pineapple-src/externals/libressl/crypto/x509/x509_constraints.c
2022-04-24 22:29:35 +02:00

1233 lines
30 KiB
C
Executable file

/* $OpenBSD: x509_constraints.c,v 1.26 2022/03/26 16:34:21 tb Exp $ */
/*
* Copyright (c) 2020 Bob Beck <beck@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 <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <openssl/safestack.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include "x509_internal.h"
/* RFC 2821 section 4.5.3.1 */
#define LOCAL_PART_MAX_LEN 64
#define DOMAIN_PART_MAX_LEN 255
struct x509_constraints_name *
x509_constraints_name_new(void)
{
return (calloc(1, sizeof(struct x509_constraints_name)));
}
void
x509_constraints_name_clear(struct x509_constraints_name *name)
{
free(name->name);
free(name->local);
free(name->der);
memset(name, 0, sizeof(*name));
}
void
x509_constraints_name_free(struct x509_constraints_name *name)
{
if (name == NULL)
return;
x509_constraints_name_clear(name);
free(name);
}
struct x509_constraints_name *
x509_constraints_name_dup(struct x509_constraints_name *name)
{
struct x509_constraints_name *new;
if ((new = x509_constraints_name_new()) == NULL)
goto err;
new->type = name->type;
new->af = name->af;
new->der_len = name->der_len;
if (name->der_len > 0) {
if ((new->der = malloc(name->der_len)) == NULL)
goto err;
memcpy(new->der, name->der, name->der_len);
}
if (name->name != NULL && (new->name = strdup(name->name)) == NULL)
goto err;
if (name->local != NULL && (new->local = strdup(name->local)) == NULL)
goto err;
memcpy(new->address, name->address, sizeof(name->address));
return new;
err:
x509_constraints_name_free(new);
return NULL;
}
struct x509_constraints_names *
x509_constraints_names_new(size_t names_max)
{
struct x509_constraints_names *new;
if ((new = calloc(1, sizeof(struct x509_constraints_names))) == NULL)
return NULL;
new->names_max = names_max;
return new;
}
void
x509_constraints_names_clear(struct x509_constraints_names *names)
{
size_t i;
for (i = 0; i < names->names_count; i++)
x509_constraints_name_free(names->names[i]);
free(names->names);
memset(names, 0, sizeof(*names));
}
void
x509_constraints_names_free(struct x509_constraints_names *names)
{
if (names == NULL)
return;
x509_constraints_names_clear(names);
free(names);
}
int
x509_constraints_names_add(struct x509_constraints_names *names,
struct x509_constraints_name *name)
{
if (names->names_count >= names->names_max)
return 0;
if (names->names_count == names->names_len) {
struct x509_constraints_name **tmp;
if ((tmp = recallocarray(names->names, names->names_len,
names->names_len + 32, sizeof(*tmp))) == NULL)
return 0;
names->names_len += 32;
names->names = tmp;
}
names->names[names->names_count] = name;
names->names_count++;
return 1;
}
struct x509_constraints_names *
x509_constraints_names_dup(struct x509_constraints_names *names)
{
struct x509_constraints_names *new = NULL;
struct x509_constraints_name *name = NULL;
size_t i;
if (names == NULL)
return NULL;
if ((new = x509_constraints_names_new(names->names_max)) == NULL)
goto err;
for (i = 0; i < names->names_count; i++) {
if ((name = x509_constraints_name_dup(names->names[i])) == NULL)
goto err;
if (!x509_constraints_names_add(new, name))
goto err;
}
return new;
err:
x509_constraints_names_free(new);
x509_constraints_name_free(name);
return NULL;
}
/*
* Validate that the name contains only a hostname consisting of RFC
* 5890 compliant A-labels (see RFC 6066 section 3). This is more
* permissive to allow for a leading '.' for a subdomain based
* constraint, as well as allowing for '_' which is commonly accepted
* by nonconformant DNS implementaitons.
