PR: 2909
Contributed by: Florian Weimer <fweimer@redhat.com>
Fixes to X509 hostname and email address checking. Wildcard matching support.
New test program and manual page.
diff --git a/crypto/x509v3/Makefile b/crypto/x509v3/Makefile
index 07e2df4..b54f540 100644
--- a/crypto/x509v3/Makefile
+++ b/crypto/x509v3/Makefile
@@ -13,7 +13,7 @@
CFLAGS= $(INCLUDES) $(CFLAG)
GENERAL=Makefile README
-TEST=
+TEST=v3nametest.c
APPS=
LIB=$(TOP)/libcrypto.a
diff --git a/crypto/x509v3/v3_utl.c b/crypto/x509v3/v3_utl.c
index db9f05e..ffd9f0d 100644
--- a/crypto/x509v3/v3_utl.c
+++ b/crypto/x509v3/v3_utl.c
@@ -568,12 +568,177 @@
sk_OPENSSL_STRING_pop_free(sk, str_free);
}
+typedef int (*equal_fn)(const unsigned char *pattern, size_t pattern_len,
+ const unsigned char *subject, size_t subject_len);
+
+/* Compare while ASCII ignoring case. */
+static int equal_nocase(const unsigned char *pattern, size_t pattern_len,
+ const unsigned char *subject, size_t subject_len)
+ {
+ if (pattern_len != subject_len)
+ return 0;
+ while (pattern_len)
+ {
+ unsigned char l = *pattern;
+ unsigned char r = *subject;
+ /* The pattern must not contain NUL characters. */
+ if (l == 0)
+ return 0;
+ if (l != r)
+ {
+ if ('A' <= l && l <= 'Z')
+ l = (l - 'A') + 'a';
+ if ('A' <= r && r <= 'Z')
+ r = (r - 'A') + 'a';
+ if (l != r)
+ return 0;
+ }
+ ++pattern;
+ ++subject;
+ --pattern_len;
+ }
+ return 1;
+ }
+
+/* Compare using memcmp. */
+static int equal_case(const unsigned char *pattern, size_t pattern_len,
+ const unsigned char *subject, size_t subject_len)
+{
+ /* The pattern must not contain NUL characters. */
+ if (memchr(pattern, '\0', pattern_len) != NULL)
+ return 0;
+ if (pattern_len != subject_len)
+ return 0;
+ return !memcmp(pattern, subject, pattern_len);
+}
+
+/* RFC 5280, section 7.5, requires that only the domain is compared in
+ a case-insensitive manner. */
+static int equal_email(const unsigned char *a, size_t a_len,
+ const unsigned char *b, size_t b_len)
+ {
+ size_t i = a_len;
+ if (a_len != b_len)
+ return 0;
+ /* We search backwards for the '@' character, so that we do
+ not have to deal with quoted local-parts. The domain part
+ is compared in a case-insensitive manner. */
+ while (i > 0)
+ {
+ --i;
+ if (a[i] == '@' || b[i] == '@')
+ {
+ if (!equal_nocase(a + i, a_len - i,
+ b + i, a_len - i))
+ return 0;
+ break;
+ }
+ }
+ if (i == 0)
+ i = a_len;
+ return equal_case(a, i, b, i);
+ }
+
+/* Compare the prefix and suffix with the subject, and check that the
+ characters in-between are valid. */
+static int wildcard_match(const unsigned char *prefix, size_t prefix_len,
+ const unsigned char *suffix, size_t suffix_len,
+ const unsigned char *subject, size_t subject_len)
+ {
+ const unsigned char *wildcard_start;
+ const unsigned char *wildcard_end;
+ const unsigned char *p;
+ if (subject_len < prefix_len + suffix_len)
+ return 0;
+ if (!equal_nocase(prefix, prefix_len, subject, prefix_len))
+ return 0;
+ wildcard_start = subject + prefix_len;
+ wildcard_end = subject + (subject_len - suffix_len);
+ if (!equal_nocase(wildcard_end, suffix_len, suffix, suffix_len))
+ return 0;
+ /* The wildcard must match at least one character. */
+ if (wildcard_start == wildcard_end)
+ return 0;
+ /* Check that the part matched by the wildcard contains only
+ permitted characters and only matches a single label. */
+ for (p = wildcard_start; p != wildcard_end; ++p)
+ if (!(('0' <= *p && *p <= '9') ||
+ ('A' <= *p && *p <= 'Z') ||
+ ('a' <= *p && *p <= 'z') ||
+ *p == '-'))
+ return 0;
+ return 1;
+ }
+
+/* Checks if the memory region consistens of [0-9A-Za-z.-]. */
+static int valid_domain_characters(const unsigned char *p, size_t len)
+ {
+ while (len)
+ {
+ if (!(('0' <= *p && *p <= '9') ||
+ ('A' <= *p && *p <= 'Z') ||
+ ('a' <= *p && *p <= 'z') ||
+ *p == '-' || *p == '.'))
