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dot11decrypt: Fix AAD calculation for legacy ccmp implementation 

Re-implement below change but for the legacy ccmp decryption used on
3.2 release track but also on later releases when Wireshark is built
with older versions of libgcrypt:

e5e37add9a 802.11 Decrypt: Fix AAD Calculation when HT-Control present in a QoS Data Frame

Ping #17577.
This commit is contained in:
Mikael Kanstrup 2021-09-08 13:36:24 +02:00 committed by Wireshark GitLab Utility
parent 4e7d10eea1
commit c58c106b30
1 changed files with 10 additions and 2 deletions
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12
epan/crypt/dot11decrypt_ccmp_compat.c
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@ -33,6 +33,9 @@
#define AES_BLOCK_LEN 16
#define FC1_AAD_MASK 0xc7
#define FC1_AAD_QOS_MASK 0x47
/****************************************************************************/
/* Internal macros */
@ -106,7 +109,7 @@ static void ccmp_init_blocks(
b0[15] = (UINT8)(dlen & 0xff);
/* AAD:
* FC with bits 4..6 and 11..13 masked to zero; 14 is always one
* FC with bits 4..6 and 11..13 masked to zero; 14 is always one; 15 zero when QoS Control field present
* A1 | A2 | A3
* SC with bits 4..15 (seq#) masked to zero
* A4 (if present)
@ -118,7 +121,12 @@ static void ccmp_init_blocks(
aad[2] = (UINT8)(wh->fc[0] & 0x8f); /* XXX magic #s */
else
aad[2] = wh->fc[0];
aad[3] = (UINT8)(wh->fc[1] & 0xc7); /* XXX magic #s */
if (DOT11DECRYPT_IS_QOS_DATA(wh)) {
aad[3] = (UINT8)((wh->fc[1] & FC1_AAD_QOS_MASK) | 0x40);
} else {
aad[3] = (UINT8)((wh->fc[1] & FC1_AAD_MASK) | 0x40);
}
/* NB: we know 3 addresses are contiguous */
memcpy(aad + 4, (guint8 *)wh->addr1, 3 * DOT11DECRYPT_MAC_LEN);
aad[22] = (UINT8)(wh->seq[0] & DOT11DECRYPT_SEQ_FRAG_MASK);