/*
* Gather (Read) entire SSL2 records from socket into buffer.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "cert.h"
#include "ssl.h"
#include "sslimpl.h"
#include "sslproto.h"
/* Forward static declarations */
static SECStatus ssl2_HandleV3HandshakeRecord(sslSocket *ss);
/*
** Gather a single record of data from the receiving stream. This code
** first gathers the header (2 or 3 bytes long depending on the value of
** the most significant bit in the first byte) then gathers up the data
** for the record into gs->buf. This code handles non-blocking I/O
** and is to be called multiple times until ss->sec.recordLen != 0.
** This function decrypts the gathered record in place, in gs_buf.
*
* Caller must hold RecvBufLock.
*
* Returns +1 when it has gathered a complete SSLV2 record.
* Returns 0 if it hits EOF.
* Returns -1 (SECFailure) on any error
* Returns -2 (SECWouldBlock) when it gathers an SSL v3 client hello header.
**
** The SSL2 Gather State machine has 4 states:
** GS_INIT - Done reading in previous record. Haven't begun to read in
** next record. When ssl2_GatherData is called with the machine
** in this state, the machine will attempt to read the first 3
** bytes of the SSL2 record header, and will advance the state
** to GS_HEADER.
**
** GS_HEADER - The machine is in this state while waiting for the completion
** of the first 3 bytes of the SSL2 record. When complete, the
** machine will compute the remaining unread length of this record
** and will initiate a read of that many bytes. The machine will
** advance to one of two states, depending on whether the record
** is encrypted (GS_MAC), or unencrypted (GS_DATA).
**
** GS_MAC - The machine is in this state while waiting for the remainder
** of the SSL2 record to be read in. When the read is completed,
** the machine checks the record for valid length, decrypts it,
** and checks and discards the MAC, then advances to GS_INIT.
**
** GS_DATA - The machine is in this state while waiting for the remainder
** of the unencrypted SSL2 record to be read in. Upon completion,
** the machine advances to the GS_INIT state and returns the data.
*/
int
ssl2_GatherData(sslSocket *ss, sslGather *gs, int flags)
{
unsigned char * bp;
unsigned char * pBuf;
int nb, err, rv;
PORT_Assert( ss->opt.noLocks || ssl_HaveRecvBufLock(ss) );
if (gs->state == GS_INIT) {
/* Initialize gathering engine */
gs->state = GS_HEADER;
gs->remainder = 3;
gs->count = 3;
gs->offset = 0;
gs->recordLen = 0;
gs->recordPadding = 0;
gs->hdr[2] = 0;
gs->writeOffset = 0;
gs->readOffset = 0;
}
if (gs->encrypted) {
PORT_Assert(ss->sec.hash != 0);
}
pBuf = gs->buf.buf;
for (;;) {
SSL_TRC(30, ("%d: SSL[%d]: gather state %d (need %d more)",
SSL_GETPID(), ss->fd, gs->state, gs->remainder));
bp = ((gs->state != GS_HEADER) ? pBuf : gs->hdr) + gs->offset;
nb = ssl_DefRecv(ss, bp, gs->remainder, flags);
if (nb > 0) {
PRINT_BUF(60, (ss, "raw gather data:", bp, nb));
}
if (nb == 0) {
/* EOF */
SSL_TRC(30, ("%d: SSL[%d]: EOF", SSL_GETPID(), ss->fd));
rv = 0;
break;
}
if (nb < 0) {
SSL_DBG(("%d: SSL[%d]: recv error %d", SSL_GETPID(), ss->fd,
PR_GetError()));
rv = SECFailure;
break;
}
gs->offset += nb;
gs->remainder -= nb;
if (gs->remainder > 0) {
continue;
}
/* Probably finished this piece */
switch (gs->state) {
case GS_HEADER:
if (!SSL3_ALL_VERSIONS_DISABLED(&ss->vrange) && !ss->firstHsDone) {
PORT_Assert( ss->opt.noLocks || ssl_Have1stHandshakeLock(ss) );
/* If this looks like an SSL3 handshake record,
** and we're expecting an SSL2 Hello message from our peer,
** handle it here.
*/
if (gs->hdr[0] == content_handshake) {
if ((ss->nextHandshake == ssl2_HandleClientHelloMessage) ||
(ss->nextHandshake == ssl2_HandleServerHelloMessage)) {
rv = ssl2_HandleV3HandshakeRecord(ss);
if (rv == SECFailure) {
return SECFailure;
}
}
/* XXX_1 The call stack to here is:
* ssl_Do1stHandshake -> ssl_GatherRecord1stHandshake ->
* ssl2_GatherRecord -> here.
* We want to return all the way out to ssl_Do1stHandshake,
* and have it call ssl_GatherRecord1stHandshake again.
* ssl_GatherRecord1stHandshake will call
* ssl3_GatherCompleteHandshake when it is called again.
*
* Returning SECWouldBlock here causes
* ssl_GatherRecord1stHandshake to return without clearing
* ss->handshake, ensuring that ssl_Do1stHandshake will
* call it again immediately.
