TLS: explicit ignore client certificate (#1776)

TLS classification usually stops after processing *server* certificates
(if any). That means, that *client* certificate, if present, is usually
ignored.
However in some corner cases (i.e. unidirectional traffic) we might end
up processing client certificate and exposing its metadata: the issue is
that the application will think that this metadata are about the server
and not about the client.
So, for the time being, always ignore client certificate processing.

As a future work, we might find an efficient way to process and export both
certificates.

4 files changed, 62 insertions, 0 deletions

diff --git a/tests/pcap/tls_client_certificate_with_missing_server_one.pcapng b/tests/pcap/tls_client_certificate_with_missing_server_one.pcapng
new file mode 100644
index 000000000..40cb1eb30
--- /dev/null
+++ b/tests/pcap/tls_client_certificate_with_missing_server_one.pcapng
diff --git a/tests/pcap/tls_unidirectional.pcap b/tests/pcap/tls_unidirectional.pcap
new file mode 100644
index 000000000..c46674086
--- /dev/null
+++ b/tests/pcap/tls_unidirectional.pcap
diff --git a/tests/result/tls_client_certificate_with_missing_server_one.pcapng.out b/tests/result/tls_client_certificate_with_missing_server_one.pcapng.out
new file mode 100644
index 000000000..65d569510
--- /dev/null
+++ b/tests/result/tls_client_certificate_with_missing_server_one.pcapng.out
@@ -0,0 +1,31 @@
+Guessed flow protos:	0
+
+DPI Packets (TCP):	16	(8.00 pkts/flow)
+Confidence DPI              : 2 (flows)
+Num dissector calls: 4 (2.00 diss/flow)
+LRU cache ookla:      0/0/0 (insert/search/found)
+LRU cache bittorrent: 0/0/0 (insert/search/found)
+LRU cache zoom:       0/0/0 (insert/search/found)
+LRU cache stun:       0/0/0 (insert/search/found)
+LRU cache tls_cert:   0/3/0 (insert/search/found)
+LRU cache mining:     0/0/0 (insert/search/found)
+LRU cache msteams:    0/0/0 (insert/search/found)
+Automa host:          0/0 (search/found)
+Automa domain:        0/0 (search/found)
+Automa tls cert:      0/0 (search/found)
+Automa risk mask:     0/0 (search/found)
+Automa common alpns:  0/0 (search/found)
+Patricia risk mask:   4/0 (search/found)
+Patricia risk:        0/0 (search/found)
+Patricia protocols:   4/0 (search/found)
+
+TLS	17	5526	2
+
+JA3 Host Stats: 
+		 IP Address                  	 # JA3C     
+	1	 192.168.1.128            	 1      
+	2	 195.181.174.176          	 1      
+
+
+	1	TCP 195.181.174.176:443 <-> 192.168.1.128:48260 [proto: 91/TLS][IP: 0/Unknown][Encrypted][Confidence: DPI][cat: Web/5][3 pkts/1654 bytes <-> 6 pkts/1779 bytes][Goodput ratio: 87/78][0.04 sec][ALPN: anydesk/6.2.0/linux][bytes ratio: -0.036 (Mixed)][IAT c2s/s2c min/avg/max/stddev: 3/0 10/8 17/20 7/9][Pkt Len c2s/s2c min/avg/max/stddev: 66/66 551/296 1514/1160 681/400][Risk: ** Missing SNI TLS Extn **][Risk Score: 50][TLSv1.2][JA3C: 29b5a018fa5992fe23560c16af0dc9fc][JA3S: e58f0b3c1e9eefb8ee4f92aeceee5858][Firefox][Cipher: TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384][Plen Bins: 0,0,0,0,0,0,0,0,0,33,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,33,0,0,0,0,0,0,0,0,0,0,33,0,0]