*
* if "wildcards" is set it allows '*' to occur in the string at the end of a
* component.
*/
static int
x509_constraints_valid_domain_internal(uint8_t *name, size_t len, int wildcards)
{
uint8_t prev, c = 0;
int component = 0;
int first;
size_t i;
if (len > DOMAIN_PART_MAX_LEN)
return 0;
for (i = 0; i < len; i++) {
prev = c;
c = name[i];
first = (i == 0);
/* Everything has to be ASCII, with no NUL byte */
if (!isascii(c) || c == '\0')
return 0;
/* It must be alphanumeric, a '-', '.', '_' or '*' */
if (!isalnum(c) && c != '-' && c != '.' && c != '_' && c != '*')
return 0;
/* if it is a '*', fail if not wildcards */
if (!wildcards && c == '*')
return 0;
/* '-' must not start a component or be at the end. */
if (c == '-' && (component == 0 || i == len - 1))
return 0;
/*
* '.' must not be at the end. It may be first overall
* but must not otherwise start a component.
*/
if (c == '.' && ((component == 0 && !first) || i == len - 1))
return 0;
if (c == '.') {
/* Components can not end with a dash. */
if (prev == '-')
return 0;
/* Start new component */
component = 0;
continue;
}
/*
* Wildcards can only occur at the end of a component.
* c*.com is valid, c*c.com is not.
*/
if (prev == '*')
return 0;
/* Components must be 63 chars or less. */
if (++component > 63)
return 0;
}
return 1;
}
int
x509_constraints_valid_domain(uint8_t *name, size_t len)
{
if (len == 0)
return 0;
/*
* A domain may not be less than two characters, so you can't
* have a require subdomain name with less than that.
*/
if (len < 3 && name[0] == '.')
return 0;
return x509_constraints_valid_domain_internal(name, len, 0);
}
int
x509_constraints_valid_host(uint8_t *name, size_t len)
{
struct sockaddr_in sin4;
struct sockaddr_in6 sin6;
if (len == 0)
return 0;
if (name[0] == '.') /* leading . not allowed in a host name*/
return 0;
if (inet_pton(AF_INET, name, &sin4) == 1)
return 0;
if (inet_pton(AF_INET6, name, &sin6) == 1)
return 0;
return x509_constraints_valid_domain_internal(name, len, 0);
}
int
x509_constraints_valid_sandns(uint8_t *name, size_t len)
{
if (len == 0)
return 0;
if (name[0] == '.') /* leading . not allowed in a SAN DNS name */
return 0;
/*
* A domain may not be less than two characters, so you
* can't wildcard a single domain of less than that
*/
if (len < 4 && name[0] == '*')
return 0;
/*
* A wildcard may only be followed by a '.'
*/
if (len >= 4 && name[0] == '*' && name[1] != '.')
return 0;
return x509_constraints_valid_domain_internal(name, len, 1);
}
static inline int
local_part_ok(char c)
{
return (('0' <= c && c <= '9') || ('a' <= c && c <= 'z') ||
('A' <= c && c <= 'Z') || c == '!' || c == '#' || c == '$' ||
c == '%' || c == '&' || c == '\'' || c == '*' || c == '+' ||
c == '-' || c == '/' || c == '=' || c == '?' || c == '^' ||
c == '_' || c == '`' || c == '{' || c == '|' || c == '}' ||
c == '~' || c == '.');
}
/*
* Parse "candidate" as an RFC 2821 mailbox.
* Returns 0 if candidate is not a valid mailbox or if an error occurs.
