217 lines
7.9 KiB
Diff
217 lines
7.9 KiB
Diff
=== modified file 'src/openssl.c'
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--- src/openssl.c 2009-09-22 16:16:43 +0000
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+++ src/openssl.c 2009-10-24 23:06:44 +0000
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@@ -39,7 +39,7 @@
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#include <string.h>
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#include <openssl/ssl.h>
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-#include <openssl/x509.h>
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+#include <openssl/x509v3.h>
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#include <openssl/err.h>
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#include <openssl/rand.h>
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@@ -486,9 +486,11 @@
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ssl_check_certificate (int fd, const char *host)
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{
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X509 *cert;
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+ GENERAL_NAMES *subjectAltNames;
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char common_name[256];
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long vresult;
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bool success = true;
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+ bool alt_name_checked = false;
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/* If the user has specified --no-check-cert, we still want to warn
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him about problems with the server's certificate. */
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@@ -536,7 +538,8 @@
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break;
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case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN:
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case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT:
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- logprintf (LOG_NOTQUIET, _(" Self-signed certificate encountered.\n"));
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+ logprintf (LOG_NOTQUIET,
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+ _(" Self-signed certificate encountered.\n"));
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break;
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case X509_V_ERR_CERT_NOT_YET_VALID:
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logprintf (LOG_NOTQUIET, _(" Issued certificate not yet valid.\n"));
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@@ -558,10 +561,6 @@
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/* Check that HOST matches the common name in the certificate.
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#### The following remains to be done:
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- - It should use dNSName/ipAddress subjectAltName extensions if
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- available; according to rfc2818: "If a subjectAltName extension
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- of type dNSName is present, that MUST be used as the identity."
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-
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- When matching against common names, it should loop over all
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common names and choose the most specific one, i.e. the last
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one, not the first one, which the current code picks.
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@@ -569,50 +568,123 @@
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- Ensure that ASN1 strings from the certificate are encoded as
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UTF-8 which can be meaningfully compared to HOST. */
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- X509_NAME *xname = X509_get_subject_name(cert);
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- common_name[0] = '\0';
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- X509_NAME_get_text_by_NID (xname, NID_commonName, common_name,
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- sizeof (common_name));
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+ subjectAltNames = X509_get_ext_d2i (cert, NID_subject_alt_name, NULL, NULL);
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- if (!pattern_match (common_name, host))
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+ if (subjectAltNames)
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{
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- logprintf (LOG_NOTQUIET, _("\
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-%s: certificate common name %s doesn't match requested host name %s.\n"),
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- severity, quote_n (0, common_name), quote_n (1, host));
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- success = false;
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+ /* Test subject alternative names */
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+
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+ /* Do we want to check for dNSNAmes or ipAddresses (see RFC 2818)?
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+ * Signal it by host_in_octet_string. */
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+ ASN1_OCTET_STRING *host_in_octet_string = NULL;
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+ host_in_octet_string = a2i_IPADDRESS (host);
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+
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+ int numaltnames = sk_GENERAL_NAME_num (subjectAltNames);
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+ int i;
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+ for (i=0; i < numaltnames; i++)
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+ {
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+ const GENERAL_NAME *name =
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+ sk_GENERAL_NAME_value (subjectAltNames, i);
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+ if (name)
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+ {
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+ if (host_in_octet_string)
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+ {
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+ if (name->type == GEN_IPADD)
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+ {
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+ /* Check for ipAddress */
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+ /* TODO: Should we convert between IPv4-mapped IPv6
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+ * addresses and IPv4 addresses? */
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+ alt_name_checked = true;
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+ if (!ASN1_STRING_cmp (host_in_octet_string,
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+ name->d.iPAddress))
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+ break;
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+ }
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+ }
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+ else if (name->type == GEN_DNS)
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+ {
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+ /* Check for dNSName */
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+ alt_name_checked = true;
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+ /* dNSName should be IA5String (i.e. ASCII), however who
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+ * does trust CA? Convert it into UTF-8 for sure. */
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+ unsigned char *name_in_utf8 = NULL;
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+ if (0 <= ASN1_STRING_to_UTF8 (&name_in_utf8, name->d.dNSName))
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+ {
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+ /* Compare and check for NULL attack in ASN1_STRING */
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+ if (pattern_match ((char *)name_in_utf8, host) &&
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+ (strlen ((char *)name_in_utf8) ==
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+ ASN1_STRING_length (name->d.dNSName)))
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+ {
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+ OPENSSL_free (name_in_utf8);
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+ break;
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+ }
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+ OPENSSL_free (name_in_utf8);
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+ }
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+ }
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+ }
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+ }
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+ sk_GENERAL_NAME_free (subjectAltNames);
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+ if (host_in_octet_string)
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+ ASN1_OCTET_STRING_free(host_in_octet_string);
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+
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+ if (alt_name_checked == true && i >= numaltnames)
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+ {
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+ logprintf (LOG_NOTQUIET,
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+ _("%s: no certificate subject alternative name matches\n"
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+ "\trequested host name %s.\n"),
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+ severity, quote_n (1, host));
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+ success = false;
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+ }
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}
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- else
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+
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+ if (alt_name_checked == false)
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{
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- /* We now determine the length of the ASN1 string. If it differs from
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- * common_name's length, then there is a \0 before the string terminates.
