/* * 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 "ssl_locl.h" #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8) #define RSMBLY_BITMASK_MARK(bitmask, start, end) \ { \ if ((end) - (start) <= 8) { \ long ii; \ for (ii = (start); ii < (end); ii++) \ bitmask[((ii) >> 3)] |= (1 << ((ii)&7)); \ } else { \ long ii; \ bitmask[((start) >> 3)] |= bitmask_start_values[((start)&7)]; \ for (ii = (((start) >> 3) + 1); ii < ((((end)-1)) >> 3); ii++) \ bitmask[ii] = 0xff; \ bitmask[(((end)-1) >> 3)] |= bitmask_end_values[((end)&7)]; \ } \ } #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) \ { \ long ii; \ assert((msg_len) > 0); \ is_complete = 1; \ if (bitmask[(((msg_len)-1) >> 3)] != bitmask_end_values[((msg_len)&7)]) \ is_complete = 0; \ if (is_complete) \ for (ii = (((msg_len)-1) >> 3) - 1; ii >= 0; ii--) \ if (bitmask[ii] != 0xff) { \ is_complete = 0; \ break; \ } \ } static const uint8_t bitmask_start_values[] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80}; static const uint8_t bitmask_end_values[] = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f}; /* 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; 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 long dtls1_get_message_fragment(SSL *s, int stn, long max, int *ok); static hm_fragment *dtls1_hm_fragment_new(unsigned long frag_len, int reassembly) { hm_fragment *frag = NULL; unsigned char *buf = NULL; unsigned char *bitmask = NULL; frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment)); if (frag == NULL) { return NULL; } if (frag_len) { buf = (unsigned char *)OPENSSL_malloc(frag_len); if (buf == NULL) { OPENSSL_free(frag); return NULL; } } /* zero length fragment gets zero frag->fragment */ frag->fragment = buf; /* Initialize reassembly bitmask if necessary */ if (reassembly) { bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len)); if (bitmask == NULL) { if (buf != NULL) { OPENSSL_free(buf); } OPENSSL_free(frag); return NULL; } memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len)); } frag->reassembly = bitmask; return frag; } void dtls1_hm_fragment_free(hm_fragment *frag) { if (frag->fragment) { OPENSSL_free(frag->fragment); } if (frag->reassembly) { OPENSSL_free(frag->reassembly); } OPENSSL_free(frag); } /* 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; } /* Obtain handshake message of message type 'mt' (any if mt == -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 mt, long max, int hash_message, int *ok) { int i, al; struct hm_header_st *msg_hdr; uint8_t *p; unsigned long msg_len; /* 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_GET_MESSAGE_DONT_HASH_MESSAGE call cannot be combined * with reuse_message; the SSL_GET_MESSAGE_DONT_HASH_MESSAGE * would have to have been applied to the previous call. */ assert(hash_message != SSL_GET_MESSAGE_DONT_HASH_MESSAGE); s->s3->tmp.reuse_message = 0; if (mt >= 0 && s->s3->tmp.message_type != mt) { 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; } msg_hdr = &s->d1->r_msg_hdr; memset(msg_hdr, 0x00, sizeof(struct hm_header_st)); again: i = dtls1_get_message_fragment(s, stn, max, ok); if (i == DTLS1_HM_BAD_FRAGMENT || i == DTLS1_HM_FRAGMENT_RETRY) { /* bad fragment received */ goto again; } else if (i <= 0 && !*ok) { return i; } p = (uint8_t *)s->init_buf->data; msg_len = msg_hdr->msg_len; /* reconstruct message header */ *(p++) = msg_hdr->type; l2n3(msg_len, p); s2n(msg_hdr->seq, p); l2n3(0, p); l2n3(msg_len, p); p -= DTLS1_HM_HEADER_LENGTH; msg_len += DTLS1_HM_HEADER_LENGTH; s->init_msg = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; if (hash_message != SSL_GET_MESSAGE_DONT_HASH_MESSAGE && !ssl3_hash_current_message(s)) { goto err; } if (s->msg_callback) { s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, p, msg_len, s, s->msg_callback_arg); } memset(msg_hdr, 0x00, sizeof(struct hm_header_st)); s->d1->handshake_read_seq++; return s->init_num; f_err: ssl3_send_alert(s, SSL3_AL_FATAL, al); err: *ok = 0; return -1; } static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr, int