Re: [PATCH] scsi: target: iscsi: Replace strlcat() with snprintf()

[Alejandro Colomar <alx+linux-hardening@kernel.org>]

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Hi Mariia,

> Date: 2026-11-10 01:31:37-0800
> From: Mariia Nikitash <nikitash.mariiaw@gmail.com>
>
> In preparation for removing the deprecated strlcat() API[1], replace
> the strlcat() call with snprintf() to construct the AuthMethod value
> directly from param->value.
> 
> Since buf1 contains unmodified copy of param->value, formatting
> original value and suffix together preserves the NUL-terminated
> output, including partial or omitted ",None" suffixes when the
> 256-byte buffer is too small.
> 
> Link: https://github.com/KSPP/linux/issues/370 [1]
> Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>
> ---
>  drivers/target/iscsi/iscsi_target_tpg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/target/iscsi/iscsi_target_tpg.c b/drivers/target/iscsi/iscsi_target_tpg.c
> index 99772364c88e..aad82a37538f 100644
> --- a/drivers/target/iscsi/iscsi_target_tpg.c
> +++ b/drivers/target/iscsi/iscsi_target_tpg.c
> @@ -624,7 +624,7 @@ int iscsit_ta_authentication(struct iscsi_portal_group *tpg, u32 authentication)
>  		none = strstr(buf1, NONE);
>  		if (none)
>  			goto out;
> -		strlcat(buf1, "," NONE, sizeof(buf1));
> +		snprintf(buf1, sizeof(buf1), "%s," NONE, param->value);

This rewrites the string written a few lines above.  It seems rather
confusing.  I very much prefer strlcat(3) here.  Of course, an
strscpy_at() would be better, but snprintf(3) seems wrong.

For other readers, here's the same diff with some more context:

	@@ -622,11 +622,11 @@ int iscsit_ta_authentication(struct iscsi_portal_group *tpg, u32 authentication)
		} else {
			snprintf(buf1, sizeof(buf1), "%s", param->value);
			none = strstr(buf1, NONE);
			if (none)
				goto out;
	-               strlcat(buf1, "," NONE, sizeof(buf1));
	+               snprintf(buf1, sizeof(buf1), "%s," NONE, param->value);
			if (iscsi_update_param_value(param, buf1) < 0)
				return -EINVAL;
		}
	 
	 out:

So far, NAK by me.


Have a lovely day!
Alex

>  		if (iscsi_update_param_value(param, buf1) < 0)
>  			return -EINVAL;
>  	}
> -- 
> 2.43.0
> 
> 

-- 
<https://www.alejandro-colomar.es>

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