[pulseaudio-discuss] [PATCH v6 13/37] raop: Extract encryption related code into a separate file

Hajime Fujita crisp.fujita at gmail.com
Sun Jan 31 20:16:10 PST 2016


From: Martin Blanchard <tchaik at gmx.com>

That makes the raop_client.c code smaller/cleaner and will simplify
addition of more crypto related stuffs like authentication.
---
 src/Makefile.am                |   1 +
 src/modules/raop/raop_client.c | 116 +++++++++-----------------------
 src/modules/raop/raop_client.h |   3 +-
 src/modules/raop/raop_crypto.c | 146 +++++++++++++++++++++++++++++++++++++++++
 src/modules/raop/raop_crypto.h |  35 ++++++++++
 5 files changed, 215 insertions(+), 86 deletions(-)
 create mode 100644 src/modules/raop/raop_crypto.c
 create mode 100644 src/modules/raop/raop_crypto.h

diff --git a/src/Makefile.am b/src/Makefile.am
index d60cc19..e5b9131 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1133,6 +1133,7 @@ librtp_la_LIBADD = $(AM_LIBADD) libpulsecore- at PA_MAJORMINOR@.la libpulsecommon-@
 
 libraop_la_SOURCES = \
         modules/raop/raop_client.c modules/raop/raop_client.h \
+        modules/raop/raop_crypto.c modules/raop/raop_crypto.h \
         modules/raop/base64.c modules/raop/base64.h \
         modules/raop/raop_packet_buffer.h modules/raop/raop_packet_buffer.c
 libraop_la_CFLAGS = $(AM_CFLAGS) $(OPENSSL_CFLAGS) -I$(top_srcdir)/src/modules/rtp
diff --git a/src/modules/raop/raop_client.c b/src/modules/raop/raop_client.c
index e6e3737..5c825eb 100644
--- a/src/modules/raop/raop_client.c
+++ b/src/modules/raop/raop_client.c
@@ -32,13 +32,6 @@
 #include <sys/filio.h>
 #endif
 
-/* TODO: Replace OpenSSL with NSS */
-#include <openssl/err.h>
-#include <openssl/rand.h>
-#include <openssl/aes.h>
-#include <openssl/rsa.h>
-#include <openssl/engine.h>
-
 #include <pulse/xmalloc.h>
 #include <pulse/timeval.h>
 #include <pulse/sample.h>
@@ -56,12 +49,11 @@
 #include <pulsecore/random.h>
 
 #include "raop_client.h"
-#include "rtsp_client.h"
-#include "base64.h"
 
+#include "rtsp_client.h"
 #include "raop_packet_buffer.h"
-
-#define AES_CHUNKSIZE 16
+#include "raop_crypto.h"
+#include "base64.h"
 
 #define JACK_STATUS_DISCONNECTED 0
 #define JACK_STATUS_CONNECTED 1
@@ -100,12 +92,8 @@ struct pa_raop_client {
     uint8_t jack_type;
     uint8_t jack_status;
 
-    /* Encryption Related bits */
     int encryption; /* Enable encryption? */
-    AES_KEY aes;
-    uint8_t aes_iv[AES_CHUNKSIZE]; /* Initialization vector for aes-cbc */
-    uint8_t aes_nv[AES_CHUNKSIZE]; /* Next vector for aes-cbc */
-    uint8_t aes_key[AES_CHUNKSIZE]; /* Key for aes-cbc */
+    pa_raop_secret *aes;
 
     uint16_t seq;
     uint32_t rtptime;
@@ -240,50 +228,6 @@ static inline void bit_writer(uint8_t **buffer, uint8_t *bit_pos, int *size, uin
     }
 }
 
