diff options
Diffstat (limited to 'security/nss/lib/ssl/ssl3gthr.c')
| -rw-r--r-- | security/nss/lib/ssl/ssl3gthr.c | 573 |
1 files changed, 573 insertions, 0 deletions
diff --git a/security/nss/lib/ssl/ssl3gthr.c b/security/nss/lib/ssl/ssl3gthr.c new file mode 100644 index 000000000..2bcc1d0aa --- /dev/null +++ b/security/nss/lib/ssl/ssl3gthr.c @@ -0,0 +1,573 @@ +/* + * Gather (Read) entire SSL3 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" +#include "ssl3prot.h" + +struct ssl2GatherStr { + /* true when ssl3_GatherData encounters an SSLv2 handshake */ + PRBool isV2; + + /* number of bytes of padding appended to the message content */ + PRUint8 padding; +}; + +typedef struct ssl2GatherStr ssl2Gather; + +/* Caller should hold RecvBufLock. */ +SECStatus +ssl3_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 +ssl3_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); + } +} + +/* Checks whether a given buffer is likely an SSLv3 record header. */ +PRBool +ssl3_isLikelyV3Hello(const unsigned char *buf) +{ + /* Even if this was a V2 record header we couldn't possibly parse it + * correctly as the second bit denotes a vaguely-defined security escape. */ + if (buf[0] & 0x40) { + return PR_TRUE; + } + + /* Check for a typical V3 record header. */ + return (PRBool)(buf[0] >= content_change_cipher_spec && + buf[0] <= content_application_data && + buf[1] == MSB(SSL_LIBRARY_VERSION_3_0)); +} + +/* + * Attempt to read in an entire SSL3 record. + * Blocks here for blocking sockets, otherwise returns -1 with + * PR_WOULD_BLOCK_ERROR when socket would block. + * + * returns 1 if received a complete SSL3 record. + * returns 0 if recv returns EOF + * returns -1 if recv returns < 0 + * (The error value may have already been set to PR_WOULD_BLOCK_ERROR) + * + * Caller must hold the recv buf lock. + * + * The Gather state machine has 3 states: GS_INIT, GS_HEADER, GS_DATA. + * GS_HEADER: waiting for the 5-byte SSL3 record header to come in. + * GS_DATA: waiting for the body of the SSL3 record to come in. + * + * This loop returns when either + * (a) an error or EOF occurs, + * (b) PR_WOULD_BLOCK_ERROR, + * (c) data (entire SSL3 record) has been received. + */ +static int +ssl3_GatherData(sslSocket *ss, sslGather *gs, int flags, ssl2Gather *ssl2gs) +{ + unsigned char *bp; + unsigned char *lbp; + int nb; + int err; + int rv = 1; + PRUint8 v2HdrLength = 0; + + PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss)); + if (gs->state == GS_INIT) { + gs->state = GS_HEADER; + gs->remainder = ss->ssl3.hs.shortHeaders ? 2 : 5; + gs->offset = 0; + gs->writeOffset = 0; + gs->readOffset = 0; + gs->inbuf.len = 0; + } + + lbp = gs->inbuf.buf; + for (;;) { + SSL_TRC(30, ("%d: SSL3[%d]: gather state %d (need %d more)", + SSL_GETPID(), ss->fd, gs->state, gs->remainder)); + bp = ((gs->state != GS_HEADER) ? lbp : gs->hdr) + gs->offset; + nb = ssl_DefRecv(ss, bp, gs->remainder, flags); + + if (nb > 0) { + PRINT_BUF(60, (ss, "raw gather data:", bp, nb)); + } else if (nb == 0) { + /* EOF */ + SSL_TRC(30, ("%d: SSL3[%d]: EOF", SSL_GETPID(), ss->fd)); + rv = 0; + break; + } else /* if (nb < 0) */ { + SSL_DBG(("%d: SSL3[%d]: recv error %d", SSL_GETPID(), ss->fd, + PR_GetError())); + rv = SECFailure; + break; + } + + PORT_Assert((unsigned int)nb <= gs->remainder); + if ((unsigned int)nb > gs->remainder) { + /* ssl_DefRecv is misbehaving! this error is fatal to SSL. */ + gs->state = GS_INIT; /* so we don't crash next time */ + rv = SECFailure; + break; + } + + gs->offset += nb; + gs->remainder -= nb; + if (gs->state == GS_DATA) + gs->inbuf.len += nb; + + /* if there's more to go, read some more. */ + if (gs->remainder > 0) { + continue; + } + + /* have received entire record header, or entire record. */ + switch (gs->state) { + case GS_HEADER: + /* Check for SSLv2 handshakes. Always assume SSLv3 on clients, + * support SSLv2 handshakes only when ssl2gs != NULL. */ + if (!ssl2gs || ssl3_isLikelyV3Hello(gs->hdr)) { + /* Should have a non-SSLv2 record header in gs->hdr. Extract + * the length of the following encrypted data, and then + * read in the rest of the record into gs->inbuf. */ + if (ss->ssl3.hs.shortHeaders) { + PRUint16 len = (gs->hdr[0] << 8) | gs->hdr[1]; + if (!(len & 0x8000)) { + SSL_DBG(("%d: SSL3[%d]: incorrectly formatted header")); + SSL3_SendAlert(ss, alert_fatal, illegal_parameter); + gs->state = GS_INIT; + PORT_SetError(SSL_ERROR_BAD_MAC_READ); + return SECFailure; + } + gs->remainder = len & ~0x8000; + } else { + gs->remainder = (gs->hdr[3] << 8) | gs->hdr[4]; + } + } else { + /* Probably an SSLv2 record header. No need to handle any + * security escapes (gs->hdr[0] & 0x40) as we wouldn't get + * here if one was set. See ssl3_isLikelyV3Hello(). */ + gs->remainder = ((gs->hdr[0] & 0x7f) << 8) | gs->hdr[1]; + ssl2gs->isV2 = PR_TRUE; + v2HdrLength = 2; + + /* Is it a 3-byte header with padding? */ + if (!(gs->hdr[0] & 0x80)) { + ssl2gs->padding = gs->hdr[2]; + v2HdrLength++; + } + } + + /* This is the max length for an encrypted SSLv3+ fragment. */ + if (!v2HdrLength && + gs->remainder > (MAX_FRAGMENT_LENGTH + 2048)) { + SSL3_SendAlert(ss, alert_fatal, unexpected_message); + gs->state = GS_INIT; + PORT_SetError(SSL_ERROR_RX_RECORD_TOO_LONG); + return SECFailure; + } + + gs->state = GS_DATA; + gs->offset = 0; + gs->inbuf.len = 0; + + if (gs->remainder > gs->inbuf.space) { + err = sslBuffer_Grow(&gs->inbuf, gs->remainder); + if (err) { /* realloc has set error code to no mem. */ + return err; + } + lbp = gs->inbuf.buf; + } + + /* When we encounter an SSLv2 hello we've read 2 or 3 bytes too + * many into the gs->hdr[] buffer. Copy them over into inbuf so + * that we can properly process the hello record later. */ + if (v2HdrLength) { + gs->inbuf.len = 5 - v2HdrLength; + PORT_Memcpy(lbp, gs->hdr + v2HdrLength, gs->inbuf.len); + gs->remainder -= gs->inbuf.len; + lbp += gs->inbuf.len; + } + + break; /* End this case. Continue around the loop. */ + + case GS_DATA: + /* + ** SSL3 record has been completely received. + */ + SSL_TRC(10, ("%d: SSL[%d]: got record of %d bytes", + SSL_GETPID(), ss->fd, gs->inbuf.len)); + gs->state = GS_INIT; + return 1; + } + } + + return rv; +} + +/* + * Read in an entire DTLS record. + * + * Blocks here for blocking sockets, otherwise returns -1 with + * PR_WOULD_BLOCK_ERROR when socket would block. + * + * This is simpler than SSL because we are reading on a datagram socket + * and datagrams must contain >=1 complete records. + * + * returns 1 if received a complete DTLS record. + * returns 0 if recv returns EOF + * returns -1 if recv returns < 0 + * (The error value may have already been set to