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 73E842EA16D; Tue, 22 Jul 2025 14:10:43 +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=1753193443; cv=none; b=o3WU0U+GxVnSWJ5/RM36Xf2pMF12hBq7RCqcDnZz4/T5yFxUAyAgiDdxy3j4I79DkzhbSaHf+riTiQ9fmOwjzxMr5A6DEXhj/7bpx/3jCPxiwZqXU9sm9dbdO2LhKq3oo0h/LZMeY9t0xKHi+HjYmnUs2EUd6eOgiYNk5yWez9w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753193443; c=relaxed/simple; bh=Zn0vw1ylmebz+oFv+HgBAiRIvevp8332MJK9clsuG8A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PR7ND/yqoT2LfBh7SonKw5NArFX8X6ASysxY9Ie5Ok9R0vMJ2k2hXeNMLba3nQlE3lJ1ISGBmYANswDIHtaCX3wAhENktsX9qwGJfFVcVXu+8q0ipPUzTNIhZzFFnAY5P+TazYZeMBT6ULEzbf5fwL8SKww2FhoQse1Hjgltgpk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yILruHOF; 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="yILruHOF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6371C4CEEB; Tue, 22 Jul 2025 14:10:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1753193443; bh=Zn0vw1ylmebz+oFv+HgBAiRIvevp8332MJK9clsuG8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yILruHOFVUTOppWkFLYceD7g6I4QvMZiVenFzkdW7zKttBqnxkZAY2Srnku8UYp5Z VUdvR4YDx5GgYTY71y1S8tbHlufRcQn1z8FgRLfd0vXlRtVM+7UW6lcVKxEM6fXhX8 qdGBUpV7NFyHFEkdya4ULpCiYzHjOyEsrGvpx4Ig= 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 6.15 093/187] comedi: Fail COMEDI_INSNLIST ioctl if n_insns is too large Date: Tue, 22 Jul 2025 15:44:23 +0200 Message-ID: <20250722134349.220965198@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250722134345.761035548@linuxfoundation.org> References: <20250722134345.761035548@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 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit 08ae4b20f5e82101d77326ecab9089e110f224cc upstream. 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 --- drivers/comedi/comedi_fops.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) --- a/drivers/comedi/comedi_fops.c +++ b/drivers/comedi/comedi_fops.c @@ -1589,6 +1589,16 @@ 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 @@ -2239,6 +2249,9 @@ 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; @@ -3090,6 +3103,9 @@ 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;