From b2ba81e761f476dd86ceceab2654d7cca6e00c0f Mon Sep 17 00:00:00 2001
From: vysheng <mail@vysheng.ru>
Date: Wed, 25 Dec 2013 03:42:05 +0400
Subject: [PATCH] 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);