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 562C141E6B2 for ; Mon, 17 Aug 2026 13:11:36 +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=1786972298; cv=none; b=X37ANjno3JZQn7g5Y73+ZOS1hSYgmdjap1G3rZ+NIBBt0drKf2sPMU5Ejp5zJ8+89mh2EP4P8yGWWLudf0lmSNE9EwkjDJY2vzbMQSNHWMgXJs4tBT7b842Evp68ixYpefWdoanLPWZPHWQ3fuzxmj0WiiUFojn+NRzrhLHtzUU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786972298; c=relaxed/simple; bh=teS2ZFl9fLvu5DyDO8rFZZYNt/zL/TTiddNC1aYmkq8=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=oRIWzbLphbnMH/5siyysWFc77NbGln5sUyOkM4kcLXT/4wcdVtZRkDl7RKqHV5E84cimbSz+6kd0z1JMCHXNehYA2nMlDkp3jQCi/Ba5KTYgrEVzxz9RCXVJDB0DPG3Yv0RCiPcobCKnq8uaDfQ+zVRBDg5kG52+So5RuYVEYt0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UUYOw9+D; 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="UUYOw9+D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63ECC1F00A3A; Mon, 17 Aug 2026 13:11:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786972295; bh=2IlWTiv+kB8/Eh86PQWYfzgAXL0f9+nxmF1R+QIE2kw=; h=Subject:To:Cc:From:Date; b=UUYOw9+DL55xZiVXh4TG5ebHUX7LrvsyuLaEgBPGsrqsNf1g7hoJZtWiNpItiYn2z qllxlwlHcD14FXpB/z9PF1aVLF6W9ABlnfI1+X+K2PTP7ZCseBZAeXuRHlK6EWYSkd NASobd11KS8rZee49p66A3qJV/hQitBIdL9Rx/PI= Subject: FAILED: patch "[PATCH] ALSA: usx2y: bound the hwdep mmap fault offset" failed to apply to 5.10-stable tree To: baul.lee@xbow.com,federico.kirschbaum@xbow.com,tiwai@suse.de Cc: From: Date: Mon, 17 Aug 2026 14:57:20 +0200 Message-ID: <2026081720-deviant-snipping-e432@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 2ca1eea3cd17930daffe9e429a7c89232036ec24 # git commit -s git send-email --to '' --in-reply-to '2026081720-deviant-snipping-e432@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 2ca1eea3cd17930daffe9e429a7c89232036ec24 Mon Sep 17 00:00:00 2001 From: Baul Lee Date: Wed, 5 Aug 2026 10:34:45 +0900 Subject: [PATCH] ALSA: usx2y: bound the hwdep mmap fault offset snd_us428ctls_vm_fault() turns the faulting page offset into a kernel address with no bound of any kind: offset = vmf->pgoff << PAGE_SHIFT; vaddr = (char *)(...)->us428ctls_sharedmem + offset; page = virt_to_page(vaddr); get_page(page); vmf->page = page; return 0; snd_us428ctls_mmap() checks only the length of the mapping, never the offset, and us428ctls_sharedmem is a single page from alloc_pages_exact(). For a character device file_mmap_size_max() returns ULONG_MAX, so the mm layer imposes no ceiling either. Every page offset above zero resolves to a struct page outside the object, and the handler installs it into the caller's address space read-write; the vma is not marked read-only. The caller picks the page frame with a single mmap() argument and gets read-write access to a page of kernel memory it does not own; an offset that lands in an unpopulated vmemmap region oopses instead. A process that can open the hwdep node of an attached US-X2Y reaches this after loading the FPGA image through the same node; no capability check is involved. On 7.2.0-rc5 (arm64), mmap() with a large offset: Unable to handle kernel paging request at virtual address fffffdffc45d5ac8 pc : snd_us428ctls_vm_fault+0x68/0x140 [snd_usb_usx2y] Call trace: snd_us428ctls_vm_fault+0x68/0x140 [snd_usb_usx2y] __do_fault __handle_mm_fault handle_mm_fault el0_da Reject any offset outside the shared region. The pcm hwdep handler in usx2yhwdeppcm.c computes its address the same way and needs the same bound. Discovered by XBOW, triaged by Baul Lee Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Federico Kirschbaum Reported-by: Baul Lee Cc: stable@vger.kernel.org Signed-off-by: Baul Lee Link: https://patch.msgid.link/20260805013445.38283-1-baul.lee@xbow.com Signed-off-by: Takashi Iwai diff --git a/sound/usb/usx2y/usX2Yhwdep.c b/sound/usb/usx2y/usX2Yhwdep.c index 4d7925184826..7f153a2fcdd8 100644 --- a/sound/usb/usx2y/usX2Yhwdep.c +++ b/sound/usb/usx2y/usX2Yhwdep.c @@ -25,6 +25,8 @@ static vm_fault_t snd_us428ctls_vm_fault(struct vm_fault *vmf) void *vaddr; offset = vmf->pgoff << PAGE_SHIFT; + if (offset >= US428_SHAREDMEM_PAGES) + return VM_FAULT_SIGBUS; vaddr = (char *)((struct usx2ydev *)vmf->vma->vm_private_data)->us428ctls_sharedmem + offset; page = virt_to_page(vaddr); get_page(page); diff --git a/sound/usb/usx2y/usx2yhwdeppcm.c b/sound/usb/usx2y/usx2yhwdeppcm.c index 7c90214485d9..f1d5b4b797ad 100644 --- a/sound/usb/usx2y/usx2yhwdeppcm.c +++ b/sound/usb/usx2y/usx2yhwdeppcm.c @@ -672,6 +672,8 @@ static vm_fault_t snd_usx2y_hwdep_pcm_vm_fault(struct vm_fault *vmf) void *vaddr; offset = vmf->pgoff << PAGE_SHIFT; + if (offset >= USX2Y_HWDEP_PCM_PAGES) + return VM_FAULT_SIGBUS; vaddr = (char *)((struct usx2ydev *)vmf->vma->vm_private_data)->hwdep_pcm_shm + offset; vmf->page = virt_to_page(vaddr); get_page(vmf->page);