*/
#include <stdio.h>
+#include <limits.h>
#include <errno.h>
#define USE_SOCKETS
#include "ssl_locl.h"
return(n);
}
+/* 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
+
/* 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.
unsigned char *p;
unsigned char md[EVP_MAX_MD_SIZE];
short version;
- int mac_size;
- int clear=0;
+ unsigned mac_size, orig_len;
size_t extra;
- int decryption_failed_or_bad_record_mac = 0;
- unsigned char *mac = NULL;
+ unsigned empty_record_count = 0;
rr= &(s->s3->rrec);
sess=s->session;
if (version != s->version)
{
SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
- if ((s->version & 0xFF00) == (version & 0xFF00))
+ if ((s->version & 0xFF00) == (version & 0xFF00) && !s->enc_write_ctx && !s->write_hash)
/* Send back error using their minor version number :-) */
s->version = (unsigned short)version;
al=SSL_AD_PROTOCOL_VERSION;
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)
{
- if (enc_err == 0)
- /* SSLerr() and ssl3_send_alert() have been called */
- goto err;
-
- /* Otherwise enc_err == -1, which indicates bad padding
- * (rec->length has not been changed in this case).
- * To minimize information leaked via timing, we will perform
- * the MAC computation anyway. */
- decryption_failed_or_bad_record_mac = 1;
+ al=SSL_AD_DECRYPTION_FAILED;
+ SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
+ goto f_err;
}
#ifdef TLS_DEBUG
#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))
- 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 */
+ /* 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 >= 0);
+ OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
- if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_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 (then rr->length is visible from ciphertext anyway) */
- al=SSL_AD_RECORD_OVERFLOW;
- SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
+ al=SSL_AD_DECODE_ERROR;
+ SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
goto f_err;
-#else
- decryption_failed_or_bad_record_mac = 1;
-#endif
}
- /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
- if (rr->length >= (unsigned int)mac_size)
+
+ 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, orig_len);
rr->length -= mac_size;
- mac = &rr->data[rr->length];
}
else
{
- /* record (minus padding) is too short to contain a MAC */
-#if 0 /* OK only for stream ciphers */
- al=SSL_AD_DECODE_ERROR;
- SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
- goto f_err;
-#else
- decryption_failed_or_bad_record_mac = 1;
- rr->length = 0;
-#endif
- }
- i=s->method->ssl3_enc->mac(s,md,0);
- if (i < 0 || mac == NULL || memcmp(md, mac, (size_t)mac_size) != 0)
- {
- decryption_failed_or_bad_record_mac = 1;
+ /* 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+extra+mac_size)
+ enc_err = -1;
}
- if (decryption_failed_or_bad_record_mac)
+ 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
s->packet_length=0;
/* just read a 0 length packet */
- if (rr->length == 0) goto again;
+ if (rr->length == 0)
+ {
+ empty_record_count++;
+ if (empty_record_count > MAX_EMPTY_RECORDS)
+ {
+ al=SSL_AD_UNEXPECTED_MESSAGE;
+ SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_RECORD_TOO_SMALL);
+ goto f_err;
+ }
+ goto again;
+ }
#if 0
fprintf(stderr, "Ultimate Record type=%d, Length=%d\n", rr->type, rr->length);
int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len)
{
const unsigned char *buf=buf_;
- unsigned int tot,n,nw;
- int i;
+ unsigned int n,nw;
+ int i,tot;
s->rwstate=SSL_NOTHING;
+ OPENSSL_assert(s->s3->wnum <= INT_MAX);
tot=s->s3->wnum;
s->s3->wnum=0;
}
}
+ /* ensure that if we end up with a smaller value of data to write
+ * out than the the original len from a write which didn't complete
+ * for non-blocking I/O and also somehow ended up avoiding
+ * the check for this in ssl3_write_pending/SSL_R_BAD_WRITE_RETRY as
