mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-07 11:13:41 +02:00
4e0130faed
* qatar/master: srtp: Include rtpdec.h for RTP_MAX_PACKET_LENGTH rtpdec: Increase max rtp packet size to 8192 lavf: Use RTP_MAX_PACKET_LENGTH instead of 1500 h264pred: Add a few missing const declarations for ff_cropTbl derived pointers Merged-by: Michael Niedermayer <michaelni@gmx.at>
473 lines
14 KiB
C
473 lines
14 KiB
C
/*
|
|
* SRTP encryption/decryption
|
|
* Copyright (c) 2012 Martin Storsjo
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include "libavutil/base64.h"
|
|
#include "libavutil/aes.h"
|
|
#include "libavutil/hmac.h"
|
|
#include "libavutil/intreadwrite.h"
|
|
#include "libavutil/log.h"
|
|
#include "rtp.h"
|
|
#include "rtpdec.h"
|
|
#include "srtp.h"
|
|
|
|
void ff_srtp_free(struct SRTPContext *s)
|
|
{
|
|
if (!s)
|
|
return;
|
|
av_freep(&s->aes);
|
|
if (s->hmac)
|
|
av_hmac_free(s->hmac);
|
|
s->hmac = NULL;
|
|
}
|
|
|
|
static void encrypt_counter(struct AVAES *aes, uint8_t *iv, uint8_t *outbuf,
|
|
int outlen)
|
|
{
|
|
int i, j, outpos;
|
|
for (i = 0, outpos = 0; outpos < outlen; i++) {
|
|
uint8_t keystream[16];
|
|
AV_WB16(&iv[14], i);
|
|
av_aes_crypt(aes, keystream, iv, 1, NULL, 0);
|
|
for (j = 0; j < 16 && outpos < outlen; j++, outpos++)
|
|
outbuf[outpos] ^= keystream[j];
|
|
}
|
|
}
|
|
|
|
static void derive_key(struct AVAES *aes, const uint8_t *salt, int label,
|
|
uint8_t *out, int outlen)
|
|
{
|
|
uint8_t input[16] = { 0 };
|
|
memcpy(input, salt, 14);
|
|
// Key derivation rate assumed to be zero
|
|
input[14 - 7] ^= label;
|
|
memset(out, 0, outlen);
|
|
encrypt_counter(aes, input, out, outlen);
|
|
}
|
|
|
|
int ff_srtp_set_crypto(struct SRTPContext *s, const char *suite,
|
|
const char *params)
|
|
{
|
|
uint8_t buf[30];
|
|
|
|
ff_srtp_free(s);
|
|
|
|
// RFC 4568
|
|
if (!strcmp(suite, "AES_CM_128_HMAC_SHA1_80") ||
|
|
!strcmp(suite, "SRTP_AES128_CM_HMAC_SHA1_80")) {
|
|
s->rtp_hmac_size = s->rtcp_hmac_size = 10;
|
|
} else if (!strcmp(suite, "AES_CM_128_HMAC_SHA1_32")) {
|
|
s->rtp_hmac_size = s->rtcp_hmac_size = 4;
|
|
} else if (!strcmp(suite, "SRTP_AES128_CM_HMAC_SHA1_32")) {
|
|
// RFC 5764 section 4.1.2
|
|
s->rtp_hmac_size = 4;
|
|
s->rtcp_hmac_size = 10;
|
|
} else {
|
|
av_log(NULL, AV_LOG_WARNING, "SRTP Crypto suite %s not supported\n",
|
|
suite);
|
|
return AVERROR(EINVAL);
|
|
}
|
|
if (av_base64_decode(buf, params, sizeof(buf)) != sizeof(buf)) {
|
|
av_log(NULL, AV_LOG_WARNING, "Incorrect amount of SRTP params\n");
|
|
return AVERROR(EINVAL);
|
|
}
|
|
// MKI and lifetime not handled yet
|
|
s->aes = av_aes_alloc();
|
|
s->hmac = av_hmac_alloc(AV_HMAC_SHA1);
|
|
if (!s->aes || !s->hmac)
|
|
return AVERROR(ENOMEM);
|
|
