Tolerate fragmentation and interleaving in the SSL 3/TLS record layer.
diff --git a/ssl/s3_pkt.c b/ssl/s3_pkt.c
index 2f56df3..fcb3d17 100644
--- a/ssl/s3_pkt.c
+++ b/ssl/s3_pkt.c
@@ -125,6 +125,7 @@
static int do_uncompress(SSL *ssl);
static int do_change_cipher_spec(SSL *ssl);
+/* used only by ssl3_get_record */
static int ssl3_read_n(SSL *s, int n, int max, int extend)
{
/* If extend == 0, obtain new n-byte packet; if extend == 1, increase
@@ -184,7 +185,7 @@
memmove(s->s3->rbuf.buf, s->packet, off+newb);
s->packet = s->s3->rbuf.buf;
}
-
+
while (newb < n)
{
/* Now we have off+newb bytes at the front of s->s3->rbuf.buf and need
@@ -226,11 +227,11 @@
* ssl->s3->rrec.data, - data
* ssl->s3->rrec.length, - number of bytes
*/
+/* used only by ssl3_read_bytes */
static int ssl3_get_record(SSL *s)
{
int ssl_major,ssl_minor,al;
int n,i,ret= -1;
- SSL3_BUFFER *rb;
SSL3_RECORD *rr;
SSL_SESSION *sess;
unsigned char *p;
@@ -240,7 +241,6 @@
int clear=0,extra;
rr= &(s->s3->rrec);
- rb= &(s->s3->rbuf);
sess=s->session;
if (s->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER)
@@ -499,7 +499,7 @@
nw=SSL3_RT_MAX_PLAIN_LENGTH;
else
nw=n;
-
+
i=do_ssl3_write(s,type,&(buf[tot]),nw);
if (i <= 0)
{
@@ -546,7 +546,7 @@
}
if (len == 0) return(len);
-
+
wr= &(s->s3->wrec);
wb= &(s->s3->wbuf);
sess=s->session;
@@ -569,11 +569,11 @@
*(p++)=(s->version>>8);
*(p++)=s->version&0xff;
-
+
/* record where we are to write out packet length */
plen=p;
p+=2;
-
+
/* lets setup the record stuff. */
wr->data=p;
wr->length=(int)len;
@@ -680,6 +680,33 @@
}
}
+/* Return up to 'len' payload bytes received in 'type' records.
+ * 'type' is one of the following:
+ *
+ * - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
+ * - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
+ * - 0 (during a shutdown, no data has to be returned)
+ *
+ * If we don't have stored data to work from, read a SSL/TLS record first
+ * (possibly multiple records if we still don't have anything to return).
+ *
+ * This function must handle any surprises the peer may have for us, such as
+ * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
+ * a surprise, but handled as if it were), or renegotiation requests.
+ * Also if record payloads contain fragments too small to process, we store
+ * them until there is enough for the respective protocol (the record protocol
+ * may use arbitrary fragmentation and even interleaving):
+ * Change cipher spec protocol
+ * just 1 byte needed, no need for keeping anything stored
+ * Alert protocol
+ * 2 bytes needed (AlertLevel, AlertDescription)
+ * Handshake protocol
+ * 4 bytes needed (HandshakeType, uint24 length) -- we just have
+ * to detect unexpected Client Hello and Hello Request messages
+ * here, anything else is handled by higher layers
+ * Application data protocol
+ * none of our business
+ */
int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len)
{
int al,i,j,n,ret;
@@ -691,8 +718,37 @@
if (!ssl3_setup_buffers(s))
return(-1);
+ if ((type != SSL3_RT_APPLICATION_DATA) && (type != SSL3_RT_HANDSHAKE) && type)
+ {
+ SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_INTERNAL_ERROR);
+ return -1;
+ }
+
+ if ((type == SSL3_RT_HANDSHAKE) && (s->s3->handshake_fragment_len > 0))
+ /* (partially) satisfy request from storage */
+ {
+ unsigned char *src = s->s3->handshake_fragment;