* Returns 1 if candidate is a mailbox and adds newly allocated
* local and domain parts of the mailbox to "name->local" and name->name"
*/
int
x509_constraints_parse_mailbox(uint8_t *candidate, size_t len,
struct x509_constraints_name *name)
{
char working[DOMAIN_PART_MAX_LEN + 1] = { 0 };
char *candidate_local = NULL;
char *candidate_domain = NULL;
size_t i, wi = 0;
int accept = 0;
int quoted = 0;
if (candidate == NULL)
return 0;
/* It can't be bigger than the local part, domain part and the '@' */
if (len > LOCAL_PART_MAX_LEN + DOMAIN_PART_MAX_LEN + 1)
return 0;
for (i = 0; i < len; i++) {
char c = candidate[i];
/* non ascii, cr, lf, or nul is never allowed */
if (!isascii(c) || c == '\r' || c == '\n' || c == '\0')
goto bad;
if (i == 0) {
/* local part is quoted part */
if (c == '"')
quoted = 1;
/* can not start with a . */
if (c == '.')
goto bad;
}
if (accept) {
if (wi >= DOMAIN_PART_MAX_LEN)
goto bad;
working[wi++] = c;
accept = 0;
continue;
}
if (candidate_local != NULL) {
/* We are looking for the domain part */
if (wi >= DOMAIN_PART_MAX_LEN)
goto bad;
working[wi++] = c;
if (i == len - 1) {
if (wi == 0)
goto bad;
if (candidate_domain != NULL)
goto bad;
candidate_domain = strdup(working);
if (candidate_domain == NULL)
goto bad;
}
continue;
}
/* We are looking for the local part */
if (wi >= LOCAL_PART_MAX_LEN)
break;
if (quoted) {
if (c == '\\') {
accept = 1;
continue;
}
if (c == '"' && i != 0) {
/* end the quoted part. @ must be next */
if (i + 1 == len || candidate[i + 1] != '@')
goto bad;
quoted = 0;
}
/*
* XXX Go strangely permits sp but forbids ht
* mimic that for now
*/
if (c == 9)
goto bad;
if (wi >= LOCAL_PART_MAX_LEN)
goto bad;
working[wi++] = c;
continue; /* all's good inside our quoted string */
}
if (c == '@') {
if (wi == 0)
goto bad;
if (candidate_local != NULL)
goto bad;
candidate_local = strdup(working);
if (candidate_local == NULL)
goto bad;
memset(working, 0, sizeof(working));
wi = 0;
continue;
}
if (c == '\\') {
/*
* RFC 3936 hints these can happen outside of
* quotend string. don't include the \ but
* next character must be ok.
*/
if (i + 1 == len)
goto bad;
if (!local_part_ok(candidate[i + 1]))
goto bad;
accept = 1;
}
if (!local_part_ok(c))
goto bad;
if (wi >= LOCAL_PART_MAX_LEN)
goto bad;
working[wi++] = c;
}
if (candidate_local == NULL || candidate_domain == NULL)
goto bad;
if (!x509_constraints_valid_host(candidate_domain,
strlen(candidate_domain)))
goto bad;
if (name != NULL) {
name->local = candidate_local;
name->name = candidate_domain;
name->type = GEN_EMAIL;
} else {
free(candidate_local);
free(candidate_domain);
}
return 1;
bad:
free(candidate_local);
free(candidate_domain);
return 0;
}
int
x509_constraints_valid_domain_constraint(uint8_t *constraint, size_t len)
{
if (len == 0)
return 1; /* empty constraints match */
/*
* A domain may not be less than two characters, so you
* can't match a single domain of less than that
*/
if (len < 3 && constraint[0] == '.')
return 0;
return x509_constraints_valid_domain_internal(constraint, len, 0);
}
/*
* Extract the host part of a URI, returns the host part as a c string
* the caller must free, or or NULL if it could not be found or is
* invalid.
*
* RFC 3986:
* the authority part of a uri starts with // and is terminated with
* the next '/', '?', '#' or end of the URI.
*
* The authority itself contains [userinfo '@'] host [: port]
*
* so the host starts at the start or after the '@', and ends
* with end of URI, '/', '?', "#', or ':'.
