/* * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL license (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy * in the file LICENSE in the source distribution or at * https://www.openssl.org/source/license.html */ #include #include "../ssl_locl.h" #include "internal/constant_time_locl.h" #include #include "record_locl.h" static const unsigned char ssl3_pad_1[48] = { 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36 }; static const unsigned char ssl3_pad_2[48] = { 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c }; /* * Clear the contents of an SSL3_RECORD but retain any memory allocated */ void SSL3_RECORD_clear(SSL3_RECORD *r, unsigned int num_recs) { unsigned char *comp; unsigned int i; for (i = 0; i < num_recs; i++) { comp = r[i].comp; memset(&r[i], 0, sizeof(*r)); r[i].comp = comp; } } void SSL3_RECORD_release(SSL3_RECORD *r, unsigned int num_recs) { unsigned int i; for (i = 0; i < num_recs; i++) { OPENSSL_free(r[i].comp); r[i].comp = NULL; } } void SSL3_RECORD_set_seq_num(SSL3_RECORD *r, const unsigned char *seq_num) { memcpy(r->seq_num, seq_num, SEQ_NUM_SIZE); } /* * Peeks ahead into "read_ahead" data to see if we have a whole record waiting * for us in the buffer. */ static int ssl3_record_app_data_waiting(SSL *s) { SSL3_BUFFER *rbuf; int left, len; unsigned char *p; rbuf = RECORD_LAYER_get_rbuf(&s->rlayer); p = SSL3_BUFFER_get_buf(rbuf); if (p == NULL) return 0; left = SSL3_BUFFER_get_left(rbuf); if (left < SSL3_RT_HEADER_LENGTH) return 0; p += SSL3_BUFFER_get_offset(rbuf); /* * We only check the type and record length, we will sanity check version * etc later */ if (*p != SSL3_RT_APPLICATION_DATA) return 0; p += 3; n2s(p, len); if (left < SSL3_RT_HEADER_LENGTH + len) return 0; return 1; } /* * 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 #define SSL2_RT_HEADER_LENGTH 2 /*- * Call this to get new input records. * It will return <= 0 if more data is needed, normally due to an error * or non-blocking IO. * When it finishes, |numrpipes| records have been decoded. For each record 'i': * rr[i].type - is the type of record * rr[i].data, - data * rr[i].length, - number of bytes * Multiple records will only be returned if the record types are all * SSL3_RT_APPLICATION_DATA. The number of records returned will always be <= * |max_pipelines| */ /* used only by ssl3_read_bytes */ int ssl3_get_record(SSL *s) { int ssl_major, ssl_minor, al; int enc_err, n, i, ret = -1; SSL3_RECORD *rr; SSL3_BUFFER *rbuf; SSL_SESSION *sess; unsigned char *p; unsigned char md[EVP_MAX_MD_SIZE]; short version; unsigned mac_size; int imac_size; unsigned int num_recs = 0; unsigned int max_recs; unsigned int j; rr = RECORD_LAYER_get_rrec(&s->rlayer); rbuf = RECORD_LAYER_get_rbuf(&s->rlayer); max_recs = s->max_pipelines; if (max_recs == 0) max_recs = 1; sess = s->session; do { /* check if we have the header */ if ((RECORD_LAYER_get_rstate(&s->rlayer) != SSL_ST_READ_BODY) || (RECORD_LAYER_get_packet_length(&s->rlayer) < SSL3_RT_HEADER_LENGTH)) { n = ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, SSL3_BUFFER_get_len(rbuf), 0, num_recs == 0 ? 1 : 0); if (n <= 0) return (n); /* error or non-blocking */ RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_BODY); p = RECORD_LAYER_get_packet(&s->rlayer); /* * The first record received by the server may be a V2ClientHello. */ if (s->server && RECORD_LAYER_is_first_record(&s->rlayer) && (p[0] & 0x80) && (p[2] == SSL2_MT_CLIENT_HELLO)) { /* * SSLv2 style record * * |num_recs| here will actually always be 0 because * |num_recs > 0| only ever occurs when we are processing * multiple app data records - which we know isn't the case here * because it is an SSLv2ClientHello. We keep it using * |num_recs| for the sake of consistency */ rr[num_recs].type = SSL3_RT_HANDSHAKE; rr[num_recs].rec_version = SSL2_VERSION; rr[num_recs].length = ((p[0] & 0x7f) << 8) | p[1]; if (rr[num_recs].length > SSL3_BUFFER_get_len(rbuf) - SSL2_RT_HEADER_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_PACKET_LENGTH_TOO_LONG); goto f_err; } if (rr[num_recs].length < MIN_SSL2_RECORD_LEN) { al = SSL_AD_HANDSHAKE_FAILURE; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_LENGTH_TOO_SHORT); goto f_err; } } else { /* SSLv3+ style record */ 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[num_recs].type = *(p++); ssl_major = *(p++); ssl_minor = *(p++); version = (ssl_major << 8) | ssl_minor; rr[num_recs].rec_version = version; n2s(p, rr[num_recs].length); /* Lets check version */ if (!s->first_packet && version != s->version) { SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_WRONG_VERSION_NUMBER); if ((s->version & 0xFF00) == (version & 0xFF00) && !s->enc_write_ctx && !s->write_hash) { if (rr->type == SSL3_RT_ALERT) { /* * The record is using an incorrect version number, * but what we've got appears to be an alert. We * haven't read the body yet to check whether its a * fatal or not - but chances are it is. We probably * shouldn't send a fatal alert back. We'll just * end. */ goto err; } /* * Send back error using their minor version number :-) */ s->version = (unsigned short)version; } al = SSL_AD_PROTOCOL_VERSION; goto f_err; } if ((version >> 