/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * 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 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 acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS 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 AUTHOR OR 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. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ /* ==================================================================== * Copyright (c) 1998-2002 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 * openssl-core@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 #include #include #include "internal.h" static int do_ssl3_write(SSL *s, int type, const uint8_t *buf, unsigned int len, char fragment); static int ssl3_get_record(SSL *s); int ssl3_read_n(SSL *s, int n, int extend) { /* If |extend| is 0, obtain new n-byte packet; * if |extend| is 1, increase packet by another n bytes. * * The packet will be in the sub-array of |s->s3->rbuf.buf| specified by * |s->packet| and |s->packet_length|. (If DTLS and |extend| is 0, additional * bytes will be read into |rbuf|, up to the size of the buffer.) * * TODO(davidben): |dtls1_get_record| and |ssl3_get_record| have very * different needs. Separate the two record layers. In DTLS, |BIO_read| is * called at most once, and only when |extend| is 0. In TLS, the buffer never * contains more than one record. */ int i, len, left; uintptr_t align = 0; uint8_t *pkt; SSL3_BUFFER *rb; if (n <= 0) { return n; } rb = &s->s3->rbuf; if (rb->buf == NULL && !ssl3_setup_read_buffer(s)) { return -1; } left = rb->left; align = (uintptr_t)rb->buf + SSL3_RT_HEADER_LENGTH; align = (0 - align) & (SSL3_ALIGN_PAYLOAD - 1); if (!extend) { /* start with empty packet ... */ if (left == 0) { rb->offset = align; } else if (align != 0 && left >= SSL3_RT_HEADER_LENGTH) { /* check if next packet length is large enough to justify payload * alignment... */ pkt = rb->buf + rb->offset; if (pkt[0] == SSL3_RT_APPLICATION_DATA && (pkt[3] << 8 | pkt[4]) >= 128) { /* Note that even if packet is corrupted and its length field is * insane, we can only be led to wrong decision about whether memmove * will occur or not. Header values has no effect on memmove arguments * and therefore no buffer overrun can be triggered. */ memmove(rb->buf + align, pkt, left); rb->offset = align; } } s->packet = rb->buf + rb->offset; s->packet_length = 0; /* ... now we can act as if 'extend' was set */ } /* For DTLS/UDP reads should not span multiple packets because the read * operation returns the whole packet at once (as long as it fits into the * buffer). Moreover, if |extend| is true, we must not read another packet, * even if the entire packet was consumed. */ if (SSL_IS_DTLS(s) && ((left > 0 && n > left) || extend)) { n = left; } /* if there is enough in the buffer from a previous read, take some */ if (left >= n) { s->packet_length += n; rb->left = left - n; rb->offset += n; return n; } /* else we need to read more data */ len = s->packet_length; pkt = rb->buf + align; /* Move any available bytes to front of buffer: |len| bytes already pointed * to by |packet|, |left| extra ones at the end. */ if (s->packet != pkt) { /* len > 0 */ memmove(pkt, s->packet, len + left); s->packet = pkt; rb->offset = len + align; } if (n > (int)(rb->len - rb->offset)) { OPENSSL_PUT_ERROR(SSL, ssl3_read_n, ERR_R_INTERNAL_ERROR); return -1; } int max = n; if (SSL_IS_DTLS(s) && !extend) { max = rb->len - rb->offset; } while (left < n) { /* Now we have len+left bytes at the front of s->s3->rbuf.buf and need to * read in more until we have len+n (up to len+max if possible). */ ERR_clear_system_error(); if (s->rbio != NULL) { s->rwstate = SSL_READING; i = BIO_read(s->rbio, pkt + len + left, max - left); } else { OPENSSL_PUT_ERROR(SSL, ssl3_read_n, SSL_R_READ_BIO_NOT_SET); i = -1; } if (i <= 0) { rb->left = left; if (len + left == 0) { ssl3_release_read_buffer(s); } return i; } left += i; /* reads should *never* span multiple packets for DTLS because the * underlying transport protocol is message oriented as opposed to byte * oriented as in the TLS case. */ if (SSL_IS_DTLS(s) && n > left) { n = left; /* makes the while condition false */ } } /* done reading, now the book-keeping */ rb->offset += n; rb->left = left - n; s->packet_length += n; s->rwstate = SSL_NOTHING; return n; } /* MAX_EMPTY_RECORDS defines the number of consecutive, empty records that will * be processed per call to ssl3_get_record. Without this limit an attacker * could send empty records at a faster rate than we can process and cause * ssl3_get_record to loop forever. */ #define MAX_EMPTY_RECORDS 32 /* Call this to get a new input record. It will return <= 0 if more data is * needed, normally due to an error or non-blocking IO. When it finishes, one * packet has been decoded and can be found in * ssl->s3->rrec.type - is the type of record * ssl->s3->rrec.data - data * ssl->s3->rrec.length - number of bytes */ /* used only by ssl3_read_bytes */ static int ssl3_get_record(SSL *s) { uint8_t ssl_major, ssl_minor; int al, n, i, ret = -1; SSL3_RECORD *rr = &s->s3->rrec; uint8_t *p; uint16_t version; size_t extra; unsigned empty_record_count = 0; again: /* check if we have the header */ if (s->rstate != SSL_ST_READ_BODY || s->packet_length < SSL3_RT_HEADER_LENGTH) { n = ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, 0); if (n <= 0) { return n; /* error or non-blocking */ } s->rstate = SSL_ST_READ_BODY; /* Some bytes were read, so the read buffer must be existant and * |s->s3->init_extra| is defined. */ assert(s->s3->rbuf.buf != NULL); extra = s->s3->init_extra ? SSL3_RT_MAX_EXTRA : 0; p = s->packet; if (s->msg_callback) { s->msg_callback(0, 0, SSL3_RT_HEADER, p, 5, s, s->msg_callback_arg); } /* Pull apart the header into the SSL3_RECORD */ rr->type = *(p++); ssl_major = *(p++); ssl_minor = *(p++); version = (((uint16_t)ssl_major) << 8) | ssl_minor; n2s(p, rr->length); if (s->s3->have_version && version != s->version) { OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_WRONG_VERSION_NUMBER); al = SSL_AD_PROTOCOL_VERSION; goto f_err; } if ((version >> 8) != SSL3_VERSION_MAJOR) { OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_WRONG_VERSION_NUMBER); goto err; } if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH + extra) { al = SSL_AD_RECORD_OVERFLOW; OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_ENCRYPTED_LENGTH_TOO_LONG); goto f_err; } /* now s->rstate == SSL_ST_READ_BODY */ } else { /* |packet_length| is non-zero and |s->rstate| is |SSL_ST_READ_BODY|. The * read buffer must be existant and |s->s3->init_extra| is defined. */ assert(s->s3->rbuf.buf != NULL); extra = s->s3->init_extra ? SSL3_RT_MAX_EXTRA : 0; } /* s->rstate == SSL_ST_READ_BODY, get and decode the data */ if (rr->length > s->packet_length - SSL3_RT_HEADER_LENGTH) { /* now s->packet_length == SSL3_RT_HEADER_LENGTH */ i = rr->length; n = ssl3_read_n(s, i, 1); if (n <= 0) { /* Error or non-blocking IO. Now |n| == |rr->length|, and * |s->packet_length| == |SSL3_RT_HEADER_LENGTH| + |rr->length|. */ return n; } } s->rstate = SSL_ST_READ_HEADER; /* set state for later operations */ /* |rr->data| points to |rr->length| bytes of ciphertext in |s->packet|. */ rr->data = &s->packet[SSL3_RT_HEADER_LENGTH]; /* Decrypt the packet in-place. * * TODO(davidben): This assumes |s->version| is the same as the record-layer * version which isn't always true, but it only differs with the NULL cipher * which ignores the parameter. */ size_t plaintext_len; if (!SSL_AEAD_CTX_open(s->aead_read_ctx, rr->data, &plaintext_len, rr->length, rr->type, s->version, s->s3->read_sequence, rr->data, rr->length)) { al = SSL_AD_BAD_RECORD_MAC; OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); goto f_err; } if (!ssl3_record_sequence_update(s->s3->read_sequence, 8)) { goto err; } if (plaintext_len > SSL3_RT_MAX_PLAIN_LENGTH + extra) { al = SSL_AD_RECORD_OVERFLOW; OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_DATA_LENGTH_TOO_LONG); goto f_err; } assert(plaintext_len <= (1u << 16)); rr->length = plaintext_len; rr->off = 0; /* So at this point the following is true: * ssl->s3->rrec.type is the type of record; * ssl->s3->rrec.length is the number of bytes in the record; * ssl->s3->rrec.off is the offset to first valid byte; * ssl->s3->rrec.data the first byte of the record body. */ /* we have pulled in a full packet so zero things */ s->packet_length = 0; /* just read a 0 length packet */ if (rr->length == 0) { empty_record_count++; if (empty_record_count > MAX_EMPTY_RECORDS) { al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_TOO_MANY_EMPTY_FRAGMENTS); goto f_err; } goto again; } return 1; f_err: ssl3_send_alert(s, SSL3_AL_FATAL, al); err: return ret; } /* Call this to write data in records of type |type|. It will return <= 0 if * not all data has been sent or non-blocking IO. */ int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len) { const uint8_t *buf = buf_; unsigned int tot, n, nw; int i; s->rwstate = SSL_NOTHING; assert(s->s3->wnum <= INT_MAX); tot = s->s3->wnum; s->s3->wnum = 0; if (!s->in_handshake && SSL_in_init(s) && !SSL_in_false_start(s)) { i = s->handshake_func(s); if (i < 0) { return i; } if (i == 0) { OPENSSL_PUT_ERROR(SSL, ssl3_write_bytes, SSL_R_SSL_HANDSHAKE_FAILURE); return -1; } } /* Ensure that if we end up with a smaller value of data to write out than * the the original len from a write which didn't complete for non-blocking * I/O and also somehow ended up avoiding the check for this in * ssl3_write_pending/SSL_R_BAD_WRITE_RETRY as it must never be possible to * end up with (len-tot) as a large number that will then promptly send * beyond the end of the users buffer ... so we trap and report the error in * a way the user will notice. */ if (len < 0 || (size_t)len < tot) { OPENSSL_PUT_ERROR(SSL, ssl3_write_bytes, SSL_R_BAD_LENGTH); return -1; } int record_split_done = 0; n = (len - tot); for (;;) { /* max contains the maximum number of bytes that we can put into a * record. */ unsigned max = s->max_send_fragment; /* fragment is true if do_ssl3_write should send the first byte in its own * record in order to randomise a CBC IV. */ int fragment = 0; if (!record_split_done && s->s3->need_record_splitting && type == SSL3_RT_APPLICATION_DATA) { /* Only the the first record per write call needs to be split. The * remaining plaintext was determined before the IV was randomized. */ fragment = 1; record_split_done = 1; } if (n > max) { nw = max; } else { nw = n; } i = do_ssl3_write(s, type, &buf[tot], nw, fragment); if (i <= 0) { s->s3->wnum = tot; return i; } if (i == (int)n || (type == SSL3_RT_APPLICATION_DATA && (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE))) { return tot + i; } n -= i; tot += i; } } /* ssl3_seal_record seals a new record of type |type| and plaintext |in| and * writes it to |out|. At most |max_out| bytes will be written. It returns one * on success and zero on error. On success, it updates the write sequence * number. */ static int ssl3_seal_record(SSL *s, uint8_t *out, size_t *out_len, size_t max_out, uint8_t type, const uint8_t *in, size_t in_len) { if (max_out < SSL3_RT_HEADER_LENGTH) { OPENSSL_PUT_ERROR(SSL, ssl3_seal_record, SSL_R_BUFFER_TOO_SMALL); return 0; } out[0] = type; /* Some servers hang if initial ClientHello is larger than 256 bytes and * record version number > TLS 1.0. */ uint16_t wire_version = s->version; if (!s->s3->have_version && s->version > SSL3_VERSION) { wire_version = TLS1_VERSION; } out[1] = wire_version >> 8; out[2] = wire_version & 0xff; size_t ciphertext_len; if (!SSL_AEAD_CTX_seal(s->aead_write_ctx, out + SSL3_RT_HEADER_LENGTH, &ciphertext_len, max_out - SSL3_RT_HEADER_LENGTH, type, wire_version, s->s3->write_sequence, in, in_len) || !ssl3_record_sequence_update(s->s3->write_sequence, 8)) { return 0; } if (ciphertext_len >= 1 << 16) { OPENSSL_PUT_ERROR(SSL, ssl3_seal_record, ERR_R_OVERFLOW); return 0; } out[3] = ciphertext_len >> 8; out[4] = ciphertext_len & 0xff; *out_len = SSL3_RT_HEADER_LENGTH + ciphertext_len; if (s->msg_callback) { s->msg_callback(1 /* write */, 0, SSL3_RT_HEADER, out, SSL3_RT_HEADER_LENGTH, s, s->msg_callback_arg); } return 1; } /* do_ssl3_write writes an SSL record of the given type. If |fragment| is 1 * then it splits the record into a one byte record and a record with the rest * of the data in order to randomise a CBC IV. */ static int do_ssl3_write(SSL *s, int type, const uint8_t *buf, unsigned int len, char fragment) { SSL3_BUFFER *wb = &s->s3->wbuf; /* first check if there is a SSL3_BUFFER still being written out. This will * happen with non blocking IO */ if (wb->left != 0) { return ssl3_write_pending(s, type, buf, len); } /* If we have an alert to send, lets send it */ if (s->s3->alert_dispatch) { int ret = s->method->ssl_dispatch_alert(s); if (ret <= 0) { return ret; } /* if it went, fall through and send more stuff */ } if (wb->buf == NULL && !ssl3_setup_write_buffer(s)) { return -1; } if (len == 0) { return 0; } if (len == 1) { /* No sense in fragmenting a one-byte record. */ fragment = 0; } /* Align the output so the ciphertext is aligned to |SSL3_ALIGN_PAYLOAD|. */ uintptr_t align; if (fragment) { /* Only CBC-mode ciphers require fragmenting. CBC-mode ciphertext is a * multiple of the block size which we may assume is aligned. Thus we only * need to account for a second copy of the record header. */ align = (uintptr_t)wb->buf + 2 * SSL3_RT_HEADER_LENGTH; } else { align = (uintptr_t)wb->buf + SSL3_RT_HEADER_LENGTH; } align = (0 - align) & (SSL3_ALIGN_PAYLOAD - 1); uint8_t *out = wb->buf + align; wb->offset = align; size_t max_out = wb->len - wb->offset; const uint8_t *orig_buf = buf; unsigned int orig_len = len; size_t fragment_len = 0; if (fragment) { /* Write the first byte in its own record as a countermeasure against * known-IV weaknesses in CBC ciphersuites. (See * http://www.openssl.org/~bodo/tls-cbc.txt.) */ if (!ssl3_seal_record(s, out, &fragment_len, max_out, type, buf, 1)) { return -1; } out += fragment_len; max_out -= fragment_len; buf++; len--; } assert((((uintptr_t)out + SSL3_RT_HEADER_LENGTH) & (SSL3_ALIGN_PAYLOAD - 1)) == 0); size_t ciphertext_len; if (!ssl3_seal_record(s, out, &ciphertext_len, max_out, type, buf, len)) { return -1; } ciphertext_len += fragment_len; /* now let's set up wb */ wb->left = ciphertext_len; /* memorize arguments so that ssl3_write_pending can detect bad write retries * later */ s->s3->wpend_tot = orig_len; s->s3->wpend_buf = orig_buf; s->s3->wpend_type = type; s->s3->wpend_ret = orig_len; /* we now just need to write the buffer */ return ssl3_write_pending(s, type, orig_buf, orig_len); } /* if s->s3->wbuf.left != 0, we need to call this */ int ssl3_write_pending(SSL *s, int type, const uint8_t *buf, unsigned int len) { int i; SSL3_BUFFER *wb = &(s->s3->wbuf); if (s->s3->wpend_tot > (int)len || (s->s3->wpend_buf != buf && !(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER)) || s->s3->wpend_type != type) { OPENSSL_PUT_ERROR(SSL, ssl3_write_pending, SSL_R_BAD_WRITE_RETRY); return -1; } for (;;) { ERR_clear_system_error(); if (s->wbio != NULL) { s->rwstate = SSL_WRITING; i = BIO_write(s->wbio, (char *)&(wb->buf[wb->offset]), (unsigned int)wb->left); } else { OPENSSL_PUT_ERROR(SSL, ssl3_write_pending, SSL_R_BIO_NOT_SET); i = -1; } if (i == wb->left) { wb->left = 0; wb->offset += i; ssl3_release_write_buffer(s); s->rwstate = SSL_NOTHING; return s->s3->wpend_ret; } else if (i <= 0) { if (SSL_IS_DTLS(s)) { /* For DTLS, just drop it. That's kind of the whole point in * using a datagram service */ wb->left = 0; } return i; } /* TODO(davidben): This codepath is used in DTLS, but the write * payload may not split across packets. */ wb->offset += i; wb->left -= i; } } /* ssl3_expect_change_cipher_spec informs the record layer that a * ChangeCipherSpec record is required at this point. If a Handshake record is * received before ChangeCipherSpec, the connection will fail. Moreover, if * there are unprocessed handshake bytes, the handshake will also fail and the * function returns zero. Otherwise, the function returns one. */ int ssl3_expect_change_cipher_spec(SSL *s) { if (s->s3->handshake_fragment_len > 0 || s->s3->tmp.reuse_message) { OPENSSL_PUT_ERROR(SSL, ssl3_expect_change_cipher_spec, SSL_R_UNPROCESSED_HANDSHAKE_DATA); return 0; } s->s3->flags |= SSL3_FLAGS_EXPECT_CCS; return 1; } /* Return up to 'len' payload bytes received in 'type' records. * 'type' is one of the following: * * - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us) * - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us) * - 0 (during a shutdown, no data has to be returned) * * If we don't have stored data to work from, read a SSL/TLS record first * (possibly multiple records if we still don't have anything to return). * * This function must handle any surprises the peer may have for us, such as * Alert records (e.g. close_notify), ChangeCipherSpec records (not really * a surprise, but handled as if it were), or renegotiation requests. * Also if record payloads contain fragments too small to process, we store * them until there is enough for the respective protocol (the record protocol * may use arbitrary fragmentation and even interleaving): * Change cipher spec protocol * just 1 byte needed, no need for keeping anything stored * Alert protocol * 2 bytes needed (AlertLevel, AlertDescription) * Handshake protocol * 4 bytes needed (HandshakeType, uint24 length) -- we just have * to detect unexpected Client Hello and Hello Request messages * here, anything else is handled by higher layers * Application data protocol * none of our business */ int ssl3_read_bytes(SSL *s, int type, uint8_t *buf, int len, int peek) { int al, i, ret; unsigned int n; SSL3_RECORD *rr; void (*cb)(const SSL *ssl, int type2, int val) = NULL; if ((type && type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_HANDSHAKE) || (peek && type != SSL3_RT_APPLICATION_DATA)) { OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, ERR_R_INTERNAL_ERROR); return -1; } if (type == SSL3_RT_HANDSHAKE && s->s3->handshake_fragment_len > 0) { /* (partially) satisfy request from storage */ uint8_t *src = s->s3->handshake_fragment; uint8_t *dst = buf; unsigned int k; /* peek == 0 */ n = 0; while (len > 0 && s->s3->handshake_fragment_len > 0) { *dst++ = *src++; len--; s->s3->handshake_fragment_len--; n++; } /* move any remaining fragment bytes: */ for (k = 0; k < s->s3->handshake_fragment_len; k++) { s->s3->handshake_fragment[k] = *src++; } return n; } /* Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */ /* This may require multiple iterations. False Start will cause * |s->handshake_func| to signal success one step early, but the handshake * must be completely finished before other modes are accepted. * * TODO(davidben): Move this check up to a higher level. */ while (!s->in_handshake && SSL_in_init(s)) { assert(type == SSL3_RT_APPLICATION_DATA); i = s->handshake_func(s); if (i < 0) { return i; } if (i == 0) { OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE); return -1; } } start: s->rwstate = SSL_NOTHING; /* s->s3->rrec.type - is the type of record * s->s3->rrec.data - data * s->s3->rrec.off - offset into 'data' for next read * s->s3->rrec.length - number of bytes. */ rr = &s->s3->rrec; /* get new packet if necessary */ if (rr->length == 0 || s->rstate == SSL_ST_READ_BODY) { ret = ssl3_get_record(s); if (ret <= 0) { return ret; } } /* we now have a packet which can be read and processed */ /* |change_cipher_spec is set when we receive a ChangeCipherSpec and reset by * ssl3_get_finished. */ if (s->s3->change_cipher_spec && rr->type != SSL3_RT_HANDSHAKE && rr->type != SSL3_RT_ALERT) { al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_DATA_BETWEEN_CCS_AND_FINISHED); goto f_err; } /* If we are expecting a ChangeCipherSpec, it is illegal to receive a * Handshake record. */ if (rr->type == SSL3_RT_HANDSHAKE && (s->s3->flags & SSL3_FLAGS_EXPECT_CCS)) { al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_HANDSHAKE_RECORD_BEFORE_CCS); goto f_err; } /* If the other end has shut down, throw anything we read away (even in * 'peek' mode) */ if (s->shutdown & SSL_RECEIVED_SHUTDOWN) { rr->length = 0; s->rwstate = SSL_NOTHING; return 0; } if (type == rr->type) { /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */ /* make sure that we are not getting application data when we are doing a * handshake for the first time */ if (SSL_in_init(s) && type == SSL3_RT_APPLICATION_DATA && s->aead_read_ctx == NULL) { /* TODO(davidben): Is this check redundant with the handshake_func * check? */ al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_APP_DATA_IN_HANDSHAKE); goto f_err; } if (len <= 0) { return len; } if ((unsigned int)len > rr->length) { n = rr->length; } else { n = (unsigned int)len; } memcpy(buf, &(rr->data[rr->off]), n); if (!peek) { rr->length -= n; rr->off += n; if (rr->length == 0) { s->rstate = SSL_ST_READ_HEADER; rr->off = 0; if (s->s3->rbuf.left == 0) { ssl3_release_read_buffer(s); } } } return n; } /* Process unexpected records. */ if (rr->type == SSL3_RT_HANDSHAKE) { /* If peer renegotiations are disabled, all out-of-order handshake records * are fatal. Renegotiations as a server are never supported. */ if (!s->accept_peer_renegotiations || s->server) { al = SSL_AD_NO_RENEGOTIATION; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_NO_RENEGOTIATION); goto f_err; } /* HelloRequests may be fragmented across multiple records. */ const size_t size = sizeof(s->s3->handshake_fragment); const size_t avail = size - s->s3->handshake_fragment_len; const size_t todo = (rr->length < avail) ? rr->length : avail; memcpy(s->s3->handshake_fragment + s->s3->handshake_fragment_len, &rr->data[rr->off], todo); rr->off += todo; rr->length -= todo; s->s3->handshake_fragment_len += todo; if (s->s3->handshake_fragment_len < size) { goto start; /* fragment was too small */ } /* Parse out and consume a HelloRequest. */ if (s->s3->handshake_fragment[0] != SSL3_MT_HELLO_REQUEST || s->s3->handshake_fragment[1] != 0 || s->s3->handshake_fragment[2] != 0 || s->s3->handshake_fragment[3] != 0) { al = SSL_AD_DECODE_ERROR; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_HELLO_REQUEST); goto f_err; } s->s3->handshake_fragment_len = 0; if (s->msg_callback) { s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->s3->handshake_fragment, 4, s, s->msg_callback_arg); } if (SSL_is_init_finished(s) && !s->s3->renegotiate) { ssl3_renegotiate(s); if (ssl3_renegotiate_check(s)) { i = s->handshake_func(s); if (i < 0) { return i; } if (i == 0) { OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE); return -1; } } } /* we either finished a handshake or ignored the request, now try again to * obtain the (application) data we were asked for */ goto start; } /* If an alert record, process one alert out of the record. Note that we allow * a single record to contain multiple alerts. */ if (rr->type == SSL3_RT_ALERT) { /* Alerts may not be fragmented. */ if (rr->length < 2) { al = SSL_AD_DECODE_ERROR; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_ALERT); goto f_err; } if (s->msg_callback) { s->msg_callback(0, s->version, SSL3_RT_ALERT, &rr->data[rr->off], 2, s, s->msg_callback_arg); } const uint8_t alert_level = rr->data[rr->off++]; const uint8_t alert_descr = rr->data[rr->off++]; rr->length -= 2; if (s->info_callback != NULL) { cb = s->info_callback; } else if (s->ctx->info_callback != NULL) { cb = s->ctx->info_callback; } if (cb != NULL) { uint16_t alert = (alert_level << 8) | alert_descr; cb(s, SSL_CB_READ_ALERT, alert); } if (alert_level == SSL3_AL_WARNING) { s->s3->warn_alert = alert_descr; if (alert_descr == SSL_AD_CLOSE_NOTIFY) { s->shutdown |= SSL_RECEIVED_SHUTDOWN; return 0; } /* This is a warning but we receive it if we requested renegotiation and * the peer denied it. Terminate with a fatal alert because if * application tried to renegotiatie it presumably had a good reason and * expects it to succeed. * * In future we might have a renegotiation where we don't care if the * peer refused it where we carry on. */ else if (alert_descr == SSL_AD_NO_RENEGOTIATION) { al = SSL_AD_HANDSHAKE_FAILURE; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_NO_RENEGOTIATION); goto f_err; } } else if (alert_level == SSL3_AL_FATAL) { char tmp[16]; s->rwstate = SSL_NOTHING; s->s3->fatal_alert = alert_descr; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_AD_REASON_OFFSET + alert_descr); BIO_snprintf(tmp, sizeof(tmp), "%d", alert_descr); ERR_add_error_data(2, "SSL alert number ", tmp); s->shutdown |= SSL_RECEIVED_SHUTDOWN; SSL_CTX_remove_session(s->ctx, s->session); return 0; } else { al = SSL_AD_ILLEGAL_PARAMETER; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNKNOWN_ALERT_TYPE); goto f_err; } goto start; } if (s->shutdown & SSL_SENT_SHUTDOWN) { /* but we have not received a shutdown */ s->rwstate = SSL_NOTHING; rr->length = 0; return 0; } if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) { /* 'Change Cipher Spec' is just a single byte, so we know exactly what the * record payload has to look like */ if (rr->length != 1 || rr->off != 0 || rr->data[0] != SSL3_MT_CCS) { al = SSL_AD_ILLEGAL_PARAMETER; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_CHANGE_CIPHER_SPEC); goto f_err; } /* Check we have a cipher to change to */ if (s->s3->tmp.new_cipher == NULL) { al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_CCS_RECEIVED_EARLY); goto f_err; } if (!(s->s3->flags & SSL3_FLAGS_EXPECT_CCS)) { al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_CCS_RECEIVED_EARLY); goto f_err; } s->s3->flags &= ~SSL3_FLAGS_EXPECT_CCS; rr->length = 0; if (s->msg_callback) { s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1, s, s->msg_callback_arg); } s->s3->change_cipher_spec = 1; if (!ssl3_do_change_cipher_spec(s)) { goto err; } else { goto start; } } /* We already handled these. */ assert(rr->type != SSL3_RT_CHANGE_CIPHER_SPEC && rr->type != SSL3_RT_ALERT && rr->type != SSL3_RT_HANDSHAKE); al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNEXPECTED_RECORD); f_err: ssl3_send_alert(s, SSL3_AL_FATAL, al); err: return -1; } int ssl3_do_change_cipher_spec(SSL *s) { int i; if (s->state & SSL_ST_ACCEPT) { i = SSL3_CHANGE_CIPHER_SERVER_READ; } else { i = SSL3_CHANGE_CIPHER_CLIENT_READ; } if (s->s3->tmp.key_block == NULL) { if (s->session == NULL || s->session->master_key_length == 0) { /* might happen if dtls1_read_bytes() calls this */ OPENSSL_PUT_ERROR(SSL, ssl3_do_change_cipher_spec, SSL_R_CCS_RECEIVED_EARLY); return 0; } s->session->cipher = s->s3->tmp.new_cipher; if (!s->enc_method->setup_key_block(s)) { return 0; } } if (!s->enc_method->change_cipher_state(s, i)) { return 0; } return 1; } int ssl3_send_alert(SSL *s, int level, int desc) { /* Map tls/ssl alert value to correct one */ desc = s->enc_method->alert_value(desc); if (s->version == SSL3_VERSION && desc == SSL_AD_PROTOCOL_VERSION) { /* SSL 3.0 does not have protocol_version alerts */ desc = SSL_AD_HANDSHAKE_FAILURE; } if (desc < 0) { return -1; } /* If a fatal one, remove from cache */ if (level == 2 && s->session != NULL) { SSL_CTX_remove_session(s->ctx, s->session); } s->s3->alert_dispatch = 1; s->s3->send_alert[0] = level; s->s3->send_alert[1] = desc; if (s->s3->wbuf.left == 0) { /* data is still being written out. */ return s->method->ssl_dispatch_alert(s); } /* else data is still being written out, we will get written some time in the * future */ return -1; } int ssl3_dispatch_alert(SSL *s) { int i, j; void (*cb)(const SSL *ssl, int type, int val) = NULL; s->s3->alert_dispatch = 0; i = do_ssl3_write(s, SSL3_RT_ALERT, &s->s3->send_alert[0], 2, 0); if (i <= 0) { s->s3->alert_dispatch = 1; } else { /* Alert sent to BIO. If it is important, flush it now. If the message * does not get sent due to non-blocking IO, we will not worry too much. */ if (s->s3->send_alert[0] == SSL3_AL_FATAL) { BIO_flush(s->wbio); } if (s->msg_callback) { s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert, 2, s, s->msg_callback_arg); } if (s->info_callback != NULL) { cb = s->info_callback; } else if (s->ctx->info_callback != NULL) { cb = s->ctx->info_callback; } if (cb != NULL) { j = (s->s3->send_alert[0] << 8) | s->s3->send_alert[1]; cb(s, SSL_CB_WRITE_ALERT, j); } } return i; }