-static int rsa_encrypt(uint8_t *text, int len, uint8_t *res) {
-    const char n[] =
-        "59dE8qLieItsH1WgjrcFRKj6eUWqi+bGLOX1HL3U3GhC/j0Qg90u3sG/1CUtwC"
-        "5vOYvfDmFI6oSFXi5ELabWJmT2dKHzBJKa3k9ok+8t9ucRqMd6DZHJ2YCCLlDR"
-        "KSKv6kDqnw4UwPdpOMXziC/AMj3Z/lUVX1G7WSHCAWKf1zNS1eLvqr+boEjXuB"
-        "OitnZ/bDzPHrTOZz0Dew0uowxf/+sG+NCK3eQJVxqcaJ/vEHKIVd2M+5qL71yJ"
-        "Q+87X6oV3eaYvt3zWZYD6z5vYTcrtij2VZ9Zmni/UAaHqn9JdsBWLUEpVviYnh"
-        "imNVvYFZeCXg/IdTQ+x4IRdiXNv5hEew==";
-    const char e[] = "AQAB";
-    uint8_t modules[256];
-    uint8_t exponent[8];
-    int size;
-    RSA *rsa;
-
-    rsa = RSA_new();
-    size = pa_base64_decode(n, modules);
-    rsa->n = BN_bin2bn(modules, size, NULL);
-    size = pa_base64_decode(e, exponent);
-    rsa->e = BN_bin2bn(exponent, size, NULL);
-
-    size = RSA_public_encrypt(len, text, res, rsa, RSA_PKCS1_OAEP_PADDING);
-    RSA_free(rsa);
-    return size;
-}
-
-static int aes_encrypt(pa_raop_client *c, uint8_t *data, int size) {
-    uint8_t *buf;
-    int i=0, j;
-
-    pa_assert(c);
-
-    memcpy(c->aes_nv, c->aes_iv, AES_CHUNKSIZE);
-    while (i+AES_CHUNKSIZE <= size) {
-        buf = data + i;
-        for (j=0; j<AES_CHUNKSIZE; ++j)
-            buf[j] ^= c->aes_nv[j];
-
-        AES_encrypt(buf, buf, &c->aes);
-        memcpy(c->aes_nv, buf, AES_CHUNKSIZE);
-        i += AES_CHUNKSIZE;
-    }
-    return i;
-}
-
 static inline void rtrimchar(char *str, char rc) {
     char *sp = str + strlen(str) - 1;
     while (sp >= str && *sp == rc) {
@@ -570,8 +514,6 @@ static ssize_t udp_send_audio_packet(pa_raop_client *c, bool retrans, uint8_t *b
 }
 
 static void do_rtsp_announce(pa_raop_client *c) {
-    int i;
-    uint8_t rsakey[512];
     char *key, *iv, *sac = NULL, *sdp;
     uint16_t rand_data;
     const char *ip;
@@ -583,22 +525,20 @@ static void do_rtsp_announce(pa_raop_client *c) {
     pa_rtsp_set_url(c->rtsp, url);
     pa_xfree(url);
 
-    /* Now encrypt our aes_public key to send to the device. */
-    i = rsa_encrypt(c->aes_key, AES_CHUNKSIZE, rsakey);
-    pa_base64_encode(rsakey, i, &key);
-    rtrimchar(key, '=');
-    pa_base64_encode(c->aes_iv, AES_CHUNKSIZE, &iv);
-    rtrimchar(iv, '=');
-
     /* UDP protocol does not need "Apple-Challenge" at announce. */
     if (c->protocol == RAOP_TCP) {
         pa_random(&rand_data, sizeof(rand_data));
-        pa_base64_encode(&rand_data, AES_CHUNKSIZE, &sac);
+        pa_base64_encode(&rand_data, sizeof(rand_data), &sac);
         rtrimchar(sac, '=');
         pa_rtsp_add_header(c->rtsp, "Apple-Challenge", sac);
     }
 
