procfs: replace all non-returning strlcpy with strscpy

strlcpy() reads the entire source buffer first. This read may exceed the
destination size limit. This is both inefficient and can lead to linear
read overflows if a source string is not NUL-terminated [1]. In an effort
to remove strlcpy() completely [2], replace strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Azeem Shaikh <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Reviewed-by: Alexey Dobriyan <[e-mail]>
Cc: Baoquan He <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: Kefeng Wang <[e-mail]>
Cc: Liu Shixin <[e-mail]>
Cc: Lorenzo Stoakes <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

fs/proc/kcore.c

···
 		char *notes;
 		size_t i = 0;
 
-		strlcpy(prpsinfo.pr_psargs, saved_command_line,
+		strscpy(prpsinfo.pr_psargs, saved_command_line,
 			sizeof(prpsinfo.pr_psargs));
 
 		notes = kzalloc(notes_len, GFP_KERNEL);