Cyril, thanks for the test case. When I used 'valgrind' on it I found where gzip is accessing uninitialized data. I pushed into gzip master the patch at the end of this message; it fixed things for me.
The Debian patch, which zeros out a lot of buffers, should work if gzip is compressing regular files, but may have problems in unusual cases if gzip compresses data from pipes, devices, or other non-regular files, because in that case short reads may later cause garbage to be put into the dictionary. So I suggest using the following patch instead. http://git.savannah.gnu.org/cgit/gzip.git/commit/?id=0a284baeaedca68017f46d2646e4c921aa98a90d >From b9de47462b1b487cf4024b4c157ee5ac6c5849c3 Mon Sep 17 00:00:00 2001 From: Paul Eggert <egg...@cs.ucla.edu> Date: Sun, 18 Mar 2012 11:07:02 -0700 Subject: [PATCH] gzip: fix nondeterministic compression results Reported by Jakub Wilk in <http://bugs.debian.org/647522>. * deflate.c (fill_window): Don't let garbage pollute the dictionary. --- deflate.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/deflate.c b/deflate.c index 6c19552..5405f10 100644 --- a/deflate.c +++ b/deflate.c @@ -571,6 +571,8 @@ local void fill_window() n = read_buf((char*)window+strstart+lookahead, more); if (n == 0 || n == (unsigned)EOF) { eofile = 1; + /* Don't let garbage pollute the dictionary. */ + memzero (window + strstart + lookahead, MIN_MATCH - 1); } else { lookahead += n; } -- 1.7.6.5 -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