8) != SSL3_VERSION_MAJOR) { if (RECORD_LAYER_is_first_record(&s->rlayer)) { /* Go back to start of packet, look at the five bytes * that we have. */ p = RECORD_LAYER_get_packet(&s->rlayer); if (strncmp((char *)p, "GET ", 4) == 0 || strncmp((char *)p, "POST ", 5) == 0 || strncmp((char *)p, "HEAD ", 5) == 0 || strncmp((char *)p, "PUT ", 4) == 0) { SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_HTTP_REQUEST); goto err; } else if (strncmp((char *)p, "CONNE", 5) == 0) { SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_HTTPS_PROXY_REQUEST); goto err; } /* Doesn't look like TLS - don't send an alert */ SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_WRONG_VERSION_NUMBER); goto err; } else { SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_WRONG_VERSION_NUMBER); al = SSL_AD_PROTOCOL_VERSION; goto f_err; } } if (rr[num_recs].length > SSL3_BUFFER_get_len(rbuf) - SSL3_RT_HEADER_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_PACKET_LENGTH_TOO_LONG); goto f_err; } } /* now s->rlayer.rstate == SSL_ST_READ_BODY */ } /* * s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data. * Calculate how much more data we need to read for the rest of the * record */ if (rr[num_recs].rec_version == SSL2_VERSION) { i = rr[num_recs].length + SSL2_RT_HEADER_LENGTH - SSL3_RT_HEADER_LENGTH; } else { i = rr[num_recs].length; } if (i > 0) { /* now s->packet_length == SSL3_RT_HEADER_LENGTH */ n = ssl3_read_n(s, i, i, 1, 0); if (n <= 0) return (n); /* error or non-blocking io */ } /* set state for later operations */ RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_HEADER); /* * At this point, s->packet_length == SSL3_RT_HEADER_LENGTH + rr->length, * or s->packet_length == SSL2_RT_HEADER_LENGTH + rr->length * and we have that many bytes in s->packet */ if (rr[num_recs].rec_version == SSL2_VERSION) { rr[num_recs].input = &(RECORD_LAYER_get_packet(&s->rlayer)[SSL2_RT_HEADER_LENGTH]); } else { rr[num_recs].input = &(RECORD_LAYER_get_packet(&s->rlayer)[SSL3_RT_HEADER_LENGTH]); } /* * ok, we can now read from 's->packet' data into 'rr' rr->input points * at rr->length bytes, which need to be copied into rr->data by either * the decryption or by the decompression When the data is 'copied' into * the rr->data buffer, rr->input will be pointed at the new buffer */ /* * We now have - encrypted [ MAC [ compressed [ plain ] ] ] rr->length * bytes of encrypted compressed stuff. */ /* check is not needed I believe */ if (rr[num_recs].length > SSL3_RT_MAX_ENCRYPTED_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_ENCRYPTED_LENGTH_TOO_LONG); goto f_err; } /* decrypt in place in 'rr->input' */ rr[num_recs].data = rr[num_recs].input; rr[num_recs].orig_len = rr[num_recs].length; /* Mark this record as not read by upper layers yet */ rr[num_recs].read = 0; num_recs++; /* we have pulled in a full packet so zero things */ RECORD_LAYER_reset_packet_length(&s->rlayer); RECORD_LAYER_clear_first_record(&s->rlayer); } while (num_recs < max_recs && rr[num_recs - 1].type == SSL3_RT_APPLICATION_DATA && SSL_USE_EXPLICIT_IV(s) && s->enc_read_ctx != NULL && (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_read_ctx)) & EVP_CIPH_FLAG_PIPELINE) && ssl3_record_app_data_waiting(s)); /* * If in encrypt-then-mac mode calculate mac from encrypted record. All * the details below are public so no timing details can leak. */ if (SSL_READ_ETM(s) && s->read_hash) { unsigned char *mac; imac_size = EVP_MD_CTX_size(s->read_hash); assert(imac_size >= 0 && imac_size <= EVP_MAX_MD_SIZE); if (imac_size < 0 || imac_size > EVP_MAX_MD_SIZE) { al = SSL_AD_INTERNAL_ERROR; SSLerr(SSL_F_SSL3_GET_RECORD, ERR_LIB_EVP); goto f_err; } mac_size = (unsigned)imac_size; for (j = 0; j < num_recs; j++) { if (rr[j].length < mac_size) { al = SSL_AD_DECODE_ERROR; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_LENGTH_TOO_SHORT); goto f_err; } rr[j].length -= mac_size; mac = rr[j].data + rr[j].length; i = s->method->ssl3_enc->mac(s, &rr[j], md, 0 /* not send */ ); if (i < 0 || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) { al = SSL_AD_BAD_RECORD_MAC; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); goto f_err; } } } enc_err = s->method->ssl3_enc->enc(s, rr, num_recs, 0); /*- * enc_err is: * 0: (in non-constant time) if the record is publically invalid. * 1: if the padding is valid * -1: if the padding is invalid */ if (enc_err == 0) { al = SSL_AD_DECRYPTION_FAILED; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_BLOCK_CIPHER_PAD_IS_WRONG); goto f_err; } #ifdef SSL_DEBUG printf("dec %d\n", rr->length); { unsigned int z; for (z = 0; z < rr->length; z++) printf("%02X%c", rr->data[z], ((z + 1) % 16) ? ' ' : '\n'); } printf("\n"); #endif /* r->length is now the compressed data plus mac */ if ((sess != NULL) && (s->enc_read_ctx != NULL) && (!SSL_READ_ETM(s) && EVP_MD_CTX_md(s->read_hash) != NULL)) { /* s->read_hash != NULL => mac_size != -1 */ unsigned char *mac = NULL; unsigned char mac_tmp[EVP_MAX_MD_SIZE]; mac_size = EVP_MD_CTX_size(s->read_hash); OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE); for (j = 0; j < num_recs; j++) { /* * orig_len is the length of the record before any padding was * removed. This is public information, as