/* $OpenBSD: x509_ncons.c,v 1.11 2024/07/13 15:08:58 tb Exp $ */ /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL * project. */ /* ==================================================================== * Copyright (c) 2003 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * licensing@OpenSSL.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). * */ #include #include #include #include #include #include #include "x509_local.h" static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval); static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, BIO *bp, int ind); static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method, STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name); static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip); static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc); static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen); static int nc_dn(X509_NAME *sub, X509_NAME *nm); static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns); static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml); static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base); static const X509V3_EXT_METHOD x509v3_ext_name_constraints = { .ext_nid = NID_name_constraints, .ext_flags = 0, .it = &NAME_CONSTRAINTS_it, .ext_new = NULL, .ext_free = NULL, .d2i = NULL, .i2d = NULL, .i2s = NULL, .s2i = NULL, .i2v = NULL, .v2i = v2i_NAME_CONSTRAINTS, .i2r = i2r_NAME_CONSTRAINTS, .r2i = NULL, .usr_data = NULL, }; const X509V3_EXT_METHOD * x509v3_ext_method_name_constraints(void) { return &x509v3_ext_name_constraints; } static const ASN1_TEMPLATE GENERAL_SUBTREE_seq_tt[] = { { .flags = 0, .tag = 0, .offset = offsetof(GENERAL_SUBTREE, base), .field_name = "base", .item = &GENERAL_NAME_it, }, { .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL, .tag = 0, .offset = offsetof(GENERAL_SUBTREE, minimum), .field_name = "minimum", .item = &ASN1_INTEGER_it, }, { .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL, .tag = 1, .offset = offsetof(GENERAL_SUBTREE, maximum), .field_name = "maximum", .item = &ASN1_INTEGER_it, }, }; const ASN1_ITEM GENERAL_SUBTREE_it = { .itype = ASN1_ITYPE_SEQUENCE, .utype = V_ASN1_SEQUENCE, .templates = GENERAL_SUBTREE_seq_tt, .tcount = sizeof(GENERAL_SUBTREE_seq_tt) / sizeof(ASN1_TEMPLATE), .funcs = NULL, .size = sizeof(GENERAL_SUBTREE), .sname = "GENERAL_SUBTREE", }; LCRYPTO_ALIAS(GENERAL_SUBTREE_it); static const ASN1_TEMPLATE NAME_CONSTRAINTS_seq_tt[] = { { .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL, .tag = 0, .offset = offsetof(NAME_CONSTRAINTS, permittedSubtrees), .field_name = "permittedSubtrees", .item = &GENERAL_SUBTREE_it, }, { .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL, .tag = 1, .offset = offsetof(NAME_CONSTRAINTS, excludedSubtrees), .field_name = "excludedSubtrees", .item = &GENERAL_SUBTREE_it, }, }; const ASN1_ITEM NAME_CONSTRAINTS_it = { .itype = ASN1_ITYPE_SEQUENCE, .utype = V_ASN1_SEQUENCE, .templates = NAME_CONSTRAINTS_seq_tt, .tcount = sizeof(NAME_CONSTRAINTS_seq_tt) / sizeof(ASN1_TEMPLATE), .funcs = NULL, .size = sizeof(NAME_CONSTRAINTS), .sname = "NAME_CONSTRAINTS", }; LCRYPTO_ALIAS(NAME_CONSTRAINTS_it); GENERAL_SUBTREE * GENERAL_SUBTREE_new(void) { return (GENERAL_SUBTREE*)ASN1_item_new(&GENERAL_SUBTREE_it); } LCRYPTO_ALIAS(GENERAL_SUBTREE_new); void GENERAL_SUBTREE_free(GENERAL_SUBTREE *a) { ASN1_item_free((ASN1_VALUE *)a, &GENERAL_SUBTREE_it); } LCRYPTO_ALIAS(GENERAL_SUBTREE_free); NAME_CONSTRAINTS * NAME_CONSTRAINTS_new(void) { return (NAME_CONSTRAINTS*)ASN1_item_new(&NAME_CONSTRAINTS_it); } LCRYPTO_ALIAS(NAME_CONSTRAINTS_new); void NAME_CONSTRAINTS_free(NAME_CONSTRAINTS *a) { ASN1_item_free((ASN1_VALUE *)a, &NAME_CONSTRAINTS_it); } LCRYPTO_ALIAS(NAME_CONSTRAINTS_free); static void * v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval) { int i; CONF_VALUE tval, *val; STACK_OF(GENERAL_SUBTREE) **ptree = NULL; NAME_CONSTRAINTS *ncons = NULL; GENERAL_SUBTREE *sub = NULL; ncons = NAME_CONSTRAINTS_new(); if (!ncons) goto memerr; for (i = 0; i < sk_CONF_VALUE_num(nval); i++) { val = sk_CONF_VALUE_value(nval, i); if (!strncmp(val->name, "permitted", 9) && val->name[9]) { ptree = &ncons->permittedSubtrees; tval.name = val->name + 10; } else if (!strncmp(val->name, "excluded", 8) && val->name[8]) { ptree = &ncons->excludedSubtrees; tval.name = val->name + 9; } else { X509V3error(X509V3_R_INVALID_SYNTAX); goto err; } tval.value = val->value; sub = GENERAL_SUBTREE_new(); if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1)) goto err; if (!