RTMPE protocol support

This adds two protocols, but one of them is an internal implementation
detail just used as an abstraction layer/generalization in the code. The
RTMPE protocol implementation uses ffrtmpcrypt:// as an alternative to the
tcp:// protocol. This allows moving most of the lower level logic out
from the higher level generic rtmp code.
Signed-off-by: Martin Storsjö <martin@martin.st>

Changelog

@@ -39,6 +39,7 @@ version <next>:
 - RTMPTS protocol support
 - JPEG 2000 encoding support through OpenJPEG
 - G.723.1 demuxer and decoder
+- RTMPE protocol support
 
 
 version 0.8:

configure

@@ -950,6 +950,7 @@ CONFIG_LIST="
     fastdiv
     fft
     frei0r
+    gcrypt
     gnutls
     gpl
     gray
@@ -982,6 +983,7 @@ CONFIG_LIST="
     mdct
     memalign_hack
     mpegaudiodsp
+    nettle
     network
     nonfree
     openssl
@@ -1543,6 +1545,9 @@ vfwcap_indev_extralibs="-lavicap32"
 x11_grab_device_indev_deps="x11grab XShmCreateImage"
 
 # protocols
+ffrtmpcrypt_protocol_deps="!librtmp_protocol"
+ffrtmpcrypt_protocol_deps_any="gcrypt nettle openssl"
+ffrtmpcrypt_protocol_select="tcp_protocol"
 ffrtmphttp_protocol_deps="!librtmp_protocol"
 ffrtmphttp_protocol_select="http_protocol"
 gopher_protocol_deps="network"
@@ -1560,6 +1565,7 @@ mmsh_protocol_select="http_protocol"
 mmst_protocol_deps="network"
 rtmp_protocol_deps="!librtmp_protocol"
 rtmp_protocol_select="tcp_protocol"
+rtmpe_protocol_select="ffrtmpcrypt_protocol"
 rtmps_protocol_deps="!librtmp_protocol"
 rtmps_protocol_select="tls_protocol"
 rtmpt_protocol_select="ffrtmphttp_protocol"
@@ -3014,6 +3020,11 @@ enabled openssl    && { check_lib openssl/ssl.h SSL_library_init -lssl -lcrypto
                         check_lib openssl/ssl.h SSL_library_init -lssl -lcrypto -lws2_32 -lgdi32 ||
                         die "ERROR: openssl not found"; }
 
+if enabled gnutls; then
+    { check_lib nettle/bignum.h nettle_mpz_get_str_256 -lnettle -lhogweed -lgmp && enable nettle; } ||
+    { check_lib gcrypt.h gcry_mpi_new -lgcrypt && enable gcrypt; }
+fi
+
 # libdc1394 check
 if enabled libdc1394; then
     { check_lib dc1394/dc1394.h dc1394_new -ldc1394 -lraw1394 &&

doc/general.texi

@@ -844,7 +844,7 @@ performance on systems without hardware floating point support).
 @item MMST         @tab X
 @item pipe         @tab X
 @item RTMP         @tab X
-@item RTMPE        @tab E
+@item RTMPE        @tab X
 @item RTMPS        @tab X
 @item RTMPT        @tab X
 @item RTMPTE       @tab E

doc/protocols.texi

@@ -247,6 +247,15 @@ For example to read with @command{avplay} a multimedia resource named
 avplay rtmp://myserver/vod/sample
 @end example
 
+@section rtmpe
+
+Encrypted Real-Time Messaging Protocol.
+
+The Encrypted Real-Time Messaging Protocol (RTMPE) is used for
+streaming multimedia content within standard cryptographic primitives,
+consisting of Diffie-Hellman key exchange and HMACSHA256, generating
+a pair of RC4 keys.
+
 @section rtmps
 
 Real-Time Messaging Protocol over a secure SSL connection.

