From f8793376a5a4956c9203bfe89e4d1c0a6121afd2 Mon Sep 17 00:00:00 2001
From: vysheng <mail@vysheng.ru>
Date: Wed, 25 Dec 2013 03:42:05 +0400
Subject: [PATCH 1/6] Fixed random on sensible parts (generation auth_key,
 session_id and keys for secret chats)

---
 main.c           |  4 ++++
 mtproto-client.c | 19 ++++++++++++++-----
 mtproto-client.h |  1 +
 queries.c        |  6 ++++--
 4 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/main.c b/main.c
index 1de65d8..f0cd56d 100644
--- a/main.c
+++ b/main.c
@@ -78,6 +78,7 @@ char *binlog_file_name;
 int binlog_enabled;
 extern int log_level;
 int sync_from_start;
+int allow_weak_random;
 
 void set_default_username (const char *s) {
   if (default_username) { 
@@ -375,6 +376,9 @@ void args_parse (int argc, char **argv) {
     case 'E':
       disable_auto_accept = 1;
       break;
+    case 'w':
+      allow_weak_random = 1;
+      break;
     case 'h':
     default:
       usage ();
diff --git a/mtproto-client.c b/mtproto-client.c
index c22bb5a..a010d85 100644
--- a/mtproto-client.c
+++ b/mtproto-client.c
@@ -69,7 +69,7 @@ char new_nonce[256];
 char server_nonce[256];
 extern int binlog_enabled;
 extern int disable_auto_accept;
-
+extern int allow_weak_random;
 
 int total_packets_sent;
 long long total_data_sent;
@@ -98,6 +98,15 @@ double get_utime (int clock_id) {
   return res;
 }
 
+void do_rand (void *s, int l) {
+  if (RAND_bytes (s, l) < 0) {
+    if (allow_weak_random) {
+      RAND_pseudo_bytes (s, l);
+    } else {
+      assert (0 && "End of random. If you want, you can start with -w");
+    }
+  }
+}
 
 
 #define STATS_BUFF_SIZE        (64 << 10)
@@ -223,7 +232,7 @@ int rpc_send_message (struct connection *c, void *data, int len) {
 
 int send_req_pq_packet (struct connection *c) {
   assert (c_state == st_init);
-  assert (RAND_pseudo_bytes ((unsigned char *) nonce, 16) >= 0);
+  do_rand (nonce, 16);
   unenc_msg_header.out_msg_id = 0;
   clear_packet ();
   out_int (CODE_req_pq);
@@ -371,7 +380,7 @@ int process_respq_answer (struct connection *c, char *packet, int len) {
   //out_int (0x0501);  // q=5
   out_ints ((int *) nonce, 4);
   out_ints ((int *) server_nonce, 4);
-  assert (RAND_pseudo_bytes ((unsigned char *) new_nonce, 32) >= 0);
+  do_rand (new_nonce, 32);
   out_ints ((int *) new_nonce, 8);
   sha1 ((unsigned char *) (packet_buffer + 5), (packet_ptr - packet_buffer - 5) * 4, (unsigned char *) packet_buffer);
 
@@ -564,7 +573,7 @@ int process_dh_answer (struct connection *c, char *packet, int len) {
   BN_init (&dh_g);
   BN_set_word (&dh_g, g);
 
-  assert (RAND_pseudo_bytes ((unsigned char *)s_power, 256) >= 0);
+  do_rand (s_power, 256);
   BIGNUM *dh_power = BN_new ();
   assert (BN_bin2bn ((unsigned char *)s_power, 256, dh_power) == dh_power);
 
@@ -683,7 +692,7 @@ void init_enc_msg (struct session *S, int useful) {
 //  assert (DC->server_salt);
   enc_msg.server_salt = DC->server_salt;
   if (!S->session_id) {
-    assert (RAND_pseudo_bytes ((unsigned char *) &S->session_id, 8) >= 0);
+    do_rand (&S->session_id, 8);
   }
   enc_msg.session_id = S->session_id;
   //enc_msg.auth_key_id2 = auth_key_id;
diff --git a/mtproto-client.h b/mtproto-client.h
index 458d6c5..5f04dea 100644
--- a/mtproto-client.h
+++ b/mtproto-client.h
@@ -29,4 +29,5 @@ void work_update_binlog (void);
 int check_g (unsigned char p[256], BIGNUM *g);
 int check_g_bn (BIGNUM *p, BIGNUM *g);
 int check_DH_params (BIGNUM *p, int g);
+void do_rand (void *s, int l);
 #endif
diff --git a/queries.c b/queries.c
index ec35d15..3719de7 100644
--- a/queries.c
+++ b/queries.c
@@ -2263,8 +2263,10 @@ void do_send_accept_encr_chat (struct secret_chat *E, unsigned char *random) {
     }
   }
   if (ok) { return; } // Already generated key for this chat
-  for (i = 0; i < 64; i++) {
-    *(((int *)random) + i) ^= mrand48 ();
+  unsigned char random_here[256];
+  do_rand (random_here, 256);
+  for (i = 0; i < 256; i++) {
+    random[i] ^= random_here[i];
   }
   BIGNUM *b = BN_bin2bn (random, 256, 0);
   assert (b);