*ptree) *ptree = sk_GENERAL_SUBTREE_new_null(); if (!*ptree || !sk_GENERAL_SUBTREE_push(*ptree, sub)) goto memerr; sub = NULL; } return ncons; memerr: X509V3error(ERR_R_MALLOC_FAILURE); err: NAME_CONSTRAINTS_free(ncons); GENERAL_SUBTREE_free(sub); return NULL; } static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, BIO *bp, int ind) { NAME_CONSTRAINTS *ncons = a; do_i2r_name_constraints(method, ncons->permittedSubtrees, bp, ind, "Permitted"); do_i2r_name_constraints(method, ncons->excludedSubtrees, bp, ind, "Excluded"); return 1; } static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method, STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name) { GENERAL_SUBTREE *tree; int i; if (sk_GENERAL_SUBTREE_num(trees) > 0) BIO_printf(bp, "%*s%s:\n", ind, "", name); for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) { tree = sk_GENERAL_SUBTREE_value(trees, i); BIO_printf(bp, "%*s", ind + 2, ""); if (tree->base->type == GEN_IPADD) print_nc_ipadd(bp, tree->base->d.ip); else GENERAL_NAME_print(bp, tree->base); BIO_puts(bp, "\n"); } return 1; } static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip) { int i, len; unsigned char *p; p = ip->data; len = ip->length; BIO_puts(bp, "IP:"); if (len == 8) { BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]); } else if (len == 32) { for (i = 0; i < 16; i++) { BIO_printf(bp, "%X", p[0] << 8 | p[1]); p += 2; if (i == 7) BIO_puts(bp, "/"); else if (i != 15) BIO_puts(bp, ":"); } } else BIO_printf(bp, "IP Address:"); return 1; } /* Check a certificate conforms to a specified set of constraints. * Return values: * X509_V_OK: All constraints obeyed. * X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation. * X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation. * X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type. * X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type. * X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad unsupported constraint syntax. * X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: bad or unsupported syntax of name */ int NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc) { int r, i; X509_NAME *nm; nm = X509_get_subject_name(x); if (X509_NAME_entry_count(nm) > 0) { GENERAL_NAME gntmp; gntmp.type = GEN_DIRNAME; gntmp.d.directoryName = nm; r = nc_match(&gntmp, nc); if (r != X509_V_OK) return r; gntmp.type = GEN_EMAIL; /* Process any email address attributes in subject name */ for (i = -1;;) { X509_NAME_ENTRY *ne; i = X509_NAME_get_index_by_NID(nm, NID_pkcs9_emailAddress, i); if (i == -1) break; ne = X509_NAME_get_entry(nm, i); gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne); if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING) return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; r = nc_match(&gntmp, nc); if (r != X509_V_OK) return r; } } for (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) { GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i); r = nc_match(gen, nc); if (r != X509_V_OK) return r; } return X509_V_OK; } LCRYPTO_ALIAS(NAME_CONSTRAINTS_check); static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc) { GENERAL_SUBTREE *sub; int i, r, match = 0; /* Permitted subtrees: if any subtrees exist of matching the type * at least one subtree must match. */ for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) { sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i); if (gen->type != sub->base->type) continue; if (sub->minimum || sub->maximum) return X509_V_ERR_SUBTREE_MINMAX; /* If we already have a match don't bother trying any more */ if (match == 2) continue; if (match == 0) match = 1; r = nc_match_single(gen, sub->base); if (r == X509_V_OK) match = 2; else if (r != X509_V_ERR_PERMITTED_VIOLATION) return r; } if (match == 1) return X509_V_ERR_PERMITTED_VIOLATION; /* Excluded subtrees: must not match any of these */ for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) { sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i); if (gen->type != sub->base->type) continue; if (sub->minimum || sub->maximum) return X509_V_ERR_SUBTREE_MINMAX; r = nc_match_single(gen, sub->base); if (r == X509_V_OK) return X509_V_ERR_EXCLUDED_VIOLATION; else if (r != X509_V_ERR_PERMITTED_VIOLATION) return r; } return X509_V_OK; } static int nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base) { switch (base->type) { case GEN_DIRNAME: return nc_dn(gen->d.directoryName, base->d.directoryName); case GEN_DNS: return nc_dns(gen->d.dNSName, base->d.dNSName); case GEN_EMAIL: return nc_email(gen->d.rfc822Name, base->d.rfc822Name); case GEN_URI: return nc_uri(gen->d.uniformResourceIdentifier, base->d.uniformResourceIdentifier); default: return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE; } } /* directoryName name constraint matching. * The canonical encoding of X509_NAME makes this comparison easy. It is * matched if the subtree is a subset of the name. */ static int nc_dn(X509_NAME *nm, X509_NAME *base) { /* Ensure canonical encodings are up to date. */ if (nm->modified && i2d_X509_NAME(nm, NULL) < 0) return X509_V_ERR_OUT_OF_MEM; if (base->modified && i2d_X509_NAME(base, NULL) < 0) return X509_V_ERR_OUT_OF_MEM; if (base->canon_enclen > nm->canon_enclen) return X509_V_ERR_PERMITTED_VIOLATION; if (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen)) return X509_V_ERR_PERMITTED_VIOLATION; return X509_V_OK; } static int nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base) { char *baseptr = (char *)base->data; char *dnsptr = (char *)dns->data; /* Empty matches everything */ if (!*baseptr) return X509_V_OK; /* Otherwise can add zero or more components on the left so * compare RHS and if dns is longer and expect '.' as preceding * character. */ if (dns->length > base->length) { dnsptr += dns->length - base->length; if (baseptr[0] != '.' && dnsptr[-1] != '.') return X509_V_ERR_PERMITTED_VIOLATION; } if (strcasecmp(baseptr, dnsptr)) return X509_V_ERR_PERMITTED_VIOLATION; return X509_V_OK; } static int nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base) { const char *baseptr = (char *)base->data; const char *emlptr = (char *)eml->data; const char *baseat = strchr(baseptr, '@'); const char *emlat = strchr(emlptr, '@'); if (!emlat) return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; /* Special case: initial '.' is RHS match */ if (!baseat && (*baseptr == '.')) { if (eml->length > base->length) { emlptr += eml->length - base->length; if (!strcasecmp(baseptr, emlptr)) return X509_V_OK; } return X509_V_ERR_PERMITTED_VIOLATION; } /* If we have anything before '@' match local part */ if (baseat) { if (baseat != baseptr) { if ((baseat - baseptr) != (emlat - emlptr)) return X509_V_ERR_PERMITTED_VIOLATION; /* Case sensitive match of local part */ if (strncmp(baseptr, emlptr, emlat - emlptr)) return X509_V_ERR_PERMITTED_VIOLATION; } /* Position base after '@' */ baseptr = baseat + 1; } emlptr = emlat + 1; /* Just have hostname left to match: case insensitive */ if (strcasecmp(baseptr, emlptr)) return X509_V_ERR_PERMITTED_VIOLATION; return X509_V_OK; } static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base) { const char *baseptr = (char *)base->data; const char *hostptr = (char *)uri->data; const char *p = strchr(hostptr, ':'); int hostlen; /* Check for foo:// and skip past it */ if (!p || (p[1] != '/') || (p[2] != '/')) return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; hostptr = p + 3; /* Determine length of hostname part of URI */ /* Look for a port indicator as end of hostname first */ p = strchr(hostptr, ':'); /* Otherwise look for trailing slash */ if (!p) p = strchr(hostptr, '/'); if (!p) hostlen = strlen(hostptr); else hostlen = p - hostptr; if (hostlen == 0) return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; /* Special case: initial '.' is RHS match */ if (*baseptr == '.') { if (hostlen > base->length) { p = hostptr + hostlen - base->length; if (!strncasecmp(p, baseptr, base->length)) return X509_V_OK; } return X509_V_ERR_PERMITTED_VIOLATION; } if ((base->length != (int)hostlen) || strncasecmp(hostptr, baseptr, hostlen)) return X509_V_ERR_PERMITTED_VIOLATION; return X509_V_OK; }