btrfs: zlib: zero-initialize zlib workspace

commit eadd7deca0ad8a83edb2b894d8326c78e78635d6 upstream.

KMSAN reports uses of uninitialized memory in zlib's longest_match()
called on memory originating from zlib_alloc_workspace().
This issue is known by zlib maintainers and is claimed to be harmless,
but to be on the safe side we'd better initialize the memory.

Link: https://zlib.net/zlib_faq.html#faq36
Reported-by: syzbot+14d9e7602ebdf7ec0a60@syzkaller.appspotmail.com
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Potapenko 2023-01-24 12:32:34 +01:00 committed by Greg Kroah-Hartman
parent ed29d8b309
commit 7e43bb69bc

View File

@ -74,7 +74,7 @@ static struct list_head *zlib_alloc_workspace(unsigned int level)
workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
zlib_inflate_workspacesize());
workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
workspace->strm.workspace = kvzalloc(workspacesize, GFP_KERNEL);
workspace->level = level;
workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!workspace->strm.workspace || !workspace->buf)