From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5149D3D8914; Wed, 20 May 2026 16:54:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779296077; cv=none; b=XlWEAYtBA0KVYckgXMdSu6P5iLzPr4g94V/qz25tbWAwvblVisTFfg+7u225FBxS7lLk21dla/qOzFLd9dwa2Fqa4UH0/EMDEMzUkery/jTtkvcIj7fpefqB4r6xnBEK/0gq90u1Bfvj7XMOmM0dLKhLAJgYXGe4f4AXslJsmlM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779296077; c=relaxed/simple; bh=lxSfV2QjgngY0mzVwwrf9Q1VNBFN+ukZ6aHlOr7TNSQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hsoPV+CYrVOltKduqImmsYmYDkdj/2b196x1QjTJxJGUPZQQzpr84ey+8IxJEi5J9a0gJXmuSjnqSXkaRcRYh/SLsY3XprSGm2eU4FUtuBurtF/k4EUOayRz2ZUTMCjEVgqzb6X3MExwUTj7d2AWa53wRx/ghBzKRPH1VonWRYA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gkmAQElh; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="gkmAQElh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5C2A1F000E9; Wed, 20 May 2026 16:54:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779296076; bh=CCWfoPBT2K9kh38f4f7nPJPi6hKyHXIDlDwwn9jRePU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gkmAQElhmfcnQH9VkIbmVs5tjWfh3CZyXx+0m4lgtpFS8lk2TKuAtHCAiP1Ps2kGR GRPqOtCdn5W9BBDgKYaFWFASc9rMpv2xgJjkGySJ6jAG+lUoZMM+5UhtS24/yYS3H7 jqOc6hvzvcHUb6GutI7sa8Wuy9NCcCLIrH9TThxs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+7be88937363ac7ab7bb0@syzkaller.appspotmail.com, Edward Adam Davis , Konstantin Komarov , Sasha Levin Subject: [PATCH 7.0 0663/1146] fs/ntfs3: prevent uninitialized lcn caused by zero len Date: Wed, 20 May 2026 18:15:13 +0200 Message-ID: <20260520162203.188129188@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162148.390695140@linuxfoundation.org> References: <20260520162148.390695140@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Edward Adam Davis [ Upstream commit e98266e823a1fa06fe6499df61aeaac2fd6f7a49 ] syzbot reported a uninit-value in ntfs_iomap_begin [1]. Since runs was not touched yet, run_lookup_entry() immediately fails and returns false, which makes the value of "*len" 0. Simultaneously, the new value and err value are also 0, causing the logic in attr_data_get_block_locked() to jump directly to ok, ultimately resulting in *lcn being triggered before it is set [1]. In ntfs_iomap_begin(), the check for a 0 value in clen is moved forward to before updating lcn to avoid this [1]. [1] BUG: KMSAN: uninit-value in ntfs_iomap_begin+0x8c0/0x1460 fs/ntfs3/inode.c:825 ntfs_iomap_begin+0x8c0/0x1460 fs/ntfs3/inode.c:825 iomap_iter+0x9b7/0x1540 fs/iomap/iter.c:110 Local variable lcn created at: ntfs_iomap_begin+0x15d/0x1460 fs/ntfs3/inode.c:786 Fixes: 10d7c95af043 ("fs/ntfs3: add delayed-allocation (delalloc) support") Reported-by: syzbot+7be88937363ac7ab7bb0@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7be88937363ac7ab7bb0 Tested-by: syzbot+7be88937363ac7ab7bb0@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin --- fs/ntfs3/inode.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c index 6e65066ebcc1a..eac421cf98a87 100644 --- a/fs/ntfs3/inode.c +++ b/fs/ntfs3/inode.c @@ -822,6 +822,11 @@ static int ntfs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, return err; } + if (!clen) { + /* broken file? */ + return -EINVAL; + } + if (lcn == EOF_LCN) { /* request out of file. */ if (flags & IOMAP_REPORT) { @@ -855,11 +860,6 @@ 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; -- 2.53.0