/* * DTLS implementation written by Nagendra Modadugu * (nagendra@cs.stanford.edu) for the OpenSSL project 2005. */ /* ==================================================================== * Copyright (c) 1998-2005 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). * */ /* 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.] */ #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" /* TODO(davidben): 28 comes from the size of IP + UDP header. Is this reasonable * for these values? Notably, why is kMinMTU a function of the transport * protocol's overhead rather than, say, what's needed to hold a minimally-sized * handshake fragment plus protocol overhead. */ /* kMinMTU is the minimum acceptable MTU value. */ static const unsigned int kMinMTU = 256 - 28; /* kDefaultMTU is the default MTU value to use if neither the user nor * the underlying BIO supplies one. */ static const unsigned int kDefaultMTU = 1500 - 28; /* kMaxHandshakeBuffer is the maximum number of handshake messages ahead of the * current one to buffer. */ static const unsigned int kHandshakeBufferSize = 10; static void dtls1_fix_message_header(SSL *s, unsigned long frag_off, unsigned long frag_len); static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p); static hm_fragment *dtls1_hm_fragment_new(unsigned long frag_len, int reassembly) { hm_fragment *frag = NULL; uint8_t *buf = NULL; uint8_t *bitmask = NULL; frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment)); if (frag == NULL) { OPENSSL_PUT_ERROR(SSL, dtls1_hm_fragment_new, ERR_R_MALLOC_FAILURE); return NULL; } if (frag_len) { buf = (uint8_t *)OPENSSL_malloc(frag_len); if (buf == NULL) { OPENSSL_PUT_ERROR(SSL, dtls1_hm_fragment_new, ERR_R_MALLOC_FAILURE); OPENSSL_free(frag); return NULL; } } /* zero length fragment gets zero frag->fragment */ frag->fragment = buf; /* Initialize reassembly bitmask if necessary */ if (reassembly && frag_len > 0) { if (frag_len + 7 < frag_len) { OPENSSL_PUT_ERROR(SSL, dtls1_hm_fragment_new, ERR_R_OVERFLOW); return NULL; } size_t bitmask_len = (frag_len + 7) / 8; bitmask = (uint8_t *)OPENSSL_malloc(bitmask_len); if (bitmask == NULL) { OPENSSL_PUT_ERROR(SSL, dtls1_hm_fragment_new, ERR_R_MALLOC_FAILURE); if (buf != NULL) { OPENSSL_free(buf); } OPENSSL_free(frag); return NULL; } memset(bitmask, 0, bitmask_len); } frag->reassembly = bitmask; return frag; } void dtls1_hm_fragment_free(hm_fragment *frag) { if (frag == NULL) { return; } OPENSSL_free(frag->fragment); OPENSSL_free(frag->reassembly); OPENSSL_free(frag); } #if !defined(inline) #define inline __inline #endif /* bit_range returns a |uint8_t| with bits |start|, inclusive, to |end|, * exclusive, set. */ static inline uint8_t bit_range(size_t start, size_t end) { return (uint8_t)(~((1u << start) - 1) & ((1u << end) - 1)); } /* dtls1_hm_fragment_mark marks bytes |start|, inclusive, to |end|, exclusive, * as received in |frag|. If |frag| becomes complete, it clears * |frag->reassembly|. The range must be within the bounds of |frag|'s message * and |frag->reassembly| must not be NULL. */ static void dtls1_hm_fragment_mark(hm_fragment *frag, size_t start, size_t end) { size_t i; size_t msg_len = frag->msg_header.msg_len; if (frag->reassembly == NULL || start > end || end > msg_len) { assert(0); return; } /* A zero-length message will never have a pending reassembly. */ assert(msg_len > 0); if ((start >> 3) == (end >> 3)) { frag->reassembly[start >> 3] |= bit_range(start & 7, end & 7); } else { frag->reassembly[start >> 3] |= bit_range(start & 7, 8); for (i = (start >> 3) + 1; i < (end >> 3); i++) { frag->reassembly[i] = 0xff; } if ((end & 7) != 0) { frag->reassembly[end >> 3] |= bit_range(0, end & 7); } } /* Check if the fragment is complete. */ for (i = 0; i < (msg_len >> 3); i++) { if (frag->reassembly[i] != 0xff) { return; } } if ((msg_len & 7) != 0 && frag->reassembly[msg_len >> 