libavformat/Makefile

@@ -341,6 +341,7 @@ OBJS-$(CONFIG_LIBRTMP)                   += librtmp.o
 OBJS-$(CONFIG_APPLEHTTP_PROTOCOL)        += hlsproto.o
 OBJS-$(CONFIG_CONCAT_PROTOCOL)           += concat.o
 OBJS-$(CONFIG_CRYPTO_PROTOCOL)           += crypto.o
+OBJS-$(CONFIG_FFRTMPCRYPT_PROTOCOL)      += rtmpcrypt.o rtmpdh.o
 OBJS-$(CONFIG_FFRTMPHTTP_PROTOCOL)       += rtmphttp.o
 OBJS-$(CONFIG_FILE_PROTOCOL)             += file.o
 OBJS-$(CONFIG_GOPHER_PROTOCOL)           += gopher.o
@@ -353,6 +354,7 @@ OBJS-$(CONFIG_MMST_PROTOCOL)             += mmst.o mms.o asf.o
 OBJS-$(CONFIG_MD5_PROTOCOL)              += md5proto.o
 OBJS-$(CONFIG_PIPE_PROTOCOL)             += file.o
 OBJS-$(CONFIG_RTMP_PROTOCOL)             += rtmpproto.o rtmppkt.o
+OBJS-$(CONFIG_RTMPE_PROTOCOL)            += rtmpproto.o rtmppkt.o
 OBJS-$(CONFIG_RTMPS_PROTOCOL)            += rtmpproto.o rtmppkt.o
 OBJS-$(CONFIG_RTMPT_PROTOCOL)            += rtmpproto.o rtmppkt.o
 OBJS-$(CONFIG_RTMPTS_PROTOCOL)           += rtmpproto.o rtmppkt.o

libavformat/allformats.c

@@ -247,6 +247,7 @@ void av_register_all(void)
 #endif
     REGISTER_PROTOCOL (CONCAT, concat);
     REGISTER_PROTOCOL (CRYPTO, crypto);
+    REGISTER_PROTOCOL (FFRTMPCRYPT, ffrtmpcrypt);
     REGISTER_PROTOCOL (FFRTMPHTTP, ffrtmphttp);
     REGISTER_PROTOCOL (FILE, file);
     REGISTER_PROTOCOL (GOPHER, gopher);
@@ -259,6 +260,7 @@ void av_register_all(void)
     REGISTER_PROTOCOL (MD5,  md5);
     REGISTER_PROTOCOL (PIPE, pipe);
     REGISTER_PROTOCOL (RTMP, rtmp);
+    REGISTER_PROTOCOL (RTMPE, rtmpe);
     REGISTER_PROTOCOL (RTMPS, rtmps);
     REGISTER_PROTOCOL (RTMPT, rtmpt);
     REGISTER_PROTOCOL (RTMPTS, rtmpts);

libavformat/rtmpcrypt.h

+/*
+ * RTMPE encryption utilities
+ * Copyright (c) 2012 Samuel Pitoiset
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFORMAT_RTMPCRYPT_H
+#define AVFORMAT_RTMPCRYPT_H
+
+#include <stdint.h>
+
+#include "url.h"
+
+/**
+ * Initialize the Diffie-Hellmann context and generate the public key.
+ *
+ * @param h     an URLContext
+ * @param buf   handshake data (1536 bytes)
+ * @return zero on success, negative value otherwise
+ */
+int ff_rtmpe_gen_pub_key(URLContext *h, uint8_t *buf);
+
+/**
+ * Compute the shared secret key and initialize the RC4 encryption.
+ *
+ * @param h             an URLContext
+ * @param serverdata    server data (1536 bytes)
+ * @param clientdata    client data (1536 bytes)
+ * @param type          the position of the server digest
+ * @return zero on success, negative value otherwise
+ */
+int ff_rtmpe_compute_secret_key(URLContext *h, const uint8_t *serverdata,
+                                const uint8_t *clientdata, int type);
+
+/**
+ * Encrypt the signature.
+ *
+ * @param h             an URLContext
+ * @param signature     the signature to encrypt
+ * @param digest        the digest used for finding the encryption key
+ * @param type          type of encryption (8 for XTEA, 9 for Blowfish)
+ */
+void ff_rtmpe_encrypt_sig(URLContext *h, uint8_t *signature,
+                          const uint8_t *digest, int type);
+
+/**
+ * Update the keystream and set RC4 keys for encryption.
+ *
+ * @param h an URLContext
+ * @return zero on success, negative value otherwise
+ */
+int ff_rtmpe_update_keystream(URLContext *h);
+
+#endif /* AVFORMAT_RTMPCRYPT_H */

