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packet-lwm:Move gcry_cipher_open() and gcry_cipher_close() out of loop 

Instead of calling gcry_cipher_open() and gcry_cipher_close() in
a loop, call gcry_cipher_reset to avoid
creating and releasing contexts.

Besides the performance improvement,
this should also fix Coverity 1450453,
which detects the multiple calls to gcry_cipher_close()
as a double-free.
This commit is contained in:
Moshe Kaplan 2020-11-27 13:14:50 -05:00 committed by AndersBroman
parent 27c00ca0e9
commit 6a6f58c9aa
1 changed files with 4 additions and 4 deletions
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8
epan/dissectors/packet-lwm.c
View File

@ -417,6 +417,7 @@ static int dissect_lwm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void
guint8 i;
guint32 vmic;
guint32 nwkSecurityVector[4];
int gcrypt_err;
ieee_packet = (ieee802154_packet *)data;
@ -432,12 +433,10 @@ static int dissect_lwm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void
text = (guint8 *)tvb_memdup(pinfo->pool, new_tvb, 0, payload_length);
payload_offset=0;
gcrypt_err = gcry_cipher_open(&cypher_hd, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_ECB, 0);
/*Decrypt the actual data */
while(payload_length>0)
{
int gcrypt_err;
gcrypt_err = gcry_cipher_open(&cypher_hd, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_ECB, 0);
if(gcrypt_err == 0) {
gcrypt_err = gcry_cipher_setkey(cypher_hd,(guint8 *)lwmes_key, 16);
}
@ -467,8 +466,9 @@ static int dissect_lwm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void
payload_offset += block;
payload_length -= block;
gcry_cipher_close(cypher_hd);
gcry_cipher_reset(cypher_hd);
}
gcry_cipher_close(cypher_hd);
vmic = nwkSecurityVector[0] ^ nwkSecurityVector[1] ^ nwkSecurityVector[2] ^ nwkSecurityVector[3];
length = tvb_reported_length(new_tvb) - LWM_MIC_LEN;