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Diff for /src/usr.bin/ssh/clientloop.c between version 1.396 and 1.397

version 1.396, 2023/09/04 00:08:14 version 1.397, 2023/09/10 03:25:53
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 /* Permitted RSA signature algorithms for UpdateHostkeys proofs */  /* Permitted RSA signature algorithms for UpdateHostkeys proofs */
 #define HOSTKEY_PROOF_RSA_ALGS  "rsa-sha2-512,rsa-sha2-256"  #define HOSTKEY_PROOF_RSA_ALGS  "rsa-sha2-512,rsa-sha2-256"
   
   /* Uncertainty (in percent) of keystroke timing intervals */
   #define SSH_KEYSTROKE_TIMING_FUZZ 10
   
 /* import options */  /* import options */
 extern Options options;  extern Options options;
   
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         return 1;          return 1;
 }  }
   
   /* Sets the next interval to send a keystroke or chaff packet */
   static void
   set_next_interval(const struct timespec *now, struct timespec *next_interval,
       u_int interval_ms, int starting)
   {
           struct timespec tmp;
           long long interval_ns, fuzz_ns;
           static long long rate_fuzz;
   
           interval_ns = interval_ms * (1000LL * 1000);
           fuzz_ns = (interval_ns * SSH_KEYSTROKE_TIMING_FUZZ) / 100;
           /* Center fuzz around requested interval */
           if (fuzz_ns > INT_MAX)
                   fuzz_ns = INT_MAX;
           if (fuzz_ns > interval_ns) {
                   /* Shouldn't happen */
                   fatal_f("internal error: fuzz %u%% %lldns > interval %lldns",
                       SSH_KEYSTROKE_TIMING_FUZZ, fuzz_ns, interval_ns);
           }
           /*
            * Randomise the keystroke/chaff intervals in two ways:
            * 1. Each interval has some random jitter applied to make the
            *    interval-to-interval time unpredictable.
            * 2. The overall interval rate is also randomly perturbed for each
            *    each chaffing session to make the average rate unpredictable.
            */
           if (starting)
                   rate_fuzz = arc4random_uniform(fuzz_ns);
           interval_ns -= fuzz_ns;
           interval_ns += arc4random_uniform(fuzz_ns) + rate_fuzz;
   
           tmp.tv_sec = interval_ns / (1000 * 1000 * 1000);
           tmp.tv_nsec = interval_ns % (1000 * 1000 * 1000);
   
           timespecadd(now, &tmp, next_interval);
   }
   
 /*  /*
  * Performs keystroke timing obfuscation. Returns non-zero if the   * Performs keystroke timing obfuscation. Returns non-zero if the
  * output fd should be polled.   * output fd should be polled.
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          */           */
         if (!active && ssh_packet_interactive_data_to_write(ssh) &&          if (!active && ssh_packet_interactive_data_to_write(ssh) &&
             channel_did_enqueue && ssh_packet_have_data_to_write(ssh)) {              channel_did_enqueue && ssh_packet_have_data_to_write(ssh)) {
                 debug3_f("starting: interval %d",                  debug3_f("starting: interval ~%dms",
                     options.obscure_keystroke_timing_interval);                      options.obscure_keystroke_timing_interval);
                 just_started = had_keystroke = active = 1;                  just_started = had_keystroke = active = 1;
                 nchaff = 0;                  nchaff = 0;
                 ms_to_timespec(&tmp, options.obscure_keystroke_timing_interval);                  set_next_interval(&now, &next_interval,
                 timespecadd(&now, &tmp, &next_interval);                      options.obscure_keystroke_timing_interval, 1);
         }          }
   
         /* Don't hold off if obfuscation inactive */          /* Don't hold off if obfuscation inactive */
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         n = (n < 0) ? 1 : n + 1;          n = (n < 0) ? 1 : n + 1;
   
         /* Advance to the next interval */          /* Advance to the next interval */
         ms_to_timespec(&tmp, options.obscure_keystroke_timing_interval * n);          set_next_interval(&now, &next_interval,
         timespecadd(&now, &tmp, &next_interval);              options.obscure_keystroke_timing_interval * n, 0);
         return 1;          return 1;
 }  }
   
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Removed from v.1.396  
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  Added in v.1.397