is the MAC in use, * therefore we can safely process the record in a different amount * of time if it's too short to possibly contain a MAC. */ if (rr[j].orig_len < mac_size || /* CBC records must have a padding length byte too. */ (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE && rr[j].orig_len < mac_size + 1)) { al = SSL_AD_DECODE_ERROR; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_LENGTH_TOO_SHORT); goto f_err; } if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) { /* * We update the length so that the TLS header bytes can be * constructed correctly but we need to extract the MAC in * constant time from within the record, without leaking the * contents of the padding bytes. */ mac = mac_tmp; ssl3_cbc_copy_mac(mac_tmp, &rr[j], mac_size); rr[j].length -= mac_size; } else { /* * In this case there's no padding, so |rec->orig_len| equals * |rec->length| and we checked that there's enough bytes for * |mac_size| above. */ rr[j].length -= mac_size; mac = &rr[j].data[rr[j].length]; } i = s->method->ssl3_enc->mac(s, &rr[j], md, 0 /* not send */ ); if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) enc_err = -1; if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size) enc_err = -1; } } if (enc_err < 0) { /* * A separate 'decryption_failed' alert was introduced with TLS 1.0, * SSL 3.0 only has 'bad_record_mac'. But unless a decryption * failure is directly visible from the ciphertext anyway, we should * not reveal which kind of error occurred -- this might become * visible to an attacker (e.g. via a logfile) */ al = SSL_AD_BAD_RECORD_MAC; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); goto f_err; } for (j = 0; j < num_recs; j++) { /* rr[j].length is now just compressed */ if (s->expand != NULL) { if (rr[j].length > SSL3_RT_MAX_COMPRESSED_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_COMPRESSED_LENGTH_TOO_LONG); goto f_err; } if (!ssl3_do_uncompress(s, &rr[j])) { al = SSL_AD_DECOMPRESSION_FAILURE; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_BAD_DECOMPRESSION); goto f_err; } } if (rr[j].length > SSL3_RT_MAX_PLAIN_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_DATA_LENGTH_TOO_LONG); goto f_err; } rr[j].off = 0; /*- * So at this point the following is true * rr[j].type is the type of record * rr[j].length == number of bytes in record * rr[j].off == offset to first valid byte * rr[j].data == where to take bytes from, increment after use :-). */ /* just read a 0 length packet */ if (rr[j].length == 0) { RECORD_LAYER_inc_empty_record_count(&s->rlayer); if (RECORD_LAYER_get_empty_record_count(&s->rlayer) > MAX_EMPTY_RECORDS) { al = SSL_AD_UNEXPECTED_MESSAGE; SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_RECORD_TOO_SMALL); goto f_err; } } else { RECORD_LAYER_reset_empty_record_count(&s->rlayer); } } RECORD_LAYER_set_numrpipes(&s->rlayer, num_recs); return 1; f_err: ssl3_send_alert(s, SSL3_AL_FATAL, al); err: return ret; } int ssl3_do_uncompress(SSL *ssl, SSL3_RECORD *rr) { #ifndef OPENSSL_NO_COMP int i; if (rr->comp == NULL) { rr->comp = (unsigned char *) OPENSSL_malloc(SSL3_RT_MAX_ENCRYPTED_LENGTH); } if (rr->comp == NULL) return 0; i = COMP_expand_block(ssl->expand, rr->comp, SSL3_RT_MAX_PLAIN_LENGTH, rr->data, (int)rr->length); if (i < 0) return 0; else rr->length = i; rr->data = rr->comp; #endif return 1; } int ssl3_do_compress(SSL *ssl, SSL3_RECORD *wr) { #ifndef OPENSSL_NO_COMP int i; i = COMP_compress_block(ssl->compress, wr->data, SSL3_RT_MAX_COMPRESSED_LENGTH, wr->input, (int)wr->length); if (i < 0) return (0); else wr->length = i; wr->input = wr->data; #endif return (1); } /*- * ssl3_enc encrypts/decrypts |n_recs| records in |inrecs| * * Returns: * 0: (in non-constant time) if the record is publically invalid (i.e. too * short etc). * 1: if the record's padding is valid / the encryption was successful. * -1: if the record's padding is invalid or, if sending, an internal error * occurred. */ int ssl3_enc(SSL *s, SSL3_RECORD *inrecs, unsigned int n_recs, int send) { SSL3_RECORD *rec; EVP_CIPHER_CTX *ds; unsigned long l; int bs, i, mac_size = 0; const EVP_CIPHER *enc; rec = inrecs; /* * We shouldn't ever be called with more than one record in the SSLv3 case */ if (n_recs != 1) return 0; if (send) { ds = s->enc_write_ctx; if (s->enc_write_ctx == NULL) enc = NULL; else enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx); } else { ds = s->enc_read_ctx; if (s->enc_read_ctx == NULL) enc = NULL; else enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx); } if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) { memmove(rec->data, rec->input, rec->length); rec->input = rec->data; } else { l = rec->length; bs = EVP_CIPHER_CTX_block_size(ds); /* COMPRESS */ if ((bs != 1) && send) { i = bs - ((int)l % bs); /* we need to add 'i-1' padding bytes */ l += i; /* * the last of these zero bytes will be overwritten with the * padding length. */ memset(&rec->input[rec->length], 0, i); rec->length += i; rec->input[l - 1] = (i - 1); } if (!send) { if (l == 0 || l % bs != 0) return 0; /* otherwise, rec->length >= bs */ } if (EVP_Cipher(ds, rec->data, rec->input, l) < 1) return -1; if (EVP_MD_CTX_md(s->read_hash) != NULL) mac_size = EVP_MD_CTX_size(s->read_hash); if ((bs != 1) && !send) return ssl3_cbc_remove_padding(rec, bs, mac_size); } return (1); } /*- * tls1_enc encrypts/decrypts |n_recs| in |recs|. * * Returns: * 0: (in non-constant time) if the record is publically invalid (i.e. too * short etc). * 1: if the record's padding is valid / the encryption was successful. * -1: if the record's padding/AEAD-authenticator is invalid or, if sending, * an internal error occurred. */ int tls1_enc(SSL *s, SSL3_RECORD *recs, unsigned int n_recs, int send) { EVP_CIPHER_CTX *ds; size_t reclen[SSL_MAX_PIPELINES]; unsigned char buf[SSL_MAX_PIPELINES][EVP_AEAD_TLS1_AAD_LEN]; int bs, i, j, k, pad = 0, ret, mac_size = 0; const EVP_CIPHER *enc; unsigned int ctr; if (send) { if (EVP_MD_CTX_md(s->write_hash)) { int n = EVP_MD_CTX_size(s->write_hash); OPENSSL_assert(n >= 0); } ds = s->enc_write_ctx; if (s->enc_write_ctx == NULL) enc = NULL; else { int ivlen; enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx); /* For TLSv1.1 and later explicit IV */ if (SSL_USE_EXPLICIT_IV(s) && EVP_CIPHER_mode(enc) == EVP_CIPH_CBC_MODE) ivlen = EVP_CIPHER_iv_length(enc); else ivlen = 0; if (ivlen > 1) { for (ctr = 0; ctr < n_recs; ctr++) { if (recs[ctr].data != recs[ctr].input) { /* * we can't write into the input stream: Can this ever * happen?? (steve) */ SSLerr(SSL_F_TLS1_ENC, ERR_R_INTERNAL_ERROR); return -1; } else if (RAND_bytes(recs[ctr].input, ivlen) <= 0) { SSLerr(SSL_F_TLS1_ENC, ERR_R_INTERNAL_ERROR); return -1; } } } } } else { if (EVP_MD_CTX_md(s->read_hash)) { int n = EVP_MD_CTX_size(s->read_hash); OPENSSL_assert(n >= 0); } ds = s->enc_read_ctx; if (s->enc_read_ctx == NULL) enc = NULL; else enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx); } if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) { for (ctr = 0; ctr < n_recs; ctr++) { memmove(recs[ctr].data, recs[ctr].input, recs[ctr].length); recs[ctr].input = recs[ctr].data; } ret = 1; } else { bs = EVP_CIPHER_block_size(EVP_CIPHER_CTX_cipher(ds)); if (n_recs > 1) { if (!(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds)) & EVP_CIPH_FLAG_PIPELINE)) { /* * We shouldn't have been called with pipeline data if the * cipher doesn't support pipelining */ SSLerr(SSL_F_TLS1_ENC, SSL_R_PIPELINE_FAILURE); return -1; } } for (ctr = 0; ctr < n_recs; ctr++) { reclen[ctr] = recs[ctr].length; if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds)) & EVP_CIPH_FLAG_AEAD_CIPHER) { unsigned char *seq; seq = send ? RECORD_LAYER_get_write_sequence(&s->rlayer) : RECORD_LAYER_get_read_sequence(&s->rlayer); if (SSL_IS_DTLS(s)) { /* DTLS does not support pipelining */ unsigned char dtlsseq[9], *p = dtlsseq; s2n(send ? DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer) : DTLS_RECORD_LAYER_get_r_epoch(&s->rlayer), p); memcpy(p, &seq[2], 6); memcpy(buf[ctr], dtlsseq, 8); } else { memcpy(buf[ctr], seq, 8); for (i = 7; i >= 0; i--) { /* increment */ ++seq[i]; if (seq[i] != 0) break; } } buf[ctr][8] = recs[ctr].type; buf[ctr][9] = (unsigned char)(s->version >> 8); buf[ctr][10] = (unsigned char)(s->version); buf[ctr][11] = recs[ctr].length >> 8; buf[ctr][12] = recs[ctr].length & 0xff; pad = EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_AEAD_TLS1_AAD, EVP_AEAD_TLS1_AAD_LEN, buf[ctr]); if (pad <= 0) return -1; if (send) { reclen[ctr] += pad; recs[ctr].length += pad; } } else if ((bs != 1) && send) { i = bs - ((int)reclen[ctr] % bs); /* Add weird padding of upto 256 bytes */ /* we need to add 'i' padding bytes of value j */ j = i - 1; for (k = (int)reclen[ctr]; k < (int)(reclen[ctr] + i); k++) recs[ctr].input[k] = j; reclen[ctr] += i; recs[ctr].length += i; } if (!send) { if (reclen[ctr] == 0 || reclen[ctr] % bs != 0) return 0; } } if (n_recs > 1) { unsigned char *data[SSL_MAX_PIPELINES]; /* Set the output buffers */ for (ctr = 0; ctr < n_recs; ctr++) { data[ctr] = recs[ctr].data; } if (EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_OUTPUT_BUFS, n_recs, data) <= 0) { SSLerr(SSL_F_TLS1_ENC, SSL_R_PIPELINE_FAILURE); } /* Set the input buffers */ for (ctr = 0; ctr < n_recs; ctr++) { data[ctr] = recs[ctr].input; } if (EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_INPUT_BUFS, n_recs, data) <= 0 || EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_INPUT_LENS, n_recs, reclen) <= 0) { SSLerr(SSL_F_TLS1_ENC, SSL_R_PIPELINE_FAILURE); return -1; } } i = EVP_Cipher(ds, recs[0].data, recs[0].input, reclen[0]); if ((EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds)) & EVP_CIPH_FLAG_CUSTOM_CIPHER) ? (i < 0) : (i == 0)) return -1; /* AEAD can fail to verify MAC */ if (send == 0) { if (EVP_CIPHER_mode(enc) == EVP_CIPH_GCM_MODE) { for (ctr = 0; ctr < n_recs; ctr++) { recs[ctr].data += EVP_GCM_TLS_EXPLICIT_IV_LEN; recs[ctr].input += EVP_GCM_TLS_EXPLICIT_IV_LEN; recs[ctr].length -= EVP_GCM_TLS_EXPLICIT_IV_LEN; } } else if (EVP_CIPHER_mode(enc) == EVP_CIPH_CCM_MODE) { for (ctr = 0; ctr < n_recs; ctr++) { recs[ctr].data += EVP_CCM_TLS_EXPLICIT_IV_LEN; recs[ctr].input += EVP_CCM_TLS_EXPLICIT_IV_LEN; recs[ctr].length -= EVP_CCM_TLS_EXPLICIT_IV_LEN; } } } ret = 1; if (!SSL_READ_ETM(s) && EVP_MD_CTX_md(s->read_hash) != NULL) mac_size = EVP_MD_CTX_size(s->read_hash); if ((bs != 