3] != bit_range(0, msg_len & 7)) { return; } OPENSSL_free(frag->reassembly); frag->reassembly = NULL; } /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or * SSL3_RT_CHANGE_CIPHER_SPEC) */ int dtls1_do_write(SSL *s, int type) { int ret; int curr_mtu; unsigned int len, frag_off; size_t max_overhead = 0; /* AHA! Figure out the MTU, and stick to the right size */ if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { long mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) { s->d1->mtu = (unsigned)mtu; } else { s->d1->mtu = kDefaultMTU; BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, s->d1->mtu, NULL); } } /* should have something reasonable now */ assert(s->d1->mtu >= dtls1_min_mtu()); if (s->init_off == 0 && type == SSL3_RT_HANDSHAKE) { assert(s->init_num == (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH); } /* Determine the maximum overhead of the current cipher. */ if (s->aead_write_ctx != NULL) { max_overhead = EVP_AEAD_max_overhead(s->aead_write_ctx->ctx.aead); if (s->aead_write_ctx->variable_nonce_included_in_record) { max_overhead += s->aead_write_ctx->variable_nonce_len; } } frag_off = 0; while (s->init_num) { /* Account for data in the buffering BIO; multiple records may be packed * into a single packet during the handshake. * * TODO(davidben): This is buggy; if the MTU is larger than the buffer size, * the large record will be split across two packets. Moreover, in that * case, the |dtls1_write_bytes| call may not return synchronously. This * will break on retry as the |s->init_off| and |s->init_num| adjustment * will run a second time. */ curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) - DTLS1_RT_HEADER_LENGTH - max_overhead; if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) { /* Flush the buffer and continue with a fresh packet. * * TODO(davidben): If |BIO_flush| is not synchronous and requires multiple * calls to |dtls1_do_write|, |frag_off| will be wrong. */ ret = BIO_flush(SSL_get_wbio(s)); if (ret <= 0) { return ret; } assert(BIO_wpending(SSL_get_wbio(s)) == 0); curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH - max_overhead; } /* XDTLS: this function is too long. split out the CCS part */ if (type == SSL3_RT_HANDSHAKE) { /* If this isn't the first fragment, reserve space to prepend a new * fragment header. This will override the body of a previous fragment. */ if (s->init_off != 0) { assert(s->init_off > DTLS1_HM_HEADER_LENGTH); s->init_off -= DTLS1_HM_HEADER_LENGTH; s->init_num += DTLS1_HM_HEADER_LENGTH; } if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) { /* To make forward progress, the MTU must, at minimum, fit the handshake * header and one byte of handshake body. */ OPENSSL_PUT_ERROR(SSL, dtls1_do_write, SSL_R_MTU_TOO_SMALL); return -1; } if (s->init_num > curr_mtu) { len = curr_mtu; } else { len = s->init_num; } assert(len >= DTLS1_HM_HEADER_LENGTH); dtls1_fix_message_header(s, frag_off, len - DTLS1_HM_HEADER_LENGTH); dtls1_write_message_header( s, (uint8_t *)&s->init_buf->data[s->init_off]); } else { assert(type == SSL3_RT_CHANGE_CIPHER_SPEC); /* ChangeCipherSpec cannot be fragmented. */ if (s->init_num > curr_mtu) { OPENSSL_PUT_ERROR(SSL, dtls1_do_write, SSL_R_MTU_TOO_SMALL); return -1; } len = s->init_num; } ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off], len); if (ret < 0) { return -1; } /* bad if this assert fails, only part of the handshake message got sent. * But why would this happen? */ assert(len == (unsigned int)ret); if (ret == s->init_num) { if (s->msg_callback) { s->msg_callback(1, s->version, type, s->init_buf->data, (size_t)(s->init_off + s->init_num), s, s->msg_callback_arg); } s->init_off = 0; /* done writing this message */ s->init_num = 0; return 1; } s->init_off += ret; s->init_num -= ret; frag_off += (ret -= DTLS1_HM_HEADER_LENGTH); } return 0; } /* dtls1_is_next_message_complete returns one