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Validate decrypted PATH path_len against MAX_PATH_SIZE #1662

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Validate decrypted PATH path_len against MAX_PATH_SIZE #1662

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12 changes: 12 additions & 0 deletions src/Mesh.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -155,6 +155,10 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
uint8_t path_len = data[k++];
uint8_t hash_size = (path_len >> 6) + 1;
uint8_t hash_count = path_len & 63;
if (hash_size*hash_count > MAX_PATH_SIZE) {
MESH_DEBUG_PRINTLN("%s Mesh::onRecvPacket(): bad PATH path_len=%d exceeds MAX_PATH_SIZE", getLogDateTime(), (int)path_len);
break;
}
uint8_t* path = &data[k]; k += hash_size*hash_count;
uint8_t extra_type = data[k++] & 0x0F; // upper 4 bits reserved for future use
uint8_t* extra = &data[k];
Expand Down Expand Up @@ -683,12 +687,20 @@ void Mesh::sendDirect(Packet* packet, const uint8_t* path, uint8_t path_len, uin
uint8_t pri;
if (packet->getPayloadType() == PAYLOAD_TYPE_TRACE) { // TRACE packets are different
// for TRACE packets, path is appended to end of PAYLOAD. (path is used for SNR's)
if (packet->payload_len + path_len > sizeof(packet->payload)) {
_mgr->free(packet);
return;
}
memcpy(&packet->payload[packet->payload_len], path, path_len); // NOTE: path_len here can be > 64, and NOT in the new scheme
packet->payload_len += path_len;

packet->path_len = 0;
pri = 5; // maybe make this configurable
} else {
if (path_len > MAX_PATH_SIZE) {
_mgr->free(packet);
return;
}
packet->path_len = Packet::copyPath(packet->path, path, path_len);
if (packet->getPayloadType() == PAYLOAD_TYPE_PATH) {
pri = 1; // slightly less priority
Expand Down