1) && !send) { int tmpret; for (ctr = 0; ctr < n_recs; ctr++) { tmpret = tls1_cbc_remove_padding(s, &recs[ctr], bs, mac_size); /* * If tmpret == 0 then this means publicly invalid so we can * short circuit things here. Otherwise we must respect constant * time behaviour. */ if (tmpret == 0) return 0; ret = constant_time_select_int(constant_time_eq_int(tmpret, 1), ret, -1); } } if (pad && !send) { for (ctr = 0; ctr < n_recs; ctr++) { recs[ctr].length -= pad; } } } return ret; } int n_ssl3_mac(SSL *ssl, SSL3_RECORD *rec, unsigned char *md, int send) { unsigned char *mac_sec, *seq; const EVP_MD_CTX *hash; unsigned char *p, rec_char; size_t md_size; int npad; int t; if (send) { mac_sec = &(ssl->s3->write_mac_secret[0]); seq = RECORD_LAYER_get_write_sequence(&ssl->rlayer); hash = ssl->write_hash; } else { mac_sec = &(ssl->s3->read_mac_secret[0]); seq = RECORD_LAYER_get_read_sequence(&ssl->rlayer); hash = ssl->read_hash; } t = EVP_MD_CTX_size(hash); if (t < 0) return -1; md_size = t; npad = (48 / md_size) * md_size; if (!send && EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE && ssl3_cbc_record_digest_supported(hash)) { /* * This is a CBC-encrypted record. We must avoid leaking any * timing-side channel information about how many blocks of data we * are hashing because that gives an attacker a timing-oracle. */ /*- * npad is, at most, 48 bytes and that's with MD5: * 16 + 48 + 8 (sequence bytes) + 1 + 2 = 75. * * With SHA-1 (the largest hash speced for SSLv3) the hash size * goes up 4, but npad goes down by 8, resulting in a smaller * total size. */ unsigned char header[75]; unsigned j = 0; memcpy(header + j, mac_sec, md_size); j += md_size; memcpy(header + j, ssl3_pad_1, npad); j += npad; memcpy(header + j, seq, 8); j += 8; header[j++] = rec->type; header[j++] = rec->length >> 8; header[j++] = rec->length & 0xff; /* Final param == is SSLv3 */ if (ssl3_cbc_digest_record(hash, md, &md_size, header, rec->input, rec->length + md_size, rec->orig_len, mac_sec, md_size, 1) <= 0) return -1; } else { unsigned int md_size_u; /* Chop the digest off the end :-) */ EVP_MD_CTX *md_ctx = EVP_MD_CTX_new(); if (md_ctx == NULL) return -1; rec_char = rec->type; p = md; s2n(rec->length, p); if (EVP_MD_CTX_copy_ex(md_ctx, hash) <= 0 || EVP_DigestUpdate(md_ctx, mac_sec, md_size) <= 0 || EVP_DigestUpdate(md_ctx, ssl3_pad_1, npad) <= 0 || EVP_DigestUpdate(md_ctx, seq, 8) <= 0 || EVP_DigestUpdate(md_ctx, &rec_char, 1) <= 0 || EVP_DigestUpdate(md_ctx, md, 2) <= 0 || EVP_DigestUpdate(md_ctx, rec->input, rec->length) <= 0 || EVP_DigestFinal_ex(md_ctx, md, NULL) <= 0 || EVP_MD_CTX_copy_ex(md_ctx, hash) <= 0 || EVP_DigestUpdate(md_ctx, mac_sec, md_size) <= 0 || EVP_DigestUpdate(md_ctx, ssl3_pad_2, npad) <= 0 || EVP_DigestUpdate(md_ctx, md, md_size) <= 0 || EVP_DigestFinal_ex(md_ctx, md, &md_size_u) <= 0) { EVP_MD_CTX_reset(md_ctx); return -1; } md_size = md_size_u; EVP_MD_CTX_free(md_ctx); } ssl3_record_sequence_update(seq); return (md_size); } int tls1_mac(SSL *ssl, SSL3_RECORD *rec, unsigned char *md, int send) { unsigned char *seq; EVP_MD_CTX *hash; size_t md_size; int i; EVP_MD_CTX *hmac = NULL, *mac_ctx; unsigned char header[13]; int stream_mac = (send ? (ssl->mac_flags & SSL_MAC_FLAG_WRITE_MAC_STREAM) : (ssl->mac_flags & SSL_MAC_FLAG_READ_MAC_STREAM)); int t; if (send) { seq = RECORD_LAYER_get_write_sequence(&ssl->rlayer); hash = ssl->write_hash; } else { seq = RECORD_LAYER_get_read_sequence(&ssl->rlayer); hash = ssl->read_hash; } t = EVP_MD_CTX_size(hash); OPENSSL_assert(t >= 0); md_size = t; /* I should fix this up TLS TLS TLS TLS TLS XXXXXXXX */ if (stream_mac) { mac_ctx = hash; } else { hmac = EVP_MD_CTX_new(); if (hmac == NULL || !EVP_MD_CTX_copy(hmac, hash)) return -1; mac_ctx = hmac; } if (SSL_IS_DTLS(ssl)) { unsigned char dtlsseq[8], *p = dtlsseq; s2n(send ? DTLS_RECORD_LAYER_get_w_epoch(&ssl->rlayer) : DTLS_RECORD_LAYER_get_r_epoch(&ssl->rlayer), p); memcpy(p, &seq[2], 6); memcpy(header, dtlsseq, 8); } else memcpy(header, seq, 8); header[8] = rec->type; header[9] = (unsigned char)(ssl->version >> 8); header[10] = (unsigned char)(ssl->version); header[11] = (rec->length) >> 8; header[12] = (rec->length) & 0xff; if (!send && !SSL_READ_ETM(ssl) && EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE && ssl3_cbc_record_digest_supported(mac_ctx)) { /* * This is a CBC-encrypted record. We must avoid leaking any * timing-side channel information about how many blocks of data we * are hashing because that gives an attacker a timing-oracle. */ /* Final param == not SSLv3 */ if (ssl3_cbc_digest_record(mac_ctx, md, &md_size, header, rec->input, rec->length + md_size, rec->orig_len, ssl->s3->read_mac_secret, ssl->s3->read_mac_secret_size, 0) <= 0) { EVP_MD_CTX_free(hmac); return -1; } } else { if (EVP_DigestSignUpdate(mac_ctx, header, sizeof(header)) <= 0 || EVP_DigestSignUpdate(mac_ctx, rec->input, rec->length) <= 0 || EVP_DigestSignFinal(mac_ctx, md, &md_size) <= 0) { EVP_MD_CTX_free(hmac); return -1; } if (!send && !SSL_READ_ETM(ssl) && FIPS_mode()) if (!tls_fips_digest_extra(ssl->enc_read_ctx, mac_ctx, rec->input, rec->length, rec->orig_len)) { EVP_MD_CTX_free(hmac); return -1; } } EVP_MD_CTX_free(hmac); #ifdef