+ return 0;
+ ++p;
+ --len;
+ }
+ return 1;
+ }
+
+/* Find the '*' in a wildcard pattern. If no such character is found
+ or the pattern is otherwise invalid, returns NULL. */
+static const unsigned char *wildcard_find_star(const unsigned char *pattern,
+ size_t pattern_len)
+ {
+ const unsigned char *star = memchr(pattern, '*', pattern_len);
+ size_t dot_count = 0;
+ const unsigned char *suffix_start;
+ size_t suffix_length;
+ if (star == NULL)
+ return NULL;
+ suffix_start = star + 1;
+ suffix_length = (pattern + pattern_len) - (star + 1);
+ if (!(valid_domain_characters(pattern, star - pattern) &&
+ valid_domain_characters(suffix_start, suffix_length)))
+ return NULL;
+ /* Check that the suffix matches at least two labels. */
+ while (suffix_length)
+ {
+ if (*suffix_start == '.')
+ ++dot_count;
+ ++suffix_start;
+ --suffix_length;
+ }
+ if (dot_count < 2)
+ return NULL;
+ return star;
+ }
+
+/* Compare using wildcards. */
+static int equal_wildcard(const unsigned char *pattern, size_t pattern_len,
+ const unsigned char *subject, size_t subject_len)
+ {
+ const unsigned char *star;
+ /* Do not match IDNA names. */
+ if (subject_len >=4 && memcmp(subject, "xn--", 4) == 0)
+ star = NULL;
+ else
+ star = wildcard_find_star(pattern, pattern_len);
+ if (star == NULL)
+ return equal_nocase(pattern, pattern_len,
+ subject, subject_len);
+ return wildcard_match(pattern, star - pattern,
+ star + 1, (pattern + pattern_len) - star - 1,
+ subject, subject_len);
+ }
+
/* Compare an ASN1_STRING to a supplied string. If they match
* return 1. If cmp_type > 0 only compare if string matches the
* type, otherwise convert it to UTF8.
*/
-static int do_check_string(ASN1_STRING *a, int cmp_type,
+static int do_check_string(ASN1_STRING *a, int cmp_type, equal_fn equal,
const unsigned char *b, size_t blen)
{
if (!a->data || !a->length)
@@ -582,6 +747,8 @@
{
if (cmp_type != a->type)
return 0;
+ if (cmp_type == V_ASN1_IA5STRING)
+ return equal(a->data, a->length, b, blen);
if (a->length == (int)blen && !memcmp(a->data, b, blen))
return 1;
else
@@ -593,11 +760,8 @@
unsigned char *astr;
astrlen = ASN1_STRING_to_UTF8(&astr, a);
if (astrlen < 0)
- return 0;
- if (astrlen == (int)blen && !memcmp(astr, b, blen))
- rv = 1;
- else
- rv = 0;
+ return -1;
+ rv = equal(astr, astrlen, b, blen);
OPENSSL_free(astr);
return rv;
}
@@ -610,12 +774,29 @@
X509_NAME *name = NULL;
int i;
int cnid;
+ int alt_type;
+ equal_fn equal;
if (check_type == GEN_EMAIL)
+ {
cnid = NID_pkcs9_emailAddress;
+ alt_type = V_ASN1_IA5STRING;
+ equal = equal_email;
+ }
else if (check_type == GEN_DNS)
+ {
cnid = NID_commonName;
+ alt_type = V_ASN1_IA5STRING;
+ if (flags & X509_CHECK_FLAG_NO_WILDCARDS)
+ equal = equal_nocase;
+ else
+ equal = equal_wildcard;
+ }
else
+ {
cnid = 0;
+ alt_type = V_ASN1_OCTET_STRING;
+ equal = equal_case;
+ }
if (chklen == 0)
chklen = strlen((const char *)chk);
@@ -624,11 +805,6 @@
if (gens)
{
int rv = 0;
- int alt_type;
- if (cnid)
- alt_type = V_ASN1_IA5STRING;
- else
- alt_type = V_ASN1_OCTET_STRING;
for (i = 0; i < sk_GENERAL_NAME_num(gens); i++)
{
GENERAL_NAME *gen;
@@ -642,7 +818,7 @@
cstr = gen->d.dNSName;
else
cstr = gen->d.iPAddress;
- if (do_check_string(cstr, alt_type, chk, chklen))
+ if (do_check_string(cstr, alt_type, equal, chk, chklen))
{
rv = 1;
break;
@@ -662,7 +838,7 @@
