http://git.tukaani.org/?p=xz-embedded.git;a=commitdiff;h=4cec51e1be4797a4bd8b266a1d34cabd7fdb79fd
--- busybox-1.20.2.org/archival/libarchive/unxz/xz_dec_lzma2.c
+++ busybox-1.20.2/archival/libarchive/unxz/xz_dec_lzma2.c
@@ -972,6 +972,9 @@
 			 */
 			tmp = b->in[b->in_pos++];
 
+			if (tmp == 0x00)
+				return XZ_STREAM_END;
+
 			if (tmp >= 0xE0 || tmp == 0x01) {
 				s->lzma2.need_props = true;
 				s->lzma2.need_dict_reset = false;
@@ -1004,9 +1007,6 @@
 						lzma_reset(s);
 				}
 			} else {
-				if (tmp == 0x00)
-					return XZ_STREAM_END;
-
 				if (tmp > 0x02)
 					return XZ_DATA_ERROR;
 
http://git.tukaani.org/?p=xz-embedded.git;a=commitdiff;h=9690fe69dc97eb2e7fe2804e4448a5278cde5411
--- busybox-1.20.2.org/archival/libarchive/unxz/xz_dec_bcj.c
+++ busybox-1.20.2/archival/libarchive/unxz/xz_dec_bcj.c
@@ -443,8 +443,12 @@
 	 * next filter in the chain. Apply the BCJ filter on the new data
 	 * in the output buffer. If everything cannot be filtered, copy it
 	 * to temp and rewind the output buffer position accordingly.
+	 *
+	 * This needs to be always run when temp.size == 0 to handle a special
+	 * case where the output buffer is full and the next filter has no
+	 * more output coming but hasn't returned XZ_STREAM_END yet.
 	 */
-	if (s->temp.size < b->out_size - b->out_pos) {
+	if (s->temp.size < b->out_size - b->out_pos || s->temp.size == 0) {
 		out_start = b->out_pos;
 		memcpy(b->out + b->out_pos, s->temp.buf, s->temp.size);
 		b->out_pos += s->temp.size;
@@ -467,16 +471,25 @@
 		s->temp.size = b->out_pos - out_start;
 		b->out_pos -= s->temp.size;
 		memcpy(s->temp.buf, b->out + b->out_pos, s->temp.size);
+
+		/*
+		 * If there wasn't enough input to the next filter to fill
+		 * the output buffer with unfiltered data, there's no point
+		 * to try decoding more data to temp.
+		 */
+		if (b->out_pos + s->temp.size < b->out_size)
+			return XZ_OK;
 	}
 
 	/*
-	 * If we have unfiltered data in temp, try to fill by decoding more
-	 * data from the next filter. Apply the BCJ filter on temp. Then we
-	 * hopefully can fill the actual output buffer by copying filtered
-	 * data from temp. A mix of filtered and unfiltered data may be left
-	 * in temp; it will be taken care on the next call to this function.
+	 * We have unfiltered data in temp. If the output buffer isn't full
+	 * yet, try to fill the temp buffer by decoding more data from the
+	 * next filter. Apply the BCJ filter on temp. Then we hopefully can
+	 * fill the actual output buffer by copying filtered data from temp.
+	 * A mix of filtered and unfiltered data may be left in temp; it will
+	 * be taken care on the next call to this function.
 	 */
-	if (s->temp.size > 0) {
+	if (b->out_pos < b->out_size) {
 		/* Make b->out{,_pos,_size} temporarily point to s->temp. */
 		s->out = b->out;
 		s->out_pos = b->out_pos;
http://lists.busybox.net/pipermail/busybox/2013-February/078927.html

--- busybox-1.20.2.org/archival/libarchive/decompress_unxz.c
+++ busybox-1.20.2/archival/libarchive/decompress_unxz.c
@@ -86,8 +86,40 @@
 			IF_DESKTOP(total += iobuf.out_pos;)
 			iobuf.out_pos = 0;
 		}
-		if (r == XZ_STREAM_END) {
-			break;
+		while (r == XZ_STREAM_END) {
+			/* Handle concatenated .xz Streams including possible
+			 * Stream Padding.
+			 */
+			if (iobuf.in_pos == iobuf.in_size) {
+				int rd = safe_read(src_fd, membuf, BUFSIZ);
+				if (rd < 0) {
+					bb_error_msg(bb_msg_read_error);
+					total = -1;
+					goto out;
+				}
+				if (rd == 0)
+					goto out;
+
+				iobuf.in_size = rd;
+				iobuf.in_pos = 0;
+			}
+
+			/* 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.
+			 */
+			while (iobuf.in_pos < iobuf.in_size) {
+				if (membuf[iobuf.in_pos] != 0) {
+					xz_dec_reset(state);
+					r = XZ_OK;
+					break;
+				}
+				++iobuf.in_pos;
+			}
 		}
 		if (r != XZ_OK && r != XZ_UNSUPPORTED_CHECK) {
 			bb_error_msg("corrupted data");
@@ -95,6 +127,8 @@
 			break;
 		}
 	}
+
+out:
 	xz_dec_end(state);
 	free(membuf);