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 DF3FF37FF50; Sat, 12 Sep 2026 19:25:35 +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=1789241137; cv=none; b=KrIW3UnWnxfQIOgoWkOmbst4HuN5b2hTBjfrEd15WxFcHAjPa5c/DG+2PmCUy28yTXIyTTRmPp6DUnpsgCMdro9du4WJAZZ+S7i1kNH/OA907uYXPQ8tE8Bt9qLF0PSQwpaabv+qsnsTr/oS5awQJtO6EqYudOZAL5a2iQ8znAA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789241137; c=relaxed/simple; bh=mgtj0Bls1UWOXnTjHur9m53A3O8347dQUiV5k6WaecM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UgSQsRzmurSQ3f2biOYsBZvA3Jwnz10DquqRNxGIlnUwSTY+Tjakw8udipkbSE30U3UWzgCZK9qCEMgLPhverm2PRbvzs6BoYOWto3ua8VDF4dlFZDPBy9QpBymz0tHBEOBjfFLPvaIQs5mZ+UlVH9X9LuE3o3jHt8c+du4mkaM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TtEOhvCk; 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="TtEOhvCk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C83511F000FF; Sat, 12 Sep 2026 19:25:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789241135; bh=9LIPLFKGfXK7qYlKAMtzUWyQAGlcItXRNOwUdNqm2EY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TtEOhvCkxZXTUnBbwe+zFNebc7VjzgYBRS/9JcBdaUWPLZJ9F2VLNIzYILQuJRmaX EbNmU+vcacX+posQ59I+0/3kL14QBnAH7bDQie7wv/LnNCkERtdevaxDh8v/U5atML 249UkrqpTbytHI737RCAbrjAcO+9cS0V/wthUFnU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pengpeng Hou , Tyler Hicks Subject: [PATCH 5.10 057/798] eCryptfs: bound the packet-length peek to the user buffer Date: Sat, 12 Sep 2026 08:54:45 +0200 Message-ID: <20260912065518.269822700@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065516.948645775@linuxfoundation.org> References: <20260912065516.948645775@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 5.10-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 @@ -356,7 +356,7 @@ 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) { @@ -372,7 +372,8 @@ 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;