libavformat/rtmpdh.c

+/*
+ * RTMP Diffie-Hellmann utilities
+ * Copyright (c) 2012 Samuel Pitoiset
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * RTMP Diffie-Hellmann utilities
+ */
+
+#include "config.h"
+#include "rtmpdh.h"
+
+#define P1024                                          \
+    "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
+    "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \
+    "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \
+    "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
+    "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381" \
+    "FFFFFFFFFFFFFFFF"
+
+#define Q1024                                          \
+    "7FFFFFFFFFFFFFFFE487ED5110B4611A62633145C06E0E68" \
+    "948127044533E63A0105DF531D89CD9128A5043CC71A026E" \
+    "F7CA8CD9E69D218D98158536F92F8A1BA7F09AB6B6A8E122" \
+    "F242DABB312F3F637A262174D31BF6B585FFAE5B7A035BF6" \
+    "F71C35FDAD44CFD2D74F9208BE258FF324943328F67329C0" \
+    "FFFFFFFFFFFFFFFF"
+
+#if CONFIG_NETTLE || CONFIG_GCRYPT
+#if CONFIG_NETTLE
+#define bn_new(bn)                      \
+    do {                                \
+        bn = av_malloc(sizeof(*bn));    \
+        if (bn)                         \
+            mpz_init2(bn, 1);           \
+    } while (0)
+#define bn_free(bn)     \
+    do {                \
+        mpz_clear(bn);  \
+        av_free(bn);    \
+    } while (0)
+#define bn_set_word(bn, w)          mpz_set_ui(bn, w)
+#define bn_cmp(a, b)                mpz_cmp(a, b)
+#define bn_copy(to, from)           mpz_set(to, from)
+#define bn_sub_word(bn, w)          mpz_sub_ui(bn, bn, w)
+#define bn_cmp_1(bn)                mpz_cmp_ui(bn, 1)
+#define bn_num_bytes(bn)            (mpz_sizeinbase(bn, 2) + 7) / 8
+#define bn_bn2bin(bn, buf, len)     nettle_mpz_get_str_256(len, buf, bn)
+#define bn_bin2bn(bn, buf, len)                     \
+    do {                                            \
+        bn_new(bn);                                 \
+        if (bn)                                     \
+            nettle_mpz_set_str_256_u(bn, len, buf); \
+    } while (0)
+#define bn_hex2bn(bn, buf, ret)                     \
+    do {                                            \
+        bn_new(bn);                                 \
+        if (bn)                                     \
+            ret = (mpz_set_str(bn, buf, 16) == 0);  \
+    } while (0)
+#define bn_modexp(bn, y, q, p)      mpz_powm(bn, y, q, p)
+#define bn_random(bn, num_bytes)    mpz_random(bn, num_bytes);
+#elif CONFIG_GCRYPT
+#define bn_new(bn)                  bn = gcry_mpi_new(1)
+#define bn_free(bn)                 gcry_mpi_release(bn)
+#define bn_set_word(bn, w)          gcry_mpi_set_ui(bn, w)
+#define bn_cmp(a, b)                gcry_mpi_cmp(a, b)
+#define bn_copy(to, from)           gcry_mpi_set(to, from)
+#define bn_sub_word(bn, w)          gcry_mpi_sub_ui(bn, bn, w)
+#define bn_cmp_1(bn)                gcry_mpi_cmp_ui(bn, 1)
+#define bn_num_bytes(bn)            (gcry_mpi_get_nbits(bn) + 7) / 8
+#define bn_bn2bin(bn, buf, len)     gcry_mpi_print(GCRYMPI_FMT_USG, buf, len, NULL, bn)
