X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=ssl%2Fd1_pkt.c;h=438c0913d24e7207e30e956f5dc64b36d7449905;hp=f66f33cf6395a7d2e88ea9a070ad978bf7572284;hb=d70c0be4c1e33985a79d691786db72661fdfd057;hpb=bd6941cfaa31ee8a3f8661cb98227a5cbcc0f9f3 diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c index f66f33cf63..438c0913d2 100644 --- a/ssl/d1_pkt.c +++ b/ssl/d1_pkt.c @@ -179,7 +179,6 @@ static int dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr, static int dtls1_buffer_record(SSL *s, record_pqueue *q, unsigned char *priority); static int dtls1_process_record(SSL *s); -static void dtls1_clear_timeouts(SSL *s); /* copy buffered record into SSL structure */ static int @@ -240,14 +239,6 @@ dtls1_buffer_record(SSL *s, record_pqueue *queue, unsigned char *priority) } #endif - /* insert should not fail, since duplicates are dropped */ - if (pqueue_insert(queue->q, item) == NULL) - { - OPENSSL_free(rdata); - pitem_free(item); - return(0); - } - s->packet = NULL; s->packet_length = 0; memset(&(s->s3->rbuf), 0, sizeof(SSL3_BUFFER)); @@ -260,7 +251,16 @@ dtls1_buffer_record(SSL *s, record_pqueue *queue, unsigned char *priority) pitem_free(item); return(0); } - + + /* insert should not fail, since duplicates are dropped */ + if (pqueue_insert(queue->q, item) == NULL) + { + SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR); + OPENSSL_free(rdata); + pitem_free(item); + return(0); + } + return(1); } @@ -377,14 +377,12 @@ static int dtls1_process_record(SSL *s) { int i,al; - int clear=0; int enc_err; SSL_SESSION *sess; SSL3_RECORD *rr; - unsigned int mac_size; + unsigned int mac_size, orig_len; unsigned char md[EVP_MAX_MD_SIZE]; - rr= &(s->s3->rrec); sess = s->session; @@ -415,14 +413,15 @@ dtls1_process_record(SSL *s) rr->data=rr->input; enc_err = s->method->ssl3_enc->enc(s,0); - if (enc_err <= 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) { - /* decryption failed, silently discard message */ - if (enc_err < 0) - { - rr->length = 0; - s->packet_length = 0; - } + /* For DTLS we simply ignore bad packets. */ + rr->length = 0; + s->packet_length = 0; goto err; } @@ -433,46 +432,67 @@ printf("\n"); #endif /* r->length is now the compressed data plus mac */ - if ( (sess == NULL) || - (s->enc_read_ctx == NULL) || - (s->read_hash == NULL)) - clear=1; - - if (!clear) + if ((sess != NULL) && + (s->enc_read_ctx != NULL) && + (EVP_MD_CTX_md(s->read_hash) != NULL)) { - /* !clear => s->read_hash != NULL => mac_size != -1 */ - int t; - t=EVP_MD_CTX_size(s->read_hash); - OPENSSL_assert(t >= 0); - mac_size=t; - - if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size) - { -#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */ - al=SSL_AD_RECORD_OVERFLOW; - SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG); - goto f_err; -#else - goto err; -#endif - } - /* check the MAC for rr->input (it's in mac_size bytes at the tail) */ - if (rr->length < mac_size) + /* 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); + + /* kludge: *_cbc_remove_padding passes padding length in rr->type */ + orig_len = rr->length+((unsigned int)rr->type>>8); + + /* 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 (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 && + orig_len < mac_size+1)) { -#if 0 /* OK only for stream ciphers */ al=SSL_AD_DECODE_ERROR; SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT); goto f_err; -#else - goto err; -#endif } - rr->length-=mac_size; - i=s->method->ssl3_enc->mac(s,md,0); - if (i < 0 || memcmp(md,&(rr->data[rr->length]),mac_size) != 0) + + if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) { - goto err; + /* 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, orig_len); + rr->length -= mac_size; + } + else + { + /* In this case there's no padding, so |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,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; + s->packet_length = 0; + goto err; } /* r->length is now just compressed */ @@ -695,7 +715,6 @@ again: goto again; /* get another record */ } - dtls1_clear_timeouts(s); /* done waiting */ return(1); } @@ -829,6 +848,12 @@ start: } } + if (s->d1->listen && rr->type != SSL3_RT_HANDSHAKE) + { + rr->length = 0; + goto start; + } + /* we now have a packet which can be read and processed */ if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec, @@ -1033,6 +1058,7 @@ start: !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) && !s->s3->renegotiate) { + s->d1->handshake_read_seq++; s->new_session = 1; ssl3_renegotiate(s); if (ssl3_renegotiate_check(s)) @@ -1247,6 +1273,9 @@ start: */ if (msg_hdr.type == SSL3_MT_FINISHED) { + if (dtls1_check_timeout_num(s) < 0) + return -1; + dtls1_retransmit_buffered_messages(s); rr->length = 0; goto start; @@ -1870,10 +1899,3 @@ dtls1_reset_seq_numbers(SSL *s, int rw) memset(seq, 0x00, seq_bytes); } - - -static void -dtls1_clear_timeouts(SSL *s) - { - memset(&(s->d1->timeout), 0x00, sizeof(struct dtls1_timeout_st)); - }