/* * 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); } /* 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; }