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 1D8C0A32; Tue, 22 Jul 2025 13:53:34 +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=1753192414; cv=none; b=GOrT0gUlSJoLXwwofdkrkdrXreU3g3OTQqrgiU8RD1AJu7pD91L2qBDF/VmmbH+XI7bZXQfOYtVSDhNUwHsbDTCtLfRMGYMyKDcNaUyjX4txBqTGIHHbWEzipAX0nuwVQiCCOOaBR//9JF9kj5p3iHBICavqEbYpFbWumdE4exY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753192414; c=relaxed/simple; bh=bHZQSiHYowJ7YA8tWCsaZw+hJZL9MjKRBpq1pdj3YWY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ckHCZeXpHQIX0oRIUMAL3r4UFSAngA/TBrRLZzPbE5Zz471ag1vNhHYS4ngYw80BfQaypLe2lkpvPQOiDJIITRcMarDT49ZiIlRmazMLpPRPpfnoHbAXtF4Q7zMcGf5WWBjToYaQs4TMnV+V6j77Cb1as7qwJZuUni/sixpzUpE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=e0+uEVVK; 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="e0+uEVVK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 803C0C4CEEB; Tue, 22 Jul 2025 13:53:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1753192414; bh=bHZQSiHYowJ7YA8tWCsaZw+hJZL9MjKRBpq1pdj3YWY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e0+uEVVKmF09vnb85CC/wFr79HdcU1n3esVRM986AUpDcp9z5hXoc5xi6qDlvKa6q oK/ayAuvuK7qcCJ/fN8nJTUJHqzwuzfS1bS/7E1NA5EeT5VU+vyaiDMRbkUHnGiMNj 0278QT+c8W6pdgf53k990BmFWO19GHxxDxjWtFqU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Abbott Subject: [PATCH 6.6 058/111] comedi: Fix initialization of data for instructions that write to subdevice Date: Tue, 22 Jul 2025 15:44:33 +0200 Message-ID: <20250722134335.551375621@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250722134333.375479548@linuxfoundation.org> References: <20250722134333.375479548@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit 46d8c744136ce2454aa4c35c138cc06817f92b8e upstream. Some Comedi subdevice instruction handlers are known to access instruction data elements beyond the first `insn->n` elements in some cases. The `do_insn_ioctl()` and `do_insnlist_ioctl()` functions allocate at least `MIN_SAMPLES` (16) data elements to deal with this, but they do not initialize all of that. For Comedi instruction codes that write to the subdevice, the first `insn->n` data elements are copied from user-space, but the remaining elements are left uninitialized. That could be a problem if the subdevice instruction handler reads the uninitialized data. Ensure that the first `MIN_SAMPLES` elements are initialized before calling these instruction handlers, filling the uncopied elements with 0. For `do_insnlist_ioctl()`, the same data buffer elements are used for handling a list of instructions, so ensure the first `MIN_SAMPLES` elements are initialized for each instruction that writes to the subdevice. Fixes: ed9eccbe8970 ("Staging: add comedi core") Cc: stable@vger.kernel.org # 5.13+ Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20250707161439.88385-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman --- drivers/comedi/comedi_fops.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/drivers/comedi/comedi_fops.c +++ b/drivers/comedi/comedi_fops.c @@ -1556,21 +1556,27 @@ static int do_insnlist_ioctl(struct come } for (i = 0; i < n_insns; ++i) { + unsigned int n = insns[i].n; + if (insns[i].insn & INSN_MASK_WRITE) { if (copy_from_user(data, insns[i].data, - insns[i].n * sizeof(unsigned int))) { + n * sizeof(unsigned int))) { dev_dbg(dev->class_dev, "copy_from_user failed\n"); ret = -EFAULT; goto error; } + if (n < MIN_SAMPLES) { + memset(&data[n], 0, (MIN_SAMPLES - n) * + sizeof(unsigned int)); + } } ret = parse_insn(dev, insns + i, data, file); if (ret < 0) goto error; if (insns[i].insn & INSN_MASK_READ) { if (copy_to_user(insns[i].data, data, - insns[i].n * sizeof(unsigned int))) { + n * sizeof(unsigned int))) { dev_dbg(dev->class_dev, "copy_to_user failed\n"); ret = -EFAULT; @@ -1643,6 +1649,10 @@ static int do_insn_ioctl(struct comedi_d ret = -EFAULT; goto error; } + if (insn->n < MIN_SAMPLES) { + memset(&data[insn->n], 0, + (MIN_SAMPLES - insn->n) * sizeof(unsigned int)); + } } ret = parse_insn(dev, insn, data, file); if (ret < 0)