From 0923e7df9eafec6db9c75405d7085ec8581f01bd Mon Sep 17 00:00:00 2001 From: Emilia Kasper Date: Thu, 5 Feb 2015 16:38:54 +0100 Subject: [PATCH] Fix hostname validation in the command-line tool to honour negative return values. Specifically, an ASN.1 NumericString in the certificate CN will fail UTF-8 conversion and result in a negative return value, which the "x509 -checkhost" command-line option incorrectly interpreted as success. Also update X509_check_host docs to reflect reality. Thanks to Sean Burford (Google) for reporting this issue. Reviewed-by: Richard Levitte --- apps/apps.c | 2 +- crypto/x509v3/v3_utl.c | 7 ++++++- doc/crypto/X509_check_host.pod | 7 +++++-- 3 files changed, 12 insertions(+), 4 deletions(-) diff --git a/apps/apps.c b/apps/apps.c index 97f0c0e182..bf044d40f8 100644 --- a/apps/apps.c +++ b/apps/apps.c @@ -2780,7 +2780,7 @@ void print_cert_checks(BIO *bio, X509 *x, return; if (checkhost) { BIO_printf(bio, "Hostname %s does%s match certificate\n", - checkhost, X509_check_host(x, checkhost, 0, 0, NULL) + checkhost, X509_check_host(x, checkhost, 0, 0, NULL) == 1 ? "" : " NOT"); } diff --git a/crypto/x509v3/v3_utl.c b/crypto/x509v3/v3_utl.c index 1ad3999c92..cd7a9809ca 100644 --- a/crypto/x509v3/v3_utl.c +++ b/crypto/x509v3/v3_utl.c @@ -889,8 +889,13 @@ static int do_check_string(ASN1_STRING *a, int cmp_type, equal_fn equal, int astrlen; unsigned char *astr; astrlen = ASN1_STRING_to_UTF8(&astr, a); - if (astrlen < 0) + if (astrlen < 0) { + /* + * -1 could be an internal malloc failure or a decoding error from + * malformed input; we can't distinguish. + */ return -1; + } rv = equal(astr, astrlen, (unsigned char *)b, blen, flags); if (rv > 0 && peername) *peername = BUF_strndup((char *)astr, astrlen); diff --git a/doc/crypto/X509_check_host.pod b/doc/crypto/X509_check_host.pod index f8b530df9b..0def17aac1 100644 --- a/doc/crypto/X509_check_host.pod +++ b/doc/crypto/X509_check_host.pod @@ -109,9 +109,12 @@ but would not match a peer certificate with a DNS name of =head1 RETURN VALUES The functions return 1 for a successful match, 0 for a failed match -and -1 for an internal error: typically a memory allocation failure. +and -1 for an internal error: typically a memory allocation failure +or an ASN.1 decoding error. -X509_check_ip_asc() can also return -2 if the IP address string is malformed. +All functions can also return -2 if the input is malformed. For example, +X509_check_host() returns -2 if the provided B contains embedded +NULs. =head1 NOTES -- 2.40.0