+	2	TCP 192.168.1.128:59754 <-> 192.168.1.181:7070 [proto: 91/TLS][IP: 0/Unknown][Encrypted][Confidence: DPI][cat: Web/5][6 pkts/1953 bytes <-> 2 pkts/140 bytes][Goodput ratio: 79/0][0.08 sec][bytes ratio: 0.866 (Upload)][IAT c2s/s2c min/avg/max/stddev: 0/6 15/6 54/6 20/0][Pkt Len c2s/s2c min/avg/max/stddev: 66/66 326/70 1352/74 469/4][Risk: ** Known Proto on Non Std Port **** TLS (probably) Not Carrying HTTPS **** Missing SNI TLS Extn **][Risk Score: 110][Risk Info: No ALPN][TLSv1.2][JA3C: 201999283915cc31cee6b15472ef3332][Firefox][Plen Bins: 0,0,0,0,0,0,0,0,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,50,0,0,0,0,0,0,0]
diff --git a/tests/result/tls_unidirectional.pcap.out b/tests/result/tls_unidirectional.pcap.out
new file mode 100644
index 000000000..4f8fa35e7
--- /dev/null
+++ b/tests/result/tls_unidirectional.pcap.out
@@ -0,0 +1,31 @@
+Guessed flow protos:	0
+
+DPI Packets (TCP):	12	(6.00 pkts/flow)
+Confidence DPI              : 2 (flows)
+Num dissector calls: 4 (2.00 diss/flow)
+LRU cache ookla:      0/0/0 (insert/search/found)
+LRU cache bittorrent: 0/0/0 (insert/search/found)
+LRU cache zoom:       0/0/0 (insert/search/found)
+LRU cache stun:       0/0/0 (insert/search/found)
+LRU cache tls_cert:   0/2/0 (insert/search/found)
+LRU cache mining:     0/0/0 (insert/search/found)
+LRU cache msteams:    0/0/0 (insert/search/found)
+Automa host:          1/1 (search/found)
+Automa domain:        1/0 (search/found)
+Automa tls cert:      0/0 (search/found)
+Automa risk mask:     0/0 (search/found)
+Automa common alpns:  0/0 (search/found)
+Patricia risk mask:   4/0 (search/found)
+Patricia risk:        0/0 (search/found)
+Patricia protocols:   3/1 (search/found)
+
+TLS	27	7693	1
+Google	6	6972	1
+
+JA3 Host Stats: 
+		 IP Address                  	 # JA3C     
+	1	 192.168.1.128            	 1      
+
+
+	1	TCP 192.168.1.128:48260 -> 195.181.174.176:443 [proto: 91/TLS][IP: 0/Unknown][Encrypted][Confidence: DPI][cat: Web/5][27 pkts/7693 bytes -> 0 pkts/0 bytes][Goodput ratio: 77/0][58.79 sec][ALPN: anydesk/6.2.0/linux][bytes ratio: 1.000 (Upload)][IAT c2s/s2c min/avg/max/stddev: 0/0 2023/0 10210/0 3873/0][Pkt Len c2s/s2c min/avg/max/stddev: 66/0 285/0 1514/0 460/0][Risk: ** Missing SNI TLS Extn **** Unidirectional Traffic **][Risk Score: 60][Risk Info: No server to client traffic][TLSv1.2][JA3C: 29b5a018fa5992fe23560c16af0dc9fc][Firefox][Plen Bins: 0,20,20,0,10,0,0,0,0,10,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,10,0,0,0,10,0,0,0,0,0,0,20,0,0]