*/
int
x509_constraints_uri_host(uint8_t *uri, size_t len, char **hostpart)
{
size_t i, hostlen = 0;
uint8_t *authority = NULL;
char *host = NULL;
/*
* Find first '//'. there must be at least a '//' and
* something else.
*/
if (len < 3)
return 0;
for (i = 0; i < len - 1; i++) {
if (!isascii(uri[i]))
return 0;
if (uri[i] == '/' && uri[i + 1] == '/') {
authority = uri + i + 2;
break;
}
}
if (authority == NULL)
return 0;
for (i = authority - uri; i < len; i++) {
if (!isascii(uri[i]))
return 0;
/* it has a userinfo part */
if (uri[i] == '@') {
hostlen = 0;
/* it can only have one */
if (host != NULL)
break;
/* start after the userinfo part */
host = uri + i + 1;
continue;
}
/* did we find the end? */
if (uri[i] == ':' || uri[i] == '/' || uri[i] == '?' ||
uri[i] == '#')
break;
hostlen++;
}
if (hostlen == 0)
return 0;
if (host == NULL)
host = authority;
if (!x509_constraints_valid_host(host, hostlen))
return 0;
if (hostpart != NULL)
*hostpart = strndup(host, hostlen);
return 1;
}
int
x509_constraints_sandns(char *sandns, size_t dlen, char *constraint, size_t len)
{
char *suffix;
if (len == 0)
return 1; /* an empty constraint matches everything */
/* match the end of the domain */
if (dlen < len)
return 0;
suffix = sandns + (dlen - len);
return (strncasecmp(suffix, constraint, len) == 0);
}
/*
* Validate a pre-validated domain of length dlen against a pre-validated
* constraint of length len.
*
* returns 1 if the domain and constraint match.
* returns 0 otherwise.
*
* an empty constraint matches everyting.
* constraint will be matched against the domain as a suffix if it
* starts with a '.'.
* domain will be matched against the constraint as a suffix if it
* starts with a '.'.
*/
int
x509_constraints_domain(char *domain, size_t dlen, char *constraint, size_t len)
{
if (len == 0)
return 1; /* an empty constraint matches everything */
if (constraint[0] == '.') {
/* match the end of the domain */
char *suffix;
if (dlen < len)
return 0;
suffix = domain + (dlen - len);
return (strncasecmp(suffix, constraint, len) == 0);
}
if (domain[0] == '.') {
/* match the end of the constraint */
char *suffix;
if (len < dlen)
return 0;
suffix = constraint + (len - dlen);
return (strncasecmp(suffix, domain, dlen) == 0);
}
/* otherwise we must exactly match the constraint */
if (dlen != len)
return 0;
return (strncasecmp(domain, constraint, len) == 0);
}
int
x509_constraints_uri(uint8_t *uri, size_t ulen, uint8_t *constraint, size_t len,
int *error)
{
int ret = 0;
char *hostpart = NULL;
if (!x509_constraints_uri_host(uri, ulen, &hostpart)) {
*error = X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
goto err;
}
if (hostpart == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if (!x509_constraints_valid_domain_constraint(constraint, len)) {
*error = X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX;
goto err;
}
ret = x509_constraints_domain(hostpart, strlen(hostpart), constraint,
len);
err:
free(hostpart);
return ret;
}
/*
* Verify a validated address of size alen with a validated contraint
* of size constraint_len. returns 1 if matching, 0 if not.
* Addresses are assumed to be pre-validated for a length of 4 and 8
* respectively for ipv4 addreses and constraints, and a length of
* 16 and 32 respectively for ipv6 address constraints by the caller.
*/
int
x509_constraints_ipaddr(uint8_t *address, size_t alen, uint8_t *constraint,
size_t len)
{
uint8_t *mask;
size_t i;
if (alen * 2 != len)
return 0;
mask = constraint + alen;
for (i = 0; i < alen; i++) {
if ((address[i] & mask[i]) != (constraint[i] & mask[i]))
return 0;
}
return 1;
}
/*
* Verify a canonicalized der encoded constraint dirname
* a canonicalized der encoded constraint.
