From mboxrd@z Thu Jan 1 00:00:00 1970 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 DD25BCCA48A for ; Wed, 8 Jun 2022 00:23:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1386712AbiFHAWa (ORCPT ); Tue, 7 Jun 2022 20:22:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381972AbiFGVpz (ORCPT ); Tue, 7 Jun 2022 17:45:55 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4AEB235252; Tue, 7 Jun 2022 12:07:36 -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 6241EB823B2; Tue, 7 Jun 2022 19:07:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3764C385A2; Tue, 7 Jun 2022 19:07:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654628855; bh=p/vWRLsXaxn69jFFiFCh3tIbEqu+F8JroeQeTdsr9i0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NttA6XJRqA7iWrcCM2eTtwyNY6NZSa9N0C/Hf7FMf+4rux+7c4nfohjkMrNGlSUyP mXeQH+avgnW0cp1pbhGuj2QYBTGhh5cHOwmTxwabSeRQkfmZwoXExRj4vUiq/fZjBw HvbhszrCDrFo7LTao4mCz0uJA98LMJ/CUFNFZqnU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yue Hu , Chao Yu , Gao Xiang , Sasha Levin Subject: [PATCH 5.18 480/879] erofs: fix buffer copy overflow of ztailpacking feature Date: Tue, 7 Jun 2022 18:59:58 +0200 Message-Id: <20220607165016.809309386@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607165002.659942637@linuxfoundation.org> References: <20220607165002.659942637@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Gao Xiang [ Upstream commit dcbe6803fffd387f72b48c2373b5f5ed12a5804b ] I got some KASAN report as below: [ 46.959738] ================================================================== [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370 [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188 ... [ 46.960430] Call Trace: [ 46.960430] [ 46.960430] dump_stack_lvl+0x41/0x5e [ 46.960430] print_report.cold+0xb2/0x6b7 [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370 [ 46.960430] kasan_report+0x8a/0x140 [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370 [ 46.960430] kasan_check_range+0x14d/0x1d0 [ 46.960430] memcpy+0x20/0x60 [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370 [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080 The root cause is that the tail pcluster won't be a complete filesystem block anymore. So if ztailpacking is used, the second part of an uncompressed tail pcluster may not be ``rq->pageofs_out``. Fixes: ab749badf9f4 ("erofs: support unaligned data decompression") Fixes: cecf864d3d76 ("erofs: support inline data decompression") Reviewed-by: Yue Hu Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20220512115833.24175-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang Signed-off-by: Sasha Levin --- fs/erofs/decompressor.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index 3efa686c7644..0e0d1fc0f130 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -322,6 +322,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq, PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; const unsigned int righthalf = min_t(unsigned int, rq->outputsize, PAGE_SIZE - rq->pageofs_out); + const unsigned int lefthalf = rq->outputsize - righthalf; unsigned char *src, *dst; if (nrpages_out > 2) { @@ -344,10 +345,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq, if (nrpages_out == 2) { DBG_BUGON(!rq->out[1]); if (rq->out[1] == *rq->in) { - memmove(src, src + righthalf, rq->pageofs_out); + memmove(src, src + righthalf, lefthalf); } else { dst = kmap_atomic(rq->out[1]); - memcpy(dst, src + righthalf, rq->pageofs_out); + memcpy(dst, src + righthalf, lefthalf); kunmap_atomic(dst); } } -- 2.35.1