linux-kernel - [RFC PATCH 4/4] X.509: Handle midnight alternative notation in GeneralizedTime

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160104221727.19818.76115.stgit@warthog.procyon.org.uk>
Date:	Mon, 04 Jan 2016 22:17:27 +0000
From:	David Howells <dhowells@...hat.com>
To:	keyrings@...r.kernel.org
Cc:	David Woodhouse <David.Woodhouse@...el.com>,
	Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org,
	dhowells@...hat.com, linux-security-module@...r.kernel.org,
	Rudolf Polzer <rpolzer@...gle.com>,
	John Stultz <john.stultz@...aro.org>
Subject: [RFC PATCH 4/4] X.509: Handle midnight alternative notation in
 GeneralizedTime

The ASN.1 GeneralizedTime object carries an ISO 8601 format date and time.
The time is permitted to show midnight as 00:00 or 24:00 (the latter being
equivalent of 00:00 of the following day).

The permitted value is checked in x509_decode_time() but the actual
handling is left to mktime64().

Without this patch, certain X.509 certificates will be rejected and could
lead to an unbootable kernel.

Note that with this patch we also permit any 24:mm:ss time and extend this
to UTCTime, which whilst not strictly correct don't permit much leeway in
fiddling date strings.

Reported-by: Rudolf Polzer <rpolzer@...gle.com>
Signed-off-by: David Howells <dhowells@...hat.com>
cc: David Woodhouse <David.Woodhouse@...el.com>
cc: John Stultz <john.stultz@...aro.org>
cc: Arnd Bergmann <arnd@...db.de>
---

 crypto/asymmetric_keys/x509_cert_parser.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 3379c0ba3988..70ed0852fdb2 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -548,7 +548,7 @@ int x509_decode_time(time64_t *_t,  size_t hdrlen,
 	}
 
 	if (day < 1 || day > mon_len ||
-	    hour > 23 ||
+	    hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
 	    min > 59 ||
 	    sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
 		goto invalid_time;

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/