max) { size_t frag_off, frag_len, msg_len; msg_len = msg_hdr->msg_len; frag_off = msg_hdr->frag_off; frag_len = msg_hdr->frag_len; /* sanity checking */ if ((frag_off + frag_len) > msg_len) { OPENSSL_PUT_ERROR(SSL, dtls1_preprocess_fragment, SSL_R_EXCESSIVE_MESSAGE_SIZE); return SSL_AD_ILLEGAL_PARAMETER; } if ((frag_off + frag_len) > (unsigned long)max) { OPENSSL_PUT_ERROR(SSL, dtls1_preprocess_fragment, SSL_R_EXCESSIVE_MESSAGE_SIZE); return SSL_AD_ILLEGAL_PARAMETER; } if (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */ /* msg_len is limited to 2^24, but is effectively checked * against max above */ if (!BUF_MEM_grow_clean(s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) { OPENSSL_PUT_ERROR(SSL, dtls1_preprocess_fragment, ERR_R_BUF_LIB); return SSL_AD_INTERNAL_ERROR; } s->s3->tmp.message_size = msg_len; s->d1->r_msg_hdr.msg_len = msg_len; s->s3->tmp.message_type = msg_hdr->type; s->d1->r_msg_hdr.type = msg_hdr->type; s->d1->r_msg_hdr.seq = msg_hdr->seq; } else if (msg_len != s->d1->r_msg_hdr.msg_len) { /* They must be playing with us! BTW, failure to enforce * upper limit would open possibility for buffer overrun. */ OPENSSL_PUT_ERROR(SSL, dtls1_preprocess_fragment, SSL_R_EXCESSIVE_MESSAGE_SIZE); return SSL_AD_ILLEGAL_PARAMETER; } return 0; /* no error */ } static int dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok) { /* (0) check whether the desired fragment is available * if so: * (1) copy over the fragment to s->init_buf->data[] * (2) update s->init_num */ pitem *item; hm_fragment *frag; int al; unsigned long frag_len; *ok = 0; item = pqueue_peek(s->d1->buffered_messages); if (item == NULL) { return 0; } frag = (hm_fragment *)item->data; /* Don't return if reassembly still in progress */ if (frag->reassembly != NULL) { return 0; } if (s->d1->handshake_read_seq != frag->msg_header.seq) { return 0; } frag_len = frag->msg_header.frag_len; pqueue_pop(s->d1->buffered_messages); al = dtls1_preprocess_fragment(s, &frag->msg_header, max); if (al == 0) { /* no alert */ uint8_t *p = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; memcpy(&p[frag->msg_header.frag_off], frag->fragment, frag->msg_header.frag_len); } dtls1_hm_fragment_free(frag); pitem_free(item); if (al == 0) { *ok = 1; return frag_len; } ssl3_send_alert(s, SSL3_AL_FATAL, al); s->init_num = 0; *ok = 0; return -1; } /* 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 unsigned long dtls1_max_handshake_message_len(const SSL *s) { unsigned long max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH; if (max_len < (unsigned long)s->max_cert_list) { return s->max_cert_list; } return max_len; } static int dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr, int *ok) { hm_fragment *frag = NULL; pitem *item = NULL; int i = -1, is_complete; uint8_t seq64be[8]; unsigned long frag_len = msg_hdr->frag_len; if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len || msg_hdr->msg_len > dtls1_max_handshake_message_len(s)) { goto err; } if (frag_len == 0) { return DTLS1_HM_FRAGMENT_RETRY; } /* Try to find item in queue */ memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (uint8_t)(msg_hdr->seq >> 8); seq64be[7] = (uint8_t)msg_hdr->seq; item = pqueue_find(s->d1->buffered_messages, seq64be); if (item == NULL) { frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1); if (frag == NULL) { goto err; } memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr)); frag->msg_header.frag_len = frag->msg_header.msg_len; frag->msg_header.frag_off = 0; } else { frag = (hm_fragment *)item->data; if (frag->msg_header.msg_len != msg_hdr->msg_len) { item = NULL; frag = NULL; goto err; } } /* If message is already reassembled, this must be a * retransmit and can be dropped. In this case item != NULL and so frag * does not need to be freed. */ if (frag->reassembly == NULL) { uint8_t devnull[256]; assert(item != NULL); while (frag_len) { i = s->method->ssl_read_bytes( s, SSL3_RT_HANDSHAKE, devnull, frag_len > sizeof(devnull) ? sizeof(devnull) : frag_len, 0); if (i <= 0) { goto