Initial version of libressl - a library that provides a clean, simple,

consistent and secure-by-default API for SSL clients (and soon servers).

This is a long way from complete and the interface will likely change
substantially - committing now so that further work can happen in the tree.

Initiated by tedu@ and inspired by discussions with tedu@, beck@ and
other developers.

1 files changed, 190 insertions, 0 deletions

diff --git a/src/lib/libressl/ressl_verify.c b/src/lib/libressl/ressl_verify.c
new file mode 100644
index 0000000000..e98a264f4f
--- /dev/null
+++ b/src/lib/libressl/ressl_verify.c
@@ -0,0 +1,190 @@
+/*
+ * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/socket.h>
+
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+#include <string.h>
+
+#include <openssl/x509v3.h>
+
+#include "ressl_internal.h"
+
+int ressl_match_hostname(const char *cert_hostname, const char *hostname);
+int ressl_check_subject_altname(X509 *cert, const char *host);
+int ressl_check_common_name(X509 *cert, const char *host);
+
+int
+ressl_match_hostname(const char *cert_hostname, const char *hostname)
+{
+        const char *cert_domain, *domain;
+
+        if (strcasecmp(cert_hostname, hostname) == 0)
+                return 0;
+
+        /* Wildcard match? */
+        if (cert_hostname[0] == '*') {
+                cert_domain = &cert_hostname[1];
+                if (cert_domain[0] != '.')
+                        return -1;
+                if (strlen(cert_domain) == 1)
+                        return -1;
+
+                domain = strchr(hostname, '.');
+
+                /* No wildcard match against a hostname with no domain part. */
+                if (domain == NULL || strlen(domain) == 1)
+                        return -1;
+
+                if (strcasecmp(cert_domain, domain) == 0)
+                        return 0;
+        }
+
+        return -1;
+}
+
+int
+ressl_check_subject_altname(X509 *cert, const char *host)
+{
+        STACK_OF(GENERAL_NAME) *altname_stack = NULL;
+        union { struct in_addr ip4; struct in6_addr ip6; } addrbuf;
+        int addrlen, type;
+        int count, i;
+        int rv = -1;
+
+        altname_stack = X509_get_ext_d2i(cert, NID_subject_alt_name,
+            NULL, NULL);
+        if (altname_stack == NULL)
+                return -1;
+
+        if (inet_pton(AF_INET, host, &addrbuf) == 1) {
+                type = GEN_IPADD;
+                addrlen = 4;
+        } else if (inet_pton(AF_INET6, host, &addrbuf) == 1) {
+                type = GEN_IPADD;
+                addrlen = 16;
+        } else {
+                type = GEN_DNS;
+                addrlen = 0;
+        }
+
+        count = sk_GENERAL_NAME_num(altname_stack);
+        for (i = 0; i < count; i++) {
+                GENERAL_NAME    *altname;
+
+                altname = sk_GENERAL_NAME_value(altname_stack, i);
+
+                if (altname->type != type)
+                        continue;
+
+                if (type == GEN_DNS) {
+                        unsigned char   *data;
+                        int              format;
+
+                        format = ASN1_STRING_type(altname->d.dNSName);
+                        if (format == V_ASN1_IA5STRING) {
+                                data = ASN1_STRING_data(altname->d.dNSName);
+
+                                if (ASN1_STRING_length(altname->d.dNSName) !=
+                                    (int)strlen(data)) {
+                                        fprintf(stdout, "%s: NUL byte in "
+                                            "subjectAltName, probably a "
+                                            "malicious certificate.\n",
+                                            getprogname());
+                                        rv = -2;
+                                        break;
+                                }
+
+                                if (ressl_match_hostname(data, host) == 0) {
+                                        rv = 0;
+                                        break;
+                                }
+                        } else
+                                fprintf(stdout, "%s: unhandled subjectAltName "
+                                    "dNSName encoding (%d)\n", getprogname(),
+                                    format);
+
+                } else if (type == GEN_IPADD) {
+                        unsigned char   *data;
+                        int              datalen;
+
+                        datalen = ASN1_STRING_length(altname->d.iPAddress);
+                        data = ASN1_STRING_data(altname->d.iPAddress);
+
+                        if (datalen == addrlen &&
+                            memcmp(data, &addrbuf, addrlen) == 0) {
+                                rv = 0;
+                                break;
+                        }
+                }
+        }
+
+        sk_GENERAL_NAME_free(altname_stack);
+        return rv;
+}
+
+int
+ressl_check_common_name(X509 *cert, const char *host)
+{
+        X509_NAME *name;
+        char *common_name = NULL;
+        size_t common_name_len;
+        int rv = -1;
+
+        name = X509_get_subject_name(cert);
+        if (name == NULL)
+                goto out;
+
+        common_name_len = X509_NAME_get_text_by_NID(name, NID_commonName,
+            NULL, 0);
+        if (common_name_len < 0)
+                goto out;
+
+        common_name = calloc(common_name_len + 1, 1);
+        if (common_name == NULL)
+                goto out;
+
+        X509_NAME_get_text_by_NID(name, NID_commonName, common_name,
+            common_name_len + 1);
+
+        /* NUL bytes in CN? */
+        if (common_name_len != (int)strlen(common_name)) {
+                fprintf(stdout, "%s: NUL byte in Common Name field, "
+                    "probably a malicious certificate.\n", getprogname());
+                rv = -2;
+                goto out;
+        }
+
+        if (ressl_match_hostname(common_name, host) == 0)
+                rv = 0;
+out:
+        free(common_name);
+        return rv;
+}
+
+int
+ressl_check_hostname(X509 *cert, const char *host)
+{
+        int     rv;
+
+        rv = ressl_check_subject_altname(cert, host);
+        if (rv == 0 || rv == -2)
+                return rv;
+
+        return ressl_check_common_name(cert, host);
+}