-    if (c->encryption)
+    if (c->encryption) {
+        iv = pa_raop_secret_get_iv(c->aes);
+        rtrimchar(iv, '=');
+        key = pa_raop_secret_get_key(c->aes);
+        rtrimchar(key, '=');
+
         sdp = pa_sprintf_malloc(
             "v=0\r\n"
             "o=iTunes %s 0 IN IP4 %s\r\n"
@@ -613,7 +553,10 @@ static void do_rtsp_announce(pa_raop_client *c) {
             c->sid, ip, c->host,
             c->protocol == RAOP_TCP ? 4096 : UDP_FRAMES_PER_PACKET,
             key, iv);
-    else
+
+        pa_xfree(iv);
+        pa_xfree(key);
+    } else {
         sdp = pa_sprintf_malloc(
             "v=0\r\n"
             "o=iTunes %s 0 IN IP4 %s\r\n"
@@ -625,10 +568,10 @@ static void do_rtsp_announce(pa_raop_client *c) {
             "a=fmtp:96 %d 0 16 40 10 14 2 255 0 0 44100\r\n",
             c->sid, ip, c->host,
             c->protocol == RAOP_TCP ? 4096 : UDP_FRAMES_PER_PACKET);
+    }
 
     pa_rtsp_announce(c->rtsp, sdp);
-    pa_xfree(key);
-    pa_xfree(iv);
+
     pa_xfree(sac);
     pa_xfree(sdp);
 }
@@ -746,7 +689,7 @@ static void udp_rtsp_cb(pa_rtsp_client *rtsp, pa_rtsp_state state, pa_headerlist
 
             /* Set the Apple-Challenge key */
             pa_random(&rand, sizeof(rand));
-            pa_base64_encode(&rand, AES_CHUNKSIZE, &sac);
+            pa_base64_encode(&rand, sizeof(rand), &sac);
             rtrimchar(sac, '=');
             pa_rtsp_add_header(c->rtsp, "Apple-Challenge", sac);
 
@@ -1063,6 +1006,9 @@ pa_raop_client* pa_raop_client_new(pa_core *core, const char *host, pa_raop_prot
     c->udp_control_fd = -1;
     c->udp_timing_fd = -1;
 
+    c->encryption = 0;
+    c->aes = NULL;
+
     c->udp_my_control_port     = UDP_DEFAULT_CONTROL_PORT;
     c->udp_server_control_port = UDP_DEFAULT_CONTROL_PORT;
     c->udp_my_timing_port      = UDP_DEFAULT_TIMING_PORT;
@@ -1098,11 +1044,15 @@ void pa_raop_client_free(pa_raop_client *c) {
     pa_assert(c);
 
     pa_raop_pb_delete(c->packet_buffer);
-    if (c->rtsp)
-        pa_rtsp_client_free(c->rtsp);
+
     if (c->sid)
         pa_xfree(c->sid);
+    if (c->aes)
+        pa_raop_secret_free(c->aes);
+    if (c->rtsp)
+        pa_rtsp_client_free(c->rtsp);
     pa_xfree(c->host);
+
     pa_xfree(c);
 }
 
@@ -1126,12 +1076,6 @@ int pa_raop_client_connect(pa_raop_client *c) {
     else
         c->rtsp = pa_rtsp_client_new(c->core->mainloop, c->host, c->port, "iTunes/7.6.2 (Windows; N;)");
 
-    /* Initialise the AES encryption system. */
-    pa_random(c->aes_iv, sizeof(c->aes_iv));
-    pa_random(c->aes_key, sizeof(c->aes_key));
-    memcpy(c->aes_nv, c->aes_iv, sizeof(c->aes_nv));
-    AES_set_encrypt_key(c->aes_key, 128, &c->aes);
-
     /* Generate random instance id. */
     pa_random(&rand_data, sizeof(rand_data));
     c->sid = pa_sprintf_malloc("%u", rand_data.a);
@@ -1502,7 +1446,7 @@ int pa_raop_client_encode_sample(pa_raop_client *c, pa_memchunk *raw, pa_memchun
 
     if (c->encryption) {
         /* Encrypt our data. */
-        aes_encrypt(c, (b + header_size), size);
+        pa_raop_aes_encrypt(c->aes, (b + header_size), size);
     }
 