PR_WOULD_BLOCK_ERROR) + * + * Caller must hold the recv buf lock. + * + * This loop returns when either + * (a) an error or EOF occurs, + * (b) PR_WOULD_BLOCK_ERROR, + * (c) data (entire DTLS record) has been received. + */ +static int +dtls_GatherData(sslSocket *ss, sslGather *gs, int flags) +{ + int nb; + int err; + int rv = 1; + + SSL_TRC(30, ("dtls_GatherData")); + + PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss)); + + gs->state = GS_HEADER; + gs->offset = 0; + + if (gs->dtlsPacketOffset == gs->dtlsPacket.len) { /* No data left */ + gs->dtlsPacketOffset = 0; + gs->dtlsPacket.len = 0; + + /* Resize to the maximum possible size so we can fit a full datagram */ + /* This is the max fragment length for an encrypted fragment + ** plus the size of the record header. + ** This magic constant is copied from ssl3_GatherData, with 5 changed + ** to 13 (the size of the record header). + */ + if (gs->dtlsPacket.space < MAX_FRAGMENT_LENGTH + 2048 + 13) { + err = sslBuffer_Grow(&gs->dtlsPacket, + MAX_FRAGMENT_LENGTH + 2048 + 13); + if (err) { /* realloc has set error code to no mem. */ + return err; + } + } + + /* recv() needs to read a full datagram at a time */ + nb = ssl_DefRecv(ss, gs->dtlsPacket.buf, gs->dtlsPacket.space, flags); + + if (nb > 0) { + PRINT_BUF(60, (ss, "raw gather data:", gs->dtlsPacket.buf, nb)); + } else if (nb == 0) { + /* EOF */ + SSL_TRC(30, ("%d: SSL3[%d]: EOF", SSL_GETPID(), ss->fd)); + rv = 0; + return rv; + } else /* if (nb < 0) */ { + SSL_DBG(("%d: SSL3[%d]: recv error %d", SSL_GETPID(), ss->fd, + PR_GetError())); + rv = SECFailure; + return rv; + } + + gs->dtlsPacket.len = nb; + } + + /* At this point we should have >=1 complete records lined up in + * dtlsPacket. Read off the header. + */ + if ((gs->dtlsPacket.len - gs->dtlsPacketOffset) < 13) { + SSL_DBG(("%d: SSL3[%d]: rest of DTLS packet " + "too short to contain header", + SSL_GETPID(), ss->fd)); + PR_SetError(PR_WOULD_BLOCK_ERROR, 0); + gs->dtlsPacketOffset = 0; + gs->dtlsPacket.len = 0; + rv = SECFailure; + return rv; + } + memcpy(gs->hdr, gs->dtlsPacket.buf + gs->dtlsPacketOffset, 13); + gs->dtlsPacketOffset += 13; + + /* Have received SSL3 record header in gs->hdr. */ + gs->remainder = (gs->hdr[11] << 8) | gs->hdr[12]; + + if ((gs->dtlsPacket.len - gs->dtlsPacketOffset) < gs->remainder) { + SSL_DBG(("%d: SSL3[%d]: rest of DTLS packet too short " + "to contain rest of body", + SSL_GETPID(), ss->fd)); + PR_SetError(PR_WOULD_BLOCK_ERROR, 0); + gs->dtlsPacketOffset = 0; + gs->dtlsPacket.len = 0; + rv = SECFailure; + return rv; + } + + /* OK, we have at least one complete packet, copy into inbuf */ + if (gs->remainder > gs->inbuf.space) { + err = sslBuffer_Grow(&gs->inbuf, gs->remainder); + if (err) { /* realloc has set error code to no mem. */ + return err; + } + } + + memcpy(gs->inbuf.buf, gs->dtlsPacket.buf + gs->dtlsPacketOffset, + gs->remainder); + gs->inbuf.len = gs->remainder; + gs->offset = gs->remainder; + gs->dtlsPacketOffset += gs->remainder; + gs->state = GS_INIT; + + return 1; +} + +/* Gather in a record and when complete, Handle that record. + * Repeat this until the handshake is complete, + * or until application data is available. + * + * Returns 1 when the handshake is completed without error, or + * application data is available. + * Returns 0 if ssl3_GatherData hits