/*************************************************************************** * nse_ssl_cert.cc -- NSE userdatum representing an SSL certificate. * * * ***********************IMPORTANT NMAP LICENSE TERMS************************ * * * The Nmap Security Scanner is (C) 1996-2012 Insecure.Com LLC. Nmap is * * also a registered trademark of Insecure.Com LLC. This program is free * * software; you may redistribute and/or modify it under the terms of the * * GNU General Public License as published by the Free Software * * Foundation; Version 2 with the clarifications and exceptions described * * below. This guarantees your right to use, modify, and redistribute * * this software under certain conditions. If you wish to embed Nmap * * technology into proprietary software, we sell alternative licenses * * (contact sales@insecure.com). Dozens of software vendors already * * license Nmap technology such as host discovery, port scanning, OS * * detection, version detection, and the Nmap Scripting Engine. * * * * Note that the GPL places important restrictions on "derived works", yet * * it does not provide a detailed definition of that term. To avoid * * misunderstandings, we interpret that term as broadly as copyright law * * allows. For example, we consider an application to constitute a * * "derivative work" for the purpose of this license if it does any of the * * following: * * o Integrates source code from Nmap * * o Reads or includes Nmap copyrighted data files, such as * * nmap-os-db or nmap-service-probes. * * o Executes Nmap and parses the results (as opposed to typical shell or * * execution-menu apps, which simply display raw Nmap output and so are * * not derivative works.) * * o Integrates/includes/aggregates Nmap into a proprietary executable * * installer, such as those produced by InstallShield. * * o Links to a library or executes a program that does any of the above * * * * The term "Nmap" should be taken to also include any portions or derived * * works of Nmap, as well as other software we distribute under this * * license such as Zenmap, Ncat, and Nping. This list is not exclusive, * * but is meant to clarify our interpretation of derived works with some * * common examples. Our interpretation applies only to Nmap--we don't * * speak for other people's GPL works. * * * * If you have any questions about the GPL licensing restrictions on using * * Nmap in non-GPL works, we would be happy to help. As mentioned above, * * we also offer alternative license to integrate Nmap into proprietary * * applications and appliances. These contracts have been sold to dozens * * of software vendors, and generally include a perpetual license as well * * as providing for priority support and updates. They also fund the * * continued development of Nmap. Please email sales@insecure.com for * * further information. * * * * As a special exception to the GPL terms, Insecure.Com LLC grants * * permission to link the code of this program with any version of the * * OpenSSL library which is distributed under a license identical to that * * listed in the included docs/licenses/OpenSSL.txt file, and distribute * * linked combinations including the two. 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By sending these changes to Fyodor or one of the * * Insecure.Org development mailing lists, or checking them into the Nmap * * source code repository, it is understood (unless you specify otherwise) * * that you are offering the Nmap Project (Insecure.Com LLC) the * * unlimited, non-exclusive right to reuse, modify, and relicense the * * code. Nmap will always be available Open Source, but this is important * * because the inability to relicense code has caused devastating problems * * for other Free Software projects (such as KDE and NASM). We also * * occasionally relicense the code to third parties as discussed above. * * If you wish to specify special license conditions of your * * contributions, just say so when you send them. * * * * This program is distributed in the hope that it will be useful, but * * WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Nmap * * license file for more details (it's in a COPYING file included with * * Nmap, and also available from https://svn.nmap.org/nmap/COPYING * * * ***************************************************************************/ /* $Id:$ */ #include "nbase.h" #include #include #include #include #include #include #include #include extern "C" { #include "lua.h" #include "lauxlib.h" } #include "nse_nsock.h" struct cert_userdata { X509 *cert; int attributes_table; }; SSL *nse_nsock_get_ssl(lua_State *L); /* This is a reference to a table that will be used as the metatable for certificate attribute tables. It has an __index entry that points to the