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Make some more buffer sizes dynamic.

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This commit is contained in:
Romain Tartiere 2010-10-29 12:44:12 +00:00
parent a0b9df6ece
commit 3eb8d37d08
2 changed files with 48 additions and 15 deletions
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1
libfreefare/freefare_internal.h
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@ -120,6 +120,7 @@ void *mifare_cryto_preprocess_data (MifareTag tag, void *data, size_t *nbytes,
void *mifare_cryto_postprocess_data (MifareTag tag, void *data, ssize_t *nbytes, int communication_settings);
void mifare_cbc_des (MifareDESFireKey key, uint8_t *ivect, uint8_t *data, size_t data_size, MifareDirection direction, int mac);
void rol (uint8_t *data, const size_t len);
size_t key_block_size (const MifareDESFireKey key);
void *assert_crypto_buffer_size (MifareTag tag, size_t nbytes);
#define MIFARE_ULTRALIGHT_PAGE_COUNT 16

62
libfreefare/mifare_desfire_authenticate.c
View file

@ -30,9 +30,9 @@
static void xor (const uint8_t *ivect, uint8_t *data, const size_t len);
static void mifare_des (MifareDESFireKey key, uint8_t *data, uint8_t *ivect, MifareDirection direction, int mac, size_t block_size);
static size_t padded_data_length (size_t nbytes);
static size_t maced_data_length (size_t nbytes);
static size_t enciphered_data_length (size_t nbytes);
static size_t padded_data_length (size_t nbytes, const size_t block_size);
static size_t maced_data_length (const MifareDESFireKey key, size_t nbytes);
static size_t enciphered_data_length (const MifareDESFireKey key, size_t nbytes);
static void
xor (const uint8_t *ivect, uint8_t *data, const size_t len)
@ -52,14 +52,29 @@ rol(uint8_t *data, const size_t len)
data[len-1] = first;
}
size_t
key_block_size (const MifareDESFireKey key)
{
size_t block_size;
switch (key->type) {
case T_DES:
case T_3DES:
block_size = 8;
break;
}
return block_size;
}
/*
* Size required to store nbytes of data in a buffer of size n*8.
* Size required to store nbytes of data in a buffer of size n*block_size.
*/
static size_t
padded_data_length (size_t nbytes)
padded_data_length (const size_t nbytes, const size_t block_size)
{
if (nbytes % 8)
return ((nbytes / 8) + 1) * 8;
if (nbytes % block_size)
return ((nbytes / block_size) + 1) * block_size;
else
return nbytes;
}
@ -68,17 +83,34 @@ padded_data_length (size_t nbytes)
* Buffer size required to MAC nbytes of data
*/
static size_t
maced_data_length (size_t nbytes)
maced_data_length (const MifareDESFireKey key, const size_t nbytes)
{
return nbytes + 4;
size_t mac_length;
switch (key->type) {
case T_DES:
case T_3DES:
mac_length = 4;
break;
}
return nbytes + mac_length;
}
/*
* Buffer size required to encipher nbytes of data and a two bytes CRC.
*/
static size_t
enciphered_data_length (size_t nbytes)
enciphered_data_length (const MifareDESFireKey key, const size_t nbytes)
{
return padded_data_length (nbytes + 2);
size_t crc_length;
switch (key->type) {
case T_DES:
case T_3DES:
crc_length = 2;
break;
}
size_t block_size = key_block_size (key);
return padded_data_length (nbytes + crc_length, block_size);
}
@ -111,7 +143,7 @@ mifare_cryto_preprocess_data (MifareTag tag, void *data, size_t *nbytes, int com
res = data;
break;
case 1:
edl = padded_data_length (*nbytes);
edl = padded_data_length (*nbytes, key_block_size (MIFARE_DESFIRE (tag)->session_key));
if (!(res = assert_crypto_buffer_size (tag, edl)))
abort();
@ -124,7 +156,7 @@ mifare_cryto_preprocess_data (MifareTag tag, void *data, size_t *nbytes, int com
memcpy (mac, (uint8_t *)res + edl - 8, 4);
mdl = maced_data_length (*nbytes);
mdl = maced_data_length (MIFARE_DESFIRE (tag)->session_key, *nbytes);
if (!(res = assert_crypto_buffer_size (tag, mdl)))
abort();
@ -135,7 +167,7 @@ mifare_cryto_preprocess_data (MifareTag tag, void *data, size_t *nbytes, int com
break;
case 3:
edl = enciphered_data_length (*nbytes);
edl = enciphered_data_length (MIFARE_DESFIRE (tag)->session_key, *nbytes);
if (!(res = assert_crypto_buffer_size (tag, edl)))
abort();
@ -173,7 +205,7 @@ mifare_cryto_postprocess_data (MifareTag tag, void *data, ssize_t *nbytes, int c
case 1:
*nbytes -= 4;
edl = enciphered_data_length (*nbytes);
edl = enciphered_data_length (MIFARE_DESFIRE (tag)->session_key, *nbytes);
edata = malloc (edl);
memcpy (edata, data, *nbytes);