/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * 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;

    gs->rejectV2Records = PR_FALSE;

    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] >= ssl_ct_change_cipher_spec &&

                    buf[0] <= ssl_ct_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 = 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.

                 * Always assume v3 after we received the first record. */

                if (!ssl2gs ||

                    ss->gs.rejectV2Records ||

                    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. */

                    gs->remainder = (gs->hdr[3] << 8) | gs->hdr[4];

                    gs->hdrLen = SSL3_RECORD_HEADER_LENGTH;

                } 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, record_overflow);

                    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) {

                    /* Reject v2 records that don't even carry enough data to

                     * resemble a valid ClientHello header. */

                    if (gs->remainder < SSL_HL_CLIENT_HELLO_HBYTES) {

                        SSL3_SendAlert(ss, alert_fatal, illegal_parameter);

                        PORT_SetError(SSL_ERROR_RX_MALFORMED_CLIENT_HELLO);

                        return SECFailure;

                    }

                    PORT_Assert(lbp);

                    gs->inbuf.len = 5 - v2HdrLength;

                    PORT_Memcpy(lbp, gs->hdr + v2HdrLength, gs->inbuf.len);

                    gs->remainder -= gs->inbuf.len;

                    lbp += gs->inbuf.len;

                }

                if (gs->remainder > 0) {

                    break; /* End this case.  Continue around the loop. */

                }

            /* FALL THROUGH if (gs->remainder == 0) as we just received

                 * an empty record and there's really no point in calling

                 * ssl_DefRecv() with buf=NULL and len=0. */

            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));

                /* reject any v2 records from now on */

                ss->gs.rejectV2Records = PR_TRUE;

                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;

    PRUint8 contentType;

    unsigned int headerLen;

    SECStatus rv;

    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) {

            rv = sslBuffer_Grow(&gs->dtlsPacket,

                                MAX_FRAGMENT_LENGTH + 2048 + 13);

            if (rv != SECSuccess) {

                return -1; /* Code already set. */

            }

        }

        /* 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));

            return 0;

        } else /* if (nb < 0) */ {

            SSL_DBG(("%d: SSL3[%d]: recv error %d", SSL_GETPID(), ss->fd,

                     PR_GetError()));

            return -1;

        }

        gs->dtlsPacket.len = nb;

    }

    contentType = gs->dtlsPacket.buf[gs->dtlsPacketOffset];

    if (dtls_IsLongHeader(ss->version, contentType)) {

        headerLen = 13;

    } else if (contentType == ssl_ct_application_data) {

        headerLen = 7;

    } else if ((contentType & 0xe0) == 0x20) {

        headerLen = 2;

    } else {

        SSL_DBG(("%d: SSL3[%d]: invalid first octet (%d) for DTLS",

                 SSL_GETPID(), ss->fd, contentType));

        PORT_SetError(SSL_ERROR_RX_UNKNOWN_RECORD_TYPE);

        gs->dtlsPacketOffset = 0;

        gs->dtlsPacket.len = 0;

        return -1;

    }

    /* At this point we should have >=1 complete records lined up in

     * dtlsPacket. Read off the header.

     */

    if ((gs->dtlsPacket.len - gs->dtlsPacketOffset) < headerLen) {

        SSL_DBG(("%d: SSL3[%d]: rest of DTLS packet "

                 "too short to contain header",

                 SSL_GETPID(), ss->fd));

        PORT_SetError(PR_WOULD_BLOCK_ERROR);

        gs->dtlsPacketOffset = 0;

        gs->dtlsPacket.len = 0;

        return -1;

    }

    memcpy(gs->hdr, SSL_BUFFER_BASE(&gs->dtlsPacket) + gs->dtlsPacketOffset,

           headerLen);

    gs->hdrLen = headerLen;

    gs->dtlsPacketOffset += headerLen;

    /* Have received SSL3 record header in gs->hdr. */

    if (headerLen == 13) {

        gs->remainder = (gs->hdr[11] << 8) | gs->hdr[12];