SSL_DEBUG fprintf(stderr, "seq="); { int z; for (z = 0; z < 8; z++) fprintf(stderr, "%02X ", seq[z]); fprintf(stderr, "\n"); } fprintf(stderr, "rec="); { unsigned int z; for (z = 0; z < rec->length; z++) fprintf(stderr, "%02X ", rec->data[z]); fprintf(stderr, "\n"); } #endif if (!SSL_IS_DTLS(ssl)) { for (i = 7; i >= 0; i--) { ++seq[i]; if (seq[i] != 0) break; } } #ifdef SSL_DEBUG { unsigned int z; for (z = 0; z < md_size; z++) fprintf(stderr, "%02X ", md[z]); fprintf(stderr, "\n"); } #endif return (md_size); } /*- * ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC * record in |rec| by updating |rec->length| in constant time. * * block_size: the block size of the cipher used to encrypt the record. * returns: * 0: (in non-constant time) if the record is publicly invalid. * 1: if the padding was valid * -1: otherwise. */ int ssl3_cbc_remove_padding(SSL3_RECORD *rec, unsigned block_size, unsigned mac_size) { unsigned padding_length, good; const unsigned overhead = 1 /* padding length byte */ + mac_size; /* * These lengths are all public so we can test them in non-constant time. */ if (overhead > rec->length) return 0; padding_length = rec->data[rec->length - 1]; good = constant_time_ge(rec->length, padding_length + overhead); /* SSLv3 requires that the padding is minimal. */ good &= constant_time_ge(block_size, padding_length + 1); rec->length -= good & (padding_length + 1); return constant_time_select_int(good, 1, -1); } /*- * tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC * record in |rec| in constant time and returns 1 if the padding is valid and * -1 otherwise. It also removes any explicit IV from the start of the record * without leaking any timing about whether there was enough space after the * padding was removed. * * block_size: the block size of the cipher used to encrypt the record. * returns: * 0: (in non-constant time) if the record is publicly invalid. * 1: if the padding was valid * -1: otherwise. */ int tls1_cbc_remove_padding(const SSL *s, SSL3_RECORD *rec, unsigned block_size, unsigned mac_size) { unsigned padding_length, good, to_check, i; const unsigned overhead = 1 /* padding length byte */ + mac_size; /* Check if version requires explicit IV */ if (SSL_USE_EXPLICIT_IV(s)) { /* * These lengths are all public so we can test them in non-constant * time. */ if (overhead + block_size > rec->length) return 0; /* We can now safely skip explicit IV */ rec->data += block_size; rec->input += block_size; rec->length -= block_size; rec->orig_len -= block_size; } else if (overhead > rec->length) return 0; padding_length = rec->data[rec->length - 1]; if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_read_ctx)) & EVP_CIPH_FLAG_AEAD_CIPHER) { /* padding is already verified */ rec->length -= padding_length + 1; return 1; } good = constant_time_ge(rec->length, overhead + padding_length); /* * The padding consists of a length byte at the end of the record and * then that many bytes of padding, all with the same value as the length * byte. Thus, with the length byte included, there are i+1 bytes of * padding. We can't check just |padding_length+1| bytes because that * leaks decrypted information. Therefore we always have to check the * maximum amount of padding possible. (Again, the length of the record * is public information so we can use it.) */ to_check = 256; /* maximum amount of padding, inc length byte. */ if (to_check > rec->length) to_check = rec->length; for (i = 0; i < to_check; i++) { unsigned char mask = constant_time_ge_8(padding_length, i); unsigned char b = rec->data[rec->length - 1 - i]; /* * The final |padding_length+1| bytes should all have the value * |padding_length|. Therefore the XOR should be zero. */ good &= ~(mask & (padding_length ^ b)); } /* * If any of the final |padding_length+1| bytes had the wrong value, one * or more of the lower eight bits of |good| will be cleared. */ good = constant_time_eq(0xff, good & 0xff); rec->length -= good & (padding_length + 1); return constant_time_select_int(good, 1, -1); } /*- * ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in * constant time (independent of the concrete value of rec->length, which may * vary within a 256-byte window). * * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to * this function. * * On entry: * rec->orig_len >= md_size * md_size <= EVP_MAX_MD_SIZE * * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into * a single or pair of cache-lines, then the variable memory accesses don't * actually affect the timing. CPUs with smaller cache-lines [if any] are * not multi-core and are not considered vulnerable to cache-timing attacks. */ #define CBC_MAC_ROTATE_IN_PLACE void ssl3_cbc_copy_mac(unsigned char *out, const SSL3_RECORD *rec, unsigned md_size) { #if defined(CBC_MAC_ROTATE_IN_PLACE) unsigned char rotated_mac_buf[64 + EVP_MAX_MD_SIZE]; unsigned char *rotated_mac; #else unsigned char rotated_mac[EVP_MAX_MD_SIZE]; #endif /* * mac_end is the index of |rec->data| just after the end of the MAC. */ unsigned mac_end = rec->length; unsigned mac_start = mac_end - md_size; unsigned in_mac; /* * scan_start contains the number of bytes that we can ignore because the * MAC's position can