ssl_engine_io.c

apache服务器源代码（版本号：2.2.2）

    if (!filter_ctx->pssl) {
        /* ssl_filter_io_shutdown was called */
        return ap_pass_brigade(f->next, bb);
    }

    inctx = (bio_filter_in_ctx_t *)filter_ctx->pbioRead->ptr;
    outctx = (bio_filter_out_ctx_t *)filter_ctx->pbioWrite->ptr;

    /* When we are the writer, we must initialize the inctx
     * mode so that we block for any required ssl input, because
     * output filtering is always nonblocking.
     */
    inctx->mode = AP_MODE_READBYTES;
    inctx->block = APR_BLOCK_READ;

    if ((status = ssl_io_filter_connect(filter_ctx)) != APR_SUCCESS) {
        return ssl_io_filter_error(f, bb, status);
    }

    while (!APR_BRIGADE_EMPTY(bb)) {
        apr_bucket *bucket = APR_BRIGADE_FIRST(bb);

        /* If it is a flush or EOS, we need to pass this down.
         * These types do not require translation by OpenSSL.
         */
        if (APR_BUCKET_IS_EOS(bucket) || APR_BUCKET_IS_FLUSH(bucket)) {
            if (bio_filter_out_flush(filter_ctx->pbioWrite) < 0) {
                status = outctx->rc;
                break;
            }

            if (APR_BUCKET_IS_EOS(bucket)) {
                /*
                 * By definition, nothing can come after EOS.
                 * which also means we can pass the rest of this brigade
                 * without creating a new one since it only contains the
                 * EOS bucket.
                 */

                if ((status = ap_pass_brigade(f->next, bb)) != APR_SUCCESS) {
                    return status;
                }
                break;
            }
            else {
                /* bio_filter_out_flush() already passed down a flush bucket
                 * if there was any data to be flushed.
                 */
                apr_bucket_delete(bucket);
            }
        }
        else if (AP_BUCKET_IS_EOC(bucket)) {
            /* The special "EOC" bucket means a shutdown is needed;
             * - turn off buffering in bio_filter_out_write
             * - issue the SSL_shutdown
             */
            filter_ctx->nobuffer = 1;
            status = ssl_filter_io_shutdown(filter_ctx, f->c, 0);
            if (status != APR_SUCCESS) {
                ap_log_cerror(APLOG_MARK, APLOG_INFO, status, f->c,
                              "SSL filter error shutting down I/O");
            }
            if ((status = ap_pass_brigade(f->next, bb)) != APR_SUCCESS) {
                return status;
            }
            break;
        }
        else {
            /* filter output */
            const char *data;
            apr_size_t len;

            status = apr_bucket_read(bucket, &data, &len, rblock);

            if (APR_STATUS_IS_EAGAIN(status)) {
                /* No data available: flush... */
                if (bio_filter_out_flush(filter_ctx->pbioWrite) < 0) {
                    status = outctx->rc;
                    break;
                }
                rblock = APR_BLOCK_READ;
                continue; /* and try again with a blocking read. */
            }

            rblock = APR_NONBLOCK_READ;

            if (!APR_STATUS_IS_EOF(status) && (status != APR_SUCCESS)) {
                break;
            }

            status = ssl_filter_write(f, data, len);
            apr_bucket_delete(bucket);

            if (status != APR_SUCCESS) {
                break;
            }
        }
    }

    return status;
}

/* 128K maximum buffer size by default. */
#ifndef SSL_MAX_IO_BUFFER
#define SSL_MAX_IO_BUFFER (128 * 1024)
#endif

struct modssl_buffer_ctx {
    apr_bucket_brigade *bb;
    apr_pool_t *pool;
};

int ssl_io_buffer_fill(request_rec *r)
{
    conn_rec *c = r->connection;
    struct modssl_buffer_ctx *ctx;
    apr_bucket_brigade *tempb;
    apr_off_t total = 0; /* total length buffered */
    int eos = 0; /* non-zero once EOS is seen */

    /* Create the context which will be passed to the input filter;
     * containing a setaside pool and a brigade which constrain the
     * lifetime of the buffered data. */
    ctx = apr_palloc(r->pool, sizeof *ctx);
    apr_pool_create(&ctx->pool, r->pool);
    ctx->bb = apr_brigade_create(ctx->pool, c->bucket_alloc);

