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packet-dcerpc-netlogon: implement NETLOGON_FLAG_AES decryption 

Change-Id: I2ff05f528fe8c3ab6f5407c0289064b62f3f0202
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-on: https://code.wireshark.org/review/35593
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Stefan Metzmacher 2019-08-14 14:38:37 +02:00 committed by Anders Broman
parent b00e2834cd
commit f779835844
1 changed files with 159 additions and 14 deletions
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173
epan/dissectors/packet-dcerpc-netlogon.c
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@ -6650,7 +6650,78 @@ netlogon_dissect_netrserverauthenticate23_reply(tvbuff_t *tvb, int offset,
list_size = get_keytab_as_list(&pass_list,gbl_nt_password);
debugprintf("Found %d passwords \n",list_size);
#endif
if( flags & NETLOGON_FLAG_STRONGKEY ) {
if( flags & NETLOGON_FLAG_AES )
{
#ifdef HAVE_KERBEROS
guint8 salt_buf[16] = { 0 };
guint8 sha256[HASH_SHA2_256_LENGTH];
guint64 calculated_cred;
memcpy(&salt_buf[0], (guint8*)&vars->client_challenge, 8);
memcpy(&salt_buf[8], (guint8*)&vars->server_challenge, 8);
printnbyte((guint8*)&vars->client_challenge,8,"Client challenge:","\n");
printnbyte((guint8*)&vars->server_challenge,8,"Server challenge:","\n");
printnbyte((guint8*)&server_cred,8,"Server creds:","\n");
for(i=0;i<list_size;i++)
{
password = pass_list[i];
printnbyte((guint8*)&password, 16,"NTHASH:","\n");
if (!ws_hmac_buffer(GCRY_MD_SHA256, sha256, salt_buf, sizeof(salt_buf), (guint8*) &password, 16)) {
gcry_error_t err;
gcry_cipher_hd_t cipher_hd = NULL;
guint8 iv[16] = { 0 };
/* truncate the session key to 16 bytes */
memcpy(session_key, sha256, 16);
printnbyte((guint8*)session_key, 16,"Session Key","\n");
/* Open the cipher */
err = gcry_cipher_open(&cipher_hd, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_CFB8, 0);
if (err != 0) {
g_warning("GCRY: chiper open %s/%s\n", gcry_strsource(err), gcry_strerror(err));
break;
}
/* Set the initial value */
err = gcry_cipher_setiv(cipher_hd, iv, sizeof(iv));
if (err != 0) {
g_warning("GCRY: setiv %s/%s\n", gcry_strsource(err), gcry_strerror(err));
gcry_cipher_close(cipher_hd);
break;
}
/* Set the key */
err = gcry_cipher_setkey(cipher_hd, session_key, 16);
if (err != 0) {
g_warning("GCRY: setkey %s/%s\n", gcry_strsource(err), gcry_strerror(err));
gcry_cipher_close(cipher_hd);
break;
}
calculated_cred = 0x1234567812345678;
err = gcry_cipher_encrypt(cipher_hd,
(guint8 *)&calculated_cred, 8,
(const guint8 *)&vars->server_challenge, 8);
if (err != 0) {
g_warning("GCRY: encrypt %s/%s\n", gcry_strsource(err), gcry_strerror(err));
gcry_cipher_close(cipher_hd);
break;
}
/* Done with the cipher */
gcry_cipher_close(cipher_hd);
printnbyte((guint8*)&calculated_cred,8,"Calculated creds:","\n");
if(calculated_cred==server_cred) {
found = 1;
break;
}
}
}
#endif
} else if ( flags & NETLOGON_FLAG_STRONGKEY ) {
#ifdef HAVE_KERBEROS
guint8 zeros[4] = { 0 };
guint8 md5[HASH_MD5_LENGTH];
@ -6686,14 +6757,6 @@ netlogon_dissect_netrserverauthenticate23_reply(tvbuff_t *tvb, int offset,
}
#endif
}
#if 0 /* Fix -Wduplicated-branches */
else if( flags&NETLOGON_FLAG_AES)
{
/* Not implemented */
debugprintf("AES not supported yet\n");
memset(session_key,0,16);
}
#endif
else
{
/*Not implemented*/
@ -7642,6 +7705,49 @@ static int get_seal_key(const guint8 *session_key,int key_len,guint8* seal_key)
}
static guint64 uncrypt_sequence_aes(guint8* session_key,guint64 checksum,guint64 enc_seq,unsigned char is_server _U_)
{
gcry_error_t err;
gcry_cipher_hd_t cipher_hd = NULL;
