diff options
| -rw-r--r-- | networking/tls.c | 643 |
1 files changed, 643 insertions, 0 deletions
diff --git a/networking/tls.c b/networking/tls.c new file mode 100644 index 000000000..983ed507d --- /dev/null +++ b/networking/tls.c @@ -0,0 +1,643 @@ +/* + * Licensed under GPLv2, see file LICENSE in this source tree. + * + * Copyright (C) 2017 Denys Vlasenko + */ +//config:config TLS +//config: bool "tls (debugging)" +//config: default n + +//applet:IF_TLS(APPLET(tls, BB_DIR_USR_BIN, BB_SUID_DROP)) + +//kbuild:lib-$(CONFIG_TLS) += tls.o +////kbuild:lib-$(CONFIG_TLS) += tls_ciphers.o +////kbuild:lib-$(CONFIG_TLS) += tls_aes.o +////kbuild:lib-$(CONFIG_TLS) += tls_aes_gcm.o + +//usage:#define tls_trivial_usage +//usage: "HOST[:PORT]" +//usage:#define tls_full_usage "\n\n" + +#include "libbb.h" +//#include "tls_cryptoapi.h" +//#include "tls_ciphers.h" + +#if 1 +# define dbg(...) fprintf(stderr, __VA_ARGS__) +#else +# define dbg(...) ((void)0) +#endif + +#define RECORD_TYPE_CHANGE_CIPHER_SPEC 20 +#define RECORD_TYPE_ALERT 21 +#define RECORD_TYPE_HANDSHAKE 22 +#define RECORD_TYPE_APPLICATION_DATA 23 + +#define HANDSHAKE_HELLO_REQUEST 0 +#define HANDSHAKE_CLIENT_HELLO 1 +#define HANDSHAKE_SERVER_HELLO 2 +#define HANDSHAKE_HELLO_VERIFY_REQUEST 3 +#define HANDSHAKE_NEW_SESSION_TICKET 4 +#define HANDSHAKE_CERTIFICATE 11 +#define HANDSHAKE_SERVER_KEY_EXCHANGE 12 +#define HANDSHAKE_CERTIFICATE_REQUEST 13 +#define HANDSHAKE_SERVER_HELLO_DONE 14 +#define HANDSHAKE_CERTIFICATE_VERIFY 15 +#define HANDSHAKE_CLIENT_KEY_EXCHANGE 16 +#define HANDSHAKE_FINISHED 20 + +#define SSL_NULL_WITH_NULL_NULL 0x0000 +#define SSL_RSA_WITH_NULL_MD5 0x0001 +#define SSL_RSA_WITH_NULL_SHA 0x0002 +#define SSL_RSA_WITH_RC4_128_MD5 0x0004 +#define SSL_RSA_WITH_RC4_128_SHA 0x0005 +#define SSL_RSA_WITH_3DES_EDE_CBC_SHA 0x000A /* 10 */ +#define TLS_RSA_WITH_AES_128_CBC_SHA 0x002F /* 47 */ +#define TLS_RSA_WITH_AES_256_CBC_SHA 0x0035 /* 53 */ +#define TLS_EMPTY_RENEGOTIATION_INFO_SCSV 0x00FF + +#define TLS_RSA_WITH_IDEA_CBC_SHA 0x0007 /* 7 */ +#define SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA 0x0016 /* 22 */ +#define SSL_DH_anon_WITH_RC4_128_MD5 0x0018 /* 24 */ +#define SSL_DH_anon_WITH_3DES_EDE_CBC_SHA 0x001B /* 27 */ +#define TLS_DHE_RSA_WITH_AES_128_CBC_SHA 0x0033 /* 51 */ +#define TLS_DHE_RSA_WITH_AES_256_CBC_SHA 0x0039 /* 57 */ +#define TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 0x0067 /* 103 */ +#define TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 0x006B /* 107 */ +#define TLS_DH_anon_WITH_AES_128_CBC_SHA 0x0034 /* 52 */ +#define TLS_DH_anon_WITH_AES_256_CBC_SHA 0x003A /* 58 */ +#define TLS_RSA_WITH_AES_128_CBC_SHA256 0x003C /* 60 */ +#define TLS_RSA_WITH_AES_256_CBC_SHA256 0x003D /* 61 */ +#define TLS_RSA_WITH_SEED_CBC_SHA 0x0096 /* 150 */ +#define TLS_PSK_WITH_AES_128_CBC_SHA 0x008C /* 140 */ +#define TLS_PSK_WITH_AES_128_CBC_SHA256 0x00AE /* 174 */ +#define TLS_PSK_WITH_AES_256_CBC_SHA384 0x00AF /* 175 */ +#define TLS_PSK_WITH_AES_256_CBC_SHA 0x008D /* 141 */ +#define TLS_DHE_PSK_WITH_AES_128_CBC_SHA 0x0090 /* 144 */ +#define TLS_DHE_PSK_WITH_AES_256_CBC_SHA 0x0091 /* 145 */ +#define TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA 0xC004 /* 49156 */ +#define TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA 0xC005 /* 49157 */ +#define TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA 0xC009 /* 49161 */ +#define TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA 0xC00A /* 49162 */ +#define TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA 0xC012 /* 49170 */ +#define TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 0xC013 /* 49171 */ +#define TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 0xC014 /* 49172 */ +#define TLS_ECDH_RSA_WITH_AES_128_CBC_SHA 0xC00E /* 49166 */ +#define TLS_ECDH_RSA_WITH_AES_256_CBC_SHA 0xC00F /* 49167 */ +#define TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 0xC023 /* 49187 */ +#define TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 0xC024 /* 49188 */ +#define TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256 0xC025 /* 49189 */ +#define TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384 0xC026 /* 49190 */ +#define TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 0xC027 /* 49191 */ +#define TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 0xC028 /* 49192 */ +#define TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256 0xC029 /* 49193 */ +#define TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384 0xC02A /* 49194 */ + +#define TLS_RSA_WITH_AES_128_GCM_SHA256 0x009C /* 156 */ +#define TLS_RSA_WITH_AES_256_GCM_SHA384 0x009D /* 157 */ +#define TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 0xC02B /* 49195 */ +#define TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 0xC02C /* 49196 */ +#define TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256 0xC02D /* 49197 */ +#define TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384 0xC02E /* 49198 */ +#define TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 0xC02F /* 49199 */ +#define TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 0xC030 /* 49200 */ +#define TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256 0xC031 /* 49201 */ +#define TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384 0xC032 /* 49202 */ + +//Tested against kernel.org: +//TLS 1.1 +//#define TLS_MAJ 3 +//#define TLS_MIN 2 +//#define CIPHER_ID TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA // ok, recvs SERVER_KEY_EXCHANGE +//TLS 1.2 +#define TLS_MAJ 3 +#define TLS_MIN 3 +//#define CIPHER_ID TLS_RSA_WITH_AES_256_CBC_SHA256 // ok, no SERVER_KEY_EXCHANGE +// All GCMs: +//#define CIPHER_ID TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 // SSL_ALERT_HANDSHAKE_FAILURE +//#define CIPHER_ID TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 // SSL_ALERT_HANDSHAKE_FAILURE +//#define CIPHER_ID TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 // ok, recvs SERVER_KEY_EXCHANGE +//#define CIPHER_ID TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 +//#define CIPHER_ID TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384 +//#define CIPHER_ID TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256 // SSL_ALERT_HANDSHAKE_FAILURE +//#define CIPHER_ID TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384 +//#define CIPHER_ID TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256 // SSL_ALERT_HANDSHAKE_FAILURE +//#define CIPHER_ID TLS_RSA_WITH_AES_256_GCM_SHA384 // ok, no SERVER_KEY_EXCHANGE +#define CIPHER_ID TLS_RSA_WITH_AES_128_GCM_SHA256 // ok, no SERVER_KEY_EXCHANGE +//#define CIPHER_ID TLS_DH_anon_WITH_AES_256_CBC_SHA // SSL_ALERT_HANDSHAKE_FAILURE +// (tested b/c this one doesn't req server certs... no luck) +//test TLS_RSA_WITH_AES_128_CBC_SHA, in tls 1.2 it's mandated to be always supported + +struct transport_hdr { + uint8_t type; + uint8_t proto_maj, proto_min; + uint8_t len16_hi, len16_lo; +}; + +typedef struct tls_state { + int fd; + + uint8_t *pubkey; + int pubkey_len; + + int insize; + int tail; + // RFC 5246 + // |6.2.1. Fragmentation + // | The record layer fragments information blocks into TLSPlaintext + // | records carrying data in chunks of 2^14 bytes or less. Client + // | message boundaries are not preserved in the record layer (i.e., + // | multiple client messages of the same ContentType MAY be coalesced + // | into a single TLSPlaintext record, or a single message MAY be + // | fragmented across several records) + // |... + // | length + // | The length (in bytes) of the following TLSPlaintext.fragment. + // | The length MUST NOT exceed 2^14. + // |... + // | 6.2.2. Record Compression and Decompression + // |... + // | Compression must be lossless and may not increase the content length + // | by more than 1024 bytes. If the decompression function encounters a + // | TLSCompressed.fragment that would decompress to a length in excess of + // | 2^14 bytes, it MUST report a fatal decompression failure error. + // |... + // | length + // | The length (in bytes) of the following TLSCompressed.fragment. + // | The length MUST NOT exceed 2^14 + 1024. + // + // Since our buffer also contains 5-byte headers, make it a bit bigger: + uint8_t inbuf[18*1024]; +} tls_state_t; + +static +tls_state_t *new_tls_state(void) +{ + tls_state_t *tls = xzalloc(sizeof(*tls)); + tls->fd = -1; + return tls; +} + +static unsigned get24be(const uint8_t *p) +{ + return 0x100*(0x100*p[0] + p[1]) + p[2]; +} + +static void dump(const void *vp, int len) +{ + char hexbuf[32 * 1024 + 4]; + const uint8_t *p = vp; + + while (len > 0) { + unsigned xhdr_len; + if (len < 5) { + bin2hex(hexbuf, (void*)p, len)[0] = '\0'; + dbg("< |%s|\n", hexbuf); + return; + } + xhdr_len = 0x100*p[3] + p[4]; + dbg("< hdr_type:%u ver:%u.%u len:%u", p[0], p[1], p[2], xhdr_len); + p += 5; + len -= 5; + if (len >= 4 && p[-5] == RECORD_TYPE_HANDSHAKE) { + unsigned len24 = get24be(p + 1); + dbg(" type:%u len24:%u", p[0], len24); + } + if (xhdr_len > len) + xhdr_len = len; + bin2hex(hexbuf, (void*)p, xhdr_len)[0] = '\0'; + dbg(" |%s|\n", hexbuf); + p += xhdr_len; + len -= xhdr_len; + } +} + +static void tls_error_die(tls_state_t *tls) +{ + dump(tls->inbuf, tls->insize + tls->tail); + xfunc_die(); +} + +static int xread_tls_block(tls_state_t *tls) +{ + int len; + int total; + int target; + + dbg("insize:%u tail:%u\n", tls->insize, tls->tail); + memmove(tls->inbuf, tls->inbuf + tls->insize, tls->tail); + errno = 0; + total = tls->tail; + target = sizeof(tls->inbuf); + for (;;) { + if (total >= sizeof(struct transport_hdr) && target == sizeof(tls->inbuf)) { + struct transport_hdr *xhdr = (void*)tls->inbuf; + target = sizeof(*xhdr) + (0x100 * xhdr->len16_hi + xhdr->len16_lo); + } + /* if total >= target, we have a full packet (and possibly more)... */ + if (target - total <= 0) + break; + len = safe_read(tls->fd, tls->inbuf + total, sizeof(tls->inbuf) - total); + if (len <= 0) + bb_perror_msg_and_die("short read"); + total += len; + } + tls->tail = -(target - total); + tls->insize = target; + target -= sizeof(struct transport_hdr); + dbg("got block len:%u\n", target); + return target; +} + +static void send_client_hello(tls_state_t *tls) +{ + struct client_hello { + struct transport_hdr xhdr; + uint8_t type; + uint8_t len24_hi, len24_mid, len24_lo; + uint8_t proto_maj, proto_min; + uint8_t rand32[32]; + uint8_t session_id_len; + /* uint8_t session_id[]; */ + uint8_t cipherid_len16_hi, cipherid_len16_lo; + uint8_t cipherid[2 * 1]; /* actually variable */ + uint8_t comprtypes_len; + uint8_t comprtypes[1]; /* actually variable */ + }; + struct client_hello hello; + + memset(&hello, 0, sizeof(hello)); + hello.xhdr.type = RECORD_TYPE_HANDSHAKE; + hello.xhdr.proto_maj = TLS_MAJ; + hello.xhdr.proto_min = TLS_MIN; + hello.xhdr.len16_hi = (sizeof(hello) - sizeof(hello.xhdr)) >> 8; + hello.xhdr.len16_lo = (sizeof(hello) - sizeof(hello.xhdr)); + hello.type = HANDSHAKE_CLIENT_HELLO; + hello.len24_mid = (sizeof(hello) - sizeof(hello.xhdr) - 4) >> 8; + hello.len24_lo = (sizeof(hello) - sizeof(hello.xhdr) - 4); + hello.proto_maj = TLS_MAJ; + hello.proto_min = TLS_MIN; + //fillrand(hello.rand32, sizeof(hello.rand32)); + open_read_close("/dev/urandom", hello.rand32, sizeof(hello.rand32)); + //hello.session_id_len = 0; + //hello.cipherid_len16_hi = 0; + hello.cipherid_len16_lo = 2; + hello.cipherid[0] = CIPHER_ID >> 8; + hello.cipherid[1] = CIPHER_ID & 0xff; + hello.comprtypes_len = 1; + //hello.comprtypes[0] = 0; + + xwrite(tls->fd, &hello, sizeof(hello)); +} + +static void get_server_hello_or_die(tls_state_t *tls) +{ + struct server_hello { + struct transport_hdr xhdr; + uint8_t type; + uint8_t len24_hi, len24_mid, len24_lo; + uint8_t proto_maj, proto_min; + uint8_t rand32[32]; /* first 4 bytes are unix time in BE format */ + uint8_t session_id_len; + uint8_t session_id[32]; + uint8_t cipherid_hi, cipherid_lo; + uint8_t comprtype; + /* extensions may follow, but only those which client offered in its Hello */ + }; + struct server_hello *hp; + int len; + + len = xread_tls_block(tls); + + hp = (void*)tls->inbuf; + if (len != 74 /* TODO: if we accept extensions, should be < instead of != */ + || hp->xhdr.type != RECORD_TYPE_HANDSHAKE + || hp->xhdr.proto_maj != TLS_MAJ + || hp->xhdr.proto_min != TLS_MIN + ) { + /* example: RECORD_TYPE_ALERT if server can't support our ciphers */ + tls_error_die(tls); + } + dbg("got HANDSHAKE\n"); + // 02 000046 03|03 58|78|cf|c1 50|a5|49|ee|7e|29|48|71|fe|97|fa|e8|2d|19|87|72|90|84|9d|37|a3|f0|cb|6f|5f|e3|3c|2f |20 |d8|1a|78|96|52|d6|91|01|24|b3|d6|5b|b7|d0|6c|b3|e1|78|4e|3c|95|de|74|a0|ba|eb|a7|3a|ff|bd|a2|bf |00|9c |00| + // SvHl len=70 maj.min unixtime^^^ 28randbytes^^^^^^^^^^^^^^^^^^^^^^^^^^^^_^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^_^^^ slen sid32bytes^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cipSel comprSel + if (hp->type != HANDSHAKE_SERVER_HELLO + || hp->len24_hi != 0 + || hp->len24_mid != 0 + || hp->len24_lo != 70 + || hp->proto_maj != TLS_MAJ + || hp->proto_min != TLS_MIN + || hp->session_id_len != 32 + || hp->cipherid_hi != (CIPHER_ID >> 8) + || hp->cipherid_lo != (CIPHER_ID & 0xff) + || hp->comprtype != 0 + ) { + tls_error_die(tls); + } + dbg("got SERVER_HELLO\n"); +} + +static unsigned get_der_len(uint8_t **bodyp, uint8_t *der, uint8_t *end) +{ + unsigned len; + + if (end - der < 2) + xfunc_die(); +// if ((der[0] & 0x1f) == 0x1f) /* not single-byte item code? */ +// xfunc_die(); + + len = der[1]; /* maybe it's short len */ + if (len >= 0x80) { + /* no */ + if (len != 0x82) { + /* 0x80 is "0 bytes of len", invalid DER: must use short len if can */ + /* 0x81 is "1 byte of len", invalid DER */ + /* >0x82 is "3+ bytes of len", should not happen realistically */ + xfunc_die(); + } + if (end - der < 4) + xfunc_die(); + /* it's "ii 82 xx yy" */ + len = 0x100*der[2] + der[3]; + if (len < 0x80) + xfunc_die(); /* invalid DER: must use short len if can */ + + der += 2; /* skip [code]+[82]+[2byte_len] */ + } + der += 2; /* skip [code]+[1byte_len] */ + + if (end - der < len) + xfunc_die(); + *bodyp = der; + + return len; +} + +static uint8_t *enter_der_item(uint8_t *der, uint8_t **endp) +{ + uint8_t *new_der; + unsigned len = get_der_len(&new_der, der, *endp); + dbg("entered der @%p:0x%02x len:%u inner_byte @%p:0x%02x\n", der, der[0], len, new_der, new_der[0]); + /* Move "end" position to cover only this item */ + *endp = new_der + len; + return new_der; +} + +static uint8_t *skip_der_item(uint8_t *der, uint8_t *end) +{ + uint8_t *new_der; + unsigned len = get_der_len(&new_der, der, end); + /* Skip body */ + new_der += len; + dbg("skipped der 0x%02x, next byte 0x%02x\n", der[0], new_der[0]); + return new_der; +} + +static void *find_key_in_der_cert(int *key_len, uint8_t *der, int len) +{ +/* Example: partial decode of kernel.org certificate in DER format. + * SEQ 0x05ac/1452 bytes (Certificate): 308205ac + * SEQ 0x0494/1172 bytes (tbsCertificate): 30820494 + * [ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | 0] 3 bytes: a003 + * INTEGER (version): 0201 02 + * INTEGER 0x11 bytes (serialNumber): 0211 00 9f85bf664b0cddafca508679501b2be4 + * //^^^^^^note: matrixSSL also allows [ASN_CONTEXT_SPECIFIC | ASN_PRIMITIVE | 2] = 0x82 type + * SEQ 0x0d bytes (signatureAlgo): 300d + * OID 9 bytes: 0609 2a864886f70d01010b (OID_SHA256_RSA_SIG 42.134.72.134.247.13.1.1.11) + * NULL: 0500 + * SEQ 0x5f bytes (issuer): 305f + * SET 11 bytes: 310b + * SEQ 9 bytes: 3009 + * OID 3 bytes: 0603 550406 + * Printable string "FR": 1302 4652 + * SET 14 bytes: 310e + * SEQ 12 bytes: 300c + * OID 3 bytes: 0603 550408 + * Printable string "Paris": 1305 5061726973 + * SET 14 bytes: 310e + * SEQ 12 bytes: 300c + * OID 3 bytes: 0603 550407 + * Printable string "Paris": 1305 5061726973 + * SET 14 bytes: 310e + * SEQ 12 bytes: 300c + * OID 3 bytes: 0603 55040a + * Printable string "Gandi": 1305 47616e6469 + * SET 32 bytes: 3120 + * SEQ 30 bytes: 301e + * OID 3 bytes: 0603 550403 + * Printable string "Gandi Standard SSL CA 2": 1317 + * 47616e6469205374616e646172642053534c2043412032 + * SEQ 30 bytes (validity): 301e + * TIME "161011000000Z": 170d 3136313031313030303030305a + * TIME "191011235959Z": 170d 3139313031313233353935395a + * SEQ 0x5b/91 bytes (subject): 305b //I did not decode this + * 3121301f060355040b1318446f6d61696e20436f + * 6e74726f6c2056616c6964617465643121301f06 + * 0355040b1318506f73697469766553534c204d75 + * 6c74692d446f6d61696e31133011060355040313 + * 0a6b65726e656c2e6f7267 + * SEQ 0x01a2/418 bytes (subjectPublicKeyInfo): 308201a2 + * SEQ 13 bytes (algorithm): 300d + * OID 9 bytes: 0609 2a864886f70d010101 (OID_RSA_KEY_ALG 42.134.72.134.247.13.1.1.1) + * NULL: 0500 + * BITSTRING 0x018f/399 bytes (publicKey): 0382018f + * ????: 00 + * //after the zero byte, it appears key itself uses DER encoding: + * SEQ 0x018a/394 bytes: 3082018a + * INTEGER 0x0181/385 bytes (modulus): 02820181 + * 00b1ab2fc727a3bef76780c9349bf3 + * ...24 more blocks of 15 bytes each... + * 90e895291c6bc8693b65 + * INTEGER 3 bytes (exponent): 0203 010001 + * [ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | 0x3] 0x01e5 bytes (X509v3 extensions): a38201e5 + * SEQ 0x01e1 bytes: 308201e1 + * ... + * Certificate is a DER-encoded data structure. Each DER element has a length, + * which makes it easy to skip over large compound elements of any complexity + * without parsing them. + * + * Certificate is a sequence of three elements: + * tbsCertificate (SEQ) + * signatureAlgorithm (AlgorithmIdentifier) + * signatureValue (BIT STRING) + * + * In turn, tbsCertificate is a sequence of: + * version + * serialNumber + * signatureAlgo (AlgorithmIdentifier) + * issuer (Name, has complex structure) + * validity (Validity, SEQ of two Times) + * subject (Name) + * subjectPublicKeyInfo (SEQ) + * ... + * + * subjectPublicKeyInfo is a sequence of: + * algorithm (AlgorithmIdentifier) + * publicKey (BIT STRING) + * + * Essentially, we want subjectPublicKeyInfo.publicKey + */ + uint8_t *end = der + len; + + /* enter "Certificate" item: [der, end) will be only Cert */ + der = enter_der_item(der, &end); + + /* enter "tbsCertificate" item: [der, end) will be only tbsCert */ + der = enter_der_item(der, &end); + + /* skip up to subjectPublicKeyInfo */ + der = skip_der_item(der, end); /* version */ + der = skip_der_item(der, end); /* serialNumber */ + der = skip_der_item(der, end); /* signatureAlgo */ + der = skip_der_item(der, end); /* issuer */ + der = skip_der_item(der, end); /* validity */ + der = skip_der_item(der, end); /* subject */ + + /* enter "subjectPublicKeyInfo" */ + der = enter_der_item(der, &end); + + /* skip "subjectPublicKeyInfo.algorithm" */ + der = skip_der_item(der, end); + /* enter "subjectPublicKeyInfo.publicKey" */ +// die_if_not_this_der_type(der, end, 0x03); /* must be BITSTRING */ + der = enter_der_item(der, &end); + + /* return a copy */ + *key_len = end - der; + dbg("copying key bytes:%u, first:0x%02x\n", *key_len, der[0]); + return xmemdup(der, *key_len); +} + +static void get_server_cert_or_die(tls_state_t *tls) +{ + struct transport_hdr *xhdr; + uint8_t *certbuf; + int len, len1; + + len = xread_tls_block(tls); + xhdr = (void*)tls->inbuf; + if (len < sizeof(*xhdr) + 10 + || xhdr->type != RECORD_TYPE_HANDSHAKE + || xhdr->proto_maj != TLS_MAJ + || xhdr->proto_min != TLS_MIN + ) { + tls_error_die(tls); + } + dbg("got HANDSHAKE\n"); + certbuf = (void*)(xhdr + 1); + if (certbuf[0] != HANDSHAKE_CERTIFICATE) + tls_error_die(tls); + dbg("got CERTIFICATE\n"); + // 0b 00|11|24 00|11|21 00|05|b0 30|82|05|ac|30|82|04|94|a0|03|02|01|02|02|11|00|9f|85|bf|66|4b|0c|dd|af|ca|50|86|79|50|1b|2b|e4|30|0d... (4392 bytes) + // Cert len=4388 ChainLen CertLen^ DER encoded X509 starts here. openssl x509 -in FILE -inform DER -noout -text + len1 = get24be(certbuf + 1); + if (len1 > len - 4) tls_error_die(tls); + len = len1; + + len1 = get24be(certbuf + 4); + if (len1 > len - 3) tls_error_die(tls); + len = len1; + + len1 = get24be(certbuf + 7); + if (len1 > len - 3) tls_error_die(tls); + len = len1; + + if (len) + tls->pubkey = find_key_in_der_cert(&tls->pubkey_len, certbuf + 10, len); +} + +static void tls_handshake(tls_state_t *tls) +{ + // Client RFC 5246 Server + // (*) - optional messages, not always sent + // + // ClientHello -------> + // ServerHello + // Certificate* + // ServerKeyExchange* + // CertificateRequest* + // <------- ServerHelloDone + // Certificate* + // ClientKeyExchange + // CertificateVerify* + // [ChangeCipherSpec] + // Finished -------> + // [ChangeCipherSpec] + // <------- Finished + // Application Data <------> Application Data + int len; + + send_client_hello(tls); +#if 0 /* dump */ + for (;;) { + uint8_t buf[16*1024]; + sleep(2); + len = recv(tls->fd, buf, sizeof(buf), 0); //MSG_DONTWAIT); + if (len < 0) { + if (errno == EAGAIN) + continue; + bb_perror_msg_and_die("recv"); + } + if (len == 0) + break; + dump(buf, len); + } +#endif + + get_server_hello_or_die(tls); + + //RFC 5246 + // The server MUST send a Certificate message whenever the agreed- + // upon key exchange method uses certificates for authentication + // (this includes all key exchange methods defined in this document + // except DH_anon). This message will always immediately follow the + // ServerHello message. + // + // IOW: in practice, Certificate *always* follows. + // (for example, kernel.org does not even accept DH_anon cipher id) + get_server_cert_or_die(tls); + + len = xread_tls_block(tls); + /* Next handshake type is not predetermined */ + switch (tls->inbuf[5]) { + case HANDSHAKE_SERVER_KEY_EXCHANGE: + //0c 0001c7 03|00|17|41|04|87|94|2e|2f|68|d0|c9|f4|97|a8|2d|ef|ed|67|ea|c6|f3|b3|56|47|5d|27|b6|bd|ee|70|25|30|5e|b0|8e|f6|21|5a... 459 bytes + //SvKey len^^^ + dbg("got SERVER_KEY_EXCHANGE\n"); + len = xread_tls_block(tls); + break; + case HANDSHAKE_CERTIFICATE_REQUEST: + dbg("got CERTIFICATE_REQUEST\n"); + len = xread_tls_block(tls); + break; + case HANDSHAKE_SERVER_HELLO_DONE: + // 0e 000000 (len:0) + dbg("got SERVER_HELLO_DONE\n"); + break; + default: + tls_error_die(tls); + } +} + +int tls_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int tls_main(int argc UNUSED_PARAM, char **argv) +{ + tls_state_t *tls; + len_and_sockaddr *lsa; + int fd; + + // INIT_G(); + // getopt32(argv, "myopts") + + if (!argv[1]) + bb_show_usage(); + + lsa = xhost2sockaddr(argv[1], 443); + fd = xconnect_stream(lsa); + + tls = new_tls_state(); + tls->fd = fd; + tls_handshake(tls); + + return EXIT_SUCCESS; +} |