Cypher_Stack/libsecret
2
0
Fork 0
mirror of https://gitlab.gnome.org/GNOME/libsecret.git synced 2024-12-22 04:38:55 +00:00
Code Issues Packages Projects Releases Wiki Activity

DH: Ensure that generated secret occupies the same number of bytes as prime.

Browse Source 
https://bugzilla.gnome.org/show_bug.cgi?id=778357
This commit is contained in:
Tomasz Miąsko 2017-02-09 09:45:01 +01:00 committed by Stef Walter
parent 455b70968a
commit 998065599c
1 changed files with 11 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
egg/egg-dh.c
View File

@ -314,6 +314,7 @@ egg_dh_gen_secret (gcry_mpi_t peer, gcry_mpi_t priv,
{
gcry_error_t gcry;
guchar *value;
gsize n_prime;
gsize n_value;
gcry_mpi_t k;
gint bits;
@ -330,19 +331,25 @@ egg_dh_gen_secret (gcry_mpi_t peer, gcry_mpi_t priv,
gcry_mpi_powm (k, peer, priv, prime);
/* Write out the secret */
gcry = gcry_mpi_print (GCRYMPI_FMT_USG, NULL, 0, &n_value, k);
gcry = gcry_mpi_print (GCRYMPI_FMT_USG, NULL, 0, &n_prime, prime);
g_return_val_if_fail (gcry == 0, NULL);
value = egg_secure_alloc (n_value);
gcry = gcry_mpi_print (GCRYMPI_FMT_USG, value, n_value, &n_value, k);
value = egg_secure_alloc (n_prime);
gcry = gcry_mpi_print (GCRYMPI_FMT_USG, value, n_prime, &n_value, k);
g_return_val_if_fail (gcry == 0, NULL);
/* Pad the secret with zero bytes to match length of prime in bytes. */
if (n_value < n_prime) {
memmove (value + (n_prime - n_value), value, n_value);
memset (value, 0, (n_prime - n_value));
}
#if DEBUG_DH_SECRET
g_printerr ("DH SECRET: ");
gcry_mpi_dump (k);
#endif
gcry_mpi_release (k);
*bytes = n_value;
*bytes = n_prime;
#if DEBUG_DH_SECRET
gcry_mpi_scan (&k, GCRYMPI_FMT_USG, value, bytes, NULL);