*/
int
x509_constraints_dirname(uint8_t *dirname, size_t dlen,
uint8_t *constraint, size_t len)
{
/*
* The constraint must be a prefix in DER format, so it can't be
* longer than the name it is checked against.
*/
if (len > dlen)
return 0;
return (memcmp(constraint, dirname, len) == 0);
}
/*
* De-obfuscate a GENERAL_NAME into useful bytes for a name or constraint.
*/
int
x509_constraints_general_to_bytes(GENERAL_NAME *name, uint8_t **bytes,
size_t *len)
{
*bytes = NULL;
*len = 0;
if (name->type == GEN_DNS) {
ASN1_IA5STRING *aname = name->d.dNSName;
*bytes = aname->data;
*len = aname->length;
return name->type;
}
if (name->type == GEN_EMAIL) {
ASN1_IA5STRING *aname = name->d.rfc822Name;
*bytes = aname->data;
*len = aname->length;
return name->type;
}
if (name->type == GEN_URI) {
ASN1_IA5STRING *aname = name->d.uniformResourceIdentifier;
*bytes = aname->data;
*len = aname->length;
return name->type;
}
if (name->type == GEN_DIRNAME) {
X509_NAME *dname = name->d.directoryName;
if (!dname->modified || i2d_X509_NAME(dname, NULL) >= 0) {
*bytes = dname->canon_enc;
*len = dname->canon_enclen;
return name->type;
}
}
if (name->type == GEN_IPADD) {
*bytes = name->d.ip->data;
*len = name->d.ip->length;
return name->type;
}
return 0;
}
/*
* Extract the relevant names for constraint checking from "cert",
* validate them, and add them to the list of cert names for "chain".
* returns 1 on success sets error and returns 0 on failure.
*/
int
x509_constraints_extract_names(struct x509_constraints_names *names,
X509 *cert, int is_leaf, int *error)
{
struct x509_constraints_name *vname = NULL;
X509_NAME *subject_name;
GENERAL_NAME *name;
ssize_t i = 0;
int name_type, include_cn = is_leaf, include_email = is_leaf;
/* first grab the altnames */
while ((name = sk_GENERAL_NAME_value(cert->altname, i++)) != NULL) {
uint8_t *bytes = NULL;
size_t len = 0;
if ((vname = x509_constraints_name_new()) == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
name_type = x509_constraints_general_to_bytes(name, &bytes,
&len);
switch(name_type) {
case GEN_DNS:
if (!x509_constraints_valid_sandns(bytes, len)) {
*error = X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
goto err;
}
if ((vname->name = strndup(bytes, len)) == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
vname->type = GEN_DNS;
include_cn = 0; /* don't use cn from subject */
break;
case GEN_EMAIL:
if (!x509_constraints_parse_mailbox(bytes, len,
vname)) {
*error = X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
goto err;
}
vname->type = GEN_EMAIL;
include_email = 0; /* don't use email from subject */
break;
case GEN_URI:
if (!x509_constraints_uri_host(bytes, len, &vname->name)) {
*error = X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
goto err;
}
if (vname->name == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
vname->type = GEN_URI;
break;
case GEN_DIRNAME:
if (len == 0) {
*error = X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
goto err;
}
if (bytes == NULL || ((vname->der = malloc(len)) ==
NULL)) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
memcpy(vname->der, bytes, len);
vname->der_len = len;
vname->type = GEN_DIRNAME;
break;
case GEN_IPADD:
if (len == 4)
vname->af = AF_INET;
if (len == 16)
vname->af = AF_INET6;
if (vname->af != AF_INET && vname->af != AF_INET6) {
*error = X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
goto err;
}
memcpy(vname->address, bytes, len);
vname->type = GEN_IPADD;
break;
default:
/* Ignore this name */
x509_constraints_name_free(vname);
vname = NULL;
continue;
}
if (!x509_constraints_names_add(names, vname)) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
vname = NULL;
}
x509_constraints_name_free(vname);
vname = NULL;
subject_name = X509_get_subject_name(cert);
if (X509_NAME_entry_count(subject_name) > 0) {
X509_NAME_ENTRY *email;
X509_NAME_ENTRY *cn;
/*
* This cert has a non-empty subject, so we must add