From 5cde89b5c881ce92d4cba052c178769c9b1cabac Mon Sep 17 00:00:00 2001
From: vysheng <mail@vysheng.ru>
Date: Wed, 25 Dec 2013 04:44:36 +0400
Subject: [PATCH 2/6] do_rand () renamed to secure_random ()

---
 mtproto-client.c | 10 +++++-----
 mtproto-client.h |  2 +-
 queries.c        |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/mtproto-client.c b/mtproto-client.c
index a010d85..906efbe 100644
--- a/mtproto-client.c
+++ b/mtproto-client.c
@@ -98,7 +98,7 @@ double get_utime (int clock_id) {
   return res;
 }
 
-void do_rand (void *s, int l) {
+void secure_random (void *s, int l) {
   if (RAND_bytes (s, l) < 0) {
     if (allow_weak_random) {
       RAND_pseudo_bytes (s, l);
@@ -232,7 +232,7 @@ int rpc_send_message (struct connection *c, void *data, int len) {
 
 int send_req_pq_packet (struct connection *c) {
   assert (c_state == st_init);
-  do_rand (nonce, 16);
+  secure_random (nonce, 16);
   unenc_msg_header.out_msg_id = 0;
   clear_packet ();
   out_int (CODE_req_pq);
@@ -380,7 +380,7 @@ int process_respq_answer (struct connection *c, char *packet, int len) {
   //out_int (0x0501);  // q=5
   out_ints ((int *) nonce, 4);
   out_ints ((int *) server_nonce, 4);
-  do_rand (new_nonce, 32);
+  secure_random (new_nonce, 32);
   out_ints ((int *) new_nonce, 8);
   sha1 ((unsigned char *) (packet_buffer + 5), (packet_ptr - packet_buffer - 5) * 4, (unsigned char *) packet_buffer);
 
@@ -573,7 +573,7 @@ int process_dh_answer (struct connection *c, char *packet, int len) {
   BN_init (&dh_g);
   BN_set_word (&dh_g, g);
 
-  do_rand (s_power, 256);
+  secure_random (s_power, 256);
   BIGNUM *dh_power = BN_new ();
   assert (BN_bin2bn ((unsigned char *)s_power, 256, dh_power) == dh_power);
 
@@ -692,7 +692,7 @@ void init_enc_msg (struct session *S, int useful) {
 //  assert (DC->server_salt);
   enc_msg.server_salt = DC->server_salt;
   if (!S->session_id) {
-    do_rand (&S->session_id, 8);
+    secure_random (&S->session_id, 8);
   }
   enc_msg.session_id = S->session_id;
   //enc_msg.auth_key_id2 = auth_key_id;
diff --git a/mtproto-client.h b/mtproto-client.h
index 5f04dea..0782b7b 100644
--- a/mtproto-client.h
+++ b/mtproto-client.h
@@ -29,5 +29,5 @@ void work_update_binlog (void);
 int check_g (unsigned char p[256], BIGNUM *g);
 int check_g_bn (BIGNUM *p, BIGNUM *g);
 int check_DH_params (BIGNUM *p, int g);
-void do_rand (void *s, int l);
+void secure_random (void *s, int l);
 #endif
diff --git a/queries.c b/queries.c
index 3719de7..51ab012 100644
--- a/queries.c
+++ b/queries.c
@@ -2264,7 +2264,7 @@ void do_send_accept_encr_chat (struct secret_chat *E, unsigned char *random) {
   }
   if (ok) { return; } // Already generated key for this chat
   unsigned char random_here[256];
-  do_rand (random_here, 256);
+  secure_random (random_here, 256);
   for (i = 0; i < 256; i++) {
     random[i] ^= random_here[i];
   }

From 5ea4683d16d666e0f575d310638b3e42f8449825 Mon Sep 17 00:00:00 2001
From: vysheng <mail@vysheng.ru>
Date: Wed, 25 Dec 2013 12:35:13 +0400
Subject: [PATCH 3/6] Fixed secure random.

---
 queries.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/queries.c b/queries.c
index 51ab012..962ccd5 100644
--- a/queries.c
+++ b/queries.c
@@ -1505,16 +1505,11 @@ void do_send_photo (int type, peer_id_t to_id, char *file_name) {
   if (get_peer_type (f->to_id) == PEER_ENCR_CHAT) {
     f->encr = 1;
     f->iv = malloc (32);
-    int i;
-    for (i = 0; i < 8; i++) {
-      ((int *)f->iv)[i] = mrand48 ();
-    }
+    secure_random (f->iv, 32);
     f->init_iv = malloc (32);
     memcpy (f->init_iv, f->iv, 32);
     f->key = malloc (32);
-    for (i = 0; i < 8; i++) {
-      ((int *)f->key)[i] = mrand48 ();
-    }
+    secure_random (f->key, 32);
   }
   if (f->part_size > (512 << 10)) {
     close (fd);
@@ -2362,8 +2357,10 @@ void do_create_keys_end (struct secret_chat *U) {
 void do_send_create_encr_chat (void *x, unsigned char *random) {
   int user_id = (long)x;
   int i;
-  for (i = 0; i < 64; i++) {
-    *(((int *)random) + i) ^= mrand48 ();
+  unsigned char random_here[256];
+  secure_random (random_here, 256);
+  for (i = 0; i < 256; i++) {
+    random[i] ^= random_here[i];
   }
   if (!ctx) {
     ctx = BN_CTX_new ();