guint8 iv[16] = { 0 };
memcpy(&iv[0], (guint8*)&checksum, 8);
memcpy(&iv[8], (guint8*)&checksum, 8);
/* Open the cipher */
err = gcry_cipher_open(&cipher_hd, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_CFB8, 0);
if (err != 0) {
g_warning("GCRY: chiper open %s/%s\n", gcry_strsource(err), gcry_strerror(err));
return 0;
}
/* Set the initial value */
err = gcry_cipher_setiv(cipher_hd, iv, sizeof(iv));
if (err != 0) {
g_warning("GCRY: setiv %s/%s\n", gcry_strsource(err), gcry_strerror(err));
gcry_cipher_close(cipher_hd);
return 0;
}
/* Set the key */
err = gcry_cipher_setkey(cipher_hd, session_key, 16);
if (err != 0) {
g_warning("GCRY: setkey %s/%s\n", gcry_strsource(err), gcry_strerror(err));
gcry_cipher_close(cipher_hd);
return 0;
}
err = gcry_cipher_decrypt(cipher_hd, (guint8*) &enc_seq, 8, NULL, 0);
if (err != 0) {
g_warning("GCRY: encrypt %s/%s\n", gcry_strsource(err), gcry_strerror(err));
gcry_cipher_close(cipher_hd);
return 0;
}
/* Done with the cipher */
gcry_cipher_close(cipher_hd);
return enc_seq;
}
static guint64 uncrypt_sequence_strong(guint8* session_key,guint64 checksum,guint64 enc_seq,unsigned char is_server _U_)
{
guint8 zeros[4] = { 0 };
@ -7679,8 +7785,7 @@ static guint64 uncrypt_sequence_strong(guint8* session_key,guint64 checksum,guin
static guint64 uncrypt_sequence(guint32 flags, guint8* session_key,guint64 checksum,guint64 enc_seq,unsigned char is_server _U_)
{
if (flags & NETLOGON_FLAG_AES) {
/* TODO */
return 0;
return uncrypt_sequence_aes(session_key, checksum, enc_seq, is_server);
}
if (flags & NETLOGON_FLAG_STRONGKEY) {
@ -7690,6 +7795,45 @@ static guint64 uncrypt_sequence(guint32 flags, guint8* session_key,guint64 check
return 0;
}
static gcry_error_t prepare_decryption_cipher_aes(netlogon_auth_vars *vars,
gcry_cipher_hd_t *_cipher_hd)
{
gcry_error_t err;
gcry_cipher_hd_t cipher_hd = NULL;
guint64 sequence = vars->seq;
guint8 iv[16] = { 0 };
memcpy(&iv[0], (guint8*)&sequence, 8);
memcpy(&iv[8], (guint8*)&sequence, 8);
/* Open the cipher */
err = gcry_cipher_open(&cipher_hd, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_CFB8, 0);
if (err != 0) {
g_warning("GCRY: chiper open %s/%s\n", gcry_strsource(err), gcry_strerror(err));
return 0;
}
/* Set the initial value */
err = gcry_cipher_setiv(cipher_hd, iv, sizeof(iv));
if (err != 0) {
g_warning("GCRY: setiv %s/%s\n", gcry_strsource(err), gcry_strerror(err));
gcry_cipher_close(cipher_hd);
return 0;
}
/* Set the key */
err = gcry_cipher_setkey(cipher_hd, vars->encryption_key, 16);
if (err != 0) {
g_warning("GCRY: setkey %s/%s\n", gcry_strsource(err), gcry_strerror(err));
gcry_cipher_close(cipher_hd);
return 0;
}
*_cipher_hd = cipher_hd;
return 0;
}
static gcry_error_t prepare_decryption_cipher_strong(netlogon_auth_vars *vars,
gcry_cipher_hd_t *_cipher_hd)
{
@ -7736,8 +7880,7 @@ static gcry_error_t prepare_decryption_cipher(netlogon_auth_vars *vars,
*_cipher_hd = NULL;
if (vars->flags & NETLOGON_FLAG_AES) {
/* TODO */
return GPG_ERR_UNSUPPORTED_ALGORITHM;
return prepare_decryption_cipher_aes(vars, _cipher_hd);
}
if (vars->flags & NETLOGON_FLAG_STRONGKEY) {
@ -7788,7 +7931,9 @@ dissect_packet_data(tvbuff_t *tvb ,tvbuff_t *auth_tvb _U_,
}
gcry_cipher_decrypt(cipher_hd, (guint8*)&copyconfounder, 8, NULL, 0);
decrypted = (guint8*)tvb_memdup(pinfo->pool, tvb, offset,data_len);
gcry_cipher_reset(cipher_hd);
if (!(vars->flags & NETLOGON_FLAG_AES)) {
gcry_cipher_reset(cipher_hd);
}
gcry_cipher_decrypt(cipher_hd, decrypted, data_len, NULL, 0);
gcry_cipher_close(cipher_hd);
buf = tvb_new_child_real_data(tvb, decrypted, data_len, data_len);