From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C361E35AACC; Tue, 26 Aug 2025 14:24:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756218260; cv=none; b=k6ocad7zuugPwIv7BNn31f3IoYyXUn9FNNdUgjW7PEWav9Tm9e5t+IS/UJUy693Ro2TVpeHUJIgtXkuCpkARlaY2RHt62gCZk+FzPpb9TyRsvnT4hfiFnHf6zytEYXs9vRK7h1A5V+Na+7SFRdudGy2vP7+SaNUCRPqTQdzhwlM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756218260; c=relaxed/simple; bh=77mh6PTJXiJ4ebFvt31YmOyB8j0j6GUlU0w6nnYVWhI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L5gryE9Yfmr09wYAcO7CaySziUjX1G/LJ3tbWhuUd2mOIR4qAMzoxjMdlZVXTIiutxBn6HcGUxQsmKxvj/JFflywnbwJiHtC8Lai35Mzip67/+md0JAOzrGXmuJYFF21e2StKwuRBg50a8ohk1OAa4KztQAHsjc9adNr6hAZw9g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fQP3hEE3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fQP3hEE3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 580D5C4CEF1; Tue, 26 Aug 2025 14:24:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756218260; bh=77mh6PTJXiJ4ebFvt31YmOyB8j0j6GUlU0w6nnYVWhI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fQP3hEE3nz3JyiieGeLvRRbMfsndGWGVtBqP8hIK+qpapB6mThDCOyeSKGEya3FiR bhMZ+CDduK6xW9FYvrtBxXHRIdg6QInRykhF2CUmEuP/EwKLRgthGHigfdoe/tFFMx 56Ka10kNjomCrmZ26qwWhJl8/6bN2jTP9/mpp1fI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+d6995b62e5ac7d79557a@syzkaller.appspotmail.com, Ian Abbott Subject: [PATCH 5.10 437/523] comedi: Fail COMEDI_INSNLIST ioctl if n_insns is too large Date: Tue, 26 Aug 2025 13:10:47 +0200 Message-ID: <20250826110935.233466050@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110924.562212281@linuxfoundation.org> References: <20250826110924.562212281@linuxfoundation.org> User-Agent: quilt/0.68 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: Ian Abbott [ Upstream commit 08ae4b20f5e82101d77326ecab9089e110f224cc ] The handling of the `COMEDI_INSNLIST` ioctl allocates a kernel buffer to hold the array of `struct comedi_insn`, getting the length from the `n_insns` member of the `struct comedi_insnlist` supplied by the user. The allocation will fail with a WARNING and a stack dump if it is too large. Avoid that by failing with an `-EINVAL` error if the supplied `n_insns` value is unreasonable. Define the limit on the `n_insns` value in the `MAX_INSNS` macro. Set this to the same value as `MAX_SAMPLES` (65536), which is the maximum allowed sum of the values of the member `n` in the array of `struct comedi_insn`, and sensible comedi instructions will have an `n` of at least 1. Reported-by: syzbot+d6995b62e5ac7d79557a@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d6995b62e5ac7d79557a Fixes: ed9eccbe8970 ("Staging: add comedi core") Tested-by: Ian Abbott Cc: stable@vger.kernel.org # 5.13+ Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20250704120405.83028-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_fops.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1607,6 +1607,16 @@ error: return i; } +#define MAX_INSNS MAX_SAMPLES +static int check_insnlist_len(struct comedi_device *dev, unsigned int n_insns) +{ + if (n_insns > MAX_INSNS) { + dev_dbg(dev->class_dev, "insnlist length too large\n"); + return -EINVAL; + } + return 0; +} + /* * COMEDI_INSN ioctl * synchronous instruction @@ -2261,6 +2271,9 @@ static long comedi_unlocked_ioctl(struct rc = -EFAULT; break; } + rc = check_insnlist_len(dev, insnlist.n_insns); + if (rc) + break; insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL); if (!insns) { rc = -ENOMEM; @@ -3112,6 +3125,9 @@ static int compat_insnlist(struct file * if (copy_from_user(&insnlist32, compat_ptr(arg), sizeof(insnlist32))) return -EFAULT; + rc = check_insnlist_len(dev, insnlist32.n_insns); + if (rc) + return rc; insns = kcalloc(insnlist32.n_insns, sizeof(*insns), GFP_KERNEL); if (!insns) return -ENOMEM;