[PATCH] ftrace: Replace all non-returning strlcpy with strscpy

[Azeem Shaikh]

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

Signed-off-by: Azeem Shaikh <azeemshaikh38@xxxxxxxxx>
---
 kernel/trace/ftrace.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 764668467155..6a77edb51f18 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5743,7 +5743,7 @@ bool ftrace_filter_param __initdata;
 static int __init set_ftrace_notrace(char *str)
 {
 	ftrace_filter_param = true;
-	strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
+	strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_notrace=", set_ftrace_notrace);
@@ -5751,7 +5751,7 @@ __setup("ftrace_notrace=", set_ftrace_notrace);
 static int __init set_ftrace_filter(char *str)
 {
 	ftrace_filter_param = true;
-	strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
+	strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_filter=", set_ftrace_filter);
@@ -5763,14 +5763,14 @@ static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
 
 static int __init set_graph_function(char *str)
 {
-	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
+	strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_graph_filter=", set_graph_function);
 
 static int __init set_graph_notrace_function(char *str)
 {
-	strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
+	strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
@@ -6569,8 +6569,8 @@ static int ftrace_get_trampoline_kallsym(unsigned int symnum,
 			continue;
 		*value = op->trampoline;
 		*type = 't';
-		strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
-		strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
+		strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
+		strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
 		*exported = 0;
 		return 0;
 	}
@@ -6933,7 +6933,7 @@ ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
 		if (off)
 			*off = addr - found_func->ip;
 		if (sym)
-			strlcpy(sym, found_func->name, KSYM_NAME_LEN);
+			strscpy(sym, found_func->name, KSYM_NAME_LEN);
 
 		return found_func->name;
 	}
@@ -6987,8 +6987,8 @@ int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
 
 			*value = mod_func->ip;
 			*type = 'T';
-			strlcpy(name, mod_func->name, KSYM_NAME_LEN);
-			strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
+			strscpy(name, mod_func->name, KSYM_NAME_LEN);
+			strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
 			*exported = 1;
 			preempt_enable();
 			return 0;