EOF. + * Returns -1 on read error, or PR_WOULD_BLOCK_ERROR, or handleRecord error. + * Returns -2 on SECWouldBlock return from ssl3_HandleRecord. + * + * Called from ssl_GatherRecord1stHandshake in sslcon.c, + * and from SSL_ForceHandshake in sslsecur.c + * and from ssl3_GatherAppDataRecord below (<- DoRecv in sslsecur.c). + * + * Caller must hold the recv buf lock. + */ +int +ssl3_GatherCompleteHandshake(sslSocket *ss, int flags) +{ + int rv; + SSL3Ciphertext cText; + PRBool keepGoing = PR_TRUE; + + SSL_TRC(30, ("ssl3_GatherCompleteHandshake")); + + /* ssl3_HandleRecord may end up eventually calling ssl_FinishHandshake, + * which requires the 1stHandshakeLock, which must be acquired before the + * RecvBufLock. + */ + PORT_Assert(ss->opt.noLocks || ssl_Have1stHandshakeLock(ss)); + PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss)); + + do { + PRBool handleRecordNow = PR_FALSE; + + ssl_GetSSL3HandshakeLock(ss); + + /* Without this, we may end up wrongly reporting + * SSL_ERROR_RX_UNEXPECTED_* errors if we receive any records from the + * peer while we are waiting to be restarted. + */ + if (ss->ssl3.hs.restartTarget) { + ssl_ReleaseSSL3HandshakeLock(ss); + PORT_SetError(PR_WOULD_BLOCK_ERROR); + return (int)SECFailure; + } + + /* Treat an empty msgState like a NULL msgState. (Most of the time + * when ssl3_HandleHandshake returns SECWouldBlock, it leaves + * behind a non-NULL but zero-length msgState). + * Test: async_cert_restart_server_sends_hello_request_first_in_separate_record + */ + if (ss->ssl3.hs.msgState.buf) { + if (ss->ssl3.hs.msgState.len == 0) { + ss->ssl3.hs.msgState.buf = NULL; + } else { + handleRecordNow = PR_TRUE; + } + } + + ssl_ReleaseSSL3HandshakeLock(ss); + + if (handleRecordNow) { + /* ssl3_HandleHandshake previously returned SECWouldBlock and the + * as-yet-unprocessed plaintext of that previous handshake record. + * We need to process it now before we overwrite it with the next + * handshake record. + */ + rv = ssl3_HandleRecord(ss, NULL, &ss->gs.buf); + } else { + /* State for SSLv2 client hello support. */ + ssl2Gather ssl2gs = { PR_FALSE, 0 }; + ssl2Gather *ssl2gs_ptr = NULL; + + /* If we're a server and waiting for a client hello, accept v2. */ + if (ss->sec.isServer && ss->ssl3.hs.ws == wait_client_hello) { + ssl2gs_ptr = &ssl2gs; + } + + /* bring in the next sslv3 record. */ + if (ss->recvdCloseNotify) { + /* RFC 5246 Section 7.2.1: + * Any data received after a closure alert is ignored. + */ + return 0; + } + + if (!IS_DTLS(ss)) { + /* If we're a server waiting for a ClientHello then pass + * ssl2gs to support SSLv2 ClientHello messages. */ + rv = ssl3_GatherData(ss, &ss->gs, flags, ssl2gs_ptr); + } else { + rv = dtls_GatherData(ss, &ss->gs, flags); + + /* If we got a would block error, that means that no data was + * available, so we check the timer to see if it's time to + * retransmit */ + if (rv == SECFailure && + (PORT_GetError() == PR_WOULD_BLOCK_ERROR)) { + dtls_CheckTimer(ss); + /* Restore the error in case something succeeded */ + PORT_SetError(PR_WOULD_BLOCK_ERROR); + } + } + + if (rv <= 0) { + return rv; + } + + if (ssl2gs.isV2) { + rv = ssl3_HandleV2ClientHello(ss, ss->gs.inbuf.buf, + ss->gs.inbuf.len, + ssl2gs.padding); + if (rv < 0) { + return rv; + } + } else { + /* decipher it, and handle it if it's a handshake. + * If