Commit 3ddfe3bd authored by Zong-Zhe Yang's avatar Zong-Zhe Yang Committed by Kalle Valo
Browse files

wifi: rtw89: don't request partial firmware if SECURITY_LOADPIN_ENFORCE 



Kernel logs on platform enabling SECURITY_LOADPIN_ENFORCE
------
```
LoadPin: firmware old-api-denied obj=<unknown> pid=810 cmdline="modprobe -q -- rtw89_8852ce"
rtw89_8852ce 0000:01:00.0: loading /lib/firmware/rtw89/rtw8852c_fw.bin failed with error -1
rtw89_8852ce 0000:01:00.0: Direct firmware load for rtw89/rtw8852c_fw.bin failed with error -1
rtw89_8852ce 0000:01:00.0: failed to early request firmware: -1
```

Trace
------
```
request_partial_firmware_into_buf()
> _request_firmware()
>> fw_get_filesystem_firmware()
>>> kernel_read_file_from_path_initns()
>>>> kernel_read_file()
>>>>> security_kernel_read_file()
// It will iterate enabled LSMs' hooks for kernel_read_file.
// With loadpin, it hooks loadpin_read_file.
```

If SECURITY_LOADPIN_ENFORCE is enabled, doing kernel_read_file() on partial
files will be denied and return -EPERM (-1). Then, the outer API based on it,
e.g. request_partial_firmware_into_buf(), will get the error.

In the case, we cannot get the firmware stuffs right, even though there might
be no error other than a permission issue on reading a partial file. So we have
to request full firmware if SECURITY_LOADPIN_ENFORCE is enabled. It makes us
still have a chance to do early firmware work on this kind of platforms.

Signed-off-by: default avatarZong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: default avatarPing-Ke Shih <pkshih@realtek.com>
Signed-off-by: default avatarKalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221202060521.501512-2-pkshih@realtek.com
parent c2f2924b

drivers/net/wireless/realtek/rtw89/fw.c

+21 −9
Original line number Diff line number Diff line
@@ -277,25 +277,37 @@ void rtw89_early_fw_feature_recognize(struct device *device, 
				      const struct rtw89_chip_info *chip,

				      u32 *early_feat_map)

{

	union {

		struct rtw89_mfw_hdr mfw_hdr;

		u8 fw_hdr[RTW89_FW_HDR_SIZE];

	} buf = {};

	union rtw89_compat_fw_hdr buf = {};

	const struct firmware *firmware;

	bool full_req = false;

	u32 ver_code;

	int ret;

	int i;



	/* If SECURITY_LOADPIN_ENFORCE is enabled, reading partial files will

	 * be denied (-EPERM). Then, we don't get right firmware things as

	 * expected. So, in this case, we have to request full firmware here.

	 */

	if (IS_ENABLED(CONFIG_SECURITY_LOADPIN_ENFORCE))

		full_req = true;



	if (full_req)

		ret = request_firmware(&firmware, chip->fw_name, device);

	else

		ret = request_partial_firmware_into_buf(&firmware, chip->fw_name,

						device, &buf, sizeof(buf), 0);

							device, &buf, sizeof(buf),

							0);



	if (ret) {

		dev_err(device, "failed to early request firmware: %d\n", ret);

		return;

	}



	ver_code = buf.mfw_hdr.sig != RTW89_MFW_SIG ?

		   RTW89_FW_HDR_VER_CODE(&buf.fw_hdr) :

		   RTW89_MFW_HDR_VER_CODE(&buf.mfw_hdr);

	if (full_req)

		ver_code = rtw89_compat_fw_hdr_ver_code(firmware->data);

	else

		ver_code = rtw89_compat_fw_hdr_ver_code(&buf);



	if (!ver_code)

		goto out;

drivers/net/wireless/realtek/rtw89/fw.h

+15 −0
Original line number Diff line number Diff line
@@ -3291,6 +3291,21 @@ struct fwcmd_hdr { 
	__le32 hdr1;

};



union rtw89_compat_fw_hdr {

	struct rtw89_mfw_hdr mfw_hdr;

	u8 fw_hdr[RTW89_FW_HDR_SIZE];

};



static inline u32 rtw89_compat_fw_hdr_ver_code(const void *fw_buf)

{

	const union rtw89_compat_fw_hdr *compat = (typeof(compat))fw_buf;



	if (compat->mfw_hdr.sig == RTW89_MFW_SIG)

		return RTW89_MFW_HDR_VER_CODE(&compat->mfw_hdr);

	else

		return RTW89_FW_HDR_VER_CODE(&compat->fw_hdr);

}



#define RTW89_H2C_RF_PAGE_SIZE 500

#define RTW89_H2C_RF_PAGE_NUM 3

struct rtw89_fw_h2c_rf_reg_info {