Hello hackers, so, we've been bumping lately into what seems to be a pretty well known bug, that noone cared enough to fix yet?
the symptom of the issue is that after flashing several same-model routers with the same openwrt binary, then accessing them over https, and accepting the self-signed certificate, after a few iterations on different hosts, firefox refuses to connect due to a "reused issuer and serial number" on the certificate sent by the server (openwrt) the root of the issue is that openwrt generates certificates with px5g, which as far as i dug into, bases the generated serialNumber upon the epoch (with up-to-the-second-precision) same hardware, same binary, and with the same startup date at first boot... the chances of two different routers running the /etc/init.d/uhttpd start at the exact same second are pretty high (in our experience - at least 3 in a lot of 10) routers get the correct date afterwards, with ntpdate, but then it's too late: px5g already generated the certificate with identical serialNumber as the other routers. this is aggravated by a (particularly long standing) bug in firefox https://bugzilla.mozilla.org/show_bug.cgi?id=435013 which makes it impossible to remove such information (already seen issuer+serial) from the browser PKI internal database. chromium overreacts in a comparable way. the poor linksys customers complaining in mozilla's ticket are probably doomed, after 6 years seeing the issue "Assigned To: Nobody; OK to take it and work on it " :P but maybe we can do our part on openwrt? PX5G X.509 Certificate Generator Utility v0.1 Copyright (c) 2009 Steven Barth <ste...@midlink.org> Steven, do you think it would possible to add a bit of randomness to the serialNumber generation function? i understand entropy is scarce in embedded devices, especially on first boot, and my C coding skills are null, so i'm hoping someone can throw a pointer here? relevant snippet AFAIU: from feeds/luci/libs/px5g/src/library/x509write.c /* * CertificateSerialNumber ::= INTEGER */ srand((unsigned int) time(NULL)); serial = rand(); if ((ret = asn1_add_int(serial, &chain->serial)) != 0) return ret; cheers! gui _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
