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 3D68E318ED6; Fri, 4 Sep 2026 05:46:59 +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=1788500820; cv=none; b=OE9YwfQB1AqFoRSPPxf/tU0cTKF683t2tWVmt7h2uwr4+xNbQVdri7djNjjVYF/yUEWongS4FjVZWzsP8A7SRIvAdpabSnGpJaNSJtkejpoU6TBoiarZxDuc+lcQONYhLVOjsyMDgpUzabk3LLsLNv2dtT5YGrlw2wuDuJGTwas= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788500820; c=relaxed/simple; bh=XxGaDBjZ4JQwn1955AYsqnbpASy42qOLzkuegRewwKE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kwNrWN+hoYMDU2jDrXayqaWlUplSAQLJ2OwmBRNyumU4ZSWoZBlZR4sEFUhesje68yA++twj0PAPivEGrQq79dwF8ESC0mNILqjkryNgjsY2Iu9taR2GfwMQqguX5wISPKyu7aw0tje5O3epRXnLqZHmv9zvS7MS34bRo3/FPWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=n4L7+PUR; 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="n4L7+PUR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 965A81F00A3D; Fri, 4 Sep 2026 05:46:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788500819; bh=yK6YaEGsBwC/zVCXsfowBv+7efbNgYk/l149TPT2e9U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=n4L7+PURYukrtaUimHdE13EkCo+MSMPqLYUiBq9SePoOd0BSgCeoun3t3ms+p8P3q JNlJ0nozg9Y3+ty/G2+uSdpZqLEY8Qo3+1Re49U+wICA80IV3X1atqOK+mh9fqMFIl 24OUu2O6zSXdaUXNCrx2AmjjPvgIrsG0sS6kah9w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pengpeng Hou , Tyler Hicks Subject: [PATCH 6.18 191/552] eCryptfs: bound the packet-length peek to the user buffer Date: Fri, 4 Sep 2026 06:55:48 +0200 Message-ID: <20260904045753.344231652@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pengpeng Hou commit 95540462e630edbc8504e9537d16453d6942d143 upstream. ecryptfs_miscdev_write() accepts the minimum one-byte packet-length encoding, but always copies the maximum two-byte encoding from userspace before parsing it. A six-byte message therefore reads one byte beyond the submitted user buffer. Zero-initialize the peek buffer and copy only the packet-length bytes present. The existing exact packet-size check still rejects truncated two-byte encodings after the parser determines their encoded length. Fixes: 8bf2debd5f7b ("eCryptfs: introduce device handle for userspace daemon communications") Cc: Signed-off-by: Pengpeng Hou Signed-off-by: Tyler Hicks Signed-off-by: Greg Kroah-Hartman --- fs/ecryptfs/miscdev.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/ecryptfs/miscdev.c +++ b/fs/ecryptfs/miscdev.c @@ -357,7 +357,7 @@ ecryptfs_miscdev_write(struct file *file u32 seq; size_t packet_size, packet_size_length; char *data; - unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE]; + unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE] = { }; ssize_t rc; if (count == 0) { @@ -373,7 +373,8 @@ ecryptfs_miscdev_write(struct file *file } if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET], - sizeof(packet_size_peek))) { + min_t(size_t, count - PKT_LEN_OFFSET, + sizeof(packet_size_peek)))) { printk(KERN_WARNING "%s: Error while inspecting packet size\n", __func__); return -EFAULT;