From: Lasse Collin Date: Sun, 1 May 2011 16:38:42 +0000 (+0300) Subject: XZ decompressor: Fix decoding of empty LZMA2 streams X-Git-Tag: v2.6.38.6~10 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7b17624a7f6b41678d7452ebd5a525ddc3aaf3d3;p=thirdparty%2Fkernel%2Fstable.git XZ decompressor: Fix decoding of empty LZMA2 streams commit 646032e3b05b32d3f20cb108a030593d9d792eb5 upstream. 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 Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/lib/xz/xz_dec_lzma2.c b/lib/xz/xz_dec_lzma2.c index ea5fa4fe9d678..a6cdc969ea42a 100644 --- 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;