err; } frag_len -= i; } return DTLS1_HM_FRAGMENT_RETRY; } /* read the body of the fragment (header has already been read */ i = s->method->ssl_read_bytes( s, SSL3_RT_HANDSHAKE, frag->fragment + msg_hdr->frag_off, frag_len, 0); if ((unsigned long)i != frag_len) { i = -1; } if (i <= 0) { goto err; } RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off, (long)(msg_hdr->frag_off + frag_len)); RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len, is_complete); if (is_complete) { OPENSSL_free(frag->reassembly); frag->reassembly = NULL; } if (item == NULL) { item = pitem_new(seq64be, frag); if (item == NULL) { i = -1; goto err; } item = pqueue_insert(s->d1->buffered_messages, item); /* pqueue_insert fails iff a duplicate item is inserted. * However, |item| cannot be a duplicate. If it were, * |pqueue_find|, above, would have returned it and control * would never have reached this branch. */ assert(item != NULL); } return DTLS1_HM_FRAGMENT_RETRY; err: if (frag != NULL && item == NULL) { dtls1_hm_fragment_free(frag); } *ok = 0; return i; } static int dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st *msg_hdr, int *ok) { int i = -1; hm_fragment *frag = NULL; pitem *item = NULL; uint8_t seq64be[8]; unsigned long frag_len = msg_hdr->frag_len; if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len) { goto err; } /* Try to find item in queue, to prevent duplicate entries */ memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (uint8_t)(msg_hdr->seq >> 8); seq64be[7] = (uint8_t)msg_hdr->seq; item = pqueue_find(s->d1->buffered_messages, seq64be); /* If we already have an entry and this one is a fragment, * don't discard it and rather try to reassemble it. */ if (item != NULL && frag_len != msg_hdr->msg_len) { item = NULL; } /* Discard the message if sequence number was already there, is * too far in the future, or already in the queue. */ if (msg_hdr->seq <= s->d1->handshake_read_seq || msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL) { uint8_t devnull[256]; while (frag_len) { i = s->method->ssl_read_bytes( s, SSL3_RT_HANDSHAKE, devnull, frag_len > sizeof(devnull) ? sizeof(devnull) : frag_len, 0); if (i <= 0) { goto err; } frag_len -= i; } } else { if (frag_len != msg_hdr->msg_len) { return dtls1_reassemble_fragment(s, msg_hdr, ok); } if (frag_len > dtls1_max_handshake_message_len(s)) { goto err; } frag = dtls1_hm_fragment_new(frag_len, 0); if (frag == NULL) { goto err; } memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr)); if (frag_len) { /* read the body of the fragment (header has already been read */ i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, frag->fragment, frag_len, 0); if ((unsigned long)i != frag_len) { i = -1; } if (i <= 0) { goto err; } } item = pitem_new(seq64be, frag); if (item == NULL) { goto err; } item = pqueue_insert(s->d1->buffered_messages, item); /* pqueue_insert fails iff a duplicate item is inserted. * However, |item| cannot be a duplicate. If it were, * |pqueue_find|, above, would have returned it. Then, either * |frag_len| != |msg_hdr->msg_len| in which case |item| is set * to NULL and it will have been processed with * |dtls1_reassemble_fragment|, above, or the record will have * been discarded. */ assert(item != NULL); } return DTLS1_HM_FRAGMENT_RETRY; err: if (frag != NULL && item == NULL) { dtls1_hm_fragment_free(frag); } *ok = 0; return i; } static long dtls1_get_message_fragment(SSL *s, int stn, long max, int *ok) { uint8_t wire[DTLS1_HM_HEADER_LENGTH]; unsigned long len, frag_off, frag_len; int i, al; struct hm_header_st msg_hdr; redo: /* see if we have the required fragment already */ if ((frag_len = dtls1_retrieve_buffered_fragment(s, max, ok)) || *ok) { if (*ok) { s->init_num = frag_len; } return frag_len; } /* read handshake message header */ i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, wire, DTLS1_HM_HEADER_LENGTH, 0); if (i <= 0) { /* nbio, or an error */ s->rwstate = SSL_READING; *ok = 0; return i; } /* Handshake fails if message header is incomplete */ if (i != DTLS1_HM_HEADER_LENGTH) { al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, dtls1_get_message_fragment, SSL_R_UNEXPECTED_MESSAGE); goto f_err; } /* parse the message fragment header */ dtls1_get_message_header(wire, &msg_hdr); /* if this is a future (or stale) message it gets buffered * (or dropped)--no further processing at this time. */ if (msg_hdr.seq != s->d1->handshake_read_seq) { return dtls1_process_out_of_seq_message(s, &msg_hdr, ok); } len = msg_hdr.msg_len; frag_off = msg_hdr.frag_off; frag_len = msg_hdr.frag_len; if (frag_len && frag_len < len) { return dtls1_reassemble_fragment(s, &msg_hdr, ok); } if (!s->server && s->d1->r_msg_hdr.frag_off == 0 && wire[0] == SSL3_MT_HELLO_REQUEST) { /* The server may always send 'Hello Request' messages -- * we are doing a handshake anyway now, so ignore them * if their format is correct. Does not count for * 'Finished' MAC. */ if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) { if (s->msg_callback) { s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, wire, DTLS1_HM_HEADER_LENGTH, s, s->msg_callback_arg); } s->init_num = 0; goto redo; } else { /* Incorrectly formated Hello request */ al = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, dtls1_get_message_fragment, SSL_R_UNEXPECTED_MESSAGE); goto f_err; } } if ((al = dtls1_preprocess_fragment(s, &msg_hdr, max))) { goto f_err; } /* XDTLS: ressurect this when restart is in place */ s->state = stn; if (frag_len > 0) { uint8_t *p = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &p[frag_off], frag_len, 0); /* XDTLS: fix this--message fragments cannot span multiple packets */ if (i <= 0) { s->rwstate = SSL_READING; *ok = 0; return i; } } else { i = 0; } /* XDTLS: an incorrectly formatted fragment should cause the * handshake to fail */ if (i != (int)frag_len) { al = SSL3_AD_ILLEGAL_PARAMETER; OPENSSL_PUT_ERROR(SSL, dtls1_get_message_fragment, SSL3_AD_ILLEGAL_PARAMETER); goto f_err; } *ok = 1; /* Note that s->init_num is *not* used as current offset in * s->init_buf->data, but as a counter summing up fragments' * lengths: as soon as they sum up to handshake packet * length, we assume we have got all the fragments. */ s->init_num = frag_len; return frag_len; f_err: ssl3_send_alert(s, SSL3_AL_FATAL, al); s->init_num = 0; *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) { fprintf(stderr, "invalid state reached %s:%d", __FILE__, __LINE__); 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; } int dtls1_retransmit_buffered_messages(SSL *s) { pqueue sent = s->d1->sent_messages; piterator iter; pitem *item; hm_fragment *frag; int found = 0; iter = pqueue_iterator(sent); for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) { frag = (hm_fragment *)item->data; if (dtls1_retransmit_message( s, (unsigned short)dtls1_get_queue_priority( frag->msg_header.seq, frag->msg_header.is_ccs), 0, &found) <= 0 && found) { fprintf(stderr, "dtls1_retransmit_message() failed\n"); 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; } int dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off, int *found) { int ret; /* XDTLS: for now assuming that read/writes are blocking */ pitem *item; hm_fragment *frag; unsigned long header_length; uint8_t seq64be[8]; uint8_t save_write_sequence[8]; /* assert(s->init_num == 0); assert(s->init_off == 0); */ /* XDTLS: the requested message ought to be found, otherwise error */ memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (uint8_t)(seq >> 8); seq64be[7] = (uint8_t)seq; item = pqueue_find(s->d1->sent_messages, seq64be); if (item == NULL) { fprintf(stderr, "retransmit: message %d non-existant\n", seq); *found = 0; return 0; } *found = 1; frag = (hm_fragment *)item->data; 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; } /* 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); } void dtls1_get_ccs_header(uint8_t *data, struct ccs_header_st *ccs_hdr) { memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st)); ccs_hdr->type = *(data++); } int dtls1_shutdown(SSL *s) { int ret; ret = ssl3_shutdown(s); return ret; }