if the next handshake message is * complete and zero otherwise. */ static int dtls1_is_next_message_complete(SSL *s) { pitem *item = pqueue_peek(s->d1->buffered_messages); if (item == NULL) { return 0; } hm_fragment *frag = (hm_fragment *)item->data; assert(s->d1->handshake_read_seq <= frag->msg_header.seq); return s->d1->handshake_read_seq == frag->msg_header.seq && frag->reassembly == NULL; } /* dtls1_discard_fragment_body discards a handshake fragment body of length * |frag_len|. It returns one on success and zero on error. * * TODO(davidben): This function will go away when ssl_read_bytes is gone from * the DTLS side. */ static int dtls1_discard_fragment_body(SSL *s, size_t frag_len) { uint8_t discard[256]; while (frag_len > 0) { size_t chunk = frag_len < sizeof(discard) ? frag_len : sizeof(discard); int ret = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, discard, chunk, 0); if (ret != chunk) { return 0; } frag_len -= chunk; } return 1; } /* dtls1_get_buffered_message returns the buffered message corresponding to * |msg_hdr|. If none exists, it creates a new one and inserts it in the * queue. Otherwise, it checks |msg_hdr| is consistent with the existing one. It * returns NULL on failure. The caller does not take ownership of the result. */ static hm_fragment *dtls1_get_buffered_message( SSL *s, const struct hm_header_st *msg_hdr) { uint8_t seq64be[8]; memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (uint8_t)(msg_hdr->seq >> 8); seq64be[7] = (uint8_t)msg_hdr->seq; pitem *item = pqueue_find(s->d1->buffered_messages, seq64be); hm_fragment *frag; if (item == NULL) { /* This is the first fragment from this message. */ frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1 /* reassembly buffer needed */); if (frag == NULL) { return NULL; } memcpy(&frag->msg_header, msg_hdr, sizeof(*msg_hdr)); item = pitem_new(seq64be, frag); if (item == NULL) { dtls1_hm_fragment_free(frag); return NULL; } item = pqueue_insert(s->d1->buffered_messages, item); /* |pqueue_insert| fails iff a duplicate item is inserted, but |item| cannot * be a duplicate. */ assert(item != NULL); } else { frag = item->data; assert(frag->msg_header.seq == msg_hdr->seq); if (frag->msg_header.type != msg_hdr->type || frag->msg_header.msg_len != msg_hdr->msg_len) { /* The new fragment must be compatible with the previous fragments from * this message. */ OPENSSL_PUT_ERROR(SSL, dtls1_get_buffered_message, SSL_R_FRAGMENT_MISMATCH); ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return NULL; } } return frag; } /* dtls1_max_handshake_message_len returns the maximum number of bytes * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but may * be greater if the maximum certificate list size requires it. */ static size_t dtls1_max_handshake_message_len(const SSL *s) { size_t max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH; if (max_len < (size_t)s->max_cert_list) { return (size_t)s->max_cert_list; } return max_len; } /* dtls1_process_fragment reads a handshake fragment and processes it. It * returns one if a fragment was successfully processed and 0 or -1 on error. */ static int dtls1_process_fragment(SSL *s) { /* Read handshake message header. * * TODO(davidben): ssl_read_bytes allows splitting the fragment header and * body across two records. Change this interface to consume the fragment in * one pass. */ uint8_t header[DTLS1_HM_HEADER_LENGTH]; int ret = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, header, DTLS1_HM_HEADER_LENGTH, 0); if (ret <= 0) { return ret; } if (ret != DTLS1_HM_HEADER_LENGTH) { OPENSSL_PUT_ERROR(SSL, dtls1_process_fragment, SSL_R_UNEXPECTED_MESSAGE); ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); return -1; } /* Parse the message fragment header. */ struct hm_header_st msg_hdr; dtls1_get_message_header(header, &msg_hdr); const size_t frag_off = msg_hdr.frag_off; const size_t