     /* We're done with the chunk. */
@@ -1526,7 +1470,11 @@ void pa_raop_client_tcp_set_closed_callback(pa_raop_client *c, pa_raop_client_cl
 }
 
 void pa_raop_client_set_encryption(pa_raop_client *c, int encryption) {
+    pa_assert(c);
+
     c->encryption = encryption;
+    if (c->encryption)
+        c->aes = pa_raop_secret_new();
 }
 
 void pa_raop_client_udp_set_setup_callback(pa_raop_client *c, pa_raop_client_setup_cb_t callback, void *userdata) {
diff --git a/src/modules/raop/raop_client.h b/src/modules/raop/raop_client.h
index d49c146..5d0bb14 100644
--- a/src/modules/raop/raop_client.h
+++ b/src/modules/raop/raop_client.h
@@ -50,8 +50,7 @@ pa_volume_t pa_raop_client_adjust_volume(pa_raop_client *c, pa_volume_t volume);
 int pa_raop_client_set_volume(pa_raop_client *c, pa_volume_t volume);
 int pa_raop_client_encode_sample(pa_raop_client *c, pa_memchunk *raw, pa_memchunk *encoded);
 
-int pa_raop_client_udp_handle_timing_packet(pa_raop_client *c, const uint8_t packet
-[], ssize_t size);
+int pa_raop_client_udp_handle_timing_packet(pa_raop_client *c, const uint8_t packet[], ssize_t size);
 int pa_raop_client_udp_handle_control_packet(pa_raop_client *c, const uint8_t packet[], ssize_t size);
 int pa_raop_client_udp_get_blocks_size(pa_raop_client *c, size_t *size);
 ssize_t pa_raop_client_udp_send_audio_packet(pa_raop_client *c, pa_memchunk *block);
diff --git a/src/modules/raop/raop_crypto.c b/src/modules/raop/raop_crypto.c
new file mode 100644
index 0000000..cd2934b
--- /dev/null
+++ b/src/modules/raop/raop_crypto.c
@@ -0,0 +1,146 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2013 Martin Blanchard
+
+  PulseAudio 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.
+
+  PulseAudio 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <openssl/err.h>
+#include <openssl/aes.h>
+#include <openssl/rsa.h>
+
+#include <pulse/xmalloc.h>
+
+#include <pulsecore/macro.h>
+#include <pulsecore/random.h>
+
+#include "raop_crypto.h"
+#include "base64.h"
+
+#define AES_CHUNK_SIZE 16
+
+struct pa_raop_secret {
+    uint8_t key[AES_CHUNK_SIZE]; /* Key for aes-cbc */
+    uint8_t iv[AES_CHUNK_SIZE];  /* Initialization vector for cbc */
+    AES_KEY aes;                 /* AES encryption */
+};
+
+static const char rsa_modulus[] =
+    "59dE8qLieItsH1WgjrcFRKj6eUWqi+bGLOX1HL3U3GhC/j0Qg90u3sG/1CUtwC"
+    "5vOYvfDmFI6oSFXi5ELabWJmT2dKHzBJKa3k9ok+8t9ucRqMd6DZHJ2YCCLlDR"
+    "KSKv6kDqnw4UwPdpOMXziC/AMj3Z/lUVX1G7WSHCAWKf1zNS1eLvqr+boEjXuB"
+    "OitnZ/bDzPHrTOZz0Dew0uowxf/+sG+NCK3eQJVxqcaJ/vEHKIVd2M+5qL71yJ"
+    "Q+87X6oV3eaYvt3zWZYD6z5vYTcrtij2VZ9Zmni/UAaHqn9JdsBWLUEpVviYnh"
+    "imNVvYFZeCXg/IdTQ+x4IRdiXNv5hEew==";
+
+static const char rsa_exponent[] =
+    "AQAB";
+
+static int rsa_encrypt(uint8_t *data, int len, uint8_t *str) {