+ * it must never be possible to end up with (len-tot) as a large
+ * number that will then promptly send beyond the end of the users
+ * buffer ... so we trap and report the error in a way the user
+ * will notice
+ */
+ if (len < tot)
+ {
+ SSLerr(SSL_F_SSL3_WRITE_BYTES,SSL_R_BAD_LENGTH);
+ return(-1);
+ }
+
+
n=(len-tot);
for (;;)
{
SSL3_BUFFER *wb=&(s->s3->wbuf);
SSL_SESSION *sess;
- if (wb->buf == NULL)
- if (!ssl3_setup_write_buffer(s))
- return -1;
/* first check if there is a SSL3_BUFFER still being written
* out. This will happen with non blocking IO */
/* if it went, fall through and send more stuff */
}
+ if (wb->buf == NULL)
+ if (!ssl3_setup_write_buffer(s))
+ return -1;
+
if (len == 0 && !create_empty_fragment)
return 0;
if ( (sess == NULL) ||
(s->enc_write_ctx == NULL) ||
(EVP_MD_CTX_md(s->write_hash) == NULL))
+ {
+#if 1
+ clear=s->enc_write_ctx?0:1; /* must be AEAD cipher */
+#else
clear=1;
-
- if (clear)
+#endif
mac_size=0;
+ }
else
{
mac_size=EVP_MD_CTX_size(s->write_hash);
wr->type=type;
*(p++)=(s->version>>8);
- *(p++)=s->version&0xff;
+ /* Some servers hang if iniatial client hello is larger than 256
+ * bytes and record version number > TLS 1.0
+ */
+ if (s->state == SSL3_ST_CW_CLNT_HELLO_B
+ && !s->renegotiate
+ && TLS1_get_version(s) > TLS1_VERSION)
+ *(p++) = 0x1;
+ else
+ *(p++)=s->version&0xff;
/* field where we are to write out packet length */
plen=p;
if (!ssl3_setup_read_buffer(s))
return(-1);
- if ((type && (type != SSL3_RT_APPLICATION_DATA) && (type != SSL3_RT_HANDSHAKE) && type) ||
+ if ((type && (type != SSL3_RT_APPLICATION_DATA) && (type != SSL3_RT_HANDSHAKE)) ||
(peek && (type != SSL3_RT_APPLICATION_DATA)))
{
SSLerr(SSL_F_SSL3_READ_BYTES, ERR_R_INTERNAL_ERROR);
{
s->rstate=SSL_ST_READ_HEADER;
rr->off=0;
- if (s->mode & SSL_MODE_RELEASE_BUFFERS)
+ if (s->mode & SSL_MODE_RELEASE_BUFFERS && s->s3->rbuf.left == 0)
ssl3_release_read_buffer(s);
}
}
dest = s->s3->alert_fragment;
dest_len = &s->s3->alert_fragment_len;
}
+#ifndef OPENSSL_NO_HEARTBEATS
+ else if (rr->type == TLS1_RT_HEARTBEAT)
+ {
+ tls1_process_heartbeat(s);
+
+ /* Exit and notify application to read again */
+ rr->length = 0;
+ s->rwstate=SSL_READING;
+ BIO_clear_retry_flags(SSL_get_rbio(s));
+ BIO_set_retry_read(SSL_get_rbio(s));
+ return(-1);
+ }
+#endif
if (dest_maxlen > 0)
{
goto f_err;
}
#ifdef SSL_AD_MISSING_SRP_USERNAME
- if (alert_descr == SSL_AD_MISSING_SRP_USERNAME)
+ else if (alert_descr == SSL_AD_MISSING_SRP_USERNAME)
return(0);
#endif
}
goto f_err;
}
+ if (!(s->s3->flags & SSL3_FLAGS_CCS_OK))
+ {
+ al=SSL_AD_UNEXPECTED_MESSAGE;
+ SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_CCS_RECEIVED_EARLY);
+ goto f_err;
+ }
+
+ s->s3->flags &= ~SSL3_FLAGS_CCS_OK;
+
rr->length=0;
if (s->msg_callback)
int ssl3_do_change_cipher_spec(SSL *s)
{
int i;
-#ifdef OPENSSL_NO_NEXTPROTONEG
const char *sender;
int slen;
-#endif
if (s->state & SSL_ST_ACCEPT)
i=SSL3_CHANGE_CIPHER_SERVER_READ;
if (s->s3->tmp.key_block == NULL)
{
- if (s->session == NULL)
+ if (s->session == NULL || s->session->master_key_length == 0)
{
/* might happen if dtls1_read_bytes() calls this */
SSLerr(SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC,SSL_R_CCS_RECEIVED_EARLY);
if (!s->method->ssl3_enc->change_cipher_state(s,i))
return(0);
-#ifdef OPENSSL_NO_NEXTPROTONEG
/* we have to record the message digest at
* this point so we can get it before we read
* the finished message */
slen=s->method->ssl3_enc->client_finished_label_len;
}
- s->s3->tmp.peer_finish_md_len = s->method->ssl3_enc->final_finish_mac(s,
+ i = s->method->ssl3_enc->final_finish_mac(s,
sender,slen,s->s3->tmp.peer_finish_md);
-#endif
+ if (i == 0)
+ {
+ SSLerr(SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+ s->s3->tmp.peer_finish_md_len = i;
return(1);
}
projects / openssl.git / blobdiff