Re: [linux-minidisc] compiling libnetmd and netmdcli on windows

[Thomas Arp <manner.moe@gmx.de>]

Am 14/09/2011 21:41, schrieb Michael Karcher:
> Am Mittwoch, den 14.09.2011, 09:06 +0200 schrieb Thomas Arp:
> > In netmd.cli the random number is used for creating a nonce in this
> > way:
> > unsigned char hostnonce[8] = { 0 };
> > unsigned char *buf;
> > uint64_t rand;
> > .
> > .
> > rand = (uint64_t)random();
> > buf = hostnonce;
> > netmd_copy_quadword_to_buffer(&buf, rand);
> > .
> > .
> >
> > As far as i know random() and rand() are 32bit only.
> > What about using "gcry_create_nonce(unsigned char *buffer, size_t length)" from libgcrypt instead?
> >
> > unsigned char hostnonce[8] = { 0 };
> > .
> > .
> > gcry_create_nonce(hostnonce, sizeof(hostnonce));
> Yes, go that way. Sounds nice, and we already do depend on libgcrypt.
>
> Regards,
>     Michael Karcher
O.K., here is my patch, please review.

Regards
Thomas

From 78e8e1fc7c5cdac273aa1fcc4a74fb6fec4d4076 Mon Sep 17 00:00:00 2001
From: Thomas Arp <manner.moe@gmx.de>
Date: Wed, 14 Sep 2011 23:43:21 +0200
Subject: [PATCH] make libnetmd platform independent and make use of libgcrypt
 to generate random numbers

---
 libnetmd/common.c   |    2 +-
 libnetmd/secure.c   |   22 ++++++----------------
 libnetmd/utils.c    |    9 ---------
 libnetmd/utils.h    |    5 ++++-
 netmdcli/netmdcli.c |    6 +-----
 5 files changed, 12 insertions(+), 32 deletions(-)

diff --git a/libnetmd/common.c b/libnetmd/common.c
index 1f7b660..7e039ed 100644
--- a/libnetmd/common.c
+++ b/libnetmd/common.c
@@ -62,7 +62,7 @@ static int netmd_poll(libusb_device_handle *dev, unsigned char *buf, int tries)
         }
 
         if (i > 0) {
-            sleep(1);
+            usleep(200000);
         }
     }
 
diff --git a/libnetmd/secure.c b/libnetmd/secure.c
index fce60c5..a940d9d 100644
--- a/libnetmd/secure.c
+++ b/libnetmd/secure.c
@@ -385,15 +385,6 @@ void netmd_transfer_song_packets(netmd_dev_handle *dev,
     }
 }
 
-uint64_t generate_64bit_random()
-{
-    uint64_t high, low;
-    high = ((uint64_t)random() & 0xffffffffU) << 32U;
-    low = ((uint64_t)random() & 0xffffffffU);
-
-    return high + low;
-}
-
 netmd_error netmd_prepare_packets(unsigned char* data, size_t data_lenght,
                                   netmd_track_packets **packets,
                                   size_t *packet_count,
@@ -403,11 +394,11 @@ netmd_error netmd_prepare_packets(unsigned char* data, size_t data_lenght,
     size_t chunksize = 0xffffffffU;
     netmd_track_packets *last = NULL;
     netmd_track_packets *next = NULL;
-    uint64_t rand;
 
     gcry_cipher_hd_t key_handle;
     gcry_cipher_hd_t data_handle;
     unsigned char iv[8] = { 0 };
+    unsigned char rand[8] = { 0 };
 
     netmd_error error = NETMD_NO_ERROR;
 
@@ -418,8 +409,7 @@ netmd_error netmd_prepare_packets(unsigned char* data, size_t data_lenght,
 
 
     /* generate initial iv */
-    rand = generate_64bit_random();
-    memcpy(iv, &rand, sizeof(rand));
+    gcry_create_nonce(iv, sizeof(iv));
 