+#define bn_bin2bn(bn, buf, len)     gcry_mpi_scan(&bn, GCRYMPI_FMT_USG, buf, len, NULL)
+#define bn_hex2bn(bn, buf, ret)     ret = (gcry_mpi_scan(&bn, GCRYMPI_FMT_HEX, buf, 0, 0) == 0)
+#define bn_modexp(bn, y, q, p)      gcry_mpi_powm(bn, y, q, p)
+#define bn_random(bn, num_bytes)    gcry_mpi_randomize(bn, num_bytes, GCRY_WEAK_RANDOM)
+#endif
+
+#define MAX_BYTES 18000
+
+#define dh_new()                    av_malloc(sizeof(FF_DH))
+
+static FFBigNum dh_generate_key(FF_DH *dh)
+{
+    int num_bytes;
+
+    num_bytes = bn_num_bytes(dh->p) - 1;
+    if (num_bytes <= 0 || num_bytes > MAX_BYTES)
+        return NULL;
+
+    bn_new(dh->priv_key);
+    if (!dh->priv_key)
+        return NULL;
+    bn_random(dh->priv_key, num_bytes);
+
+    bn_new(dh->pub_key);
+    if (!dh->pub_key) {
+        bn_free(dh->priv_key);
+        return NULL;
+    }
+
+    bn_modexp(dh->pub_key, dh->g, dh->priv_key, dh->p);
+
+    return dh->pub_key;
+}
+
+static int dh_compute_key(FF_DH *dh, FFBigNum pub_key_bn,
+                          uint32_t pub_key_len, uint8_t *secret_key)
+{
+    FFBigNum k;
+    int num_bytes;
+
+    num_bytes = bn_num_bytes(dh->p);
+    if (num_bytes <= 0 || num_bytes > MAX_BYTES)
+        return -1;
+
+    bn_new(k);
+    if (!k)
+        return -1;
+
+    bn_modexp(k, pub_key_bn, dh->priv_key, dh->p);
+    bn_bn2bin(k, secret_key, pub_key_len);
+    bn_free(k);
+
+    /* return the length of the shared secret key like DH_compute_key */
+    return pub_key_len;
+}
+
+void ff_dh_free(FF_DH *dh)
+{
+    bn_free(dh->p);
+    bn_free(dh->g);
+    bn_free(dh->pub_key);
+    bn_free(dh->priv_key);
+    av_free(dh);
+}
+#elif CONFIG_OPENSSL
+#define bn_new(bn)                  bn = BN_new()
+#define bn_free(bn)                 BN_free(bn)
+#define bn_set_word(bn, w)          BN_set_word(bn, w)
+#define bn_cmp(a, b)                BN_cmp(a, b)
+#define bn_copy(to, from)           BN_copy(to, from)
+#define bn_sub_word(bn, w)          BN_sub_word(bn, w)
+#define bn_cmp_1(bn)                BN_cmp(bn, BN_value_one())
+#define bn_num_bytes(bn)            BN_num_bytes(bn)
+#define bn_bn2bin(bn, buf, len)     BN_bn2bin(bn, buf)
+#define bn_bin2bn(bn, buf, len)     bn = BN_bin2bn(buf, len, 0)
+#define bn_hex2bn(bn, buf, ret)     ret = BN_hex2bn(&bn, buf)
+#define bn_modexp(bn, y, q, p)               \
+    do {                                     \
+        BN_CTX *ctx = BN_CTX_new();          \
+        if (!ctx)                            \
+            return AVERROR(ENOMEM);          \
+        if (!BN_mod_exp(bn, y, q, p, ctx)) { \
+            BN_CTX_free(ctx);                \
+            return AVERROR(EINVAL);          \
+        }                                    \
+        BN_CTX_free(ctx);                    \
+    } while (0)
+
+#define dh_new()                                DH_new()
+#define dh_generate_key(dh)                     DH_generate_key(dh)
+#define dh_compute_key(dh, pub, len, secret)    DH_compute_key(secret, pub, dh)
+
+void ff_dh_free(FF_DH *dh)
+{
+    DH_free(dh);
+}
+#endif
+
+static int dh_is_valid_public_key(FFBigNum y, FFBigNum p, FFBigNum q)