*
* If we return 1 here, ssl_GatherRecord1stHandshake will
* clear ss->handshake before returning, and thus will not
* be called again by ssl_Do1stHandshake.
*/
return SECWouldBlock;
} else if (gs->hdr[0] == content_alert) {
if (ss->nextHandshake == ssl2_HandleServerHelloMessage) {
/* XXX This is a hack. We're assuming that any failure
* XXX on the client hello is a failure to match
* XXX ciphers.
*/
PORT_SetError(SSL_ERROR_NO_CYPHER_OVERLAP);
return SECFailure;
}
}
}
/* we've got the first 3 bytes. The header may be two or three. */
if (gs->hdr[0] & 0x80) {
/* This record has a 2-byte header, and no padding */
gs->count = ((gs->hdr[0] & 0x7f) << 8) | gs->hdr[1];
gs->recordPadding = 0;
} else {
/* This record has a 3-byte header that is all read in now. */
gs->count = ((gs->hdr[0] & 0x3f) << 8) | gs->hdr[1];
/* is_escape = (gs->hdr[0] & 0x40) != 0; */
gs->recordPadding = gs->hdr[2];
}
if (!gs->count) {
PORT_SetError(SSL_ERROR_RX_RECORD_TOO_LONG);
goto cleanup;
}
if (gs->count > gs->buf.space) {
err = sslBuffer_Grow(&gs->buf, gs->count);
if (err) {
return err;
}
pBuf = gs->buf.buf;
}
if (gs->hdr[0] & 0x80) {
/* we've already read in the first byte of the body.
** Put it into the buffer.
*/
pBuf[0] = gs->hdr[2];
gs->offset = 1;
gs->remainder = gs->count - 1;
} else {
gs->offset = 0;
gs->remainder = gs->count;
}
if (gs->encrypted) {
gs->state = GS_MAC;
gs->recordLen = gs->count - gs->recordPadding
- ss->sec.hash->length;
} else {
gs->state = GS_DATA;
gs->recordLen = gs->count;
}
break;
case GS_MAC:
/* Have read in entire rest of the ciphertext.
** Check for valid length.
** Decrypt it.
** Check the MAC.
*/
PORT_Assert(gs->encrypted);
{
unsigned int macLen;
int nout;
unsigned char mac[SSL_MAX_MAC_BYTES];
ssl_GetSpecReadLock(ss); /**********************************/
/* If this is a stream cipher, blockSize will be 1,
* and this test will always be false.
* If this is a block cipher, this will detect records
* that are not a multiple of the blocksize in length.
*/
if (gs->count & (ss->sec.blockSize - 1)) {
/* This is an error. Sender is misbehaving */
SSL_DBG(("%d: SSL[%d]: sender, count=%d blockSize=%d",
SSL_GETPID(), ss->fd, gs->count,
ss->sec.blockSize));
PORT_SetError(SSL_ERROR_BAD_BLOCK_PADDING);
rv = SECFailure;
goto spec_locked_done;
}
PORT_Assert(gs->count == gs->offset);
if (gs->offset == 0) {
rv = 0; /* means EOF. */
goto spec_locked_done;
}
/* Decrypt the portion of data that we just received.
** Decrypt it in place.
*/
rv = (*ss->sec.dec)(ss->sec.readcx, pBuf, &nout, gs->offset,
pBuf, gs->offset);
if (rv != SECSuccess) {
goto spec_locked_done;
}
/* Have read in all the MAC portion of record
**
** Prepare MAC by resetting it and feeding it the shared secret
*/
macLen = ss->sec.hash->length;
if (gs->offset >= macLen) {
PRUint32 sequenceNumber = ss->sec.rcvSequence++;
unsigned char seq[4];
seq[0] = (unsigned char) (sequenceNumber >> 24);
seq[1] = (unsigned char) (sequenceNumber >> 16);
seq[2] = (unsigned char) (sequenceNumber >> 8);
seq[3] = (unsigned char) (sequenceNumber);
(*ss->sec.hash->begin)(ss->sec.hashcx);
(*ss->sec.hash->update)(ss->sec.hashcx, ss->sec.rcvSecret.data,
ss->sec.rcvSecret.len);
(*ss->sec.hash->update)(ss->sec.hashcx, pBuf + macLen,
gs->offset - macLen);
(*ss->sec.hash->update)(ss->sec.hashcx, seq, 4);
(*ss->sec.hash->end)(ss->sec.hashcx, mac, &macLen, macLen);
PORT_Assert(macLen == ss->sec.hash->length);
ssl_ReleaseSpecReadLock(ss); /******************************/
if (NSS_SecureMemcmp(mac, pBuf, macLen) != 0) {
/* MAC's didn't match... */
SSL_DBG(("%d: SSL[%d]: mac check failed, seq=%d",
SSL_GETPID(), ss->fd, ss->sec.rcvSequence));
PRINT_BUF(1, (ss, "computed mac:", mac, macLen));
PRINT_BUF(1, (ss, "received mac:", pBuf, macLen));
PORT_SetError(SSL_ERROR_BAD_MAC_READ);
rv = SECFailure;
goto cleanup;
}
} else {