    /* ... and a temporary brigade. */
    tempb = apr_brigade_create(r->pool, c->bucket_alloc);

    ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, "filling buffer");

    do {
        apr_status_t rv;
        apr_bucket *e, *next;

        /* The request body is read from the protocol-level input
         * filters; the buffering filter will reinject it from that
         * level, allowing content/resource filters to run later, if
         * necessary. */

        rv = ap_get_brigade(r->proto_input_filters, tempb, AP_MODE_READBYTES,
                            APR_BLOCK_READ, 8192);
        if (rv) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
                          "could not read request body for SSL buffer");
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        /* Iterate through the returned brigade: setaside each bucket
         * into the context's pool and move it into the brigade. */
        for (e = APR_BRIGADE_FIRST(tempb);
             e != APR_BRIGADE_SENTINEL(tempb) && !eos; e = next) {
            const char *data;
            apr_size_t len;

            next = APR_BUCKET_NEXT(e);

            if (APR_BUCKET_IS_EOS(e)) {
                eos = 1;
            } else if (!APR_BUCKET_IS_METADATA(e)) {
                rv = apr_bucket_read(e, &data, &len, APR_BLOCK_READ);
                if (rv != APR_SUCCESS) {
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
                                  "could not read bucket for SSL buffer");
                    return HTTP_INTERNAL_SERVER_ERROR;
                }
                total += len;
            }

            rv = apr_bucket_setaside(e, ctx->pool);
            if (rv != APR_SUCCESS) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
                              "could not setaside bucket for SSL buffer");
                return HTTP_INTERNAL_SERVER_ERROR;
            }

            APR_BUCKET_REMOVE(e);
            APR_BRIGADE_INSERT_TAIL(ctx->bb, e);
        }

        ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c,
                      "total of %" APR_OFF_T_FMT " bytes in buffer, eos=%d",
                      total, eos);

        /* Fail if this exceeds the maximum buffer size. */
        if (total > SSL_MAX_IO_BUFFER) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                          "request body exceeds maximum size for SSL buffer");
            return HTTP_REQUEST_ENTITY_TOO_LARGE;
        }

    } while (!eos);

    apr_brigade_destroy(tempb);

    /* Insert the filter which will supply the buffered data. */
    ap_add_input_filter(ssl_io_buffer, ctx, r, c);

    return 0;
}

/* This input filter supplies the buffered request body to the caller
 * from the brigade stored in f->ctx. */
static apr_status_t ssl_io_filter_buffer(ap_filter_t *f,
                                         apr_bucket_brigade *bb,
                                         ap_input_mode_t mode,
                                         apr_read_type_e block,
                                         apr_off_t bytes)
{
    struct modssl_buffer_ctx *ctx = f->ctx;
    apr_status_t rv;

    ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, f->c,
                  "read from buffered SSL brigade, mode %d, "
                  "%" APR_OFF_T_FMT " bytes",
                  mode, bytes);

    if (mode != AP_MODE_READBYTES && mode != AP_MODE_GETLINE) {
        return APR_ENOTIMPL;
    }

    if (mode == AP_MODE_READBYTES) {
        apr_bucket *e;

        /* Partition the buffered brigade. */
        rv = apr_brigade_partition(ctx->bb, bytes, &e);
        if (rv && rv != APR_INCOMPLETE) {
            ap_log_cerror(APLOG_MARK, APLOG_ERR, rv, f->c,
                          "could not partition buffered SSL brigade");
            ap_remove_input_filter(f);
            return rv;
        }

        /* If the buffered brigade contains less then the requested
         * length, just pass it all back. */
        if (rv == APR_INCOMPLETE) {
            APR_BRIGADE_CONCAT(bb, ctx->bb);
        } else {
            apr_bucket *d = APR_BRIGADE_FIRST(ctx->bb);

            e = APR_BUCKET_PREV(e);

            /* Unsplice the partitioned segment and move it into the
             * passed-in brigade; no convenient way to do this with
             * the APR_BRIGADE_* macros. */
            APR_RING_UNSPLICE(d, e, link);
            APR_RING_SPLICE_HEAD(&bb->list, d, e, apr_bucket, link);