+ unsigned char *dst = buf;
+
+ n = 0;
+ while ((len > 0) && (s->s3->handshake_fragment_len > 0))
+ {
+ *dst++ = *src++;
+ len--; s->s3->handshake_fragment_len--;
+ n++;
+ }
+ /* move any remaining fragment bytes: */
+ for (i = 0; i < s->s3->handshake_fragment_len; i++)
+ s->s3->handshake_fragment[i] = *src++;
+ ssl3_finish_mac(s, buf, n);
+ return n;
+ }
+
+ /* Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */
+
if (!s->in_handshake && SSL_in_init(s))
{
+ /* type == SSL3_RT_APPLICATION_DATA */
i=s->handshake_func(s);
if (i < 0) return(i);
if (i == 0)
@@ -708,7 +764,7 @@
* s->s3->rrec.data, - data
* s->s3->rrec.off, - offset into 'data' for next read
* s->s3->rrec.length, - number of bytes. */
- rr= &(s->s3->rrec);
+ rr = &(s->s3->rrec);
/* get new packet */
if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY))
@@ -719,7 +775,9 @@
/* we now have a packet which can be read and processed */
- if (s->s3->change_cipher_spec && (rr->type != SSL3_RT_HANDSHAKE))
+ if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
+ * reset by ssl3_get_finished */
+ && (rr->type != SSL3_RT_HANDSHAKE))
{
al=SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
@@ -734,13 +792,98 @@
return(0);
}
- /* Check for an incoming 'Hello Request' message from client */
- if ((rr->type == SSL3_RT_HANDSHAKE) && (rr->length == 4) &&
- (rr->data[0] == SSL3_MT_HELLO_REQUEST) &&
+
+ if (type == rr->type) /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
+ {
+ /* make sure that we are not getting application data when we
+ * are doing a handshake for the first time */
+ if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
+ (s->enc_read_ctx == NULL))
+ {
+ al=SSL_AD_UNEXPECTED_MESSAGE;
+ SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_APP_DATA_IN_HANDSHAKE);
+ goto f_err;
+ }
+
+ if (len <= 0) return(len);
+
+ if ((unsigned int)len > rr->length)
+ n=rr->length;
+ else
+ n=len;
+
+ memcpy(buf,&(rr->data[rr->off]),(unsigned int)n);
+ rr->length-=n;
+ rr->off+=n;
+ if (rr->length == 0)
+ {
+ s->rstate=SSL_ST_READ_HEADER;
+ rr->off=0;
+ }
+
+ if (type == SSL3_RT_HANDSHAKE)
+ ssl3_finish_mac(s,buf,n);
+ return(n);
+ }
+
+
+ /* If we get here, then type != rr->type; if we have a handshake
+ * message, then it was unexpected (Hello Request or Client Hello). */
+
+ /* In case of record types for which we have 'fragment' storage,
+ * fill that so that we can process the data at a fixed place.
+ */
+ {
+ int dest_maxlen = 0;
+ unsigned char *dest;
+ int *dest_len;
+
+ if (rr->type == SSL3_RT_HANDSHAKE)
+ {
+ dest_maxlen = sizeof s->s3->handshake_fragment;
+ dest = s->s3->handshake_fragment;
+ dest_len = &s->s3->handshake_fragment_len;
+ }
+ else if (rr->type == SSL3_RT_ALERT)
+ {
+ dest_maxlen = sizeof s->s3->alert_fragment;
+ dest = s->s3->alert_fragment;
+ dest_len = &s->s3->alert_fragment_len;
+ }
+
+ if (dest_maxlen > 0)
+ {
+ n = dest_maxlen - *dest_len; /* available space in 'dest' */
+ if (rr->length < n)
+ n = rr->length; /* available bytes */
+
+ /* now move 'n' bytes: */
+ while (n-- > 0)
+ {
+ dest[(*dest_len)++] = rr->data[rr->off++];
+ rr->length--;
+ }
+
+ if (*dest_len < dest_maxlen)
+ goto start; /* fragment was too small */
+ }
+ }
+
+ /* s->s3->handshake_fragment_len == 4 iff rr->type == SSL3_RT_HANDSHAKE;
+ * s->s3->alert_fragment_len == 2 iff rr->type == SSL3_RT_ALERT.
