From patchwork Tue Apr 26 08:21:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 566734 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E62AC433F5 for ; Tue, 26 Apr 2022 08:24:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344797AbiDZI1a (ORCPT ); Tue, 26 Apr 2022 04:27:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344677AbiDZI0o (ORCPT ); Tue, 26 Apr 2022 04:26:44 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13F804249B; Tue, 26 Apr 2022 01:23:18 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 948C7B81CF3; Tue, 26 Apr 2022 08:23:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10D3CC385A0; Tue, 26 Apr 2022 08:23:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650961396; bh=2ISxZrpT17ZWO7T7HiPFO4wRa/cI71OHRhKfqvSZPG8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Eb5kiQV1AqMJZ+or2qY1J0SQ76q32SvbKl4R5xhb0NCKDv+ym1TQEQpIFKbLWpHgH cgI01y/LRdxj+6r9sCAYS+Wy2P8wdzgIdvnO4IY4fgDN2JpS+bwzkhuShcyynCXlbH vHO4Aag8x9BTUWkB+D2ZXincoCe41KJA+7j2yq64= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+7a806094edd5d07ba029@syzkaller.appspotmail.com, Tadeusz Struk , Theodore Tso , stable@kernel.org Subject: [PATCH 4.9 21/24] ext4: limit length to bitmap_maxbytes - blocksize in punch_hole Date: Tue, 26 Apr 2022 10:21:15 +0200 Message-Id: <20220426081731.998414820@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220426081731.370823950@linuxfoundation.org> References: <20220426081731.370823950@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tadeusz Struk commit 2da376228a2427501feb9d15815a45dbdbdd753e upstream. Syzbot found an issue [1] in ext4_fallocate(). The C reproducer [2] calls fallocate(), passing size 0xffeffeff000ul, and offset 0x1000000ul, which, when added together exceed the bitmap_maxbytes for the inode. This triggers a BUG in ext4_ind_remove_space(). According to the comments in this function the 'end' parameter needs to be one block after the last block to be removed. In the case when the BUG is triggered it points to the last block. Modify the ext4_punch_hole() function and add constraint that caps the length to satisfy the one before laster block requirement. LINK: [1] https://syzkaller.appspot.com/bug?id=b80bd9cf348aac724a4f4dff251800106d721331 LINK: [2] https://syzkaller.appspot.com/text?tag=ReproC&x=14ba0238700000 Fixes: a4bb6b64e39a ("ext4: enable "punch hole" functionality") Reported-by: syzbot+7a806094edd5d07ba029@syzkaller.appspotmail.com Signed-off-by: Tadeusz Struk Link: https://lore.kernel.org/r/20220331200515.153214-1-tadeusz.struk@linaro.org Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inode.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3980,7 +3980,8 @@ int ext4_punch_hole(struct inode *inode, struct super_block *sb = inode->i_sb; ext4_lblk_t first_block, stop_block; struct address_space *mapping = inode->i_mapping; - loff_t first_block_offset, last_block_offset; + loff_t first_block_offset, last_block_offset, max_length; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); handle_t *handle; unsigned int credits; int ret = 0; @@ -4026,6 +4027,14 @@ int ext4_punch_hole(struct inode *inode, offset; } + /* + * For punch hole the length + offset needs to be within one block + * before last range. Adjust the length if it goes beyond that limit. + */ + max_length = sbi->s_bitmap_maxbytes - inode->i_sb->s_blocksize; + if (offset + length > max_length) + length = max_length - offset; + if (offset & (sb->s_blocksize - 1) || (offset + length) & (sb->s_blocksize - 1)) { /*