busybox: add 1.21.0 xz fix

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/busybox/busybox-1.21.0/busybox-1.21.0-xz.patch

@@ -0,0 +1,84 @@
+--- busybox-1.21.0/archival/libarchive/decompress_unxz.c
++++ busybox-1.21.0-xz/archival/libarchive/decompress_unxz.c
+@@ -40,6 +40,7 @@ static uint32_t xz_crc32(const uint8_t *
+ IF_DESKTOP(long long) int FAST_FUNC
+ unpack_xz_stream(transformer_aux_data_t *aux, int src_fd, int dst_fd)
+ {
++	enum xz_ret xz_result;
+ 	struct xz_buf iobuf;
+ 	struct xz_dec *state;
+ 	unsigned char *membuf;
+@@ -63,9 +64,8 @@ unpack_xz_stream(transformer_aux_data_t
+ 	/* Limit memory usage to about 64 MiB. */
+ 	state = xz_dec_init(XZ_DYNALLOC, 64*1024*1024);
+ 
++	xz_result = X_OK;
+ 	while (1) {
+-		enum xz_ret r;
+-
+ 		if (iobuf.in_pos == iobuf.in_size) {
+ 			int rd = safe_read(src_fd, membuf, BUFSIZ);
+ 			if (rd < 0) {
+@@ -73,28 +73,57 @@ unpack_xz_stream(transformer_aux_data_t
+ 				total = -1;
+ 				break;
+ 			}
++			if (rd == 0 && xz_result == XZ_STREAM_END)
++				break;
+ 			iobuf.in_size = rd;
+ 			iobuf.in_pos = 0;
+ 		}
++		if (xz_result == XZ_STREAM_END) {
++			/*
++			 * Try to start decoding next concatenated stream.
++			 * Stream padding must always be a multiple of four
++			 * bytes to preserve four-byte alignment. To keep the
++			 * code slightly smaller, we aren't as strict here as
++			 * the .xz spec requires. We just skip all zero-bytes
++			 * without checking the alignment and thus can accept
++			 * files that aren't valid, e.g. the XZ utils test
++			 * files bad-0pad-empty.xz and bad-0catpad-empty.xz.
++			 */
++			do {
++				if (membuf[iobuf.in_pos] != 0) {
++					xz_dec_reset(state);
++					goto do_run;
++				}
++				iobuf.in_pos++;
++			} while (iobuf.in_pos < iobuf.in_size);
++		}
++ do_run:
+ //		bb_error_msg(">in pos:%d size:%d out pos:%d size:%d",
+ //				iobuf.in_pos, iobuf.in_size, iobuf.out_pos, iobuf.out_size);
+-		r = xz_dec_run(state, &iobuf);
++		xz_result = xz_dec_run(state, &iobuf);
+ //		bb_error_msg("<in pos:%d size:%d out pos:%d size:%d r:%d",
+-//				iobuf.in_pos, iobuf.in_size, iobuf.out_pos, iobuf.out_size, r);
++//				iobuf.in_pos, iobuf.in_size, iobuf.out_pos, iobuf.out_size, xz_result);
+ 		if (iobuf.out_pos) {
+ 			xwrite(dst_fd, iobuf.out, iobuf.out_pos);
+ 			IF_DESKTOP(total += iobuf.out_pos;)
+ 			iobuf.out_pos = 0;
+ 		}
+-		if (r == XZ_STREAM_END) {
+-			break;
++		if (xz_result == XZ_STREAM_END) {
++			/*
++			 * Can just "break;" here, if not for concatenated
++			 * .xz streams.
++			 * Checking for padding may require buffer
++			 * replenishment. Can't do it here.
++			 */
++			continue;
+ 		}
+-		if (r != XZ_OK && r != XZ_UNSUPPORTED_CHECK) {
++		if (xz_result != XZ_OK && xz_result != XZ_UNSUPPORTED_CHECK) {
+ 			bb_error_msg("corrupted data");
+ 			total = -1;
+ 			break;
+ 		}
+ 	}
++
+ 	xz_dec_end(state);
+ 	free(membuf);
+