frag_len = msg_hdr.frag_len; const size_t msg_len = msg_hdr.msg_len; if (frag_off > msg_len || frag_off + frag_len < frag_off || frag_off + frag_len > msg_len || msg_len > dtls1_max_handshake_message_len(s)) { OPENSSL_PUT_ERROR(SSL, dtls1_process_fragment, SSL_R_EXCESSIVE_MESSAGE_SIZE); ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return -1; } if (msg_hdr.seq < s->d1->handshake_read_seq || msg_hdr.seq > (unsigned)s->d1->handshake_read_seq + kHandshakeBufferSize) { /* Ignore fragments from the past, or ones too far in the future. */ if (!dtls1_discard_fragment_body(s, frag_len)) { return -1; } return 1; } hm_fragment *frag = dtls1_get_buffered_message(s, &msg_hdr); if (frag == NULL) { return -1; } assert(frag->msg_header.msg_len == msg_len); if (frag->reassembly == NULL) { /* The message is already assembled. */ if (!dtls1_discard_fragment_body(s, frag_len)) { return -1; } return 1; } assert(msg_len > 0); /* Read the body of the fragment. */ ret = s->method->ssl_read_bytes( s, SSL3_RT_HANDSHAKE, frag->fragment + frag_off, frag_len, 0); if (ret != frag_len) { OPENSSL_PUT_ERROR(SSL, dtls1_process_fragment, SSL_R_UNEXPECTED_MESSAGE); ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); return -1; } dtls1_hm_fragment_mark(frag, frag_off, frag_off + frag_len); return 1; } /* dtls1_get_message reads a handshake message of message type |msg_type| (any * if |msg_type| == -1), maximum acceptable body length |max|. Read an entire * handshake message. Handshake messages arrive in fragments. */ long dtls1_get_message(SSL *s, int st1, int stn, int msg_type, long max, enum ssl_hash_message_t hash_message, int *ok) { pitem *item = NULL; hm_fragment *frag = NULL; int al; /* s3->tmp is used to store messages that are unexpected, caused * by the absence of an optional handshake message */ if (s->s3->tmp.reuse_message) { /* A ssl_dont_hash_message call cannot be combined with reuse_message; the * ssl_dont_hash_message would have to have been applied to the previous * call. */ assert(hash_message == ssl_hash_message); s->s3->tmp.reuse_message = 0; if (msg_type >= 0 && s->s3->tmp.message_type != msg_type) { al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, dtls1_get_message, SSL_R_UNEXPECTED_MESSAGE); goto f_err; } *ok = 1; s->init_msg = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; s->init_num = (int)s->s3->tmp.message_size; return s->init_num; } /* Process fragments until one is found. */ while (!dtls1_is_next_message_complete(s)) { int ret = dtls1_process_fragment(s); if (ret <= 0) { *ok = 0; return ret; } } /* Read out the next complete handshake message. */ item = pqueue_pop(s->d1->buffered_messages); assert(item != NULL); frag = (hm_fragment *)item->data; assert(s->d1->handshake_read_seq == frag->msg_header.seq); assert(frag->reassembly == NULL); if (frag->msg_header.msg_len > (size_t)max) { OPENSSL_PUT_ERROR(SSL, dtls1_get_message, SSL_R_EXCESSIVE_MESSAGE_SIZE); goto err; } CBB cbb; if (!BUF_MEM_grow(s->init_buf, (size_t)frag->msg_header.msg_len + DTLS1_HM_HEADER_LENGTH) || !CBB_init_fixed(&cbb, (uint8_t *)s->init_buf->data, s->init_buf->max)) { OPENSSL_PUT_ERROR(SSL, dtls1_get_message, ERR_R_MALLOC_FAILURE); goto err; } /* Reconstruct the assembled message. */ size_t len; if (!CBB_add_u8(&cbb, frag->msg_header.type) || !CBB_add_u24(&cbb, frag->msg_header.msg_len) || !CBB_add_u16(&cbb, frag->msg_header.seq) || !CBB_add_u24(&cbb, 0 /* frag_off */) || !CBB_add_u24(&cbb, frag->msg_header.msg_len) || !CBB_add_bytes(&cbb, frag->fragment, frag->msg_header.msg_len) || !CBB_finish(&cbb, NULL, &len)) { CBB_cleanup(&cbb); OPENSSL_PUT_ERROR(SSL, dtls1_get_message, ERR_R_INTERNAL_ERROR); goto err; } assert(len == (size_t)frag->msg_header.msg_len + DTLS1_HM_HEADER_LENGTH); s->d1->handshake_read_seq++; /* TODO(davidben): This function has a lot of implicit outputs. Simplify the * |ssl_get_message| API. */ s->s3->tmp.message_type = frag->msg_header.type; s->s3->tmp.message_size = frag->msg_header.msg_len; s->init_msg = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; s->init_num = frag->msg_header.msg_len; if (msg_type >= 0 && s->s3->tmp.message_type != msg_type) { al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, dtls1_get_message, SSL_R_UNEXPECTED_MESSAGE); goto f_err; } if (hash_message == ssl_hash_message && !ssl3_hash_current_message(s)) { goto err; } if (s->msg_callback) { s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data, s->init_num + DTLS1_HM_HEADER_LENGTH, s, s->msg_callback_arg); } pitem_free(item); dtls1_hm_fragment_free(frag); s->state = stn; *ok = 1; return s->init_num; f_err: ssl3_send_alert(s, SSL3_AL_FATAL, al); err: pitem_free(item); dtls1_hm_fragment_free(frag); *ok = 0; return -1; } /* for these 2 messages, we need to * ssl->enc_read_ctx re-init * ssl->s3->read_sequence zero * ssl->s3->read_mac_secret re-init * ssl->session->read_sym_enc assign * ssl->session->read_compression assign * ssl->session->read_hash assign */ int dtls1_send_change_cipher_spec(SSL *s, int a, int b) { uint8_t *p; if (s->state == a) { p = (uint8_t *)s->init_buf->data; *p++ = SSL3_MT_CCS; s->d1->handshake_write_seq = s->d1->next_handshake_write_seq; s->init_num = DTLS1_CCS_HEADER_LENGTH; s->init_off = 0; dtls1_set_message_header(s, SSL3_MT_CCS, 0, s->d1->handshake_write_seq, 0, 0); /* buffer the message to handle re-xmits */ dtls1_buffer_message(s, 1); s->state = b; } /* SSL3_ST_CW_CHANGE_B */ return dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC); } int dtls1_read_failed(SSL *s, int code) { if (code > 0) { assert(0); return 1; } if (!dtls1_is_timer_expired(s)) { /* not a timeout, none of our business, let higher layers handle this. In * fact, it's probably an error */ return code; } if (!SSL_in_init(s)) { /* done, no need to send a retransmit */ BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ); return code; } return dtls1_handle_timeout(s); } int dtls1_get_queue_priority(unsigned short seq, int is_ccs) { /* The index of the retransmission queue actually is the message sequence * number, since the queue only contains messages of a single handshake. * However, the ChangeCipherSpec has no message sequence number and so using * only the sequence will result in the CCS and Finished having the same * index. To prevent this, the sequence number is multiplied by 2. In case of * a CCS 1 is subtracted. This does not only differ CSS and Finished, it also * maintains the order of the index (important for priority queues) and fits * in the unsigned short variable. */ return seq * 2 - is_ccs; } static int dtls1_retransmit_message(SSL *s, hm_fragment *frag) { int ret; /* XDTLS: for now assuming that read/writes are blocking */ unsigned long header_length; uint8_t save_write_sequence[8]; /* assert(s->init_num == 0); assert(s->init_off == 0); */ if (frag->msg_header.is_ccs) { header_length = DTLS1_CCS_HEADER_LENGTH; } else { header_length = DTLS1_HM_HEADER_LENGTH; } memcpy(s->init_buf->data, frag->fragment, frag->msg_header.msg_len + header_length); s->init_num = frag->msg_header.msg_len + header_length; dtls1_set_message_header(s, frag->msg_header.type, frag->msg_header.msg_len, frag->msg_header.seq, 0, frag->msg_header.frag_len); /* Save current state. */ SSL_AEAD_CTX *aead_write_ctx = s->aead_write_ctx; uint16_t epoch = s->d1->w_epoch; /* DTLS renegotiation is unsupported, so only epochs 0 (NULL cipher) and 1 * (negotiated cipher) exist. */ assert(epoch == 0 || epoch == 1); assert(frag->msg_header.epoch <= epoch); const int fragment_from_previous_epoch = (epoch == 1 && frag->msg_header.epoch == 0); if (fragment_from_previous_epoch) { /* Rewind to the previous epoch. * * TODO(davidben): Instead of swapping out connection-global state, this * logic should pass a "use previous epoch" parameter