+ * (Possibly rr is 'empty' now, i.e. rr->length may be 0.) */
+
+ /* If we are a client, check for an incoming 'Hello Request': */
+ if ((!s->server) &&
+ (s->s3->handshake_fragment_len >= 4) &&
+ (s->s3->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
(s->session != NULL) && (s->session->cipher != NULL))
{
- if ((rr->data[1] != 0) || (rr->data[2] != 0) ||
- (rr->data[3] != 0))
+ s->s3->handshake_fragment_len = 0;
+
+ if ((s->s3->handshake_fragment[1] != 0) ||
+ (s->s3->handshake_fragment[2] != 0) ||
+ (s->s3->handshake_fragment[3] != 0))
{
al=SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_BAD_HELLO_REQUEST);
@@ -763,214 +906,176 @@
}
}
}
- rr->length=0;
-/* ZZZ */ goto start;
+ /* we either finished a handshake or ignored the request,
+ * now try again to obtain the (application) data we were asked for */
+ goto start;
}
- /* if it is not the type we want, or we have shutdown and want
- * the peer shutdown */
- if ((rr->type != type) || (s->shutdown & SSL_SENT_SHUTDOWN))
+ if (s->s3->alert_fragment_len >= 2)
{
- if (rr->type == SSL3_RT_ALERT)
+ i = s->s3->alert_fragment[0];
+ n = s->s3->alert_fragment[1];
+
+ s->s3->alert_fragment_len = 0;
+
+ if (s->info_callback != NULL)
+ cb=s->info_callback;
+ else if (s->ctx->info_callback != NULL)
+ cb=s->ctx->info_callback;
+
+ if (cb != NULL)
{
- if ((rr->length != 2) || (rr->off != 0))
+ j=(i<<8)|n;
+ cb(s,SSL_CB_READ_ALERT,j);
+ }
+
+ if (i == 1) /* warning */
+ {
+ s->s3->warn_alert=n;
+ if (n == SSL_AD_CLOSE_NOTIFY)
{
- al=SSL_AD_DECODE_ERROR;
- SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_BAD_ALERT_RECORD);
- goto f_err;
- }
-
- i=rr->data[0];
- n=rr->data[1];
-
- /* clear from buffer */
- rr->length=0;
-
- if (s->info_callback != NULL)
- cb=s->info_callback;
- else if (s->ctx->info_callback != NULL)
- cb=s->ctx->info_callback;
-
- if (cb != NULL)
- {
- j=(i<<8)|n;
- cb(s,SSL_CB_READ_ALERT,j);
- }
-
- if (i == 1) /* warning */
- {
- s->s3->warn_alert=n;
- if (n == SSL_AD_CLOSE_NOTIFY)
- {
- s->shutdown|=SSL_RECEIVED_SHUTDOWN;
- return(0);
- }
- }
- else if (i == 2) /* fatal */
- {
- char tmp[16];
-
- s->rwstate=SSL_NOTHING;
- s->s3->fatal_alert=n;
- SSLerr(SSL_F_SSL3_READ_BYTES,
- SSL_AD_REASON_OFFSET+n);
- sprintf(tmp,"%d",n);
- ERR_add_error_data(2,"SSL alert number ",tmp);
s->shutdown|=SSL_RECEIVED_SHUTDOWN;
- SSL_CTX_remove_session(s->ctx,s->session);
return(0);
}
- else
- {
- al=SSL_AD_ILLEGAL_PARAMETER;
- SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_UNKNOWN_ALERT_TYPE);
- goto f_err;
- }
-
- rr->length=0;
- goto start;
}
-
- if (s->shutdown & SSL_SENT_SHUTDOWN)
+ else if (i == 2) /* fatal */
{
+ char tmp[16];
+
s->rwstate=SSL_NOTHING;
- rr->length=0;
+ s->s3->fatal_alert=n;
+ SSLerr(SSL_F_SSL3_READ_BYTES,
+ SSL_AD_REASON_OFFSET+n);
+ sprintf(tmp,"%d",n);
+ ERR_add_error_data(2,"SSL alert number ",tmp);
+ s->shutdown|=SSL_RECEIVED_SHUTDOWN;
+ SSL_CTX_remove_session(s->ctx,s->session);
return(0);
}
-
- if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
+ else
{
- if ( (rr->length != 1) || (rr->off != 0) ||
- (rr->data[0] != SSL3_MT_CCS))
- {
- i=SSL_AD_ILLEGAL_PARAMETER;
- SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_BAD_CHANGE_CIPHER_SPEC);
- goto err;
- }
-
- rr->length=0;
- s->s3->change_cipher_spec=1;
- if (!do_change_cipher_spec(s))
- goto err;
- else
- goto start;
+ al=SSL_AD_ILLEGAL_PARAMETER;
+ SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_UNKNOWN_ALERT_TYPE);
+ goto f_err;
}
- /* else we have a handshake */
- if ((rr->type == SSL3_RT_HANDSHAKE) &&
- !s->in_handshake)
+ goto start;
+ }
+
+ if (s->shutdown & SSL_SENT_SHUTDOWN) /* but we have not received a shutdown */
+ {
+ s->rwstate=SSL_NOTHING;
+ rr->length=0;
+ return(0);
+ }
+
+ if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
+ {
+ /* 'Change Cipher Spec' is just a single byte, so we know
+ * exactly what the record payload has to look like */
+ if ( (rr->length != 1) || (rr->off != 0) ||
+ (rr->data[0] != SSL3_MT_CCS))
{
- if (((s->state&SSL_ST_MASK) == SSL_ST_OK) &&
- !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
- {
- s->state=SSL_ST_BEFORE|(s->server)
- ?SSL_ST_ACCEPT
- :SSL_ST_CONNECT;
- s->new_session=1;
- }
- n=s->handshake_func(s);
- if (n < 0) return(n);
- if (n == 0)
- {
- SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
- return(-1);
- }
+ i=SSL_AD_ILLEGAL_PARAMETER;
+ SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_BAD_CHANGE_CIPHER_SPEC);
+ goto err;
+ }
- /* In the case where we try to read application data
- * the first time, but we trigger an SSL handshake, we
- * return -1 with the retry option set. I do this
- * otherwise renegotiation can cause nasty problems
- * in the non-blocking world */
+ rr->length=0;
+ s->s3->change_cipher_spec=1;
+ if (!do_change_cipher_spec(s))
+ goto err;
+ else
+ goto start;
+ }
- s->rwstate=SSL_READING;
- bio=SSL_get_rbio(s);
- BIO_clear_retry_flags(bio);
- BIO_set_retry_read(bio);
+ /* Unexpected handshake message (Client Hello, or protocol violation) */
+ if ((s->s3->handshake_fragment_len >= 4) && !s->in_handshake)
+ {
+ if (((s->state&SSL_ST_MASK) == SSL_ST_OK) &&
+ !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
+ {
+ s->state=SSL_ST_BEFORE|(s->server)
+ ?SSL_ST_ACCEPT
+ :SSL_ST_CONNECT;
+ s->new_session=1;
+ }
+ n=s->handshake_func(s);
+ if (n < 0) return(n);
+ if (n == 0)
+ {
+ SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
return(-1);
}
- switch (rr->type)
- {
- default:
+ /* In the case where we try to read application data
+ * the first time, but we trigger an SSL handshake, we
+ * return -1 with the retry option set. I do this
+ * otherwise renegotiation can cause nasty problems
+ * in the non-blocking world */
+
+ s->rwstate=SSL_READING;
+ bio=SSL_get_rbio(s);
+ BIO_clear_retry_flags(bio);
+ BIO_set_retry_read(bio);
+ return(-1);
+ }
+
+ switch (rr->type)
+ {
+ default:
#ifndef NO_TLS
- /* TLS just ignores unknown message types */
- if (s->version == TLS1_VERSION)
- {
- goto start;
- }
+ /* TLS just ignores unknown message types */
+ if (s->version == TLS1_VERSION)
+ {
+ goto start;
+ }
#endif
- case SSL3_RT_CHANGE_CIPHER_SPEC:
- case SSL3_RT_ALERT:
- case SSL3_RT_HANDSHAKE:
+ al=SSL_AD_UNEXPECTED_MESSAGE;
+ SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
+ goto f_err;
+ case SSL3_RT_CHANGE_CIPHER_SPEC:
+ case SSL3_RT_ALERT:
+ case SSL3_RT_HANDSHAKE:
+ /* we already handled all of these, with the possible exception
+ * of SSL3_RT_HANDSHAKE when s->in_handshake is set, but that
+ * should not happen when type != rr->type */
+ al=SSL_AD_UNEXPECTED_MESSAGE;
+ SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_INTERNAL_ERROR);
+ goto f_err;
+ case SSL3_RT_APPLICATION_DATA:
+ /* At this point, we were expecting handshake data,
+ * but have application data. If the library was
+ * running inside ssl3_read() (i.e. in_read_app_data
+ * is set) and it makes sense to read application data
+ * at this point (session renegotation not yet started),
+ * we will indulge it.
+ */
+ if (s->s3->in_read_app_data &&
+ (s->s3->total_renegotiations != 0) &&
+ ((
+ (s->state & SSL_ST_CONNECT) &&
+ (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
+ (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
+ ) || (
+ (s->state & SSL_ST_ACCEPT) &&
+ (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
+ (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
+ )
+ ))
+ {
+ s->s3->in_read_app_data=0;
+ return(-1);
+ }
+ else
+ {
al=SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
goto f_err;
- case SSL3_RT_APPLICATION_DATA:
- /* At this point, we were expecting something else,
- * but have application data. What we do is set the
- * error, and return -1. On the way out, if the
- * library was running inside ssl3_read() and it makes
- * sense to read application data at this point, we
- * will indulge it. This will mostly happen during
- * session renegotiation.
- */
- if (s->s3->in_read_app_data &&
- (s->s3->total_renegotiations != 0) &&
- ((
- (s->state & SSL_ST_CONNECT) &&
- (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
- (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
- ) || (
- (s->state & SSL_ST_ACCEPT) &&
- (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
- (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
- )
- ))
- {
- s->s3->in_read_app_data=0;
- return(-1);
- }
- else
- {
- al=SSL_AD_UNEXPECTED_MESSAGE;
- SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
- goto f_err;
- }
}
- /* not reached */
}
+ /* not reached */
- /* rr->type == type */
-
- /* make sure that we are not getting application data when we
- * are doing a handshake for the first time */
- if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
- (s->enc_read_ctx == NULL))
- {
- al=SSL_AD_UNEXPECTED_MESSAGE;
- SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_APP_DATA_IN_HANDSHAKE);
- goto f_err;
- }
-
- if (len <= 0) return(len);
-
- if ((unsigned int)len > rr->length)
- n=rr->length;
- else
- n=len;
-
- memcpy(buf,&(rr->data[rr->off]),(unsigned int)n);
- rr->length-=n;
- rr->off+=n;
- if (rr->length == 0)
- {
- s->rstate=SSL_ST_READ_HEADER;
- rr->off=0;
- }
-
- if (type == SSL3_RT_HANDSHAKE)
- ssl3_finish_mac(s,buf,n);
- return(n);
f_err:
ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
@@ -1075,7 +1180,7 @@
cb=s->info_callback;
else if (s->ctx->info_callback != NULL)
cb=s->ctx->info_callback;
-
+
if (cb != NULL)
{
j=(s->s3->send_alert[0]<<8)|s->s3->send_alert[1];