memcpy(s->master_key, buf, 16);
|
|
memcpy(s->master_salt, buf + 16, 14);
|
|
|
|
// RFC 3711
|
|
av_aes_init(s->aes, s->master_key, 128, 0);
|
|
|
|
derive_key(s->aes, s->master_salt, 0x00, s->rtp_key, sizeof(s->rtp_key));
|
|
derive_key(s->aes, s->master_salt, 0x02, s->rtp_salt, sizeof(s->rtp_salt));
|
|
derive_key(s->aes, s->master_salt, 0x01, s->rtp_auth, sizeof(s->rtp_auth));
|
|
|
|
derive_key(s->aes, s->master_salt, 0x03, s->rtcp_key, sizeof(s->rtcp_key));
|
|
derive_key(s->aes, s->master_salt, 0x05, s->rtcp_salt, sizeof(s->rtcp_salt));
|
|
derive_key(s->aes, s->master_salt, 0x04, s->rtcp_auth, sizeof(s->rtcp_auth));
|
|
return 0;
|
|
}
|
|
|
|
static void create_iv(uint8_t *iv, const uint8_t *salt, uint64_t index,
|
|
uint32_t ssrc)
|
|
{
|
|
uint8_t indexbuf[8];
|
|
int i;
|
|
memset(iv, 0, 16);
|
|
AV_WB32(&iv[4], ssrc);
|
|
AV_WB64(indexbuf, index);
|
|
for (i = 0; i < 8; i++) // index << 16
|
|
iv[6 + i] ^= indexbuf[i];
|
|
for (i = 0; i < 14; i++)
|
|
iv[i] ^= salt[i];
|
|
}
|
|
|
|
int ff_srtp_decrypt(struct SRTPContext *s, uint8_t *buf, int *lenptr)
|
|
{
|
|
uint8_t iv[16] = { 0 }, hmac[20];
|
|
int len = *lenptr;
|
|
int av_uninit(seq_largest);
|
|
uint32_t ssrc, av_uninit(roc);
|
|
uint64_t index;
|
|
int rtcp, hmac_size;
|
|
|
|
// TODO: Missing replay protection
|
|
|
|
if (len < 2)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
rtcp = RTP_PT_IS_RTCP(buf[1]);
|
|
hmac_size = rtcp ? s->rtcp_hmac_size : s->rtp_hmac_size;
|
|
|
|
if (len < hmac_size)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
// Authentication HMAC
|
|
av_hmac_init(s->hmac, rtcp ? s->rtcp_auth : s->rtp_auth, sizeof(s->rtp_auth));
|
|
// If MKI is used, this should exclude the MKI as well
|
|
av_hmac_update(s->hmac, buf, len - hmac_size);
|
|
|
|
if (!rtcp) {
|
|
int seq = AV_RB16(buf + 2);
|
|
uint32_t v;
|
|
uint8_t rocbuf[4];
|
|
|
|
// RFC 3711 section 3.3.1, appendix A
|
|
seq_largest = s->seq_initialized ? s->seq_largest : seq;
|
|
v = roc = s->roc;
|
|
if (seq_largest < 32768) {
|
|
if (seq - seq_largest > 32768)
|
|
v = roc - 1;
|
|
} else {
|
|
if (seq_largest - 32768 > seq)
|
|
v = roc + 1;
|
|
}
|
|
if (v == roc) {
|
|
seq_largest = FFMAX(seq_largest, seq);
|
|
} else if (v == roc + 1) {
|
|
seq_largest = seq;
|
|
roc = v;
|
|
}
|
|
index = seq + (((uint64_t)v) << 16);
|
|
|
|
AV_WB32(rocbuf, roc);
|
|
av_hmac_update(s->hmac, rocbuf, 4);
|
|
}
|
|
|
|
av_hmac_final(s->hmac, hmac, sizeof(hmac));
|
|
if (memcmp(hmac, buf + len - hmac_size, hmac_size)) {
|
|
av_log(NULL, AV_LOG_WARNING, "HMAC mismatch\n");
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
len -= hmac_size;
|
|
*lenptr = len;
|
|
|
|
if (len < 12)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
if (rtcp) {
|
|
uint32_t srtcp_index = AV_RB32(buf + len - 4);
|
|
len -= 4;
|
|
*lenptr = len;
|
|
|
|
ssrc = AV_RB32(buf + 4);
|
|
index = srtcp_index & 0x7fffffff;
|
|
|
|
buf += 8;
|
|
len -= 8;
|
|
if (!(srtcp_index & 0x80000000))
|
|
return 0;
|
|
} else {
|
|
int ext, csrc;
|
|
s->seq_initialized = 1;
|
|
s->seq_largest = seq_largest;
|
|
s->roc = roc;
|
|
|
|
csrc = buf[0] & 0x0f;
|
|
ext = buf[0] & 0x10;
|
|
ssrc = AV_RB32(buf + 8);
|
|
|
|
buf += 12;
|
|
len -= 12;
|
|
|
|
buf += 4 * csrc;
|
|
len -= 4 * csrc;
|
|
if (len < 0)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
if (ext) {
|
|
if (len < 4)
|
|
return AVERROR_INVALIDDATA;
|
|
ext = (AV_RB16(buf + 2) + 1) * 4;
|
|
if (len < ext)
|
|
return AVERROR_INVALIDDATA;
|
|
len -= ext;
|
|
buf += ext;
|
|
}
|
|
}
|
|
|
|
create_iv(iv, rtcp ? s->rtcp_salt : s->rtp_salt, index, ssrc);
|
|
av_aes_init(s->aes, rtcp ? s->rtcp_key : s->rtp_key, 128, 0);
|
|
encrypt_counter(s->aes, iv, buf, len);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int ff_srtp_encrypt(struct SRTPContext *s, const uint8_t *in, int len,
|
|
uint8_t *out, int outlen)
|
|
{
|
|
uint8_t iv[16] = { 0 }, hmac[20];
|
|
uint64_t index;
|
|
uint32_t ssrc;
|
|
int rtcp, hmac_size, padding;
|
|
uint8_t *buf;
|
|
|
|
if (len < 8)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
rtcp = RTP_PT_IS_RTCP(in[1]);
|
|
hmac_size = rtcp ? s->rtcp_hmac_size : s->rtp_hmac_size;
|
|
padding = hmac_size;
|
|
if (rtcp)
|
|
padding += 4; // For the RTCP index
|
|
|
|
if (len + padding > outlen)
|
|
return 0;
|
|
|
|
memcpy(out, in, len);
|
|
buf = out;
|
|
|
|
if (rtcp) {
|
|
ssrc = AV_RB32(buf + 4);
|
|
index = s->rtcp_index++;
|
|
|
|
buf += 8;
|
|
len -= 8;
|
|
} else {
|
|
int ext, csrc;
|
|
int seq = AV_RB16(buf + 2);
|
|
|
|
if (len < 12)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
ssrc = AV_RB32(buf + 8);
|
|
|
|
if (seq < s->seq_largest)
|
|
s->roc++;
|
|
s->seq_largest = seq;
|
|
index = seq + (((uint64_t)s->roc) << 16);
|
|
|
|
csrc = buf[0] & 0x0f;
|
|
ext = buf[0] & 0x10;
|
|
|
|
buf += 12;
|
|
len -= 12;
|
|
|
|
buf += 4 * csrc;
|
|
len -= 4 * csrc;
|
|
if (len < 0)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
if (ext) {
|
|
if (len < 4)
|
|
return AVERROR_INVALIDDATA;
|
|
ext = (AV_RB16(buf + 2) + 1) * 4;
|
|
if (len < ext)
|
|
return AVERROR_INVALIDDATA;
|
|
len -= ext;
|
|
buf += ext;
|
|
}
|
|
}
|
|
|
|
create_iv(iv, rtcp ? s->rtcp_salt : s->rtp_salt, index, ssrc);
|
|
av_aes_init(s->aes, rtcp ? s->rtcp_key : s->rtp_key, 128, 0);
|
|
encrypt_counter(s->aes, iv, buf, len);
|
|
|
|
if (rtcp) {
|
|
AV_WB32(buf + len, 0x80000000 | index);
|
|
len += 4;
|
|
}
|
|
|
|
av_hmac_init(s->hmac, rtcp ? s->rtcp_auth : s->rtp_auth, sizeof(s->rtp_auth));
|
|
av_hmac_update(s->hmac, out, buf + len - out);
|
|
if (!rtcp) {
|
|
uint8_t rocbuf[4];
|
|
AV_WB32(rocbuf, s->roc);
|
|
av_hmac_update(s->hmac, rocbuf, 4);
|
|
}
|
|
av_hmac_final(s->hmac, hmac, sizeof(hmac));
|
|
|
|
memcpy(buf + len, hmac, hmac_size);
|
|
len += hmac_size;
|
|
return buf + len - out;
|
|
}
|
|
|
|
#ifdef TEST
|
|
#include <stdio.h>
|
|
|
|
static const char *aes128_80_key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmn";
|
|
|
|
static const uint8_t rtp_aes128_80[] = {
|
|
// RTP header
|
|
0x80, 0xe0, 0x12, 0x34, 0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,
|
|
// encrypted payload
|
|
0x62, 0x69, 0x76, 0xca, 0xc5,
|
|
// HMAC
|
|
0xa1, 0xac, 0x1b, 0xb4, 0xa0, 0x1c, 0xd5, 0x49, 0x28, 0x99,
|
|
};
|
|
|
|
static const uint8_t rtcp_aes128_80[] = {
|
|
// RTCP header
|
|
0x81, 0xc9, 0x00, 0x07, 0x12, 0x34, 0x56, 0x78,
|
|
// encrypted payload
|
|
0x8a, 0xac, 0xdc, 0xa5, 0x4c, 0xf6, 0x78, 0xa6, 0x62, 0x8f, 0x24, 0xda,
|
|
0x6c, 0x09, 0x3f, 0xa9, 0x28, 0x7a, 0xb5, 0x7f, 0x1f, 0x0f, 0xc9, 0x35,
|
|
// RTCP index
|
|
0x80, 0x00, 0x00, 0x03,
|
|
// HMAC
|
|
0xe9, 0x3b, 0xc0, 0x5c, 0x0c, 0x06, 0x9f, 0xab, 0xc0, 0xde,
|
|
};
|
|
|
|
static const char *aes128_32_key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmn";
|
|
|
|
static const uint8_t rtp_aes128_32[] = {
|
|
// RTP header
|
|
0x80, 0xe0, 0x12, 0x34, 0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,
|
|
// encrypted payload
|
|
0x62, 0x69, 0x76, 0xca, 0xc5,
|
|
// HMAC
|
|
0xa1, 0xac, 0x1b, 0xb4,
|
|
};
|
|
|
|
static const uint8_t rtcp_aes128_32[] = {
|
|
// RTCP header
|
|
0x81, 0xc9, 0x00, 0x07, 0x12, 0x34, 0x56, 0x78,
|
|
// encrypted payload
|
|
0x35, 0xe9, 0xb5, 0xff, 0x0d, 0xd1, 0xde, 0x70, 0x74, 0x10, 0xaa, 0x1b,
|
|
0xb2, 0x8d, 0xf0, 0x20, 0x02, 0x99, 0x6b, 0x1b, 0x0b, 0xd0, 0x47, 0x34,
|
|
// RTCP index
|
|
0x80, 0x00, 0x00, 0x04,
|
|
// HMAC
|
|
0x5b, 0xd2, 0xa9, 0x9d,
|
|
};
|
|
|
|
static const char *aes128_80_32_key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmn";
|
|
|
|
static const uint8_t rtp_aes128_80_32[] = {
|
|
// RTP header
|
|
0x80, 0xe0, 0x12, 0x34, 0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,
|
|
// encrypted payload
|
|
0x62, 0x69, 0x76, 0xca, 0xc5,
|
|
// HMAC
|
|
0xa1, 0xac, 0x1b, 0xb4,
|
|
};
|
|
|
|
static const uint8_t rtcp_aes128_80_32[] = {
|
|
// RTCP header
|
|
0x81, 0xc9, 0x00, 0x07, 0x12, 0x34, 0x56, 0x78,
|
|
// encrypted payload
|
|
0xd6, 0xae, 0xc1, 0x58, 0x63, 0x70, 0xc9, 0x88, 0x66, 0x26, 0x1c, 0x53,
|
|
0xff, 0x5d, 0x5d, 0x2b, 0x0f, 0x8c, 0x72, 0x3e, 0xc9, 0x1d, 0x43, 0xf9,
|
|
// RTCP index
|
|
0x80, 0x00, 0x00, 0x05,
|
|
// HMAC
|
|
0x09, 0x16, 0xb4, 0x27, 0x9a, 0xe9, 0x92, 0x26, 0x4e, 0x10,
