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WOWW: Refactor decryption logic 

This removes unnecessary empty else blocks and makes for easier reading.
This commit is contained in:
Gtker 2021-07-21 15:45:32 +02:00 committed by Wireshark GitLab Utility
parent 26bec7e580
commit db24903e4a
1 changed files with 22 additions and 29 deletions
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51
epan/dissectors/packet-woww.c
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@ -2035,39 +2035,32 @@ handle_packet_header(packet_info* pinfo,
WowwPreviousValues_t * original_header_values = wmem_tree_lookup32(wowwConversation->headers_need_decryption, pinfo->num);
if (original_header_values) {
// Header has been seen before
// Original value will need to be used for deduction
if (!session_key_is_fully_deduced(wowwConversation->known_indices, headerSize, original_header_values->idx)) {
// Not ready yet
return NULL;
}
// Header can be decrypted and added to map
if (original_header_values && !session_key_is_fully_deduced(wowwConversation->known_indices, headerSize, original_header_values->idx)) {
// If we have seen the header before AND
// we still can't decrypt it
// there's nothing to do but wait until we get more information
return NULL;
}
else {
// Header has not been seen before
if (!session_key_is_fully_deduced(wowwConversation->known_indices, headerSize, participant->idx)) {
// Packet isn't decryptable, make sure to do it later
WowwPreviousValues_t* array_index = wmem_alloc(wmem_file_scope(), 2);
array_index->idx = participant->idx;
array_index->last_encrypted_value = participant->last_encrypted_value;
wmem_tree_insert32(wowwConversation->headers_need_decryption, pinfo->num, array_index);
if (WOWW_CLIENT_TO_SERVER) {
deduce_header(wowwConversation->session_key, wowwConversation->known_indices, header, participant);
} else {
// Skip the packet, but remember to acknowledge that values changed
participant->idx = (participant->idx + headerSize) % WOWW_SESSION_KEY_LENGTH;
participant->last_encrypted_value = header[headerSize - 1];
}
if (!original_header_values && !session_key_is_fully_deduced(wowwConversation->known_indices, headerSize, participant->idx)) {
// If we haven't seen the header before AND
// we can't decrypt it now
// we make sure it gets decrypted later
WowwPreviousValues_t* array_index = wmem_alloc(wmem_file_scope(), 2);
array_index->idx = participant->idx;
array_index->last_encrypted_value = participant->last_encrypted_value;
wmem_tree_insert32(wowwConversation->headers_need_decryption, pinfo->num, array_index);
return NULL;
}
else {
// Header can be decrypted and added to map
// If it's a server header we can use it to deduce the session key
if (WOWW_CLIENT_TO_SERVER) {
deduce_header(wowwConversation->session_key, wowwConversation->known_indices, header, participant);
} else {
// Skip the packet, but remember to acknowledge that values changed
participant->idx = (participant->idx + headerSize) % WOWW_SESSION_KEY_LENGTH;
participant->last_encrypted_value = header[headerSize - 1];
}
return NULL;
}
guint8* idx = &participant->idx;