* the subject as a dirname to be compared against
* any dirname constraints
*/
if ((subject_name->modified &&
i2d_X509_NAME(subject_name, NULL) < 0) ||
(vname = x509_constraints_name_new()) == NULL ||
(vname->der = malloc(subject_name->canon_enclen)) == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
memcpy(vname->der, subject_name->canon_enc,
subject_name->canon_enclen);
vname->der_len = subject_name->canon_enclen;
vname->type = GEN_DIRNAME;
if (!x509_constraints_names_add(names, vname)) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
vname = NULL;
/*
* Get any email addresses from the subject line, and
* add them as mbox names to be compared against any
* email constraints
*/
while (include_email &&
(i = X509_NAME_get_index_by_NID(subject_name,
NID_pkcs9_emailAddress, i)) >= 0) {
ASN1_STRING *aname;
if ((email = X509_NAME_get_entry(subject_name, i)) == NULL ||
(aname = X509_NAME_ENTRY_get_data(email)) == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if ((vname = x509_constraints_name_new()) == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if (!x509_constraints_parse_mailbox(aname->data,
aname->length, vname)) {
*error = X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
goto err;
}
vname->type = GEN_EMAIL;
if (!x509_constraints_names_add(names, vname)) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
vname = NULL;
}
/*
* Include the CN as a hostname to be checked againt
* name constraints if it looks like a hostname.
*/
while (include_cn &&
(i = X509_NAME_get_index_by_NID(subject_name,
NID_commonName, i)) >= 0) {
ASN1_STRING *aname;
if ((cn = X509_NAME_get_entry(subject_name, i)) == NULL ||
(aname = X509_NAME_ENTRY_get_data(cn)) == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if (!x509_constraints_valid_host(aname->data,
aname->length))
continue; /* ignore it if not a hostname */
if ((vname = x509_constraints_name_new()) == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if ((vname->name = strndup(aname->data,
aname->length)) == NULL) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
vname->type = GEN_DNS;
if (!x509_constraints_names_add(names, vname)) {
*error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
vname = NULL;
}
}
return 1;
err:
x509_constraints_name_free(vname);
return 0;
}
/*
* Validate a constraint in a general name, putting the relevant data
* into "name" if valid. returns 0, and sets error if the constraint is
* not valid. returns 1 if the constraint validated. name->type will be
* set to a valid type if there is constraint data in name, or unmodified
* if the GENERAL_NAME had a valid type but was ignored.
*/
int
x509_constraints_validate(GENERAL_NAME *constraint,
struct x509_constraints_name **out_name, int *out_error)
{
uint8_t *bytes = NULL;
size_t len = 0;
struct x509_constraints_name *name;
int error = X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX;
int name_type;
if (out_name == NULL || *out_name != NULL)
return 0;
if (out_error != NULL)
*out_error = 0;
if ((name = x509_constraints_name_new()) == NULL) {
error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
name_type = x509_constraints_general_to_bytes(constraint, &bytes, &len);
switch (name_type) {
case GEN_DIRNAME:
if (len == 0)
goto err; /* XXX The RFCs are delightfully vague */
if (bytes == NULL || (name->der = malloc(len)) == NULL) {
error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
memcpy(name->der, bytes, len);
name->der_len = len;
name->type = GEN_DIRNAME;
break;
case GEN_DNS:
if (!x509_constraints_valid_domain_constraint(bytes, len))
goto err;
if ((name->name = strndup(bytes, len)) == NULL) {
error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
name->type = GEN_DNS;
break;
case GEN_EMAIL:
if (len > 0 && memchr(bytes + 1, '@', len - 1) != NULL) {
if (!x509_constraints_parse_mailbox(bytes, len, name))
goto err;
break;
}
/*
* Mail constraints of the form @domain.com are accepted by
* OpenSSL and Microsoft.