+    uint8_t modules[256];
+    uint8_t exponent[8];
+    int size = 0;
+    RSA *rsa;
+
+    pa_assert(data);
+    pa_assert(str);
+
+    rsa = RSA_new();
+    size = pa_base64_decode(rsa_modulus, modules);
+    rsa->n = BN_bin2bn(modules, size, NULL);
+    size = pa_base64_decode(rsa_exponent, exponent);
+    rsa->e = BN_bin2bn(exponent, size, NULL);
+
+    size = RSA_public_encrypt(len, data, str, rsa, RSA_PKCS1_OAEP_PADDING);
+
+    RSA_free(rsa);
+    return size;
+}
+
+pa_raop_secret* pa_raop_secret_new(void) {
+    pa_raop_secret *s = pa_xnew0(pa_raop_secret, 1);
+
+    pa_assert(s);
+
+    pa_random(s->key, sizeof(s->key));
+    AES_set_encrypt_key(s->key, 128, &s->aes);
+    pa_random(s->iv, sizeof(s->iv));
+
+    return s;
+}
+
+void pa_raop_secret_free(pa_raop_secret *s) {
+    pa_assert(s);
+
+    pa_xfree(s);
+}
+
+char* pa_raop_secret_get_iv(pa_raop_secret *s) {
+    char *base64_iv = NULL;
+
+    pa_assert(s);
+
+    pa_base64_encode(s->iv, AES_CHUNK_SIZE, &base64_iv);
+
+    return base64_iv;
+}
+
+char* pa_raop_secret_get_key(pa_raop_secret *s) {
+    char *base64_key = NULL;
+    uint8_t rsa_key[512];
+    int size = 0;
+
+    pa_assert(s);
+
+    /* Encrypt our AES public key to send to the device */
+    size = rsa_encrypt(s->key, AES_CHUNK_SIZE, rsa_key);
+    pa_base64_encode(rsa_key, size, &base64_key);
+
+    return base64_key;
+}
+
+int pa_raop_aes_encrypt(pa_raop_secret *s, uint8_t *data, int len) {
+    static uint8_t nv[AES_CHUNK_SIZE];
+    uint8_t *buffer;
+    int i = 0, j;
+
+    pa_assert(s);
+    pa_assert(data);
+
+    memcpy(nv, s->iv, AES_CHUNK_SIZE);
+
+    while (i + AES_CHUNK_SIZE <= len) {
+        buffer = data + i;
+        for (j = 0; j < AES_CHUNK_SIZE; ++j)
+            buffer[j] ^= nv[j];
+
+        AES_encrypt(buffer, buffer, &s->aes);
+
+        memcpy(nv, buffer, AES_CHUNK_SIZE);
+        i += AES_CHUNK_SIZE;
+    }
+
+    return i;
+}
diff --git a/src/modules/raop/raop_crypto.h b/src/modules/raop/raop_crypto.h
new file mode 100644
index 0000000..65f7577
--- /dev/null
+++ b/src/modules/raop/raop_crypto.h
@@ -0,0 +1,35 @@
+#ifndef fooraopcryptofoo
+#define fooraopcryptofoo
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2013 Martin Blanchard
+
+  PulseAudio 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.
+
+  PulseAudio 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+typedef struct pa_raop_secret pa_raop_secret;
+
+pa_raop_secret* pa_raop_secret_new(void);
+void pa_raop_secret_free(pa_raop_secret *s);
+
+char* pa_raop_secret_get_iv(pa_raop_secret *s);
+char* pa_raop_secret_get_key(pa_raop_secret *s);
+
+int pa_raop_aes_encrypt(pa_raop_secret *s, uint8_t *data, int len);
+
+#endif
-- 
2.5.0



More information about the pulseaudio-discuss mailing list