            APR_BRIGADE_CHECK_CONSISTENCY(bb);
            APR_BRIGADE_CHECK_CONSISTENCY(ctx->bb);
        }
    }
    else {
        /* Split a line into the passed-in brigade. */
        rv = apr_brigade_split_line(bb, ctx->bb, mode, bytes);

        if (rv) {
            ap_log_cerror(APLOG_MARK, APLOG_ERR, rv, f->c,
                          "could not split line from buffered SSL brigade");
            ap_remove_input_filter(f);
            return rv;
        }
    }

    if (APR_BRIGADE_EMPTY(ctx->bb)) {
        apr_bucket *e = APR_BRIGADE_LAST(bb);

        /* Ensure that the brigade is terminated by an EOS if the
         * buffered request body has been entirely consumed. */
        if (e == APR_BRIGADE_SENTINEL(bb) || !APR_BUCKET_IS_EOS(e)) {
            e = apr_bucket_eos_create(f->c->bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(bb, e);
        }

        ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, f->c,
                      "buffered SSL brigade now exhausted; removing filter");
        ap_remove_input_filter(f);
    }

    return APR_SUCCESS;
}

static void ssl_io_input_add_filter(ssl_filter_ctx_t *filter_ctx, conn_rec *c,
                                    SSL *ssl)
{
    bio_filter_in_ctx_t *inctx;

    inctx = apr_palloc(c->pool, sizeof(*inctx));

    filter_ctx->pInputFilter = ap_add_input_filter(ssl_io_filter, inctx, NULL, c);

    filter_ctx->pbioRead = BIO_new(&bio_filter_in_method);
    filter_ctx->pbioRead->ptr = (void *)inctx;

    inctx->ssl = ssl;
    inctx->bio_out = filter_ctx->pbioWrite;
    inctx->f = filter_ctx->pInputFilter;
    inctx->rc = APR_SUCCESS;
    inctx->mode = AP_MODE_READBYTES;
    inctx->cbuf.length = 0;
    inctx->bb = apr_brigade_create(c->pool, c->bucket_alloc);
    inctx->block = APR_BLOCK_READ;
    inctx->pool = c->pool;
    inctx->filter_ctx = filter_ctx;
}

void ssl_io_filter_init(conn_rec *c, SSL *ssl)
{
    ssl_filter_ctx_t *filter_ctx;

    filter_ctx = apr_palloc(c->pool, sizeof(ssl_filter_ctx_t));

    filter_ctx->nobuffer        = 0;
    filter_ctx->pOutputFilter   = ap_add_output_filter(ssl_io_filter,
                                                   filter_ctx, NULL, c);

    filter_ctx->pbioWrite       = BIO_new(&bio_filter_out_method);
    filter_ctx->pbioWrite->ptr  = (void *)bio_filter_out_ctx_new(filter_ctx, c);

    ssl_io_input_add_filter(filter_ctx, c, ssl);

    SSL_set_bio(ssl, filter_ctx->pbioRead, filter_ctx->pbioWrite);
    filter_ctx->pssl            = ssl;

    apr_pool_cleanup_register(c->pool, (void*)filter_ctx,
                              ssl_io_filter_cleanup, apr_pool_cleanup_null);

    if (c->base_server->loglevel >= APLOG_DEBUG) {
        BIO_set_callback(SSL_get_rbio(ssl), ssl_io_data_cb);
        BIO_set_callback_arg(SSL_get_rbio(ssl), (void *)ssl);
    }

    return;
}

void ssl_io_filter_register(apr_pool_t *p)
{
    /* This filter MUST be after the HTTP_HEADER filter, but it also must be
     * a resource-level filter so it has the request_rec.
     */
    ap_register_output_filter ("UPGRADE_FILTER", ssl_io_filter_Upgrade, NULL, AP_FTYPE_PROTOCOL + 5);

    ap_register_input_filter  (ssl_io_filter, ssl_io_filter_input,  NULL, AP_FTYPE_CONNECTION + 5);
    ap_register_output_filter (ssl_io_filter, ssl_io_filter_output, NULL, AP_FTYPE_CONNECTION + 5);

    ap_register_input_filter  (ssl_io_buffer, ssl_io_filter_buffer, NULL, AP_FTYPE_PROTOCOL - 1);

    return;
}

/*  _________________________________________________________________
**
**  I/O Data Debugging
**  _________________________________________________________________
*/