+{
+    FFBigNum bn = NULL;
+    int ret = AVERROR(EINVAL);
+
+    bn_new(bn);
+    if (!bn)
+        return AVERROR(ENOMEM);
+
+    /* y must lie in [2, p - 1] */
+    bn_set_word(bn, 1);
+    if (!bn_cmp(y, bn))
+        goto fail;
+
+    /* bn = p - 2 */
+    bn_copy(bn, p);
+    bn_sub_word(bn, 1);
+    if (!bn_cmp(y, bn))
+        goto fail;
+
+    /* Verify with Sophie-Germain prime
+     *
+     * This is a nice test to make sure the public key position is calculated
+     * correctly. This test will fail in about 50% of the cases if applied to
+     * random data.
+     */
+    /* y must fulfill y^q mod p = 1 */
+    bn_modexp(bn, y, q, p);
+
+    if (bn_cmp_1(bn))
+        goto fail;
+
+    ret = 0;
+fail:
+    bn_free(bn);
+
+    return ret;
+}
+
+av_cold FF_DH *ff_dh_init(int key_len)
+{
+    FF_DH *dh;
+    int ret;
+
+    if (!(dh = dh_new()))
+        return NULL;
+
+    bn_new(dh->g);
+    if (!dh->g)
+        goto fail;
+
+    bn_hex2bn(dh->p, P1024, ret);
+    if (!ret)
+        goto fail;
+
+    bn_set_word(dh->g, 2);
+    dh->length = key_len;
+
+    return dh;
+
+fail:
+    ff_dh_free(dh);
+
+    return NULL;
+}
+
+int ff_dh_generate_public_key(FF_DH *dh)
+{
+    int ret = 0;
+
+    while (!ret) {
+        FFBigNum q1 = NULL;
+
+        if (!dh_generate_key(dh))
+            return AVERROR(EINVAL);
+
+        bn_hex2bn(q1, Q1024, ret);
+        if (!ret)
+            return AVERROR(ENOMEM);
+
+        ret = dh_is_valid_public_key(dh->pub_key, dh->p, q1);
+        bn_free(q1);
+
+        if (!ret) {
+            /* the public key is valid */
+            break;
+        }
+    }
+
+    return ret;
+}
+
+int ff_dh_write_public_key(FF_DH *dh, uint8_t *pub_key, int pub_key_len)
+{
+    int len;
+
+    /* compute the length of the public key */
+    len = bn_num_bytes(dh->pub_key);
+    if (len <= 0 || len > pub_key_len)
+        return AVERROR(EINVAL);
+
+    /* convert the public key value into big-endian form */
+    memset(pub_key, 0, pub_key_len);
+    bn_bn2bin(dh->pub_key, pub_key + pub_key_len - len, len);
+
+    return 0;
+}
+
+int ff_dh_compute_shared_secret_key(FF_DH *dh, const uint8_t *pub_key,
+                                    int pub_key_len, uint8_t *secret_key)
+{
+    FFBigNum q1 = NULL, pub_key_bn = NULL;
+    int ret;
+
+    /* convert the big-endian form of the public key into a bignum */
+    bn_bin2bn(pub_key_bn, pub_key, pub_key_len);
+    if (!pub_key_bn)
+        return AVERROR(ENOMEM);
+
+    /* convert the string containing a hexadecimal number into a bignum */
+    bn_hex2bn(q1, Q1024, ret);
+    if (!ret) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    /* when the public key is valid we have to compute the shared secret key */
+    if ((ret = dh_is_valid_public_key(pub_key_bn, dh->p, q1)) < 0) {
+        goto fail;
+    } else if ((ret = dh_compute_key(dh, pub_key_bn, pub_key_len,
+                                     secret_key)) < 0) {
+        ret = AVERROR(EINVAL);
+        goto fail;
+    }
+
+fail:
+    bn_free(pub_key_bn);
+    bn_free(q1);
+
+    return ret;
+}
+