global table of certificate functions like digest. */ static int ssl_cert_methods_index_ref = LUA_NOREF; /* Calculate the digest of the certificate using the given algorithm. */ static int ssl_cert_digest(lua_State *L) { struct cert_userdata *udata; const char *algorithm; unsigned char buf[256]; unsigned int n; const EVP_MD *md; udata = (struct cert_userdata *) luaL_checkudata(L, 1, "SSL_CERT"); algorithm = luaL_checkstring(L, 2); md = EVP_get_digestbyname(algorithm); if (md == NULL) return 0; n = sizeof(buf); if (X509_digest(udata->cert, md, buf, &n) != 1) return 0; lua_pushlstring(L, (char *) buf, n); return 1; } /* These are the contents of the table that is pointed to by the table that has ssl_cert_methods_index_ref as a reference. */ static struct luaL_Reg ssl_cert_methods[] = { { "digest", ssl_cert_digest }, { NULL, NULL }, }; /* This is a helper function for x509_name_to_table. It takes the ASN1_OBJECT passed as an argument, turns it into a table key, and pushes it on the stack. The key is a string (like "commonName") if the object has an NID known by OBJ_obj2nid; otherwise it is an array containing the OID components as strings: { "2", "5", "4", "3" }. */ static void obj_to_key(lua_State *L, const ASN1_OBJECT *obj) { int nid; nid = OBJ_obj2nid(obj); if (nid == NID_undef) { size_t size = 1; char *buf = (char *) lua_newuserdata(L, size); const char *p, *q; int i, n; while ((n = OBJ_obj2txt(buf, size, obj, 1)) < 0 || (unsigned) n >= size) { size = size * 2; buf = (char *) lua_newuserdata(L, size); memcpy(lua_touserdata(L, -1), lua_touserdata(L, -2), lua_rawlen(L, -2)); lua_replace(L, -2); } lua_newtable(L); i = 1; p = buf; q = p; while (*q != '\0') { q = strchr(p, '.'); if (q == NULL) q = strchr(p, '\0'); lua_pushlstring(L, p, q - p); lua_rawseti(L, -2, i++); p = q + 1; } lua_replace(L, -2); /* replace userdata with table */ } else { lua_pushstring(L, OBJ_nid2ln(nid)); } } /* This is a helper function for l_get_ssl_certificate. It builds a table from the given X509_NAME, using keys returned from obj_to_key as keys. The result is pushed on the stack. */ static void x509_name_to_table(lua_State *L, X509_NAME *name) { int i; lua_newtable(L); for (i = 0; i < X509_NAME_entry_count(name); i++) { X509_NAME_ENTRY *entry; const ASN1_OBJECT *obj; const ASN1_STRING *value; entry = X509_NAME_get_entry(name, i); obj = X509_NAME_ENTRY_get_object(entry); value = X509_NAME_ENTRY_get_data(entry); obj_to_key(L, obj); lua_pushlstring(L, (const char *) value->data, value->length); lua_settable(L, -3); } } /* Parse as a decimal integer the len characters starting at s. This function can only process positive numbers; if the return value is negative then a parsing error occurred. */ static int parse_int(const unsigned char *s, size_t len) { char buf[32]; char *tail; long v; if (len == 0) return -1; if (!isdigit((int) (unsigned char) s[0])) return -1; if (len > sizeof(buf) - 1) return -1; memcpy(buf, s, len); buf[len] = '\0'; errno = 0; v = strtol(buf, &tail, 10); if (errno != 0 || *tail != '\0') return -1; if ((int) v != v || v < 0) return -1; return (int) v; } /* This is a helper function for asn1_time_to_obj. It parses a textual ASN1_TIME value and stores the time in the given struct tm. It returns 0 on success and -1 on a parse error. */ static int time_to_tm(const ASN1_TIME *t, struct tm *result) { const unsigned char *p; p = t->data; if (t->length == 13 && t->data[t->length - 1] == 'Z') { /* yymmddhhmmssZ */ int year; year = parse_int(t->data, 2); if (year < 0) return -1; /* "In coming up with the worlds least efficient machine-readable time encoding format, the ISO nevertheless decided to forgo the encoding of centuries, a problem which has been kludged around by redefining the time as UTCTime if the date is 2049 or ealier, and GeneralizedTime if the date is 2050 or later." http://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt */ if (year < 50) result->tm_year = 2000 + year; else result->tm_year = 1900 + year; p = t->data + 2; } else if (t->length == 14) { /* yyyymmddhhmmss */ result->tm_year = parse_int(t->data, 4); if (result->tm_year < 0) return -1; p = t->data + 4; } else { return -1; } result->tm_mon = parse_int(p, 2); /* struct tm uses zero-indexed months. */ if (result->tm_mon == 0) return -1; result->tm_mon--; result->tm_mday = parse_int(p + 2, 2); result->tm_hour = parse_int(p + 4, 2); result->tm_min = parse_int(p + 6, 2); result->tm_sec = parse_int(p + 8, 2); if (result->tm_mon < 0 || result->tm_mday < 0 || result->tm_hour < 0 || result->tm_min < 0 || result->tm_sec < 0) { return -1; } return 0; } /* This is a helper function for asn1_time_to_obj. It converts a struct tm into a date table as returned by the Lua date os.date("!