalid chars */
goto out;
}
extp += snlen;
extn -= snlen;
}
break;
}
default:
DBG_printf("skipped\n");
break;
}
p += extlen;
n -= extlen;
}
#ifdef DEBUG_SNI_PARSER
if (n > 0) {
DBG_printf("unparsed next bytes %02x %02x %02x %02x\n",
p[0], p[1], p[2], p[3]);
}
#endif /* DEBUG_SNI_PARSER */
out:
DBG_printf("%zd bytes unparsed\n", n);
return servername;
}
#endif /* !OPENSSL_NO_TLSEXT */
/* vim: set noet ft=c: */
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