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Subject: Re: [PATCH] soc: qcom: mdt_loader: Validate that p_filesz < p_memsz
To:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Siddharth Gupta <sidgup@codeaurora.org>
Cc:     linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20210107233119.717173-1-bjorn.andersson@linaro.org>
From:   Sibi Sankar <sibis@codeaurora.org>
Message-ID: <56542220-494d-d41e-2378-f20f07caba5e@codeaurora.org>
Date:   Thu, 8 Apr 2021 16:48:05 +0530
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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@linaro.org>
> ---
>   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@codeaurora.org>

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

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