[PATCH 1/2] nvme: fix memory corruption for passthrough metadata

[Kanchan Joshi]

On Fri, Aug 11, 2023 at 10:57:36AM -0600, Keith Busch wrote:
>On Fri, Aug 11, 2023 at 09:29:05PM +0530, Kanchan Joshi wrote:
>> +static bool nvme_validate_passthru_meta(struct nvme_ctrl *ctrl,
>> +					struct nvme_ns *ns,
>> +					struct nvme_command *c,
>> +					__u64 meta, __u32 meta_len)
>> +{
>> +	/*
>> +	 * User may specify smaller meta-buffer with a larger data-buffer.
>> +	 * Driver allocated meta buffer will also be small.
>> +	 * Device can do larger dma into that, overwriting unrelated kernel
>> +	 * memory.
>> +	 */
>> +	if (ns && (meta_len || meta)) {
>> +		u16 nlb = lower_16_bits(le32_to_cpu(c->common.cdw12));
>> +
>> +		if (meta_len != (nlb + 1) * ns->ms) {
>> +			dev_err(ctrl->device,
>> +			"%s: metadata length does not match!\n", current->comm);
>> +			return false;
>> +		}
>
>Don't you need to check the command PRINFO PRACT bit to know if metadata
>length is striped/generated on the controller side?

Good point. Will add that check in v2.