only vary by 255 bytes. */ unsigned scan_start = 0; unsigned i, j; unsigned rotate_offset; OPENSSL_assert(rec->orig_len >= md_size); OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE); #if defined(CBC_MAC_ROTATE_IN_PLACE) rotated_mac = rotated_mac_buf + ((0 - (size_t)rotated_mac_buf) & 63); #endif /* This information is public so it's safe to branch based on it. */ if (rec->orig_len > md_size + 255 + 1) scan_start = rec->orig_len - (md_size + 255 + 1); in_mac = 0; rotate_offset = 0; memset(rotated_mac, 0, md_size); for (i = scan_start, j = 0; i < rec->orig_len; i++) { unsigned mac_started = constant_time_eq(i, mac_start); unsigned mac_ended = constant_time_lt(i, mac_end); unsigned char b = rec->data[i]; in_mac |= mac_started; in_mac &= mac_ended; rotate_offset |= j & mac_started; rotated_mac[j++] |= b & in_mac; j &= constant_time_lt(j, md_size); } /* Now rotate the MAC */ #if defined(CBC_MAC_ROTATE_IN_PLACE) j = 0; for (i = 0; i < md_size; i++) { /* in case cache-line is 32 bytes, touch second line */ ((volatile unsigned char *)rotated_mac)[rotate_offset ^ 32]; out[j++] = rotated_mac[rotate_offset++]; rotate_offset &= constant_time_lt(rotate_offset, md_size); } #else memset(out, 0, md_size); rotate_offset = md_size - rotate_offset; rotate_offset &= constant_time_lt(rotate_offset, md_size); for (i = 0; i < md_size; i++) { for (j = 0; j < md_size; j++) out[j] |= rotated_mac[i] & constant_time_eq_8(j, rotate_offset); rotate_offset++; rotate_offset &= constant_time_lt(rotate_offset, md_size); } #endif } int dtls1_process_record(SSL *s, DTLS1_BITMAP *bitmap) { int i, al; int enc_err; SSL_SESSION *sess; SSL3_RECORD *rr; unsigned int mac_size; unsigned char md[EVP_MAX_MD_SIZE]; rr = RECORD_LAYER_get_rrec(&s->rlayer); sess = s->session; /* * At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length, * and we have that many bytes in s->packet */ rr->input = &(RECORD_LAYER_get_packet(&s->rlayer)[DTLS1_RT_HEADER_LENGTH]); /* * ok, we can now read from 's->packet' data into 'rr' rr->input points * at rr->length bytes, which need to be copied into rr->data by either * the decryption or by the decompression When the data is 'copied' into * the rr->data buffer, rr->input will be pointed at the new buffer */ /* * We now have - encrypted [ MAC [ compressed [ plain ] ] ] rr->length * bytes of encrypted compressed stuff. */ /* check is not needed I believe */ if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_DTLS1_PROCESS_RECORD, SSL_R_ENCRYPTED_LENGTH_TOO_LONG); goto f_err; } /* decrypt in place in 'rr->input' */ rr->data = rr->input; rr->orig_len = rr->length; enc_err = s->method->ssl3_enc->enc(s, rr, 1, 0); /*- * enc_err is: * 0: (in non-constant time) if the record is publically invalid. * 1: if the padding is valid * -1: if the padding is invalid */ if (enc_err == 0) { /* For DTLS we simply ignore bad packets. */ rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); goto err; } #ifdef SSL_DEBUG printf("dec %d\n", rr->length); { unsigned int z; for (z = 0; z < rr->length; z++) printf("%02X%c", rr->data[z], ((z + 1) % 16) ? ' ' : '\n'); } printf("\n"); #endif /* r->length is now the compressed data plus mac */ if ((sess != NULL) && (s->enc_read_ctx != NULL) && (EVP_MD_CTX_md(s->read_hash) != NULL)) { /* s->read_hash != NULL => mac_size != -1 */ unsigned char *mac = NULL; unsigned char mac_tmp[EVP_MAX_MD_SIZE]; mac_size = EVP_MD_CTX_size(s->read_hash); OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE); /* * orig_len is the length of the record before any padding was * removed. This is public information, as is the MAC in use, * therefore we can safely process the record in a different amount * of time if it's too short to possibly contain a MAC. */ if (rr->orig_len < mac_size || /* CBC records must have a padding length byte too. */ (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE && rr->orig_len < mac_size + 1)) { al = SSL_AD_DECODE_ERROR; SSLerr(SSL_F_DTLS1_PROCESS_RECORD, SSL_R_LENGTH_TOO_SHORT); goto f_err; } if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) { /* * We update the length so that the TLS header bytes can be * constructed correctly but we need to extract the MAC in * constant time from within the record, without leaking the * contents of the padding bytes. */ mac = mac_tmp; ssl3_cbc_copy_mac(mac_tmp, rr, mac_size); rr->length -= mac_size; } else { /* * In this case there's no padding, so |rec->orig_len| equals * |rec->length| and we checked that there's enough bytes for * |mac_size| above. */ rr->length -= mac_size; mac = &rr->data[rr->length]; } i = s->method->ssl3_enc->mac(s, rr, md, 0 /* not send */ ); if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) enc_err = -1; if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size) enc_err = -1; } if (enc_err < 0) { /* decryption failed, silently discard message */ rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); goto err; } /* r->length is now just compressed */ if (s->expand != NULL) { if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_DTLS1_PROCESS_RECORD, SSL_R_COMPRESSED_LENGTH_TOO_LONG); goto f_err; } if (!ssl3_do_uncompress(s, rr)) { al = SSL_AD_DECOMPRESSION_FAILURE; SSLerr(SSL_F_DTLS1_PROCESS_RECORD, SSL_R_BAD_DECOMPRESSION); goto f_err; } } if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_DTLS1_PROCESS_RECORD, SSL_R_DATA_LENGTH_TOO_LONG); goto f_err; } rr->off = 0; /*- * So at this point the following is true * ssl->s3->rrec.type is the type of record * ssl->s3->rrec.length == number of bytes in record * ssl->s3->rrec.off == offset to first valid byte * ssl->s3->rrec.data == where to take bytes from, increment * after use :-). */ /* we have pulled in a full packet so zero things */ RECORD_LAYER_reset_packet_length(&s->rlayer); /* Mark receipt of record. */ dtls1_record_bitmap_update(s, bitmap); return (1); f_err: ssl3_send_alert(s, SSL3_AL_FATAL, al); err: return (0); } /* * retrieve a buffered record that belongs to the current epoch, ie, * processed */ #define dtls1_get_processed_record(s) \ dtls1_retrieve_buffered_record((s), \ &(DTLS_RECORD_LAYER_get_processed_rcds(&s->rlayer))) /*- * 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 dtls1_read_bytes */ int dtls1_get_record(SSL *s) { int ssl_major, ssl_minor; int i, n; SSL3_RECORD *rr; unsigned char *p = NULL; unsigned short version; DTLS1_BITMAP *bitmap; unsigned int is_next_epoch; rr = RECORD_LAYER_get_rrec(&s->rlayer); again: /* * The epoch may have changed. If so, process all the pending records. * This is a non-blocking operation. */ if (!dtls1_process_buffered_records(s)) return -1; /* if we're renegotiating, then there may be buffered records */ if (dtls1_get_processed_record(s)) return 1; /* get something from the wire */ /* check if we have the header */ if ((RECORD_LAYER_get_rstate(&s->rlayer) != SSL_ST_READ_BODY) || (RECORD_LAYER_get_packet_length(&s->rlayer) < DTLS1_RT_HEADER_LENGTH)) { n = ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH, SSL3_BUFFER_get_len(&s->rlayer.rbuf), 0, 1); /* read timeout is handled by dtls1_read_bytes */ if (n <= 0) return (n); /* error or non-blocking */ /* this packet contained a partial record, dump it */ if (RECORD_LAYER_get_packet_length(&s->rlayer) != DTLS1_RT_HEADER_LENGTH) { RECORD_LAYER_reset_packet_length(&s->rlayer); goto again; } RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_BODY); p = RECORD_LAYER_get_packet(&s->rlayer); if (s->msg_callback) s->msg_callback(0, 0, SSL3_RT_HEADER, p, DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg); /* Pull apart the header into the DTLS1_RECORD */ rr->type = *(p++); ssl_major = *(p++); ssl_minor = *(p++); version = (ssl_major << 8) | ssl_minor; /* sequence number is 64 bits, with top 2 bytes = epoch */ n2s(p, rr->epoch); memcpy(&(RECORD_LAYER_get_read_sequence(&s->rlayer)[2]), p, 6); p += 6; n2s(p, rr->length); /* Lets check version */ if (!s->first_packet) { if (version != s->version) { /* unexpected version, silently discard */ rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); goto again; } } if ((version & 0xff00) != (s->version & 0xff00)) { /* wrong version, silently discard record */ rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); goto again; } if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) { /* record too long, silently discard it */ rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); goto again; } /* now s->rlayer.rstate == SSL_ST_READ_BODY */ } /* s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data */ if (rr->length > RECORD_LAYER_get_packet_length(&s->rlayer) - DTLS1_RT_HEADER_LENGTH) { /* now s->packet_length == DTLS1_RT_HEADER_LENGTH */ i = rr->length; n = ssl3_read_n(s, i, i, 1, 1); /* this packet contained a partial record, dump it */ if (n != i) { rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); goto again; } /* * now n == rr->length, and s->packet_length == * DTLS1_RT_HEADER_LENGTH + rr->length */ } /* set state for later operations */ RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_HEADER); /* match epochs. NULL means the packet is dropped on the floor */ bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch); if (bitmap == NULL) { rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */ goto again; /* get another record */ } #ifndef OPENSSL_NO_SCTP /* Only do replay check if no SCTP bio */ if (!BIO_dgram_is_sctp(SSL_get_rbio(s))) { #endif /* Check whether this is a repeat, or aged record. */ /* * TODO: Does it make sense to have replay protection in epoch 0 where * we have no integrity negotiated yet? */ if (!dtls1_record_replay_check(s, bitmap)) { rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */ goto again; /* get another record */ } #ifndef OPENSSL_NO_SCTP } #endif /* just read a 0 length packet */ if (rr->length == 0) goto again; /* * If this record is from the next epoch (either HM or ALERT), and a * handshake is currently in progress, buffer it since it cannot be * processed at this time. */ if (is_next_epoch) { if ((SSL_in_init(s) || ossl_statem_get_in_handshake(s))) { if (dtls1_buffer_record (s, &(DTLS_RECORD_LAYER_get_unprocessed_rcds(&s->rlayer)), rr->seq_num) < 0) return -1; } rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); goto again; } if (!dtls1_process_record(s, bitmap)) { rr->length = 0; RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */ goto again; /* get another record */ } return (1); }