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