Re: [PATCH] soc: qcom: mdt_loader: Validate that p_filesz < p_memsz

[Sibi Sankar]

Hey Bjorn,
Thanks for the patch!

On 1/8/21 5:01 AM, Bjorn Andersson wrote:
> The code validates that segments of p_memsz bytes of a segment will fit
> in the provided memory region, but does not validate that p_filesz bytes
> will, which means that an incorrectly crafted ELF header might write
> beyond the provided memory region.
>
> Fixes: 051fb70fd4ea ("remoteproc: qcom: Driver for the self-authenticating Hexagon v5")
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
>   drivers/soc/qcom/mdt_loader.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/drivers/soc/qcom/mdt_loader.c b/drivers/soc/qcom/mdt_loader.c
> index e01d18e9ad2b..5180b5996830 100644
> --- a/drivers/soc/qcom/mdt_loader.c
> +++ b/drivers/soc/qcom/mdt_loader.c
> @@ -230,6 +230,14 @@ static int __qcom_mdt_load(struct device *dev, const struct firmware *fw,
>   			break;
>   		}
>   
> +		if (phdr->p_filesz > phdr->p_memsz) {
> +			dev_err(dev,
> +				"refusing to load segment %d with p_filesz > p_memsz\n",
> +				i);
> +			ret = -EINVAL;
> +			break;
> +		}
> +

Reviewed-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>

>   		ptr = mem_region + offset;
>   
>   		if (phdr->p_filesz && phdr->p_offset < fw->size) {

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