libavformat/rtmpdh.h

+/*
+ * RTMP Diffie-Hellmann utilities
+ * Copyright (c) 2012 Samuel Pitoiset
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFORMAT_RTMPDH_H
+#define AVFORMAT_RTMPDH_H
+
+#include "avformat.h"
+#include "config.h"
+
+#if CONFIG_NETTLE || CONFIG_GCRYPT
+#if CONFIG_NETTLE
+#include <gmp.h>
+#include <nettle/bignum.h>
+
+typedef mpz_ptr FFBigNum;
+#elif CONFIG_GCRYPT
+#include <gcrypt.h>
+
+typedef gcry_mpi_t FFBigNum;
+#endif
+
+typedef struct FF_DH {
+  FFBigNum p;
+  FFBigNum g;
+  FFBigNum pub_key;
+  FFBigNum priv_key;
+  long length;
+} FF_DH;
+
+#elif CONFIG_OPENSSL
+#include <openssl/bn.h>
+#include <openssl/dh.h>
+
+typedef BIGNUM *FFBigNum;
+typedef DH FF_DH;
+#endif
+
+/**
+ * Initialize a Diffie-Hellmann context.
+ *
+ * @param key_len length of the key
+ * @return a new Diffie-Hellmann context on success, NULL otherwise
+ */
+FF_DH *ff_dh_init(int key_len);
+
+/**
+ * Free a Diffie-Hellmann context.
+ *
+ * @param dh a Diffie-Hellmann context to free
+ */
+void ff_dh_free(FF_DH *dh);
+
+/**
+ * Generate a public key.
+ *
+ * @param dh a Diffie-Hellmann context
+ * @return zero on success, negative value otherwise
+ */
+int ff_dh_generate_public_key(FF_DH *dh);
+
+/**
+ * Write the public key into the given buffer.
+ *
+ * @param dh            a Diffie-Hellmann context, containing the public key to write
+ * @param pub_key       the buffer where the public key is written
+ * @param pub_key_len   the length of the buffer
+ * @return zero on success, negative value otherwise
+ */
+int ff_dh_write_public_key(FF_DH *dh, uint8_t *pub_key, int pub_key_len);
+
+/**
+ * Compute the shared secret key from the private FF_DH value and the
+ * other party's public value.
+ *
+ * @param dh            a Diffie-Hellmann context, containing the private key
+ * @param pub_key       the buffer containing the public key
+ * @param pub_key_len   the length of the buffer
+ * @param secret_key    the buffer where the secret key is written
+ * @return length of the shared secret key on success, negative value otherwise
+ */
+int ff_dh_compute_shared_secret_key(FF_DH *dh, const uint8_t *pub_key,
+                                    int pub_key_len, uint8_t *secret_key);
+
+#endif /* AVFORMAT_RTMPDH_H */

libavformat/rtmpproto.c

@@ -37,6 +37,7 @@
 
 #include "flv.h"
 #include "rtmp.h"
+#include "rtmpcrypt.h"
 #include "rtmppkt.h"
 #include "url.h"
 
@@ -92,6 +93,7 @@ typedef struct RTMPContext {
     int           server_bw;                  ///< server bandwidth
     int           client_buffer_time;         ///< client buffer time in ms
     int           flush_interval;             ///< number of packets flushed in the same request (RTMPT only)
+    int           encrypted;                  ///< use an encrypted connection (RTMPE only)
 } RTMPContext;
 
