linux-kernel - Re: [PATCH] rtw89: Fix crash by loading compressed firmware file

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Message-ID: <s5hpmrfgj93.wl-tiwai@suse.de>
Date:   Fri, 05 Nov 2021 08:21:44 +0100
From:   Takashi Iwai <tiwai@...e.de>
To:     Ping-Ke Shih <pkshih@...ltek.com>
Cc:     Kalle Valo <kvalo@...eaurora.org>, linux-wireless@...r.kernel.org,
        linux-kernel@...r.kernel.org, Larry Finger <Larry.Finger@...il.com>
Subject: Re: [PATCH] rtw89: Fix crash by loading compressed firmware file

On Fri, 05 Nov 2021 08:17:25 +0100,
Takashi Iwai wrote:
> 
> When a firmware is loaded in the compressed format or via user-mode
> helper, it's mapped in read-only, and the rtw89 driver crashes at
> rtw89_fw_download() when it tries to modify some data.
> 
> This patch is an attemp to avoid the crash by re-allocating the data
> via vmalloc() for the data modification.

Alternatively, we may drop the code that modifies the loaded firmware
data?  At least SET_FW_HDR_PART_SIZE() in rtw89_fw_hdr_parser() looks
writing it, and I have no idea why this overwrite is needed.


thanks,

Takashi

> 
> Buglink: https://bugzilla.opensuse.org/show_bug.cgi?id=1188303
> Signed-off-by: Takashi Iwai <tiwai@...e.de>
> 
> ---
>  drivers/net/wireless/realtek/rtw89/core.h |  3 ++-
>  drivers/net/wireless/realtek/rtw89/fw.c   | 15 ++++++++++-----
>  2 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtw89/core.h b/drivers/net/wireless/realtek/rtw89/core.h
> index c2885e4dd882..048855e05697 100644
> --- a/drivers/net/wireless/realtek/rtw89/core.h
> +++ b/drivers/net/wireless/realtek/rtw89/core.h
> @@ -2309,7 +2309,8 @@ struct rtw89_fw_suit {
>  	RTW89_FW_VER_CODE((s)->major_ver, (s)->minor_ver, (s)->sub_ver, (s)->sub_idex)
>  
>  struct rtw89_fw_info {
> -	const struct firmware *firmware;
> +	const void *firmware;
> +	size_t firmware_size;
>  	struct rtw89_dev *rtwdev;
>  	struct completion completion;
>  	u8 h2c_seq;
> diff --git a/drivers/net/wireless/realtek/rtw89/fw.c b/drivers/net/wireless/realtek/rtw89/fw.c
> index 212aaf577d3c..b59fecaeea25 100644
> --- a/drivers/net/wireless/realtek/rtw89/fw.c
> +++ b/drivers/net/wireless/realtek/rtw89/fw.c
> @@ -124,8 +124,8 @@ int rtw89_mfw_recognize(struct rtw89_dev *rtwdev, enum rtw89_fw_type type,
>  			struct rtw89_fw_suit *fw_suit)
>  {
>  	struct rtw89_fw_info *fw_info = &rtwdev->fw;
> -	const u8 *mfw = fw_info->firmware->data;
> -	u32 mfw_len = fw_info->firmware->size;
> +	const u8 *mfw = fw_info->firmware;
> +	u32 mfw_len = fw_info->firmware_size;
>  	const struct rtw89_mfw_hdr *mfw_hdr = (const struct rtw89_mfw_hdr *)mfw;
>  	const struct rtw89_mfw_info *mfw_info;
>  	int i;
> @@ -489,7 +489,10 @@ static void rtw89_load_firmware_cb(const struct firmware *firmware, void *contex
>  		return;
>  	}
>  
> -	fw->firmware = firmware;
> +	fw->firmware = vmalloc(firmware->size);
> +	if (fw->firmware)
> +		memcpy((void *)fw->firmware, firmware->data, firmware->size);
> +	release_firmware(firmware);
>  	complete_all(&fw->completion);
>  }
>  
> @@ -518,8 +521,10 @@ void rtw89_unload_firmware(struct rtw89_dev *rtwdev)
>  
>  	rtw89_wait_firmware_completion(rtwdev);
>  
> -	if (fw->firmware)
> -		release_firmware(fw->firmware);
> +	if (fw->firmware) {
> +		vfree(fw->firmware);
> +		fw->firmware = NULL;
> +	}
>  }
>  
>  #define H2C_CAM_LEN 60
> -- 
> 2.26.2
>