*/
if (len > 0 && bytes[0] == '@') {
bytes++;
len--;
}
if (!x509_constraints_valid_domain_constraint(bytes, len))
goto err;
if ((name->name = strndup(bytes, len)) == NULL) {
error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
name->type = GEN_EMAIL;
break;
case GEN_IPADD:
/* Constraints are ip then mask */
if (len == 8)
name->af = AF_INET;
else if (len == 32)
name->af = AF_INET6;
else
goto err;
memcpy(&name->address[0], bytes, len);
name->type = GEN_IPADD;
break;
case GEN_URI:
if (!x509_constraints_valid_domain_constraint(bytes, len))
goto err;
if ((name->name = strndup(bytes, len)) == NULL) {
error = X509_V_ERR_OUT_OF_MEM;
goto err;
}
name->type = GEN_URI;
break;
default:
break;
}
*out_name = name;
return 1;
err:
x509_constraints_name_free(name);
if (out_error != NULL)
*out_error = error;
return 0;
}
int
x509_constraints_extract_constraints(X509 *cert,
struct x509_constraints_names *permitted,
struct x509_constraints_names *excluded,
int *error)
{
struct x509_constraints_name *vname = NULL;
NAME_CONSTRAINTS *nc = cert->nc;
GENERAL_SUBTREE *subtree;
int i;
if (nc == NULL)
return 1;
for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) {
subtree = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i);
if (subtree->minimum || subtree->maximum) {
*error = X509_V_ERR_SUBTREE_MINMAX;
return 0;
}
if (!x509_constraints_validate(subtree->base, &vname, error))
return 0;
if (vname->type == 0) {
x509_constraints_name_free(vname);
vname = NULL;
continue;
}
if (!x509_constraints_names_add(permitted, vname)) {
x509_constraints_name_free(vname);
vname = NULL;
*error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
vname = NULL;
}
for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) {
subtree = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i);
if (subtree->minimum || subtree->maximum) {
*error = X509_V_ERR_SUBTREE_MINMAX;
return 0;
}
if (!x509_constraints_validate(subtree->base, &vname, error))
return 0;
if (vname->type == 0) {
x509_constraints_name_free(vname);
vname = NULL;
continue;
}
if (!x509_constraints_names_add(excluded, vname)) {
x509_constraints_name_free(vname);
vname = NULL;
*error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
vname = NULL;
}
return 1;
}
/*
* Match a validated name in "name" against a validated constraint in
* "constraint" return 1 if then name matches, 0 otherwise.
*/
int
x509_constraints_match(struct x509_constraints_name *name,
struct x509_constraints_name *constraint)
{
if (name->type != constraint->type)
return 0;
if (name->type == GEN_DNS)
return x509_constraints_sandns(name->name, strlen(name->name),
constraint->name, strlen(constraint->name));
if (name->type == GEN_URI)
return x509_constraints_domain(name->name, strlen(name->name),
constraint->name, strlen(constraint->name));
if (name->type == GEN_IPADD) {
size_t nlen = name->af == AF_INET ? 4 : 16;
size_t clen = name->af == AF_INET ? 8 : 32;
if (name->af != AF_INET && name->af != AF_INET6)
return 0;
if (constraint->af != AF_INET && constraint->af != AF_INET6)
return 0;
if (name->af != constraint->af)
return 0;
return x509_constraints_ipaddr(name->address, nlen,
constraint->address, clen);
}
if (name->type == GEN_EMAIL) {
if (constraint->local) {
/* mailbox local and domain parts must exactly match */
return (strcmp(name->local, constraint->local) == 0 &&
strcmp(name->name, constraint->name) == 0);
}
/* otherwise match the constraint to the domain part */
return x509_constraints_domain(name->name, strlen(name->name),
constraint->name, strlen(constraint->name));
}
if (name->type == GEN_DIRNAME)
return x509_constraints_dirname(name->der, name->der_len,
constraint->der, constraint->der_len);
return 0;
}
/*
* Make sure every name in names does not match any excluded
* constraints, and does match at least one permitted constraint if
* any are present. Returns 1 if ok, 0, and sets error if not.
