XZ decompressor: Fix decoding of empty LZMA2 streams

The old code considered valid empty LZMA2 streams to be corrupt. Note that a typical empty .xz file has no LZMA2 data at all, and thus most .xz files having no uncompressed data are handled correctly even without this fix. Signed-off-by: Lasse Collin <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
k1132 · May 2, 2011 · 646032e · 646032e
1 parent 3fd9952
commit 646032e
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/lib/xz/xz_dec_lzma2.c b/lib/xz/xz_dec_lzma2.c
@@ -969,6 +969,9 @@ XZ_EXTERN enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s,
 			 */
 			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;
@@ -1001,9 +1004,6 @@ XZ_EXTERN enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s,
 						lzma_reset(s);
 				}
 			} else {
-				if (tmp == 0x00)
-					return XZ_STREAM_END;
-
 				if (tmp > 0x02)
 					return XZ_DATA_ERROR;