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 B4B46260582; Tue, 26 Aug 2025 13:37:23 +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=1756215443; cv=none; b=AMGYcyFSq5QAfWJmDETwvht28ycRoCjW6xcUwJGqX4E3F1U55kmMy7iU7SM/I1XYz23pAHNaMnizJRsN+DqRX/lI5OfRjJhRif3SLN5WYo5vv63kWmsoCetsd7hUHOfaKTHzXUz7VeNpqv++zPqoWBOSw6Kwj7yi/Fp5ftnIB5E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756215443; c=relaxed/simple; bh=XSFXDlyN4ENA0q4Rb/Ui+kKFasHL0pL9kh0ONGCayFg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kca38pJLyMds7IV/Rb41yMuiQgXkaS06pEDV0RZ+uLhNBiVxgNM0a0SH4jKDq02vT2LruLi1C0cc+0u060fs86B++EdiSC1R4k/i1JLqptVCnkHWy8xXXrH3t4fBRAPfxkIMs/y9RFv58ur3jgvGE8lkL+jn27e0E8qLtRvqnhc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MKJIyBQT; 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="MKJIyBQT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43C1EC4CEF1; Tue, 26 Aug 2025 13:37:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756215443; bh=XSFXDlyN4ENA0q4Rb/Ui+kKFasHL0pL9kh0ONGCayFg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MKJIyBQTYG1Q7IhWNk9wLBBTw8SNnEyzcEQ1F+C4MoRZgMOUyYrQFvCvRPJPpj5Tb YGJqEfUm9RYb8zvGZBDsUqSf84CDzuw6F/OSJAHgRatmo+F8xjtobGAso4qznz1q1C LxyY+P8ZDqIbn+Dx1KKTUu17vrrxVa45djhD6kZ0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Abbott Subject: [PATCH 5.15 036/644] comedi: Fix initialization of data for instructions that write to subdevice Date: Tue, 26 Aug 2025 13:02:07 +0200 Message-ID: <20250826110947.405394509@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110946.507083938@linuxfoundation.org> References: <20250826110946.507083938@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 5.15-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 @@ -1551,21 +1551,27 @@ 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; @@ -1638,6 +1644,10 @@ 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)