From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f177.google.com (mail-yw1-f177.google.com [209.85.128.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0DAB7202F71 for ; Tue, 30 Jun 2026 21:17:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782854280; cv=none; b=GxRcPjIEQSD6VVcT39LW/CZCOG5LIxlNIAWoJHFlzAltJkpG8JwbxiSeA0SjOYXpsS5V8P3iK2/eKyGmSX43WjXRozjpTEvqgSNJd009astQs+JiXLUnLCl8jR6IcL6O5tazux9CivvJL348kWZYT24oPu38xgiqXtB7oisiJZA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782854280; c=relaxed/simple; bh=1gfTG8r17InAvWVOuauyVqtQhqiNXbc6nH97XNyOiec=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Sqysz8Ll7kO4B9aGmfzoylfCpRstydyeTUAB4mQUsev77NKsA8fJf1jxRvt0G8RTH3CSPuMJVFBted4ybYBY7MAcO61hrnMphke5gwIsoxyLq+FQz3G/l7Xzp1Kx8ZP3I4kE8AVEEwBnd/dL3JOIS5C0fuiwv9DftBEHHwtxGXE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=I1AIU53+; arc=none smtp.client-ip=209.85.128.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="I1AIU53+" Received: by mail-yw1-f177.google.com with SMTP id 00721157ae682-804e46366d7so43606257b3.2 for ; Tue, 30 Jun 2026 14:17:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1782854278; x=1783459078; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=xPhVhhlEs/4/VupytmipRMbVj77VuW2OuCbqLDIFyug=; b=I1AIU53+mkXf8gnACaus9jvVWmHmjdaEkyG/XjqRUT1WVL2mD4vxtt1vkdoTM23Rx4 Xw8gFRpDNn3nKgWe2i4zy1TiavG7ml2LFPPlrfuYz5czT+ex2r7CaOeh63EJNCqH9teT o5vYhOXR0Lg3QR+zfN4ridCdy5NtMAy3+bmEqhxASiuLJeky8i+dIDQYYXBIOxWRbYJ+ 6rg0PzOMUCjx6F0zHJZIqoiZOrECaFA0Ch3xQwRodL5svuS2fcANzFIkK7xxnqrg68hX rpH/lGRgq7Xsc7kZfDzgbYA4MRuB5JgyWk5OhshK2RdHzzdnb7iwFFx4mFyh0Ts4qR31 eDkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782854278; x=1783459078; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=xPhVhhlEs/4/VupytmipRMbVj77VuW2OuCbqLDIFyug=; b=sq4bhPdulFkOjTUKMmK3DD+diySTbFqv9ACXVMDTyMNqU82I17og9ER+Do6+i9QwqF dZgF/Yq0sb1Y7CFHDffpeV9/okBFogmJdXjWyWR6hicqGm3drzEiCQ3xL8/affdv3KK9 jOuYBe/AhSGJHcOXZb0Xi6AH94y8xWV/OFmY8t3a0PEaE/C4IFEaFiP2PkzgpuE5/Og9 99X3Ey5sIIj4/vc6RBasdbwABQSFWxtqYOtybDat4YUX9nN4SLMVDaURl0rRmE8NRbS5 CEpEzZd3Ff7riNIwMaqa0nTA5iQrPlYV78aF+5XZNYpJ/OQtdlLs3ALFrx5qq1txygUG 2ZOg== X-Forwarded-Encrypted: i=1; AHgh+RpGVAWwgAg1pX5fay4rCJ4oRe85MlrKLROXSK1l8RiRDJKzqonWtqC45JAEURXT+QezX8LDbfcm9jOrflg=@vger.kernel.org X-Gm-Message-State: AOJu0YzRo2dCUnZr0SMT5NiH/iL0B9Go6smgvDlvIhr/kaxrLNeBm+Is 6GwU/BFp3M2o5SH/BRROy/wDQTL2Ztaw6pY/TZSGP1wyIK396TPYTJg5 X-Gm-Gg: AfdE7cnXnB1FhXrRDcsDBD2IFzmCp1jb0Qvw7/QWvnuwtESqc8dcO3bLVUrk7DGSwUq fy+A7Cjky/Ndb99J10TZqZw3bqka/mGcs+9Qa1I3Vxjw7DsmIoOBXQ9X5dneqw4npUAwBrI5i5H /XDErWrSQMcOwFu0PN3HCFUBUNQ0SFwK2jge2YfUGY2F5SlV3lmSFMke7d6SBB5Zc9K1h/mIRkz rAF786PIYtyDkhus/5LrcYL0cVY3Eqxzr9skQ+sr1DdYS1CXc5PHpu58ifj1jmEDRh6jcFrGtpO qZHdu4C2OdN1IDKXqW6uS9Aal9kbQiLzJRhlNHD+nsSQOAFrSjrGkJkiiUwq5MHT7S0ajnzywF3 yerSKJNNIuNCq4cJ9/GTQvwyVpXis/7reYiG+eRSDy2OfZJ1toTKZnCRcgpIanUaT+//Z3OBZD1 nJfnxr1BicHtIYm/0M5PJeife3KKOBQFzd7ElS X-Received: by 2002:a05:690c:670f:b0:80c:85b6:765f with SMTP id 00721157ae682-810da90d417mr63206517b3.68.1782854277959; Tue, 30 Jun 2026 14:17:57 -0700 (PDT) Received: from Dev-Null-MSI ([2a0d:3344:52ac:a808:98a4:4381:be45:536f]) by smtp.gmail.com with ESMTPSA id 00721157ae682-8128d450908sm13827b3.36.2026.06.30.14.17.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Jun 2026 14:17:57 -0700 (PDT) From: Yousef Alhouseen To: Konstantin Komarov Cc: ntfs3@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, syzbot+4b4ec878e25fafefa70f@syzkaller.appspotmail.com, Yousef Alhouseen Subject: [PATCH] ntfs3: reject empty iomap before reading its LCN Date: Tue, 30 Jun 2026 23:17:43 +0200 Message-ID: <20260630211743.50400-1-alhouseenyousef@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit attr_data_get_block() can return success with a zero run length when no cached or on-disk mapping covers a read VCN. In that case it does not initialize the LCN output. Check the returned length before comparing the LCN against the special mapping values. This preserves the existing -EINVAL result for an empty mapping without passing an uninitialized LCN to the comparisons. Fixes: ecbb433f9a8e ("fs/ntfs3: fold file size handling into ntfs_set_size()") Reported-by: syzbot+4b4ec878e25fafefa70f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4b4ec878e25fafefa70f Cc: stable@vger.kernel.org Signed-off-by: Yousef Alhouseen --- fs/ntfs3/inode.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c index c43101cc064d..a428f03a695d 100644 --- a/fs/ntfs3/inode.c +++ b/fs/ntfs3/inode.c @@ -777,6 +777,8 @@ static int ntfs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, if (err) { return err; } + if (!clen) + return -EINVAL; if (lcn == EOF_LCN) { /* request out of file. */ @@ -811,11 +813,6 @@ static int ntfs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, return 0; } - if (!clen) { - /* broken file? */ - return -EINVAL; - } - iomap->bdev = inode->i_sb->s_bdev; iomap->offset = offset; iomap->length = ((loff_t)clen << cluster_bits) - off; -- 2.55.0