Input filter support for mod_deflate. (76c24a97) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP Apache Httpd

modules/filters/mod_deflate.c

+253 −2

Changes for modules/filters/mod_deflate.c: 253 added lines, 2 removed lines.
Original line number	Diff line number	Diff line
		@@ -147,6 +147,22 @@ static void putLong(char *string, unsigned long x)
		}
		}

		/* Inputs a string and returns a long.
		*/
		static unsigned long getLong(char *string)
		{
		int n = 3;
		unsigned long x = 0;

		while (n) {
		x \|= (unsigned long)((unsigned char)string[n--]) & 0xff;
		x <<= 8;
		}

		x \|= (unsigned long)((unsigned char)string[0]) & 0xff;
		return x;
		}

		static void create_deflate_server_config(apr_pool_t p, server_rec *s)
		{
		deflate_filter_config c = apr_pcalloc(p, sizeof c);
		@@ -217,14 +233,14 @@ static const char deflate_set_memlevel(cmd_parms cmd, void *dummy,
		}

		/* magic header */
		static int deflate_magic[2] = { 0x1f, 0x8b };
		static char deflate_magic[2] = { '\037', '\213' };

		typedef struct deflate_ctx_t
		{
		z_stream stream;
		unsigned char *buffer;
		unsigned long crc;
		apr_bucket_brigade *bb;
		apr_bucket_brigade bb, proc_bb;
		} deflate_ctx;

		static apr_status_t deflate_out_filter(ap_filter_t *f,
		@@ -504,10 +520,245 @@ static apr_status_t deflate_out_filter(ap_filter_t *f,
		return APR_SUCCESS;
		}

		/* This is the deflate input filter (inflates). */
		static apr_status_t deflate_in_filter(ap_filter_t *f,
		apr_bucket_brigade *bb,
		ap_input_mode_t mode,
		apr_read_type_e block,
		apr_off_t readbytes)
		{
		apr_bucket *bkt;
		request_rec *r = f->r;
		deflate_ctx *ctx = f->ctx;
		int zRC;
		apr_status_t rv;
		deflate_filter_config *c;

		/* just get out of the way of things we don't want. */
		if (mode != AP_MODE_READBYTES) {
		return ap_get_brigade(f->next, bb, mode, block, readbytes);
		}

		c = ap_get_module_config(r->server->module_config, &deflate_module);

		if (!ctx) {
		int found = 0;
		char *token, deflate_hdr[10];
		const char *encoding;
		apr_size_t len;

		/* only work on main request/no subrequests */
		if (r->main) {
		ap_remove_input_filter(f);
		return ap_get_brigade(f->next, bb, mode, block, readbytes);
		}

		/* Let's see what our current Content-Encoding is.
		* If gzip is present, don't gzip again. (We could, but let's not.)
		*/
		encoding = apr_table_get(r->headers_in, "Content-Encoding");
		if (encoding) {
		const char *tmp = encoding;

		token = ap_get_token(r->pool, &tmp, 0);
		while (token && token[0]) {
		if (!strcasecmp(token, "gzip")) {
		found = 1;
		break;
		}
		/* Otherwise, skip token */
		tmp++;
		token = ap_get_token(r->pool, &tmp, 0);
		}
		}

		if (found == 0) {
		ap_remove_input_filter(f);
		return ap_get_brigade(f->next, bb, mode, block, readbytes);
		}

		f->ctx = ctx = apr_pcalloc(f->r->pool, sizeof(*ctx));
		ctx->bb = apr_brigade_create(r->pool, f->c->bucket_alloc);
		ctx->proc_bb = apr_brigade_create(r->pool, f->c->bucket_alloc);
		ctx->buffer = apr_palloc(r->pool, c->bufferSize);

		rv = ap_get_brigade(f->next, ctx->bb, AP_MODE_READBYTES, block, 10);
		if (rv != APR_SUCCESS) {
		return rv;
		}

		len = 10;
		rv = apr_brigade_flatten(ctx->bb, deflate_hdr, &len);
		if (rv != APR_SUCCESS) {
		return rv;
		}

		/* We didn't get the magic bytes. */
		if (len != 10 \|\|
		deflate_hdr[0] != deflate_magic[0] \|\|
		deflate_hdr[1] != deflate_magic[1]) {
		return APR_EGENERAL;
		}

		/* We can't handle flags for now. */
		if (deflate_hdr[3] != 0) {
		return APR_EGENERAL;
		}

		zRC = inflateInit2(&ctx->stream, c->windowSize);

		if (zRC != Z_OK) {
		f->ctx = NULL;
		ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
		"unable to init Zlib: "
		"inflateInit2 returned %d: URL %s",
		zRC, r->uri);
		ap_remove_input_filter(f);
		return ap_get_brigade(f->next, bb, mode, block, readbytes);
		}

