From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rustam Kovhaev Subject: [PATCH] reiserfs: add check for an invalid ih_entry_count Date: Sun, 1 Nov 2020 06:09:58 -0800 Message-ID: <20201101140958.3650143-1-rkovhaev@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=/9og09u1zo9NX9D44RRZapG5HLQMVJBUImJCPrX7E10=; b=XBh/ZQG09VwZL2EiUVzXO6QoYMWPFNyQYMfhzBF87zIMxDKw/abftzYZmS6wvWLkbS g7P2btAbHk+L2gY3o938IL/n3CQPr3ao8xbur4ni1agGW4PpkVC/AtOHgUgTvn13Q57A OEdeSwKAUBJVOZ6jggwWuREPbU+2R8JCK4v4wHDtQtOr1aX1rSx+CHw00EY4KWF7gWJx s9JrWfTd9NRMreR8tY6zF23u/nzMQFTcIGAdb+cbQOeswmQjsYiYr513w8dx7skmOWKx V6yjWK6ab2pFmq1MkJG9VLBexCPbmSk+maswIuLhitqmUXIN2oBm7+0cZbYfOIF5bLN7 ZHDw== List-ID: Content-Type: text/plain; charset="us-ascii" To: alex.shi@linux.alibaba.com, jack@suse.cz, akpm@linux-foundation.org, yeyunfeng@huawei.com Cc: reiserfs-devel@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, Rustam Kovhaev when directory item has an invalid value set for ih_entry_count it might trigger use-after-free or out-of-bounds read in bin_search_in_dir_item() ih_entry_count * IH_SIZE for directory item should not be larger than ih_item_len Reported-and-tested-by: syzbot+83b6f7cf9922cae5c4d7@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=83b6f7cf9922cae5c4d7 Signed-off-by: Rustam Kovhaev --- fs/reiserfs/stree.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c index 8bf88d690729..476a7ff49482 100644 --- a/fs/reiserfs/stree.c +++ b/fs/reiserfs/stree.c @@ -454,6 +454,12 @@ static int is_leaf(char *buf, int blocksize, struct buffer_head *bh) "(second one): %h", ih); return 0; } + if (is_direntry_le_ih(ih) && (ih_item_len(ih) < (ih_entry_count(ih) * IH_SIZE))) { + reiserfs_warning(NULL, "reiserfs-5093", + "item entry count seems wrong %h", + ih); + return 0; + } prev_location = ih_location(ih); } -- 2.28.0