ASN1_STRING *str;
ne = X509_NAME_get_entry(name, i);
str = X509_NAME_ENTRY_get_data(ne);
- if (do_check_string(str, -1, chk, chklen))
+ if (do_check_string(str, -1, equal, chk, chklen))
return 1;
}
return 0;
@@ -692,7 +868,7 @@
int iplen;
iplen = a2i_ipadd(ipout, ipasc);
if (iplen == 0)
- return 0;
+ return -2;
return do_x509_check(x, ipout, (size_t)iplen, flags, GEN_IPADD);
}
diff --git a/crypto/x509v3/v3nametest.c b/crypto/x509v3/v3nametest.c
new file mode 100644
index 0000000..5bf1201
--- /dev/null
+++ b/crypto/x509v3/v3nametest.c
@@ -0,0 +1,346 @@
+#include <openssl/x509.h>
+#include <openssl/x509v3.h>
+#include <string.h>
+
+static const char *const names[] =
+ {
+ "a", "b", ".", "*", "@",
+ ".a", "a.", ".b", "b.", ".*", "*.", "*@", "@*", "a@", "@a", "b@", "..",
+ "@@", "**",
+ "*.com", "*com", "*.*.com", "*com", "com*", "*example.com",
+ "*@example.com", "test@*.example.com",
+ "example.com", "www.example.com", "test.www.example.com",
+ "*.example.com", "*.www.example.com", "test.*.example.com", "www.*.com",
+ "example.net", "xn--rger-koa.example.com",
+ "a.example.com", "b.example.com",
+ "postmaster@example.com", "Postmaster@example.com",
+ "postmaster@EXAMPLE.COM",
+ NULL
+ };
+
+static const char *const exceptions[] =
+ {
+ "set CN: host: [*.example.com] does not match [*.example.com]",
+ "set CN: host: [*.example.com] matches [a.example.com]",
+ "set CN: host: [*.example.com] matches [b.example.com]",
+ "set CN: host: [*.example.com] matches [www.example.com]",
+ "set CN: host: [test.*.example.com] does not match [test.*.example.com]",
+ "set CN: host: [test.*.example.com] matches [test.www.example.com]",
+ "set CN: host: [*.www.example.com] does not match [*.www.example.com]",
+ "set CN: host: [*.www.example.com] matches [test.www.example.com]",
+ "set emailAddress: email: [postmaster@example.com] does not match [Postmaster@example.com]",
+ "set emailAddress: email: [postmaster@EXAMPLE.COM] does not match [Postmaster@example.com]",
+ "set emailAddress: email: [Postmaster@example.com] does not match [postmaster@example.com]",
+ "set emailAddress: email: [Postmaster@example.com] does not match [postmaster@EXAMPLE.COM]",
+ "set dnsName: host: [*.example.com] matches [www.example.com]",
+ "set dnsName: host: [*.example.com] does not match [*.example.com]",
+ "set dnsName: host: [*.example.com] matches [a.example.com]",
+ "set dnsName: host: [*.example.com] matches [b.example.com]",
+ "set dnsName: host: [*.www.example.com] matches [test.www.example.com]",
+ "set dnsName: host: [*.www.example.com] does not match [*.www.example.com]",
+ "set dnsName: host: [test.*.example.com] matches [test.www.example.com]",
+ "set dnsName: host: [test.*.example.com] does not match [test.*.example.com]",
+ "set rfc822Name: email: [postmaster@example.com] does not match [Postmaster@example.com]",
+ "set rfc822Name: email: [Postmaster@example.com] does not match [postmaster@example.com]",
+ "set rfc822Name: email: [Postmaster@example.com] does not match [postmaster@EXAMPLE.COM]",
+ "set rfc822Name: email: [postmaster@EXAMPLE.COM] does not match [Postmaster@example.com]",
+ NULL
+ };
+
+static int is_exception(const char *msg)
+ {
+ const char *const *p;
+ for (p = exceptions; *p; ++p)
+ if (strcmp(msg, *p) == 0)
+ return 1;
+ return 0;
+ }
+
+static int set_cn(X509 *crt, ...)