+	2	TCP 142.250.27.188:5228 -> 10.140.72.24:12654 [VLAN: 308][proto: 91.126/TLS.Google][IP: 126/Google][Encrypted][Confidence: DPI][cat: Web/5][6 pkts/6972 bytes -> 0 pkts/0 bytes][Goodput ratio: 94/0][0.16 sec][bytes ratio: 1.000 (Upload)][IAT c2s/s2c min/avg/max/stddev: 0/0 32/0 160/0 64/0][Pkt Len c2s/s2c min/avg/max/stddev: 78/0 1162/0 1418/0 490/0][Risk: ** Known Proto on Non Std Port **** Unidirectional Traffic **][Risk Score: 60][Risk Info: No client to server traffic][ServerNames: *.google.com,*.appengine.google.com,*.bdn.dev,*.cloud.google.com,*.crowdsource.google.com,*.datacompute.google.com,*.google.ca,*.google.cl,*.google.co.in,*.google.co.jp,*.google.co.uk,*.google.com.ar,*.google.com.au,*.google.com.br,*.google.com.co,*.google.com.mx,*.google.com.tr,*.google.com.vn,*.google.de,*.google.es,*.google.fr,*.google.hu,*.google.it,*.google.nl,*.google.pl,*.google.pt,*.googleadapis.com,*.googleapis.cn,*.googlevideo.com,*.gstatic.cn,*.gstatic-cn.com,googlecnapps.cn,*.googlecnapps.cn,googleapps-cn.com,*.googleapps-cn.com,gkecnapps.cn,*.gkecnapps.cn,googledownloads.cn,*.googledownloads.cn,recaptcha.net.cn,*.recaptcha.net.cn,widevine.cn,*.widevine.cn,ampproject.org.cn,*.ampproject.org.cn,ampproject.net.cn,*.ampproject.net.cn,google-analytics-cn.com,*.google-analytics-cn.com,googleadservices-cn.com,*.googleadservices-cn.com,googlevads-cn.com,*.googlevads-cn.com,googleapis-cn.com,*.googleapis-cn.com,googleoptimize-cn.com,*.googleoptimize-cn.com,doubleclick-cn.net,*.doubleclick-cn.net,*.fls.doubleclick-cn.net,*.g.doubleclick-cn.net,doubleclick.cn,*.doubleclick.cn,*.fls.doubleclick.cn,*.g.doubleclick.cn,dartsearch-cn.net,*.dartsearch-cn.net,googletraveladservices-cn.com,*.googletraveladservices-cn.com,googletagservices-cn.com,*.googletagservices-cn.com,googletagmanager-cn.com,*.googletagmanager-cn.com,googlesyndication-cn.com,*.googlesyndication-cn.com,*.safeframe.googlesyndication-cn.com,app-measurement-cn.com,*.app-measurement-cn.com,gvt1-cn.com,*.gvt1-cn.com,gvt2-cn.com,*.gvt2-cn.com,2mdn-cn.net,*.2mdn-cn.net,googleflights-cn.net,*.googleflights-cn.net,admob-cn.com,*.admob-cn.com,*.gstatic.com,*.metric.gstatic.com,*.gvt1.com,*.gcpcdn.gvt1.com,*.gvt2.com,*.gcp.gvt2.com,*.url.google.com,*.youtube-nocookie.com,*.ytimg.com,android.com,*.android.com,*.flash.android.com,g.cn,*.g.cn,g.co,*.g.co,goo.gl,www.goo.gl,google-analytics.com,*.google-analytics.com,google.com,googlecommerce.com,*.googlecommerce.com,ggpht.cn,*.ggpht.cn,urchin.com,*.urchin.com,youtu.be,youtube.com,*.youtube.com,youtubeeducation.com,*.youtubeeducation.com,youtubekids.com,*.youtubekids.com,yt.be,*.yt.be,android.clients.google.com,developer.android.google.cn,developers.android.google.cn,source.android.google.cn][JA3S: 84aaf6d03fc8c5bfb56d1d188735b268][Issuer: C=US, O=Google Trust Services LLC, CN=GTS CA 1C3][Subject: CN=*.google.com][Certificate SHA-1: 02:64:CA:2E:8A:2F:BB:C4:97:9D:A7:AC:2B:47:FF:DE:28:0E:71:B1][Validity: 2021-11-01 02:19:52 - 2022-01-24 02:19:51][Cipher: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256][Plen Bins: 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,20,0,0,0,0,0,80,0,0,0,0,0]