Jan Beulich
2011-Sep-22 15:16 UTC
[Xen-devel] [PATCH] XZ decompressor: Fix decoding of empty LZMA2 streams
From: Lasse Collin <lasse.collin@tukaani.org>
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 <lasse.collin@tukaani.org>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/common/xz/dec_lzma2.c
+++ b/xen/common/xz/dec_lzma2.c
@@ -969,6 +969,9 @@ XZ_EXTERN enum xz_ret INIT xz_dec_lzma2_
*/
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 INIT xz_dec_lzma2_
lzma_reset(s);
}
} else {
- if (tmp == 0x00)
- return XZ_STREAM_END;
-
if (tmp > 0x02)
return XZ_DATA_ERROR;
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