diff options
Diffstat (limited to 'openssl-1.1.0h/ssl/record/ssl3_record.c')
| -rw-r--r-- | openssl-1.1.0h/ssl/record/ssl3_record.c | 1641 |
1 files changed, 1641 insertions, 0 deletions
diff --git a/openssl-1.1.0h/ssl/record/ssl3_record.c b/openssl-1.1.0h/ssl/record/ssl3_record.c new file mode 100644 index 0000000..c7a54fe --- /dev/null +++ b/openssl-1.1.0h/ssl/record/ssl3_record.c @@ -0,0 +1,1641 @@ +/* + * Copyright 1995-2018 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 <assert.h> +#include "../ssl_locl.h" +#include "internal/constant_time_locl.h" +#include <openssl/rand.h> +#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 sending) +{ + 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 (sending) { + 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) && sending) { + 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 (!sending) { + 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) && !sending) + 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 sending) +{ + 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 (n_recs == 0) + return 0; + + if (sending) { + 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 = sending ? 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(sending ? 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 (sending) { + reclen[ctr] += pad; + recs[ctr].length += pad; + } + + } else if ((bs != 1) && sending) { + 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 (!sending) { + 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 (sending == 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) && !sending) { + 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 && !sending) { + 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 sending) +{ + unsigned char *mac_sec, *seq; + const EVP_MD_CTX *hash; + unsigned char *p, rec_char; + size_t md_size; + int npad; + int t; + + if (sending) { + 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 (!sending && + 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_free(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 sending) +{ + 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 = (sending ? (ssl->mac_flags & SSL_MAC_FLAG_WRITE_MAC_STREAM) + : (ssl->mac_flags & SSL_MAC_FLAG_READ_MAC_STREAM)); + int t; + + if (sending) { + 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)) { + EVP_MD_CTX_free(hmac); + return -1; + } + mac_ctx = hmac; + } + + if (SSL_IS_DTLS(ssl)) { + unsigned char dtlsseq[8], *p = dtlsseq; + + s2n(sending ? 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 (!sending && !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 (!sending && !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, i.e. 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 the version. We tolerate alerts that don't have the exact + * version number (e.g. because of protocol version errors) + */ + if (!s->first_packet && rr->type != SSL3_RT_ALERT) { + 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); + +} |