    } else if (headerLen == 7) {

        gs->remainder = (gs->hdr[5] << 8) | gs->hdr[6];

    } else {

        PORT_Assert(headerLen == 2);

        gs->remainder = gs->dtlsPacket.len - gs->dtlsPacketOffset;

    }

    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));

        PORT_SetError(PR_WOULD_BLOCK_ERROR);

        gs->dtlsPacketOffset = 0;

        gs->dtlsPacket.len = 0;

        return -1;

    }

    /* OK, we have at least one complete packet, copy into inbuf */

    gs->inbuf.len = 0;

    rv = sslBuffer_Append(&gs->inbuf,

                          SSL_BUFFER_BASE(&gs->dtlsPacket) + gs->dtlsPacketOffset,

                          gs->remainder);

    if (rv != SECSuccess) {

        return -1; /* code already set. */

    }

    gs->offset = gs->remainder;

    gs->dtlsPacketOffset += gs->remainder;

    gs->state = GS_INIT;

    SSL_TRC(20, ("%d: SSL3[%d]: dtls gathered record type=%d len=%d",

                 SSL_GETPID(), ss->fd, contentType, gs->inbuf.len));

    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;

    if (ss->ssl3.fatalAlertSent) {

        SSL_TRC(3, ("%d: SSL3[%d] Cannot gather data; fatal alert already sent",

                    SSL_GETPID(), ss->fd));

        PORT_SetError(SSL_ERROR_HANDSHAKE_FAILED);

        return SECFailure;

    }

    SSL_TRC(30, ("%d: SSL3[%d]: ssl3_GatherCompleteHandshake",

                 SSL_GETPID(), ss->fd));

    /* 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;

        PRBool processingEarlyData;

        ssl_GetSSL3HandshakeLock(ss);

        processingEarlyData = ss->ssl3.hs.zeroRttState == ssl_0rtt_accepted;

        /* 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.

             */

            SSL_DBG(("%d: SSL3[%d]: resuming handshake",

                     SSL_GETPID(), ss->fd));

            PORT_Assert(!IS_DTLS(ss));

            rv = ssl3_HandleNonApplicationData(ss, ssl_ct_handshake,

                                               0, 0, &ss->gs.buf);

        } else {

            /* State for SSLv2 client hello support. */

            ssl2Gather ssl2gs = { PR_FALSE, 0 };

            ssl2Gather *ssl2gs_ptr = NULL;

            if (ss->sec.isServer && ss->opt.enableV2CompatibleHello &&

                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)) {

                /* Passing a non-NULL ssl2gs here enables detection of

                 * SSLv2-compatible 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.

                 *

                 * cText only needs to be valid for this next function call, so

                 * it can borrow gs.hdr.

                 */

                cText.hdr = ss->gs.hdr;

                cText.hdrLen = ss->gs.hdrLen;

                cText.buf = &ss->gs.inbuf;

                rv = ssl3_HandleRecord(ss, &cText);

            }

        }

        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);

            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;

            }

        } else if (processingEarlyData &&

                   ss->ssl3.hs.zeroRttState == ssl_0rtt_done &&

                   !PR_CLIST_IS_EMPTY(&ss->ssl3.hs.bufferedEarlyData)) {

            /* If we were processing early data and we are no longer, then force

             * the handshake to block.  This ensures that early data is

             * delivered to the application before the handshake completes. */

            ssl_ReleaseSSL3HandshakeLock(ss);

            PORT_SetError(PR_WOULD_BLOCK_ERROR);

            return SECWouldBlock;

        }

        ssl_ReleaseSSL3HandshakeLock(ss);

    } while (keepGoing);

    /* Service the DTLS timer so that the post-handshake timers

     * fire. */

    if (IS_DTLS(ss) && (ss->ssl3.hs.ws == idle_handshake)) {

        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;

}