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 49E974F4051; Wed, 30 Sep 2026 18:09:12 +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=1790791753; cv=none; b=YegZrYfGfI5WgOQCKN8i08UbkSl+kf26CJ+yNq+rpfZCI2Z+Stwd95ZioflJA6VsCTMZvDS6cpGg3h2KICjv87jwXnBx+C9dVTwxb7D9glLvpDoJ5OVbZzJXPyNEGV8oUP3dwTcZMgkBi2kbWvFoqHMGVWWUNAevsT/xiPNHQSY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791753; c=relaxed/simple; bh=otThHe0QIRWQsV4vRsHRzhBs417d6XOk7pWP2fGUP5U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NQj1h2CZ7OuhSlA02Lnw0Rxt+iTdI5STuKJ+DAlJTWoveyI+luGhqYdGpocbx9wX1OG9SZSoRULaFxesjlauMyaakUUgzMFoLtzTgQQcJnMTmS5R9Cb400YJ4YBeVtYVGhmsb9rUBoaL+wh65Nw0bIguJnfR/Oa4yu7mimcgjm0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LHDjaZQE; 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="LHDjaZQE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7C691F000FF; Wed, 30 Sep 2026 18:09:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790791752; bh=ktHoesQt5Yndcj70qF8OsGnK5DrURRDc41i6m9ES7gA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=LHDjaZQEq9gY6IHwzZRwob2iRRb/wZjCKZJyPw9hCLuin+4+HYFrWCL09gjfXUWgX Y9TLlndePDUSDPVueFpYATvHUFlNtgqMEjHbqCbdvVC/rashUvMpEU/AmlBqYtCJU0 GuQzyA11fLO/el7uL2QRwZUj+P2rwGQRsyeRAW9I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kazuki Hanai , Takashi Iwai , Sasha Levin Subject: [PATCH 5.15 411/752] ALSA: us122l: Prevent write upgrades for read mappings Date: Wed, 30 Sep 2026 17:24:41 +0200 Message-ID: <20260930152407.169380377@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kazuki Hanai [ Upstream commit 71c610aeb1770302ac9c9e0b9a4ecd37f1311928 ] The hwdep mmap callback rejects read-buffer mappings that are initially writable, but leaves VM_MAYWRITE set on mappings created with PROT_READ. A process that can open the hwdep node O_RDWR can later use mprotect() to make the mapping writable. The read allocation begins with struct usb_stream. Its read_size member is used by the fault handler to decide which pages belong to the read buffer. The read VMA intentionally remains expandable because pcm_usb_stream uses mremap() after reading that size. Changing read_size first can therefore map and access pages beyond the allocation. The same member is also consumed by usb_stream_free(), where changing it can make free_pages_exact() release pages outside the allocation. Clear VM_MAYWRITE for read-buffer mappings after rejecting an initially writable VMA. This keeps the separate output-buffer mapping writable while preventing later permission upgrades. Fixes: 030a07e44129 ("ALSA: Add USB US122L driver") Cc: stable@vger.kernel.org Signed-off-by: Kazuki Hanai Link: https://patch.msgid.link/20260908110053.2950767-1-hnkz.64@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/usb/usx2y/us122l.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c index 23d7d542a3de6..21c5a7fcea768 100644 --- a/sound/usb/usx2y/us122l.c +++ b/sound/usb/usx2y/us122l.c @@ -209,9 +209,12 @@ static int usb_stream_hwdep_mmap(struct snd_hwdep *hw, mutex_lock(&us122l->mutex); s = us122l->sk.s; read = offset < s->read_size; - if (read && area->vm_flags & VM_WRITE) { - err = -EPERM; - goto out; + if (read) { + if (area->vm_flags & VM_WRITE) { + err = -EPERM; + goto out; + } + area->vm_flags &= ~VM_MAYWRITE; } snd_printdd(KERN_DEBUG "%lu %u\n", size, read ? s->read_size : s->write_size); -- 2.53.0