[PATCH] staging: greybus: replace strncpy() with strlcpy() in firmware test tool

[PATCH] staging: greybus: replace strncpy() with strlcpy() in firmware test tool

[Dharanitharan R]

The sample userspace firmware-management tool uses strncpy() to copy
firmware tags. strncpy() does not guarantee null-termination and can
leave buffers unterminated. For userspace code, strlcpy() is the
recommended safe alternative.

Replace all strncpy() calls with strlcpy().

Signed-off-by: Dharanitharan <dharanitharan725@gmail.com>
---
 .../greybus/Documentation/firmware/firmware.c      | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/greybus/Documentation/firmware/firmware.c b/drivers/staging/greybus/Documentation/firmware/firmware.c
index 3b35ef6d4adb..224eb8f4e39c 100644
--- a/drivers/staging/greybus/Documentation/firmware/firmware.c
+++ b/drivers/staging/greybus/Documentation/firmware/firmware.c
@@ -63,8 +63,9 @@ static int update_intf_firmware(int fd)
 	intf_load.major = 0;
 	intf_load.minor = 0;
 
-	strncpy((char *)&intf_load.firmware_tag, firmware_tag,
-		GB_FIRMWARE_U_TAG_MAX_SIZE);
+    strlcpy(intf_load.firmware_tag, firmware_tag,
+       GB_FIRMWARE_U_TAG_MAX_SIZE);
+
 
 	ret = ioctl(fd, FW_MGMT_IOC_INTF_LOAD_AND_VALIDATE, &intf_load);
 	if (ret < 0) {
@@ -101,8 +102,9 @@ static int update_backend_firmware(int fd)
 	/* Get Backend Firmware Version */
 	printf("Getting Backend Firmware Version\n");
 
-	strncpy((char *)&backend_fw_info.firmware_tag, firmware_tag,
-		GB_FIRMWARE_U_TAG_MAX_SIZE);
+    strlcpy(backend_fw_info.firmware_tag, firmware_tag,
+       GB_FIRMWARE_U_TAG_MAX_SIZE);
+
 
 retry_fw_version:
 	ret = ioctl(fd, FW_MGMT_IOC_GET_BACKEND_FW, &backend_fw_info);
@@ -129,8 +131,8 @@ static int update_backend_firmware(int fd)
 	/* Try Backend Firmware Update over Unipro */
 	printf("Updating Backend Firmware\n");
 
-	strncpy((char *)&backend_update.firmware_tag, firmware_tag,
-		GB_FIRMWARE_U_TAG_MAX_SIZE);
+    strlcpy(backend_update.firmware_tag, firmware_tag,
+       GB_FIRMWARE_U_TAG_MAX_SIZE);
 
 retry_fw_update:
 	backend_update.status = 0;
-- 
2.43.0

Re: [PATCH] staging: greybus: replace strncpy() with strlcpy() in firmware test tool

[Greg KH]

On Mon, Nov 17, 2025 at 06:50:03AM +0000, Dharanitharan R wrote:
> The sample userspace firmware-management tool uses strncpy() to copy
> firmware tags. strncpy() does not guarantee null-termination and can
> leave buffers unterminated. For userspace code, strlcpy() is the
> recommended safe alternative.
> 
> Replace all strncpy() calls with strlcpy().
> 
> Signed-off-by: Dharanitharan <dharanitharan725@gmail.com>
> ---
>  .../greybus/Documentation/firmware/firmware.c      | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/staging/greybus/Documentation/firmware/firmware.c b/drivers/staging/greybus/Documentation/firmware/firmware.c
> index 3b35ef6d4adb..224eb8f4e39c 100644
> --- a/drivers/staging/greybus/Documentation/firmware/firmware.c
> +++ b/drivers/staging/greybus/Documentation/firmware/firmware.c
> @@ -63,8 +63,9 @@ static int update_intf_firmware(int fd)
>  	intf_load.major = 0;
>  	intf_load.minor = 0;
>  
> -	strncpy((char *)&intf_load.firmware_tag, firmware_tag,
> -		GB_FIRMWARE_U_TAG_MAX_SIZE);
> +    strlcpy(intf_load.firmware_tag, firmware_tag,
> +       GB_FIRMWARE_U_TAG_MAX_SIZE);
> +

What happened to the indentation?

:(

Re: [PATCH] staging: greybus: replace strncpy() with strlcpy() in firmware test tool

[Dan Carpenter]

On Mon, Nov 17, 2025 at 06:50:03AM +0000, Dharanitharan R wrote:
> The sample userspace firmware-management tool uses strncpy() to copy
> firmware tags. strncpy() does not guarantee null-termination and can
> leave buffers unterminated. For userspace code, strlcpy() is the
> recommended safe alternative.
> 
> Replace all strncpy() calls with strlcpy().

Don't use strlcpy().  Either use strscpy() or strscpy_pad() as
appropriate.  I wrote a blog about this which may be useful.

https://staticthinking.wordpress.com/2023/10/30/strcpy-strncpy-strlcpy-and-strscpy/

regards,
dan carpenter