Commit 18f44de6 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Greg Kroah-Hartman
Browse files

staging: greybus: change strncpy() to strscpy_pad() 



gcc-10 warns about a strncpy() that does not enforce zero-termination:

In file included from include/linux/string.h:369,
                 from drivers/staging/greybus/fw-management.c:9:
In function 'strncpy',
    inlined from 'fw_mgmt_backend_fw_update_operation' at drivers/staging/greybus/fw-management.c:306:2:
include/linux/fortify-string.h:108:30: error: '__builtin_strncpy' specified bound 10 equals destination size [-Werror=stringop-truncation]
  108 | #define __underlying_strncpy __builtin_strncpy
      |                              ^
include/linux/fortify-string.h:187:9: note: in expansion of macro '__underlying_strncpy'
  187 |  return __underlying_strncpy(p, q, size);
      |         ^~~~~~~~~~~~~~~~~~~~

For some reason, I cannot reproduce this with gcc-9 or gcc-11, and I only
get a warning for one of the four related strncpy()s, so I'm not
sure what's going on.

Change all four to strscpy_pad(), which is the safest replacement here,
as it avoids ending up with uninitialized stack data in the tag name.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: default avatarJustin Stitt <justinstitt@google.com>
Link: https://github.com/KSPP/linux/issues/90 [1]
Link: https://lore.kernel.org/r/20240408194821.3183462-3-arnd@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c3a8f7df

drivers/staging/greybus/fw-management.c

+5 −7
Original line number Diff line number Diff line
@@ -123,8 +123,7 @@ static int fw_mgmt_interface_fw_version_operation(struct fw_mgmt *fw_mgmt, 
	fw_info->major = le16_to_cpu(response.major);

	fw_info->minor = le16_to_cpu(response.minor);



	strncpy(fw_info->firmware_tag, response.firmware_tag,

		GB_FIRMWARE_TAG_MAX_SIZE);

	strscpy_pad(fw_info->firmware_tag, response.firmware_tag);



	/*

	 * The firmware-tag should be NULL terminated, otherwise throw error but
@@ -153,7 +152,7 @@ static int fw_mgmt_load_and_validate_operation(struct fw_mgmt *fw_mgmt, 
	}



	request.load_method = load_method;

	strncpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);

	strscpy_pad(request.firmware_tag, tag);



	/*

	 * The firmware-tag should be NULL terminated, otherwise throw error and
@@ -249,8 +248,7 @@ static int fw_mgmt_backend_fw_version_operation(struct fw_mgmt *fw_mgmt, 
	struct gb_fw_mgmt_backend_fw_version_response response;

	int ret;



	strncpy(request.firmware_tag, fw_info->firmware_tag,

		GB_FIRMWARE_TAG_MAX_SIZE);

	strscpy_pad(request.firmware_tag, fw_info->firmware_tag);



	/*

	 * The firmware-tag should be NULL terminated, otherwise throw error and
@@ -303,13 +301,13 @@ static int fw_mgmt_backend_fw_update_operation(struct fw_mgmt *fw_mgmt, 
	struct gb_fw_mgmt_backend_fw_update_request request;

	int ret;



	strncpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);

	ret = strscpy_pad(request.firmware_tag, tag);



	/*

	 * The firmware-tag should be NULL terminated, otherwise throw error and

	 * fail.

	 */

	if (request.firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {

	if (ret == -E2BIG) {

		dev_err(fw_mgmt->parent, "backend-update: firmware-tag is not NULL terminated\n");

		return -EINVAL;

	}