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 <rpol...@google.com> Signed-off-by: David Howells <dhowe...@redhat.com> cc: David Woodhouse <david.woodho...@intel.com> cc: John Stultz <john.stu...@linaro.org> cc: Arnd Bergmann <a...@arndb.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-security-module" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html