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- * This can be an instance of a null-prefix attack.
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- *
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- * https://www.blackhat.com/html/bh-usa-09/bh-usa-09-archives.html#Marlinspike
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- * */
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-
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- int i = -1, j;
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- X509_NAME_ENTRY *xentry;
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- ASN1_STRING *sdata;
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-
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- if (xname) {
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- for (;;)
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- {
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- j = X509_NAME_get_index_by_NID (xname, NID_commonName, i);
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- if (j == -1) break;
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- i = j;
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+ /* Test commomName */
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+ X509_NAME *xname = X509_get_subject_name(cert);
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+ common_name[0] = '\0';
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+ X509_NAME_get_text_by_NID (xname, NID_commonName, common_name,
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+ sizeof (common_name));
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+
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+ if (!pattern_match (common_name, host))
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+ {
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+ logprintf (LOG_NOTQUIET, _("\
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+ %s: certificate common name %s doesn't match requested host name %s.\n"),
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+ severity, quote_n (0, common_name), quote_n (1, host));
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+ success = false;
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+ }
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+ else
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+ {
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+ /* We now determine the length of the ASN1 string. If it
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+ * differs from common_name's length, then there is a \0
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+ * before the string terminates. This can be an instance of a
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+ * null-prefix attack.
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+ *
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+ * https://www.blackhat.com/html/bh-usa-09/bh-usa-09-archives.html#Marlinspike
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+ * */
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+
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+ int i = -1, j;
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+ X509_NAME_ENTRY *xentry;
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+ ASN1_STRING *sdata;
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+
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+ if (xname) {
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+ for (;;)
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+ {
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+ j = X509_NAME_get_index_by_NID (xname, NID_commonName, i);
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+ if (j == -1) break;
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+ i = j;
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+ }
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}
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- }
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- xentry = X509_NAME_get_entry(xname,i);
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- sdata = X509_NAME_ENTRY_get_data(xentry);
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- if (strlen (common_name) != ASN1_STRING_length (sdata))
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- {
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- logprintf (LOG_NOTQUIET, _("\
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-%s: certificate common name is invalid (contains a NUL character).\n\
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-This may be an indication that the host is not who it claims to be\n\
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-(that is, it is not the real %s).\n"),
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- severity, quote (host));
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- success = false;
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+ xentry = X509_NAME_get_entry(xname,i);
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+ sdata = X509_NAME_ENTRY_get_data(xentry);
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+ if (strlen (common_name) != ASN1_STRING_length (sdata))
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+ {
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+ logprintf (LOG_NOTQUIET, _("\
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+ %s: certificate common name is invalid (contains a NUL character).\n\
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+ This may be an indication that the host is not who it claims to be\n\
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+ (that is, it is not the real %s).\n"),
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+ severity, quote (host));
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+ success = false;
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+ }
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}
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}
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@@ -631,3 +703,7 @@
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/* Allow --no-check-cert to disable certificate checking. */
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return opt.check_cert ? success : true;
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}
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+
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+/*
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+ * vim: tabstop=2 shiftwidth=2 softtabstop=2
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+ */
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