*/
int
x509_constraints_check(struct x509_constraints_names *names,
struct x509_constraints_names *permitted,
struct x509_constraints_names *excluded, int *error)
{
size_t i, j;
for (i = 0; i < names->names_count; i++) {
int permitted_seen = 0;
int permitted_matched = 0;
for (j = 0; j < excluded->names_count; j++) {
if (x509_constraints_match(names->names[i],
excluded->names[j])) {
*error = X509_V_ERR_EXCLUDED_VIOLATION;
return 0;
}
}
for (j = 0; j < permitted->names_count; j++) {
if (permitted->names[j]->type == names->names[i]->type)
permitted_seen++;
if (x509_constraints_match(names->names[i],
permitted->names[j])) {
permitted_matched++;
break;
}
}
if (permitted_seen && !permitted_matched) {
*error = X509_V_ERR_PERMITTED_VIOLATION;
return 0;
}
}
return 1;
}
/*
* Walk a validated chain of X509 certs, starting at the leaf, and
* validate the name constraints in the chain. Intended for use with
* the legacy X509 validtion code in x509_vfy.c
*
* returns 1 if the constraints are ok, 0 otherwise, setting error and
* depth
*/
int
x509_constraints_chain(STACK_OF(X509) *chain, int *error, int *depth)
{
int chain_length, verify_err = X509_V_ERR_UNSPECIFIED, i = 0;
struct x509_constraints_names *names = NULL;
struct x509_constraints_names *excluded = NULL;
struct x509_constraints_names *permitted = NULL;
size_t constraints_count = 0;
X509 *cert;
if (chain == NULL || (chain_length = sk_X509_num(chain)) == 0)
goto err;
if (chain_length == 1)
return 1;
if ((names = x509_constraints_names_new(
X509_VERIFY_MAX_CHAIN_NAMES)) == NULL) {
verify_err = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if ((cert = sk_X509_value(chain, 0)) == NULL)
goto err;
if (!x509_constraints_extract_names(names, cert, 1, &verify_err))
goto err;
for (i = 1; i < chain_length; i++) {
if ((cert = sk_X509_value(chain, i)) == NULL)
goto err;
if (cert->nc != NULL) {
if ((permitted = x509_constraints_names_new(
X509_VERIFY_MAX_CHAIN_CONSTRAINTS)) == NULL) {
verify_err = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if ((excluded = x509_constraints_names_new(
X509_VERIFY_MAX_CHAIN_CONSTRAINTS)) == NULL) {
verify_err = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if (!x509_constraints_extract_constraints(cert,
permitted, excluded, &verify_err))
goto err;
constraints_count += permitted->names_count;
constraints_count += excluded->names_count;
if (constraints_count >
X509_VERIFY_MAX_CHAIN_CONSTRAINTS) {
verify_err = X509_V_ERR_OUT_OF_MEM;
goto err;
}
if (!x509_constraints_check(names, permitted, excluded,
&verify_err))
goto err;
x509_constraints_names_free(excluded);
excluded = NULL;
x509_constraints_names_free(permitted);
permitted = NULL;
}
if (!x509_constraints_extract_names(names, cert, 0,
&verify_err))
goto err;
}
x509_constraints_names_free(names);
return 1;
err:
*error = verify_err;
*depth = i;
x509_constraints_names_free(excluded);
x509_constraints_names_free(permitted);
x509_constraints_names_free(names);
return 0;
}