		/* initialize deflate output buffer */
		ctx->stream.next_out = ctx->buffer;
		ctx->stream.avail_out = c->bufferSize;

		apr_brigade_cleanup(ctx->bb);
		}

		if (APR_BRIGADE_EMPTY(ctx->proc_bb)) {
		rv = ap_get_brigade(f->next, ctx->bb, mode, block, readbytes);

		if (rv != APR_SUCCESS) {
		return rv;
		}

		APR_BRIGADE_FOREACH(bkt, ctx->bb) {
		const char *data;
		apr_size_t len;

		/* If we actually see the EOS, that means we screwed up! */
		if (APR_BUCKET_IS_EOS(bkt)) {
		return APR_EGENERAL;
		}

		if (APR_BUCKET_IS_FLUSH(bkt)) {
		apr_bucket *tmp_heap;
		zRC = inflate(&(ctx->stream), Z_SYNC_FLUSH);
		if (zRC != Z_OK) {
		return APR_EGENERAL;
		}

		ctx->stream.next_out = ctx->buffer;
		len = c->bufferSize - ctx->stream.avail_out;

		ctx->crc = crc32(ctx->crc, (const Bytef *)ctx->buffer, len);
		tmp_heap = apr_bucket_heap_create((char *)ctx->buffer, len,
		NULL, f->c->bucket_alloc);
		APR_BRIGADE_INSERT_TAIL(ctx->proc_bb, tmp_heap);
		ctx->stream.avail_out = c->bufferSize;

		/* Move everything to the returning brigade. */
		APR_BUCKET_REMOVE(bkt);
		APR_BRIGADE_CONCAT(bb, ctx->bb);
		break;
		}

		/* read */
		apr_bucket_read(bkt, &data, &len, APR_BLOCK_READ);

		/* pass through zlib inflate. */
		ctx->stream.next_in = (unsigned char *)data;
		ctx->stream.avail_in = len;

		while (ctx->stream.avail_in != 0) {
		if (ctx->stream.avail_out == 0) {
		apr_bucket *tmp_heap;
		ctx->stream.next_out = ctx->buffer;
		len = c->bufferSize - ctx->stream.avail_out;

		ctx->crc = crc32(ctx->crc, (const Bytef *)ctx->buffer, len);
		tmp_heap = apr_bucket_heap_create((char *)ctx->buffer, len,
		NULL, f->c->bucket_alloc);
		APR_BRIGADE_INSERT_TAIL(ctx->proc_bb, tmp_heap);
		ctx->stream.avail_out = c->bufferSize;
		}

		zRC = inflate(&ctx->stream, Z_NO_FLUSH);

		if (zRC == Z_STREAM_END) {
		break;
		}

		if (zRC != Z_OK) {
		return APR_EGENERAL;
		}
		}
		if (zRC == Z_STREAM_END) {
		apr_bucket tmp_heap, eos;

		ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
		"Zlib: Inflated %ld to %ld : URL %s",
		ctx->stream.total_in, ctx->stream.total_out,
		r->uri);

		len = c->bufferSize - ctx->stream.avail_out;

		ctx->crc = crc32(ctx->crc, (const Bytef *)ctx->buffer, len);
		tmp_heap = apr_bucket_heap_create((char *)ctx->buffer, len,
		NULL, f->c->bucket_alloc);
		APR_BRIGADE_INSERT_TAIL(ctx->proc_bb, tmp_heap);
		ctx->stream.avail_out = c->bufferSize;

		/* Is the remaining 8 bytes already in the avail stream? */
		if (ctx->stream.avail_in >= 8) {
		unsigned long compCRC, compLen;
		compCRC = getLong(ctx->stream.next_in);
		if (ctx->crc != compCRC) {
		return APR_EGENERAL;
		}
		ctx->stream.next_in += 4;
		compLen = getLong(ctx->stream.next_in);
		if (ctx->stream.total_out != compLen) {
		return APR_EGENERAL;
		}
		}
		else {
		/* FIXME: We need to grab the 8 verification bytes
		* from the wire! */
		return APR_EGENERAL;
		}

		inflateEnd(&ctx->stream);
		apr_brigade_cleanup(ctx->bb);

		eos = apr_bucket_eos_create(f->c->bucket_alloc);
		APR_BRIGADE_INSERT_TAIL(ctx->proc_bb, eos);
		break;
		}
		}
		}

		if (!APR_BRIGADE_EMPTY(ctx->proc_bb)) {
		apr_bucket_brigade *newbb;

		/* May return APR_INCOMPLETE which is fine by us. */
		apr_brigade_partition(ctx->proc_bb, readbytes, &bkt);

		newbb = apr_brigade_split(ctx->proc_bb, bkt);
		APR_BRIGADE_CONCAT(bb, ctx->proc_bb);
		APR_BRIGADE_CONCAT(ctx->proc_bb, newbb);
		}



		return APR_SUCCESS;
		}

		static void register_hooks(apr_pool_t *p)
		{
		ap_register_output_filter(deflateFilterName, deflate_out_filter,
		AP_FTYPE_CONTENT_SET);
		ap_register_input_filter(deflateFilterName, deflate_in_filter,
		AP_FTYPE_CONTENT_SET);
		}

		static const command_rec deflate_filter_cmds[] = {