Re: [PATCH] remoteproc: qcom_q6v5_mss: Validate p_filesz in ELF loader

[Mathieu Poirier <mathieu.poirier@linaro.org>]

Hi Bjorn,

On Thu, Jan 07, 2021 at 03:50:53PM -0800, Bjorn Andersson wrote:
> Analog to the issue in the common mdt_loader code the MSS ELF loader
> does not validate that p_filesz bytes will fit in the memory region and
> that the loaded segments are not truncated. Fix this in the same way
> as proposed for the mdt_loader.
> 
> Fixes: 135b9e8d1cd8 ("remoteproc: qcom_q6v5_mss: Validate modem blob firmware size before load")
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  drivers/remoteproc/qcom_q6v5_mss.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
> index 66106ba25ba3..2b59e0cbdce1 100644
> --- a/drivers/remoteproc/qcom_q6v5_mss.c
> +++ b/drivers/remoteproc/qcom_q6v5_mss.c
> @@ -1210,6 +1210,14 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>  			goto release_firmware;
>  		}
>  
> +		if (phdr->p_filesz > phdr->p_memsz) {
> +			dev_err(qproc->dev,
> +				"refusing to load segment %d with p_filesz > p_memsz\n",
> +				i);
> +			ret = -EINVAL;
> +			break;

Based on the error handling for the above and below conditions, I would have
expected a "goto release_firmware" rather than a "break".

> +		}
> +
>  		ptr = memremap(qproc->mpss_phys + offset, phdr->p_memsz, MEMREMAP_WC);
>  		if (!ptr) {
>  			dev_err(qproc->dev,
> @@ -1241,6 +1249,15 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>  				goto release_firmware;
>  			}
>  
> +			if (seg_fw->size != phdr->p_filesz) {
> +				dev_err(qproc->dev,
> +					"failed to load segment %d from truncated file %s\n",
> +					i, fw_name);
> +				ret = -EINVAL;
> +				memunmap(ptr);
> +				break;

Same here.

> +			}
> +
>  			release_firmware(seg_fw);
>  		}

Thanks,
Mathieu

>  
> -- 
> 2.29.2
>