 #define PLAYER_KEY_OPEN_PART_LEN 30   ///< length of partial key used for first client digest signing
@@ -649,13 +651,17 @@ int ff_rtmp_calc_digest_pos(const uint8_t *buf, int off, int mod_val,
  * will be stored) into that packet.
  *
  * @param buf handshake data (1536 bytes)
+ * @param encrypted use an encrypted connection (RTMPE)
  * @return offset to the digest inside input data
  */
-static int rtmp_handshake_imprint_with_digest(uint8_t *buf)
+static int rtmp_handshake_imprint_with_digest(uint8_t *buf, int encrypted)
 {
     int ret, digest_pos;
 
-    digest_pos = ff_rtmp_calc_digest_pos(buf, 8, 728, 12);
+    if (encrypted)
+        digest_pos = ff_rtmp_calc_digest_pos(buf, 772, 728, 776);
+    else
+        digest_pos = ff_rtmp_calc_digest_pos(buf, 8, 728, 12);
 
     ret = ff_rtmp_calc_digest(buf, RTMP_HANDSHAKE_PACKET_SIZE, digest_pos,
                               rtmp_player_key, PLAYER_KEY_OPEN_PART_LEN,
@@ -712,8 +718,9 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
     uint8_t serverdata[RTMP_HANDSHAKE_PACKET_SIZE+1];
     int i;
     int server_pos, client_pos;
-    uint8_t digest[32];
-    int ret;
+    uint8_t digest[32], signature[32];
+    int encrypted = rt->encrypted && CONFIG_FFRTMPCRYPT_PROTOCOL;
+    int ret, type = 0;
 
     av_log(s, AV_LOG_DEBUG, "Handshaking...\n");
 
@@ -721,7 +728,24 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
     // generate handshake packet - 1536 bytes of pseudorandom data
     for (i = 9; i <= RTMP_HANDSHAKE_PACKET_SIZE; i++)
         tosend[i] = av_lfg_get(&rnd) >> 24;
-    client_pos = rtmp_handshake_imprint_with_digest(tosend + 1);
+
+    if (encrypted) {
+        /* When the client wants to use RTMPE, we have to change the command
+         * byte to 0x06 which means to use encrypted data and we have to set
+         * the flash version to at least 9.0.115.0. */
+        tosend[0] = 6;
+        tosend[5] = 128;
+        tosend[6] = 0;
+        tosend[7] = 3;
+        tosend[8] = 2;
+
+        /* Initialize the Diffie-Hellmann context and generate the public key
+         * to send to the server. */
+        if ((ret = ff_rtmpe_gen_pub_key(rt->stream, tosend + 1)) < 0)
+            return ret;
+    }
+
+    client_pos = rtmp_handshake_imprint_with_digest(tosend + 1, encrypted);
     if (client_pos < 0)
         return client_pos;
 
@@ -743,6 +767,7 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
         return ret;
     }
 
+    av_log(s, AV_LOG_DEBUG, "Type answer %d\n", serverdata[0]);
     av_log(s, AV_LOG_DEBUG, "Server version %d.%d.%d.%d\n",
            serverdata[5], serverdata[6], serverdata[7], serverdata[8]);
 
@@ -752,6 +777,7 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
             return server_pos;
 
         if (!server_pos) {
+            type = 1;
             server_pos = rtmp_validate_digest(serverdata + 1, 8);
             if (server_pos < 0)
                 return server_pos;
@@ -769,11 +795,22 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
             return ret;
 
         ret = ff_rtmp_calc_digest(clientdata, RTMP_HANDSHAKE_PACKET_SIZE - 32,
-                                  0, digest, 32, digest);
+                                  0, digest, 32, signature);
         if (ret < 0)
             return ret;
 