it's application data, ss->gs.buf will not be empty upon return. + * If it's a change cipher spec, alert, or handshake message, + * ss->gs.buf.len will be 0 when ssl3_HandleRecord returns SECSuccess. + */ + if (ss->ssl3.hs.shortHeaders) { + cText.type = content_application_data; + cText.version = SSL_LIBRARY_VERSION_TLS_1_0; + } else { + cText.type = (SSL3ContentType)ss->gs.hdr[0]; + cText.version = (ss->gs.hdr[1] << 8) | ss->gs.hdr[2]; + } + + if (IS_DTLS(ss)) { + sslSequenceNumber seq_num; + + cText.version = dtls_DTLSVersionToTLSVersion(cText.version); + /* DTLS sequence number */ + PORT_Memcpy(&seq_num, &ss->gs.hdr[3], sizeof(seq_num)); + cText.seq_num = PR_ntohll(seq_num); + } + + cText.buf = &ss->gs.inbuf; + rv = ssl3_HandleRecord(ss, &cText, &ss->gs.buf); + } + } + if (rv < 0) { + return ss->recvdCloseNotify ? 0 : rv; + } + if (ss->gs.buf.len > 0) { + /* We have application data to return to the application. This + * prioritizes returning application data to the application over + * completing any renegotiation handshake we may be doing. + */ + PORT_Assert(ss->firstHsDone); + PORT_Assert(cText.type == content_application_data); + break; + } + + PORT_Assert(keepGoing); + ssl_GetSSL3HandshakeLock(ss); + if (ss->ssl3.hs.ws == idle_handshake) { + /* We are done with the current handshake so stop trying to + * handshake. Note that it would be safe to test ss->firstHsDone + * instead of ss->ssl3.hs.ws. By testing ss->ssl3.hs.ws instead, + * we prioritize completing a renegotiation handshake over sending + * application data. + */ + PORT_Assert(ss->firstHsDone); + PORT_Assert(!ss->ssl3.hs.canFalseStart); + keepGoing = PR_FALSE; + } else if (ss->ssl3.hs.canFalseStart) { + /* Prioritize sending application data over trying to complete + * the handshake if we're false starting. + * + * If we were to do this check at the beginning of the loop instead + * of here, then this function would become be a no-op after + * receiving the ServerHelloDone in the false start case, and we + * would never complete the handshake. + */ + PORT_Assert(!ss->firstHsDone); + + if (ssl3_WaitingForServerSecondRound(ss)) { + keepGoing = PR_FALSE; + } else { + ss->ssl3.hs.canFalseStart = PR_FALSE; + } + } + ssl_ReleaseSSL3HandshakeLock(ss); + } while (keepGoing); + + /* Service the DTLS timer so that the holddown timer eventually fires. */ + if (IS_DTLS(ss)) { + dtls_CheckTimer(ss); + } + ss->gs.readOffset = 0; + ss->gs.writeOffset = ss->gs.buf.len; + return 1; +} + +/* Repeatedly gather in a record and when complete, Handle that record. + * Repeat this until some application data is received. + * + * Returns 1 when application data is available. + * Returns 0 if ssl3_GatherData hits EOF. + * Returns -1 on read error, or PR_WOULD_BLOCK_ERROR, or handleRecord error. + * Returns -2 on SECWouldBlock return from ssl3_HandleRecord. + * + * Called from DoRecv in sslsecur.c + * Caller must hold the recv buf lock. + */ +int +ssl3_GatherAppDataRecord(sslSocket *ss, int flags) +{ + int rv; + + /* ssl3_GatherCompleteHandshake requires both of these locks. */ + PORT_Assert(ss->opt.noLocks || ssl_Have1stHandshakeLock(ss)); + PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss)); + + do { + rv = ssl3_GatherCompleteHandshake(ss, flags); + } while (rv > 0 && ss->gs.buf.len == 0); + + return rv; +} |