ssl_ReleaseSpecReadLock(ss); /******************************/
}
if (gs->recordPadding + macLen <= gs->offset) {
gs->recordOffset = macLen;
gs->readOffset = macLen;
gs->writeOffset = gs->offset - gs->recordPadding;
rv = 1;
} else {
PORT_SetError(SSL_ERROR_BAD_BLOCK_PADDING);
cleanup:
/* nothing in the buffer any more. */
gs->recordOffset = 0;
gs->readOffset = 0;
gs->writeOffset = 0;
rv = SECFailure;
}
gs->recordLen = gs->writeOffset - gs->readOffset;
gs->recordPadding = 0; /* forget we did any padding. */
gs->state = GS_INIT;
if (rv > 0) {
PRINT_BUF(50, (ss, "recv clear record:",
pBuf + gs->recordOffset, gs->recordLen));
}
return rv;
spec_locked_done:
ssl_ReleaseSpecReadLock(ss);
return rv;
}
case GS_DATA:
/* Have read in all the DATA portion of record */
gs->recordOffset = 0;
gs->readOffset = 0;
gs->writeOffset = gs->offset;
PORT_Assert(gs->recordLen == gs->writeOffset - gs->readOffset);
gs->recordLen = gs->offset;
gs->recordPadding = 0;
gs->state = GS_INIT;
++ss->sec.rcvSequence;
PRINT_BUF(50, (ss, "recv clear record:",
pBuf + gs->recordOffset, gs->recordLen));
return 1;
} /* end switch gs->state */
} /* end gather loop. */
return rv;
}
/*
** Gather a single record of data from the receiving stream. This code
** first gathers the header (2 or 3 bytes long depending on the value of
** the most significant bit in the first byte) then gathers up the data
** for the record into the readBuf. This code handles non-blocking I/O
** and is to be called multiple times until ss->sec.recordLen != 0.
*
* Returns +1 when it has gathered a complete SSLV2 record.
* Returns 0 if it hits EOF.
* Returns -1 (SECFailure) on any error
* Returns -2 (SECWouldBlock)
*
* Called by ssl_GatherRecord1stHandshake in sslcon.c,
* and by DoRecv in sslsecur.c
* Caller must hold RecvBufLock.
*/
int
ssl2_GatherRecord(sslSocket *ss, int flags)
{
return ssl2_GatherData(ss, &ss->gs, flags);
}
/*
* Returns +1 when it has gathered a complete SSLV2 record.
* Returns 0 if it hits EOF.
* Returns -1 (SECFailure) on any error
* Returns -2 (SECWouldBlock)
*
* Called from SocksStartGather in sslsocks.c
* Caller must hold RecvBufLock.
*/
int
ssl2_StartGatherBytes(sslSocket *ss, sslGather *gs, unsigned int count)
{
int rv;
PORT_Assert( ss->opt.noLocks || ssl_HaveRecvBufLock(ss) );
gs->state = GS_DATA;
gs->remainder = count;
gs->count = count;
gs->offset = 0;
if (count > gs->buf.space) {
rv = sslBuffer_Grow(&gs->buf, count);
if (rv) {
return rv;
}
}
return ssl2_GatherData(ss, gs, 0);
}
/* Caller should hold RecvBufLock. */
SECStatus
ssl_InitGather(sslGather *gs)
{
SECStatus status;
gs->state = GS_INIT;
gs->writeOffset = 0;
gs->readOffset = 0;
gs->dtlsPacketOffset = 0;
gs->dtlsPacket.len = 0;
status = sslBuffer_Grow(&gs->buf, 4096);
return status;
}
/* Caller must hold RecvBufLock. */
void
ssl_DestroyGather(sslGather *gs)
{
if (gs) { /* the PORT_*Free functions check for NULL pointers. */
PORT_ZFree(gs->buf.buf, gs->buf.space);
PORT_Free(gs->inbuf.buf);
PORT_Free(gs->dtlsPacket.buf);
}
}
/* Caller must hold RecvBufLock. */
static SECStatus
ssl2_HandleV3HandshakeRecord(sslSocket *ss)
{
SECStatus rv;
PORT_Assert( ss->opt.noLocks || ssl_HaveRecvBufLock(ss) );
PORT_Assert( ss->opt.noLocks || ssl_Have1stHandshakeLock(ss) );
/* We've read in 3 bytes, there are 2 more to go in an ssl3 header. */
ss->gs.remainder = 2;
ss->gs.count = 0;
/* Clearing these handshake pointers ensures that
* ssl_Do1stHandshake won't call ssl2_HandleMessage when we return.
*/
ss->nextHandshake = 0;
ss->securityHandshake = 0;
/* Setting ss->version to an SSL 3.x value will cause
** ssl_GatherRecord1stHandshake to invoke ssl3_GatherCompleteHandshake()
** the next time it is called.
**/
rv = ssl3_NegotiateVersion(ss, SSL_LIBRARY_VERSION_MAX_SUPPORTED,
PR_TRUE);
if (rv != SECSuccess) {
return rv;
}
ss->sec.send = ssl3_SendApplicationData;
return SECSuccess;
}