-        if (memcmp(digest, clientdata + RTMP_HANDSHAKE_PACKET_SIZE - 32, 32)) {
+        if (encrypted) {
+            /* Compute the shared secret key sent by the server and initialize
+             * the RC4 encryption. */
+            if ((ret = ff_rtmpe_compute_secret_key(rt->stream, serverdata + 1,
+                                                   tosend + 1, type)) < 0)
+                return ret;
+
+            /* Encrypt the signature received by the server. */
+            ff_rtmpe_encrypt_sig(rt->stream, signature, digest, serverdata[0]);
+        }
+
+        if (memcmp(signature, clientdata + RTMP_HANDSHAKE_PACKET_SIZE - 32, 32)) {
             av_log(s, AV_LOG_ERROR, "Signature mismatch\n");
             return AVERROR(EIO);
         }
@@ -792,14 +829,47 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
         if (ret < 0)
             return ret;
 
+        if (encrypted) {
+            /* Encrypt the signature to be send to the server. */
+            ff_rtmpe_encrypt_sig(rt->stream, tosend +
+                                 RTMP_HANDSHAKE_PACKET_SIZE - 32, digest,
+                                 serverdata[0]);
+        }
+
         // write reply back to the server
         if ((ret = ffurl_write(rt->stream, tosend,
                                RTMP_HANDSHAKE_PACKET_SIZE)) < 0)
             return ret;
+
+        if (encrypted) {
+            /* Set RC4 keys for encryption and update the keystreams. */
+            if ((ret = ff_rtmpe_update_keystream(rt->stream)) < 0)
+                return ret;
+        }
     } else {
+        if (encrypted) {
+            /* Compute the shared secret key sent by the server and initialize
+             * the RC4 encryption. */
+            if ((ret = ff_rtmpe_compute_secret_key(rt->stream, serverdata + 1,
+                            tosend + 1, 1)) < 0)
+                return ret;
+
+            if (serverdata[0] == 9) {
+                /* Encrypt the signature received by the server. */
+                ff_rtmpe_encrypt_sig(rt->stream, signature, digest,
+                                     serverdata[0]);
+            }
+        }
+
         if ((ret = ffurl_write(rt->stream, serverdata + 1,
                                RTMP_HANDSHAKE_PACKET_SIZE)) < 0)
             return ret;
+
+        if (encrypted) {
+            /* Set RC4 keys for encryption and update the keystreams. */
+            if ((ret = ff_rtmpe_update_keystream(rt->stream)) < 0)
+                return ret;
+        }
     }
 
     return 0;
@@ -1122,6 +1192,10 @@ static int rtmp_open(URLContext *s, const char *uri, int flags)
         if (port < 0)
             port = RTMPS_DEFAULT_PORT;
         ff_url_join(buf, sizeof(buf), "tls", NULL, hostname, port, NULL);
+    } else if (!strcmp(proto, "rtmpe")) {
+        /* open the encrypted connection */
+        ff_url_join(buf, sizeof(buf), "ffrtmpcrypt", NULL, hostname, port, NULL);
+        rt->encrypted = 1;
     } else {
         /* open the tcp connection */
         if (port < 0)
@@ -1446,6 +1520,24 @@ URLProtocol ff_rtmp_protocol = {
     .priv_data_class= &rtmp_class,
 };
 
+static const AVClass rtmpe_class = {
+    .class_name = "rtmpe",
+    .item_name  = av_default_item_name,
+    .option     = rtmp_options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+URLProtocol ff_rtmpe_protocol = {
+    .name            = "rtmpe",
+    .url_open        = rtmp_open,
+    .url_read        = rtmp_read,
+    .url_write       = rtmp_write,
+    .url_close       = rtmp_close,
+    .priv_data_size  = sizeof(RTMPContext),
+    .flags           = URL_PROTOCOL_FLAG_NETWORK,
+    .priv_data_class = &rtmpe_class,
+};
+
 static const AVClass rtmps_class = {
     .class_name = "rtmps",
     .item_name  = av_default_item_name,

libavformat/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 54
-#define LIBAVFORMAT_VERSION_MINOR 10
+#define LIBAVFORMAT_VERSION_MINOR 11
 #define LIBAVFORMAT_VERSION_MICRO  0
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \