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authorIvan Nardi <12729895+IvanNardi@users.noreply.github.com>2021-11-24 10:46:48 +0100
committerGitHub <noreply@github.com>2021-11-24 10:46:48 +0100
commita8ffcd8bb0273d59600c6310a80b81206096c113 (patch)
tree2a62911824363509ea5e7c69afa189e98556e495 /src/lib/protocols/stun.c
parentfd02e1b3043eecc5711eb8254aadaa3f43ca7503 (diff)
Rework how hostname/SNI info is saved (#1330)
Looking at `struct ndpi_flow_struct` the two bigger fields are `host_server_name[240]` (mainly for HTTP hostnames and DNS domains) and `protos.tls_quic.client_requested_server_name[256]` (for TLS/QUIC SNIs). This commit aims to reduce `struct ndpi_flow_struct` size, according to two simple observations: 1) maximum one of these two fields is used for each flow. So it seems safe to merge them; 2) even if hostnames/SNIs might be very long, in practice they are rarely longer than a fews tens of bytes. So, using a (single) large buffer is a waste of memory for all kinds of flows. If we need to truncate the name, we keep the *last* characters, easing domain matching. Analyzing some real traffic, it seems safe to assume that the vast majority of hostnames/SNIs is shorter than 80 bytes. Hostnames/SNIs are always converted to lowercase. Attention was given so as to be sure that unit-tests outputs are not affected by this change. Because of a bug, TLS/QUIC SNI were always truncated to 64 bytes (the *first* 64 ones): as a consequence, there were some "Suspicious DGA domain name" and "TLS Certificate Mismatch" false positives.
Diffstat (limited to 'src/lib/protocols/stun.c')
-rw-r--r--src/lib/protocols/stun.c14
1 files changed, 5 insertions, 9 deletions
diff --git a/src/lib/protocols/stun.c b/src/lib/protocols/stun.c
index f0884fae3..1ffa8afef 100644
--- a/src/lib/protocols/stun.c
+++ b/src/lib/protocols/stun.c
@@ -349,25 +349,21 @@ static ndpi_int_stun_t ndpi_int_check_stun(struct ndpi_detection_module_struct *
u_int16_t realm_len = ntohs(*((u_int16_t*)&payload[offset+2]));
if(flow->host_server_name[0] == '\0') {
- u_int i;
u_int k = offset+4;
- i = ndpi_min(realm_len, sizeof(flow->host_server_name) - 1);
- i = ndpi_min(i, payload_length - k);
- memcpy(flow->host_server_name, payload + k, i);
- flow->host_server_name[i] = '\0';
-
+ ndpi_hostname_sni_set(flow, payload + k, ndpi_min(realm_len, payload_length - k));
+
#ifdef DEBUG_STUN
printf("==> [%s]\n", flow->host_server_name);
#endif
- if(strstr((char*) flow->host_server_name, "google.com") != NULL) {
+ if(strstr(flow->host_server_name, "google.com") != NULL) {
flow->guessed_host_protocol_id = NDPI_PROTOCOL_HANGOUT_DUO;
return(NDPI_IS_STUN);
- } else if(strstr((char*) flow->host_server_name, "whispersystems.org") != NULL) {
+ } else if(strstr(flow->host_server_name, "whispersystems.org") != NULL) {
flow->guessed_host_protocol_id = NDPI_PROTOCOL_SIGNAL;
return(NDPI_IS_STUN);
- } else if(strstr((char*) flow->host_server_name, "facebook") != NULL) {
+ } else if(strstr(flow->host_server_name, "facebook") != NULL) {
flow->guessed_host_protocol_id = NDPI_PROTOCOL_MESSENGER;
return(NDPI_IS_STUN);
}