*t"), with the exception that the wday and yday fields are not present. */ static void tm_to_table(lua_State *L, const struct tm *tm) { lua_newtable(L); lua_pushnumber(L, tm->tm_year); lua_setfield(L, -2, "year"); /* Lua uses one-indexed months. */ lua_pushnumber(L, tm->tm_mon + 1); lua_setfield(L, -2, "month"); lua_pushnumber(L, tm->tm_mday); lua_setfield(L, -2, "day"); lua_pushnumber(L, tm->tm_hour); lua_setfield(L, -2, "hour"); lua_pushnumber(L, tm->tm_min); lua_setfield(L, -2, "min"); lua_pushnumber(L, tm->tm_sec); lua_setfield(L, -2, "sec"); /* Omit tm_wday and tm_yday. */ } /* This is a helper function for x509_validity_to_table. It takes teh given ASN1_TIME and covnerts it to a value on the stack, which is one of nil, if the time is NULL; a date table, if the date can be parsed; and a string of the raw bytes, if the date cannot be parsed. */ static void asn1_time_to_obj(lua_State *L, const ASN1_TIME *s) { struct tm tm; if (s == NULL) { lua_pushnil(L); } else if (time_to_tm(s, &tm) == 0) { tm_to_table(L, &tm); } else { lua_pushlstring(L, (const char *) s->data, s->length); } } /* This is a helper functino for x509_validity_to_table. It builds a table with the two members "notBefore" and "notAfter", whose values are what is returned from asn1_time_to_obj. */ static void x509_validity_to_table(lua_State *L, const X509 *cert) { lua_newtable(L); asn1_time_to_obj(L, X509_get_notBefore(cert)); lua_setfield(L, -2, "notBefore"); asn1_time_to_obj(L, X509_get_notAfter(cert)); lua_setfield(L, -2, "notAfter"); } /* This is a helper function for l_get_ssl_certificate. It converts the certificate into a PEM-encoded string on the stack. */ static void cert_pem_to_string(lua_State *L, X509 *cert) { BIO *bio; char *buf; long size; bio = BIO_new(BIO_s_mem()); assert(bio != NULL); assert(PEM_write_bio_X509(bio, cert)); size = BIO_get_mem_data(bio, &buf); lua_pushlstring(L, buf, size); BIO_vfree(bio); } /* This is a helper function for l_get_ssl_certificate. It converts the public-key type to a string. */ static const char *pkey_type_to_string(int type) { switch (type) { case EVP_PKEY_RSA: return "rsa"; case EVP_PKEY_DSA: return "dsa"; case EVP_PKEY_DH: return "dh"; #ifdef EVP_PKEY_EC case EVP_PKEY_EC: return "ec"; #endif default: return "unknown"; } } int l_get_ssl_certificate(lua_State *L) { SSL *ssl; struct cert_userdata *udata; X509 *cert; X509_NAME *subject, *issuer; EVP_PKEY *pubkey; ssl = nse_nsock_get_ssl(L); cert = SSL_get_peer_certificate(ssl); if (cert == NULL) { lua_pushnil(L); return 1; } udata = (struct cert_userdata *) lua_newuserdata(L, sizeof(*udata)); udata->cert = cert; lua_newtable(L); subject = X509_get_subject_name(cert); if (subject != NULL) { x509_name_to_table(L, subject); lua_setfield(L, -2, "subject"); } issuer = X509_get_issuer_name(cert); if (issuer != NULL) { x509_name_to_table(L, issuer); lua_setfield(L, -2, "issuer"); } x509_validity_to_table(L, cert); lua_setfield(L, -2, "validity"); cert_pem_to_string(L, cert); lua_setfield(L, -2, "pem"); pubkey = X509_get_pubkey(cert); lua_newtable(L); lua_pushstring(L, pkey_type_to_string(pubkey->type)); lua_setfield(L, -2, "type"); lua_pushnumber(L, EVP_PKEY_bits(pubkey)); lua_setfield(L, -2, "bits"); lua_setfield(L, -2, "pubkey"); EVP_PKEY_free(pubkey); /* At this point the certificate-specific table of attributes is at the top of the stack. We give it a metatable with an __index entry that points into the global shared table of certificate functions. */ lua_rawgeti(L, LUA_REGISTRYINDEX, ssl_cert_methods_index_ref); lua_setmetatable(L, -2); udata->attributes_table = luaL_ref(L, LUA_REGISTRYINDEX); luaL_getmetatable(L, "SSL_CERT"); lua_setmetatable(L, -2); return 1; } static int l_ssl_cert_index(lua_State *L) { struct cert_userdata *udata; udata = (struct cert_userdata *) luaL_checkudata(L, 1, "SSL_CERT"); lua_rawgeti(L, LUA_REGISTRYINDEX, udata->attributes_table); /* The key. */ lua_pushvalue(L, 2); /* Look it up in the table of attributes. */ lua_gettable(L, -2); return 1; } static int l_ssl_cert_gc(lua_State *L) { struct cert_userdata *udata; udata = (struct cert_userdata *) luaL_checkudata(L, 1, "SSL_CERT"); X509_free(udata->cert); luaL_unref(L, LUA_REGISTRYINDEX, udata->attributes_table); return 0; } void nse_nsock_init_ssl_cert(lua_State *L) { luaL_newmetatable(L, "SSL_CERT"); lua_pushcclosure(L, l_ssl_cert_index, 0); lua_setfield(L, -2, "__index"); lua_pushcclosure(L, l_ssl_cert_gc, 0); lua_setfield(L, -2, "__gc"); /* Create a table with an __index entry that will be used as a metatable for per-certificate attribute tables. This gives the tables access to the global shared table of certificate functions. */ lua_newtable(L); lua_newtable(L); luaL_setfuncs(L, ssl_cert_methods, 0); lua_setfield(L, -2, "__index"); ssl_cert_methods_index_ref = luaL_ref(L, LUA_REGISTRYINDEX); }