     *packet_count = 0;
     while (position < data_lenght) {
@@ -450,13 +440,13 @@ netmd_error netmd_prepare_packets(unsigned char* data, size_t data_lenght,
         }
 
         /* generate key */
-        rand = generate_64bit_random();
-        gcry_cipher_decrypt(key_handle, next->key, 8, &rand, sizeof(rand));
+        gcry_randomize(rand, sizeof(rand), GCRY_STRONG_RANDOM);
+        gcry_cipher_decrypt(key_handle, next->key, 8, rand, sizeof(rand));
 
         /* crypt data */
         memcpy(next->iv, iv, 8);
         gcry_cipher_setiv(data_handle, iv, 8);
-        gcry_cipher_setkey(data_handle, &rand, sizeof(rand));
+        gcry_cipher_setkey(data_handle, rand, sizeof(rand));
         gcry_cipher_encrypt(data_handle, next->data, chunksize, data + position, chunksize);
         memcpy(iv, data + position - 8, 8);
 
@@ -577,7 +567,7 @@ netmd_error netmd_secure_real_recv_track(netmd_dev_handle *dev, uint32_t length,
 
             netmd_log(NETMD_LOG_DEBUG, "%.1f%%\n", (double)done/(double)length * 100);
         }
-        else if (read != -ETIMEDOUT) {
+        else if (read != -LIBUSB_ERROR_TIMEOUT) {
             error = NETMD_USB_ERROR;
         }
     }
diff --git a/libnetmd/utils.c b/libnetmd/utils.c
index 9b12167..0d9e65e 100644
--- a/libnetmd/utils.c
+++ b/libnetmd/utils.c
@@ -26,15 +26,6 @@
 #include "utils.h"
 #include "log.h"
 
-inline int min(int a,int b)
-{
-    if (a < b) {
-        return a;
-    }
-
-    return b;
-}
-
 inline unsigned char proper_to_bcd_single(unsigned char value)
 {
     unsigned char high, low;
diff --git a/libnetmd/utils.h b/libnetmd/utils.h
index a389b03..58996f3 100644
--- a/libnetmd/utils.h
+++ b/libnetmd/utils.h
@@ -12,7 +12,10 @@ typedef struct {
         size_t position;
 } netmd_response;
 
-int min(int a,int b);
+#ifndef min
+    #define min(a,b) ((a)<(b)?(a):(b))
+#endif
+
 unsigned char proper_to_bcd_single(unsigned char value);
 unsigned char* proper_to_bcd(unsigned int value, unsigned char* target, size_t len);
 unsigned char bcd_to_proper_single(unsigned char value);
diff --git a/netmdcli/netmdcli.c b/netmdcli/netmdcli.c
index 55ad3f0..b4e0ee3 100644
--- a/netmdcli/netmdcli.c
+++ b/netmdcli/netmdcli.c
@@ -426,8 +426,6 @@ int main(int argc, char* argv[])
             unsigned char hostnonce[8] = { 0 };
             unsigned char devnonce[8] = { 0 };
             unsigned char sessionkey[8] = { 0 };
-            unsigned char *buf;
-            uint64_t rand;
             unsigned char kek[] = { 0x14, 0xe3, 0x83, 0x4e, 0xe2, 0xd3, 0xcc, 0xa5 };
             unsigned char contentid[] = { 0x01, 0x0F, 0x50, 0x00, 0x00, 0x04,
                                           0x00, 0x00, 0x00, 0x48, 0xA2, 0x8D,
@@ -491,9 +489,7 @@ int main(int argc, char* argv[])
             }
 
             /* exchange nonces */
-            rand = (uint64_t)random();
-            buf = hostnonce;
-            netmd_copy_quadword_to_buffer(&buf, rand);
+            gcry_create_nonce(hostnonce, sizeof(hostnonce));
             error = netmd_secure_session_key_exchange(devh, hostnonce, devnonce);
             puts(netmd_strerror(error));
 
-- 
1.7.6.msysgit.0