[v3] rtlwifi: rtl8192se firmware load can overflow target buffer

From: Tim Gardner <tim.gardner@canonical.com>

Define RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE which represents the
maximimum possible firmware file size. Use it in the definition
of the buffer which receives the firmware file data.

Set RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE closer to the actual size of
the firmware file, e.g., 90000 (down from hard coded 164000). The current
size of rtlwifi/rtl8192sefw.bin is 88856.

Set max_fw_size to RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE for the size limit
check. Fix the error case where max_fw_size is not cleared if the size
limit check fails.

Cc: Chaoming Li <chaoming_li@realsil.com.cn>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
---
 drivers/net/wireless/rtlwifi/rtl8192se/fw.h |    3 ++-
 drivers/net/wireless/rtlwifi/rtl8192se/sw.c |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

Is this a fix that should go to 3.3?

On Thu, Feb 09, 2012 at 06:19:52PM -0600, Larry Finger wrote:
> From: Tim Gardner <tim.gardner@canonical.com>
> 
> Define RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE which represents the
> maximimum possible firmware file size. Use it in the definition
> of the buffer which receives the firmware file data.
> 
> Set RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE closer to the actual size of
> the firmware file, e.g., 90000 (down from hard coded 164000). The current
> size of rtlwifi/rtl8192sefw.bin is 88856.
> 
> Set max_fw_size to RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE for the size limit
> check. Fix the error case where max_fw_size is not cleared if the size
> limit check fails.
> 
> Cc: Chaoming Li <chaoming_li@realsil.com.cn>
> Cc: linux-wireless@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
> ---
>  drivers/net/wireless/rtlwifi/rtl8192se/fw.h |    3 ++-
>  drivers/net/wireless/rtlwifi/rtl8192se/sw.c |    3 ++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/rtlwifi/rtl8192se/fw.h b/drivers/net/wireless/rtlwifi/rtl8192se/fw.h
> index babe85d..b4afff6 100644
> --- a/drivers/net/wireless/rtlwifi/rtl8192se/fw.h
> +++ b/drivers/net/wireless/rtlwifi/rtl8192se/fw.h
> @@ -30,6 +30,7 @@
>  #define __REALTEK_FIRMWARE92S_H__
>  
>  #define RTL8190_MAX_FIRMWARE_CODE_SIZE		64000
> +#define RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE	90000
>  #define RTL8190_CPU_START_OFFSET		0x80
>  /* Firmware Local buffer size. 64k */
>  #define	MAX_FIRMWARE_CODE_SIZE			0xFF00
> @@ -217,7 +218,7 @@ struct rt_firmware {
>  	u8 fw_emem[RTL8190_MAX_FIRMWARE_CODE_SIZE];
>  	u32 fw_imem_len;
>  	u32 fw_emem_len;
> -	u8 sz_fw_tmpbuffer[164000];
> +	u8 sz_fw_tmpbuffer[RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE];
>  	u32 sz_fw_tmpbufferlen;
>  	u16 cmdpacket_fragthresold;
>  };
> diff --git a/drivers/net/wireless/rtlwifi/rtl8192se/sw.c b/drivers/net/wireless/rtlwifi/rtl8192se/sw.c
> index ca38dd9..345d752 100644
> --- a/drivers/net/wireless/rtlwifi/rtl8192se/sw.c
> +++ b/drivers/net/wireless/rtlwifi/rtl8192se/sw.c
> @@ -108,6 +108,7 @@ static void rtl92se_fw_cb(const struct firmware *firmware, void *context)
>  	if (firmware->size > rtlpriv->max_fw_size) {
>  		RT_TRACE(rtlpriv, COMP_ERR, DBG_EMERG,
>  			 "Firmware is too big!\n");
> +		rtlpriv->max_fw_size = 0;
>  		release_firmware(firmware);
>  		return;
>  	}
> @@ -232,7 +233,7 @@ static int rtl92s_init_sw_vars(struct ieee80211_hw *hw)
>  		return 1;
>  	}
>  
> -	rtlpriv->max_fw_size = sizeof(struct rt_firmware);
> +	rtlpriv->max_fw_size = RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE;
>  
>  	pr_info("Driver for Realtek RTL8192SE/RTL8191SE\n"
>  		"Loading firmware %s\n", rtlpriv->cfg->fw_name);
> -- 
> 1.7.9
> 
>

On 02/15/2012 12:55 PM, John W. Linville wrote:
> Is this a fix that should go to 3.3?

That code has been in the driver since 3.0 and it should probably be packported. 
On the other hand, Tim's report is the first one. My suggestion is that it go 
into 3.4.

In addition, I am working on a fix that will completely eliminate all this fixed 
storage.

Larry


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On 02/15/2012 12:14 PM, Larry Finger wrote:
> On 02/15/2012 12:55 PM, John W. Linville wrote:
>> Is this a fix that should go to 3.3?
>
> That code has been in the driver since 3.0 and it should probably be
> packported. On the other hand, Tim's report is the first one. My
> suggestion is that it go into 3.4.
>
> In addition, I am working on a fix that will completely eliminate all
> this fixed storage.
>
> Larry
>
>

I'm fine with it being 3.4 material. The patch addresses an unlikely 
scenario.

rtg