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 B473E3D8900; Wed, 30 Sep 2026 19:17:07 +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=1790795828; cv=none; b=qX/QIFjKhP9gutsa02pkn79X2Ltap3z6N2PvlREXoHMmBa+e5vr+j6vX5Zyhs9nArdrY6faAGlzek5EGQOHhEnUiRFd8mbVV3sHlAcwzmJNCTuxxHHVZfDKMwwNEjdug2EicpKzOhDrujqLSnuNDRUufwoYLQicBi7PMgOlVR4k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790795828; c=relaxed/simple; bh=CiLDUqgiPtp0zjx0aHncyXpObgd1Gu4eKYTsouxz3Fk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Szq39UPHnOHcZOPITKkQiQdNe0QpFgAsFsdyGTVzUUG/fesSLqXT1CJ9JfqBsc5+z/LtCWr4fBa2FD53Ld2p30PriiM7wbRaFCI4YF3id+V8m1UrlWiRTbYcsmlBXVd9hy6BRarTlVF+yk86ojvWESKxRwPr8ej7rxDiH7yNrWo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lbPpYQUf; 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="lbPpYQUf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 136521F000FF; Wed, 30 Sep 2026 19:17:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790795827; bh=NbJLlC+r3SjzljQlwfAm5VA5q3IX25rIB7MxqWPAVuw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lbPpYQUf5100M3ekas5qsrS4JNzcflevfqrsZKysC5SD6Y0XJ1pJ0Vuwd0DrMVMs2 hu8PEsML9V1Wt+Lffo+exOtWNXdEqsWh8sl0vBbrwDfltBxcrJSbECe7IjbxIi505G C5qAMJmAAOWd0XjUN69k354oWPdhLiR9FMIsGUHo= 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 6.6 0697/1193] ALSA: us122l: Prevent write upgrades for read mappings Date: Wed, 30 Sep 2026 17:23:01 +0200 Message-ID: <20260930152449.735838802@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152434.301151190@linuxfoundation.org> References: <20260930152434.301151190@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 6.6-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 612047ca5fe7a..36167300b8d07 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; + } + vm_flags_clear(area, VM_MAYWRITE); } snd_printdd(KERN_DEBUG "%lu %u\n", size, read ? s->read_size : s->write_size); -- 2.53.0