|
|
};
|
|
|
|
static void print_data(const uint8_t *buf, int len)
|
|
{
|
|
int i;
|
|
for (i = 0; i < len; i++)
|
|
printf("%02x", buf[i]);
|
|
printf("\n");
|
|
}
|
|
|
|
static int test_decrypt(struct SRTPContext *srtp, const uint8_t *in, int len,
|
|
uint8_t *out)
|
|
{
|
|
memcpy(out, in, len);
|
|
if (!ff_srtp_decrypt(srtp, out, &len)) {
|
|
print_data(out, len);
|
|
return len;
|
|
} else
|
|
return -1;
|
|
}
|
|
|
|
static void test_encrypt(const uint8_t *data, int in_len, const char *suite,
|
|
const char *key)
|
|
{
|
|
struct SRTPContext enc = { 0 }, dec = { 0 };
|
|
int len;
|
|
char buf[RTP_MAX_PACKET_LENGTH];
|
|
ff_srtp_set_crypto(&enc, suite, key);
|
|
ff_srtp_set_crypto(&dec, suite, key);
|
|
len = ff_srtp_encrypt(&enc, data, in_len, buf, sizeof(buf));
|
|
if (!ff_srtp_decrypt(&dec, buf, &len)) {
|
|
if (len == in_len && !memcmp(buf, data, len))
|
|
printf("Decrypted content matches input\n");
|
|
else
|
|
printf("Decrypted content doesn't match input\n");
|
|
} else {
|
|
printf("Decryption failed\n");
|
|
}
|
|
ff_srtp_free(&enc);
|
|
ff_srtp_free(&dec);
|
|
}
|
|
|
|
int main(void)
|
|
{
|
|
static const char *aes128_80_suite = "AES_CM_128_HMAC_SHA1_80";
|
|
static const char *aes128_32_suite = "AES_CM_128_HMAC_SHA1_32";
|
|
static const char *aes128_80_32_suite = "SRTP_AES128_CM_HMAC_SHA1_32";
|
|
static const char *test_key = "abcdefghijklmnopqrstuvwxyz1234567890ABCD";
|
|
uint8_t buf[RTP_MAX_PACKET_LENGTH];
|
|
struct SRTPContext srtp = { 0 };
|
|
int len;
|
|
ff_srtp_set_crypto(&srtp, aes128_80_suite, aes128_80_key);
|
|
len = test_decrypt(&srtp, rtp_aes128_80, sizeof(rtp_aes128_80), buf);
|
|
test_encrypt(buf, len, aes128_80_suite, test_key);
|
|
test_encrypt(buf, len, aes128_32_suite, test_key);
|
|
test_encrypt(buf, len, aes128_80_32_suite, test_key);
|
|
test_decrypt(&srtp, rtcp_aes128_80, sizeof(rtcp_aes128_80), buf);
|
|
test_encrypt(buf, len, aes128_80_suite, test_key);
|
|
test_encrypt(buf, len, aes128_32_suite, test_key);
|
|
test_encrypt(buf, len, aes128_80_32_suite, test_key);
|
|
ff_srtp_free(&srtp);
|
|
|
|
memset(&srtp, 0, sizeof(srtp)); // Clear the context
|
|
ff_srtp_set_crypto(&srtp, aes128_32_suite, aes128_32_key);
|
|
test_decrypt(&srtp, rtp_aes128_32, sizeof(rtp_aes128_32), buf);
|
|
test_decrypt(&srtp, rtcp_aes128_32, sizeof(rtcp_aes128_32), buf);
|
|
ff_srtp_free(&srtp);
|
|
|
|
memset(&srtp, 0, sizeof(srtp)); // Clear the context
|
|
ff_srtp_set_crypto(&srtp, aes128_80_32_suite, aes128_80_32_key);
|
|
test_decrypt(&srtp, rtp_aes128_80_32, sizeof(rtp_aes128_80_32), buf);
|
|
test_decrypt(&srtp, rtcp_aes128_80_32, sizeof(rtcp_aes128_80_32), buf);
|
|
ff_srtp_free(&srtp);
|
|
return 0;
|
|
}
|
|
#endif /* TEST */
|