#define DUMP_WIDTH 16

static void ssl_io_data_dump(server_rec *srvr,
                             MODSSL_BIO_CB_ARG_TYPE *s,
                             long len)
{
    char buf[256];
    char tmp[64];
    int i, j, rows, trunc;
    unsigned char ch;

    trunc = 0;
    for(; (len > 0) && ((s[len-1] == ' ') || (s[len-1] == '\0')); len--)
        trunc++;
    rows = (len / DUMP_WIDTH);
    if ((rows * DUMP_WIDTH) < len)
        rows++;
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, srvr,
            "+-------------------------------------------------------------------------+");
    for(i = 0 ; i< rows; i++) {
        apr_snprintf(tmp, sizeof(tmp), "| %04x: ", i * DUMP_WIDTH);
        apr_cpystrn(buf, tmp, sizeof(buf));
        for (j = 0; j < DUMP_WIDTH; j++) {
            if (((i * DUMP_WIDTH) + j) >= len)
                apr_cpystrn(buf+strlen(buf), "   ", sizeof(buf)-strlen(buf));
            else {
                ch = ((unsigned char)*((char *)(s) + i * DUMP_WIDTH + j)) & 0xff;
                apr_snprintf(tmp, sizeof(tmp), "%02x%c", ch , j==7 ? '-' : ' ');
                apr_cpystrn(buf+strlen(buf), tmp, sizeof(buf)-strlen(buf));
            }
        }
        apr_cpystrn(buf+strlen(buf), " ", sizeof(buf)-strlen(buf));
        for (j = 0; j < DUMP_WIDTH; j++) {
            if (((i * DUMP_WIDTH) + j) >= len)
                apr_cpystrn(buf+strlen(buf), " ", sizeof(buf)-strlen(buf));
            else {
                ch = ((unsigned char)*((char *)(s) + i * DUMP_WIDTH + j)) & 0xff;
                apr_snprintf(tmp, sizeof(tmp), "%c", ((ch >= ' ') && (ch <= '~')) ? ch : '.');
                apr_cpystrn(buf+strlen(buf), tmp, sizeof(buf)-strlen(buf));
            }
        }
        apr_cpystrn(buf+strlen(buf), " |", sizeof(buf)-strlen(buf));
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, srvr,
                     "%s", buf);
    }
    if (trunc > 0)
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, srvr,
                "| %04ld - <SPACES/NULS>", len + trunc);
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, srvr,
            "+-------------------------------------------------------------------------+");
    return;
}

long ssl_io_data_cb(BIO *bio, int cmd,
                    MODSSL_BIO_CB_ARG_TYPE *argp,
                    int argi, long argl, long rc)
{
    SSL *ssl;
    conn_rec *c;
    server_rec *s;

    if ((ssl = (SSL *)BIO_get_callback_arg(bio)) == NULL)
        return rc;
    if ((c = (conn_rec *)SSL_get_app_data(ssl)) == NULL)
        return rc;
    s = c->base_server;

    if (   cmd == (BIO_CB_WRITE|BIO_CB_RETURN)
        || cmd == (BIO_CB_READ |BIO_CB_RETURN) ) {
        if (rc >= 0) {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                    "%s: %s %ld/%d bytes %s BIO#%pp [mem: %pp] %s",
                    SSL_LIBRARY_NAME,
                    (cmd == (BIO_CB_WRITE|BIO_CB_RETURN) ? "write" : "read"),
                    rc, argi, (cmd == (BIO_CB_WRITE|BIO_CB_RETURN) ? "to" : "from"),
                    bio, argp,
                    (argp != NULL ? "(BIO dump follows)" : "(Oops, no memory buffer?)"));
            if (argp != NULL)
                ssl_io_data_dump(s, argp, rc);
        }
        else {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                    "%s: I/O error, %d bytes expected to %s on BIO#%pp [mem: %pp]",
                    SSL_LIBRARY_NAME, argi,
                    (cmd == (BIO_CB_WRITE|BIO_CB_RETURN) ? "write" : "read"),
                    bio, argp);
        }
    }
    return rc;
}