From cb29ce45235bc2acd672e166b85cf8752fcc3843 Mon Sep 17 00:00:00 2001
From: vysheng <mail@vysheng.ru>
Date: Wed, 25 Dec 2013 12:56:46 +0400
Subject: [PATCH 4/6] Some other things changed to secure_random

---
 queries.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/queries.c b/queries.c
index 962ccd5..af48ff3 100644
--- a/queries.c
+++ b/queries.c
@@ -310,9 +310,7 @@ void out_random (int n) {
   assert (n <= 32);
   static char buf[32];
   int i;
-  for (i = 0; i < n; i++) {
-    buf[i] = lrand48 () & 255;
-  }
+  secure_random (buf, n);
   out_cstring (buf, n);
 }
 
@@ -771,8 +769,8 @@ void encr_start (void) {
 
 void encr_finish (struct secret_chat *E) {
   int l = packet_ptr - (encr_extra +  8);
-  while (((packet_ptr - encr_extra) - 3) & 3) {
-    out_int (mrand48 ());
+  while (((packet_ptr - encr_extra) - 3) & 3) {  
+    out_rand (4);
   }
 
   *encr_extra = ((packet_ptr - encr_extra) - 1) * 4 * 256 + 0xfe;
@@ -883,10 +881,7 @@ void do_send_encr_msg (struct message *M) {
   out_int (CODE_decrypted_message);
   out_long (M->id);
   static int buf[4];
-  int i;
-  for (i = 0; i < 3; i++) {
-    buf[i] = mrand48 ();
-  }
+  secure_random (buf, 16);
   out_cstring ((void *)buf, 16);
   out_cstring ((void *)M->message, M->message_len);
   out_int (CODE_decrypted_message_media_empty);
@@ -1299,8 +1294,9 @@ void send_part (struct send_file *f) {
     if (f->encr) {
       if (x & 15) {
         assert (f->offset == f->size);
-        while (x & 15) {
-          buf[x ++] = lrand48 () & 255;
+        if (x & 15) {
+          secure_random (buf + x, (-x) & 15);
+          x = (x + 15) & ~15;
         }
       }
       
@@ -1375,7 +1371,7 @@ void send_part (struct send_file *f) {
       peer_t *P = user_chat_get (f->to_id);
       assert (P);
       out_long (P->encr_chat.access_hash);
-      long long r = -lrand48 () * (1ll << 32) - lrand48 ();
+      long long r = -lrand48 () * (1ll << 32) - lrand48 (); 
       out_long (r);
       encr_start ();
       out_int (CODE_decrypted_message);

From df3dc013061f5fdce9498319b1f0cd610a9e5a79 Mon Sep 17 00:00:00 2001
From: vysheng <mail@vysheng.ru>
Date: Wed, 25 Dec 2013 13:07:10 +0400
Subject: [PATCH 5/6] Fixed CE

---
 queries.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/queries.c b/queries.c
index af48ff3..bd5a86d 100644
--- a/queries.c
+++ b/queries.c
@@ -309,7 +309,6 @@ extern struct dc *DC_working;
 void out_random (int n) {
   assert (n <= 32);
   static char buf[32];
-  int i;
   secure_random (buf, n);
   out_cstring (buf, n);
 }
@@ -770,7 +769,9 @@ void encr_start (void) {
 void encr_finish (struct secret_chat *E) {
   int l = packet_ptr - (encr_extra +  8);
   while (((packet_ptr - encr_extra) - 3) & 3) {  
-    out_rand (4);
+    int t;
+    secure_random (&t, 4);
+    out_int (t);
   }
 
   *encr_extra = ((packet_ptr - encr_extra) - 1) * 4 * 256 + 0xfe;

From 567afd1aa578b4750ac2d4febf43f8d73fef426a Mon Sep 17 00:00:00 2001
From: vysheng <code@vysheng.ru>
Date: Thu, 26 Dec 2013 19:08:35 +0300
Subject: [PATCH 6/6] fixed Typo in Readme

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 53c48f0..0be4923 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ Clone GitHub Repository
 
     $ git clone https://github.com/vysheng/tg.git && cd tg
     
-or download and extrac zip
+or download and extract zip
 
     $ wget https://github.com/vysheng/tg/archive/master.zip -O tg-master.zip
     $ tar xzf tg-master.zip && cd tg-master