down to lower-level * functions. */ s->d1->w_epoch = frag->msg_header.epoch; s->aead_write_ctx = NULL; memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence)); memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence)); } else { /* Otherwise the messages must be from the same epoch. */ assert(frag->msg_header.epoch == epoch); } ret = dtls1_do_write(s, frag->msg_header.is_ccs ? SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE); if (fragment_from_previous_epoch) { /* Restore the current epoch. */ s->aead_write_ctx = aead_write_ctx; s->d1->w_epoch = epoch; memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence)); memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence)); } (void)BIO_flush(SSL_get_wbio(s)); return ret; } int dtls1_retransmit_buffered_messages(SSL *s) { pqueue sent = s->d1->sent_messages; piterator iter = pqueue_iterator(sent); pitem *item; for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) { hm_fragment *frag = (hm_fragment *)item->data; if (dtls1_retransmit_message(s, frag) <= 0) { return -1; } } return 1; } int dtls1_buffer_message(SSL *s, int is_ccs) { pitem *item; hm_fragment *frag; uint8_t seq64be[8]; /* this function is called immediately after a message has * been serialized */ assert(s->init_off == 0); frag = dtls1_hm_fragment_new(s->init_num, 0); if (!frag) { return 0; } memcpy(frag->fragment, s->init_buf->data, s->init_num); if (is_ccs) { assert(s->d1->w_msg_hdr.msg_len + DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num); } else { assert(s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num); } frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len; frag->msg_header.seq = s->d1->w_msg_hdr.seq; frag->msg_header.type = s->d1->w_msg_hdr.type; frag->msg_header.frag_off = 0; frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len; frag->msg_header.is_ccs = is_ccs; frag->msg_header.epoch = s->d1->w_epoch; memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (uint8_t)( dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs) >> 8); seq64be[7] = (uint8_t)( dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs)); item = pitem_new(seq64be, frag); if (item == NULL) { dtls1_hm_fragment_free(frag); return 0; } pqueue_insert(s->d1->sent_messages, item); return 1; } /* call this function when the buffered messages are no longer needed */ void dtls1_clear_record_buffer(SSL *s) { pitem *item; for (item = pqueue_pop(s->d1->sent_messages); item != NULL; item = pqueue_pop(s->d1->sent_messages)) { dtls1_hm_fragment_free((hm_fragment *)item->data); pitem_free(item); } } /* don't actually do the writing, wait till the MTU has been retrieved */ void dtls1_set_message_header(SSL *s, uint8_t mt, unsigned long len, unsigned short seq_num, unsigned long frag_off, unsigned long frag_len) { struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; msg_hdr->type = mt; msg_hdr->msg_len = len; msg_hdr->seq = seq_num; msg_hdr->frag_off = frag_off; msg_hdr->frag_len = frag_len; } static void dtls1_fix_message_header(SSL *s, unsigned long frag_off, unsigned long frag_len) { struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; msg_hdr->frag_off = frag_off; msg_hdr->frag_len = frag_len; } static uint8_t *dtls1_write_message_header(SSL *s, uint8_t *p) { struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; *p++ = msg_hdr->type; l2n3(msg_hdr->msg_len, p); s2n(msg_hdr->seq, p); l2n3(msg_hdr->frag_off, p); l2n3(msg_hdr->frag_len, p); return p; } unsigned int dtls1_min_mtu(void) { return kMinMTU; } void dtls1_get_message_header(uint8_t *data, struct hm_header_st *msg_hdr) { memset(msg_hdr, 0x00, sizeof(struct hm_header_st)); msg_hdr->type = *(data++); n2l3(data, msg_hdr->msg_len); n2s(data, msg_hdr->seq); n2l3(data, msg_hdr->frag_off); n2l3(data, msg_hdr->frag_len); } int dtls1_shutdown(SSL *s) { int ret; ret = ssl3_shutdown(s); return ret; }