+ {
+ int ret = 0;
+ X509_NAME *n = NULL;
+ va_list ap;
+ va_start(ap, crt);
+ n = X509_NAME_new();
+ if (n == NULL)
+ goto out;
+ while (1) {
+ int nid;
+ const char *name;
+ nid = va_arg(ap, int);
+ if (nid == 0)
+ break;
+ name = va_arg(ap, const char *);
+ if (!X509_NAME_add_entry_by_NID(n, nid, MBSTRING_ASC,
+ (unsigned char *)name,
+ -1, -1, 1))
+ goto out;
+ }
+ if (!X509_set_subject_name(crt, n))
+ goto out;
+ ret = 1;
+ out:
+ X509_NAME_free(n);
+ va_end(ap);
+ return ret;
+ }
+
+/*
+int X509_add_ext(X509 *x, X509_EXTENSION *ex, int loc);
+X509_EXTENSION *X509_EXTENSION_create_by_NID(X509_EXTENSION **ex,
+ int nid, int crit, ASN1_OCTET_STRING *data);
+int X509_add_ext(X509 *x, X509_EXTENSION *ex, int loc);
+*/
+
+static int set_altname(X509 *crt, ...)
+ {
+ int ret = 0;
+ GENERAL_NAMES *gens = NULL;
+ GENERAL_NAME *gen = NULL;
+ ASN1_IA5STRING *ia5 = NULL;
+ va_list ap;
+ va_start(ap, crt);
+ gens = sk_GENERAL_NAME_new_null();
+ if (gens == NULL)
+ goto out;
+ while (1) {
+ int type;
+ const char *name;
+ type = va_arg(ap, int);
+ if (type == 0)
+ break;
+ name = va_arg(ap, const char *);
+
+ gen = GENERAL_NAME_new();
+ if (gen == NULL)
+ goto out;
+ ia5 = ASN1_IA5STRING_new();
+ if (ia5 == NULL)
+ goto out;
+ if (!ASN1_STRING_set(ia5, name, -1))
+ goto out;
+ switch (type)
+ {
+ case GEN_EMAIL:
+ case GEN_DNS:
+ GENERAL_NAME_set0_value(gen, type, ia5);
+ ia5 = NULL;
+ break;
+ default:
+ abort();
+ }
+ sk_GENERAL_NAME_push(gens, gen);
+ gen = NULL;
+ }
+ if (!X509_add1_ext_i2d(crt, NID_subject_alt_name, gens, 0, 0))
+ goto out;
+ ret = 1;
+ out:
+ ASN1_IA5STRING_free(ia5);
+ GENERAL_NAME_free(gen);
+ GENERAL_NAMES_free(gens);
+ va_end(ap);
+ return ret;
+ }
+
+static int set_cn1(X509 *crt, const char *name)
+ {
+ return set_cn(crt, NID_commonName, name, 0);
+ }
+
+
+static int set_cn_and_email(X509 *crt, const char *name)
+ {
+ return set_cn(crt, NID_commonName, name,
+ NID_pkcs9_emailAddress, "dummy@example.com", 0);
+ }
+
+static int set_cn2(X509 *crt, const char *name)
+ {
+ return set_cn(crt, NID_commonName, "dummy value",
+ NID_commonName, name, 0);
+ }
+
+static int set_cn3(X509 *crt, const char *name)
+ {
+ return set_cn(crt, NID_commonName, name,
+ NID_commonName, "dummy value", 0);
+ }
+
+static int set_email1(X509 *crt, const char *name)
+ {
+ return set_cn(crt, NID_pkcs9_emailAddress, name, 0);
+ }
+
+static int set_email2(X509 *crt, const char *name)
+ {
+ return set_cn(crt, NID_pkcs9_emailAddress, "dummy@example.com",
+ NID_pkcs9_emailAddress, name, 0);
+ }
+
+static int set_email3(X509 *crt, const char *name)
+ {
+ return set_cn(crt, NID_pkcs9_emailAddress, name,
+ NID_pkcs9_emailAddress, "dummy@example.com", 0);
+ }
+
+static int set_email_and_cn(X509 *crt, const char *name)
+ {
+ return set_cn(crt, NID_pkcs9_emailAddress, name,
+ NID_commonName, "www.example.org", 0);
+ }
+
+static int set_altname_dns(X509 *crt, const char *name)
+ {
+ return set_altname(crt, GEN_DNS, name, 0);
+ }
+
+static int set_altname_email(X509 *crt, const char *name)
+ {
+ return set_altname(crt, GEN_EMAIL, name, 0);
+ }
+
+struct set_name_fn
+ {
+ int (*fn)(X509 *, const char *);
+ const char *name;
+ int host;
+ int email;
+ };
+
+static const struct set_name_fn name_fns[] =
+ {
+ {set_cn1, "set CN", 1, 0},
+ {set_cn2, "set CN", 1, 0},
+ {set_cn3, "set CN", 1, 0},
+ {set_cn_and_email, "set CN", 1, 0},
+ {set_email1, "set emailAddress", 0, 1},
+ {set_email2, "set emailAddress", 0, 1},
+ {set_email3, "set emailAddress", 0, 1},
+ {set_email_and_cn, "set emailAddress", 0, 1},
+ {set_altname_dns, "set dnsName", 1, 0},
+ {set_altname_email, "set rfc822Name", 0, 1},
+ {NULL, NULL, 0}
+ };
+
+static X509 *make_cert()
+ {
+ X509 *ret = NULL;
+ X509 *crt = NULL;
+ X509_NAME *issuer = NULL;
+ crt = X509_new();
+ if (crt == NULL)
+ goto out;
+ if (!X509_set_version(crt, 3))
+ goto out;
+ ret = crt;
+ crt = NULL;
+ out:
+ X509_NAME_free(issuer);
+ return ret;
+ }
+
+static int errors;
+
+static void check_message(const struct set_name_fn *fn, const char *op,
+ const char *nameincert, int match, const char *name)
+ {
+ char msg[1024];
+ if (match < 0)
+ return;
+ snprintf(msg, sizeof(msg), "%s: %s: [%s] %s [%s]",
+ fn->name, op, nameincert,
+ match ? "matches" : "does not match", name);
+ if (is_exception(msg))
+ return;
+ puts(msg);
+ ++errors;
+ }
+
+static void run_cert(X509 *crt, const char *nameincert,
+ const struct set_name_fn *fn)
+ {
+ const char *const *pname = names;
+ while (*pname)
+ {
+ int samename = strcasecmp(nameincert, *pname) == 0;
+ size_t namelen = strlen(*pname);
+ char *name = malloc(namelen);
+ int match, ret;
+ memcpy(name, *pname, namelen);
+
+ ret = X509_check_host(crt, (const unsigned char *)name,
+ namelen, 0);
+ match = -1;
+ if (fn->host)
+ {
+ if (ret && !samename)
+ match = 1;
+ if (!ret && samename)
+ match = 0;
+ }
+ else if (ret)
+ match = 1;
+ check_message(fn, "host", nameincert, match, *pname);
+
+ ret = X509_check_host(crt, (const unsigned char *)name,
+ namelen, X509_CHECK_FLAG_NO_WILDCARDS);
+ match = -1;
+ if (fn->host)
+ {
+ if (ret && !samename)
+ match = 1;
+ if (!ret && samename)
+ match = 0;
+ }
+ else if (ret)
+ match = 1;
+ check_message(fn, "host-no-wildcards",
+ nameincert, match, *pname);
+
+ ret = X509_check_email(crt, (const unsigned char *)name,
+ namelen, 0);
+ match = -1;
+ if (fn->email)
+ {
+ if (ret && !samename)
+ match = 1;
+ if (!ret && samename && strchr(nameincert, '@') != NULL)
+ match = 0;
+ }
+ else if (ret)
+ match = 1;
+ check_message(fn, "email", nameincert, match, *pname);
+ ++pname;
+ free(name);
+ }
+ }
+
+int
+main(void)
+ {
+ const struct set_name_fn *pfn = name_fns;
+ while (pfn->name) {
+ const char *const *pname = names;
+ while (*pname)
+ {
+ X509 *crt = make_cert();
+ if (crt == NULL)
+ {
+ fprintf(stderr, "make_cert failed\n");
+ return 1;
+ }
+ if (!pfn->fn(crt, *pname))
+ {
+ fprintf(stderr, "X509 name setting failed\n");
+ return 1;
+ }
+ run_cert(crt, *pname, pfn);
+ X509_free(crt);
+ ++pname;
+ }
+ ++pfn;
+ }
+ return errors > 0 ? 1 : 0;
+ }
diff --git a/crypto/x509v3/x509v3.h b/crypto/x509v3/x509v3.h
index 23f7091..272374e 100644
--- a/crypto/x509v3/x509v3.h
+++ b/crypto/x509v3/x509v3.h
@@ -704,6 +704,8 @@
/* Always check subject name for host match even if subject alt names present */
#define X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT 0x1
+/* Disable wild-card matching for dnsName fields and common name. */
+#define X509_CHECK_FLAG_NO_WILDCARDS 0x2
int X509_check_host(X509 *x, const unsigned char *chk, size_t chklen,
unsigned int flags);
