diff options
Diffstat (limited to 'istream.c')
| -rw-r--r-- | istream.c | 85 |
1 files changed, 84 insertions, 1 deletions
@@ -1,4 +1,4 @@ -/* $Id: istream.c,v 1.6 2001/11/24 02:01:26 ukai Exp $ */ +/* $Id: istream.c,v 1.7 2001/12/26 12:18:06 ukai Exp $ */ #include "fm.h" #include "istream.h" #include <signal.h> @@ -378,6 +378,89 @@ ssl_get_certificate(InputStream stream) BIO_free_all(bp); return s; } + +Str +ssl_check_cert_ident(SSL *handle, char *hostname) +{ + X509 *x; + int i; + Str ret = Strnew_charp("SSL error: failed to check certificate chain"); + /* + * All we need to do here is check that the CN matches. + * + * From RFC2818 3.1 Server Identity: + * If a subjectAltName extension of type dNSName is present, that MUST + * be used as the identity. Otherwise, the (most specific) Common Name + * field in the Subject field of the certificate MUST be used. Although + * the use of the Common Name is existing practice, it is deprecated and + * Certification Authorities are encouraged to use the dNSName instead. + */ + x = SSL_get_peer_certificate(handle); + if (!x) { + ret = Strnew_charp("Unable to get peer certificate"); + return ret; + } + + i = X509_get_ext_by_NID(x, NID_subject_alt_name, -1); + if (i >= 0) { + X509_EXTENSION *ex; + STACK_OF(GENERAL_NAME) *alt; + + ex = X509_get_ext(x, i); + alt = X509V3_EXT_d2i(ex); + if (alt) { + int n, len1, len2 = 0; + char *domain; + GENERAL_NAME *gn; + X509V3_EXT_METHOD *method; + + len1 = strlen(hostname); + n = sk_GENERAL_NAME_num(alt); + domain = strchr(hostname, '.'); + if (domain) + len2 = len1 - (domain - hostname); + for (i = 0; i < n; i++) { + gn = sk_GENERAL_NAME_value(alt, i); + if (gn->type == GEN_DNS) { + char *sn = ASN1_STRING_data(gn->d.ia5); + int sl = ASN1_STRING_length(gn->d.ia5); + + /* Is this an exact match? */ + if ((len1 == sl) && !strncasecmp(hostname, sn, len1)) + break; + + /* Is this a wildcard match? */ + if ((*sn == '*') && domain && (len2 == sl-1) && + !strncasecmp(domain, sn+1, len2)) + break; + } + } + method = X509V3_EXT_get(ex); + method->ext_free(alt); + if (i < n) /* Found a match */ + ret = NULL; + } + } + + if (ret != NULL) { + X509_NAME *xn; + char buf[2048]; + + xn = X509_get_subject_name(x); + + if (X509_NAME_get_text_by_NID(xn, NID_commonName, + buf, sizeof(buf)) == -1) { + ret = Strnew_charp("Unable to get common name from peer cert"); + return ret; + } + else if (strcasecmp(hostname, buf)) + ret = Sprintf("Bad cert ident %s from %s", buf, hostname); + else + ret = NULL; + } + X509_free(x); + return ret; +} #endif /* Raw level input stream functions */ |