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* [PATCH] ftrace: Replace all non-returning strlcpy with strscpy
@ 2023-05-17 14:53 Azeem Shaikh
  2023-05-17 19:14 ` Kees Cook
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Azeem Shaikh @ 2023-05-17 14:53 UTC (permalink / raw)
  To: Steven Rostedt, Masami Hiramatsu
  Cc: linux-hardening, Azeem Shaikh, Mark Rutland, linux-kernel,
	linux-trace-kernel

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@gmail.com>
---
 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;


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH] ftrace: Replace all non-returning strlcpy with strscpy
  2023-05-17 14:53 [PATCH] ftrace: Replace all non-returning strlcpy with strscpy Azeem Shaikh
@ 2023-05-17 19:14 ` Kees Cook
  2023-05-17 22:28 ` Masami Hiramatsu
  2023-05-26 17:45 ` Kees Cook
  2 siblings, 0 replies; 4+ messages in thread
From: Kees Cook @ 2023-05-17 19:14 UTC (permalink / raw)
  To: Azeem Shaikh
  Cc: Steven Rostedt, Masami Hiramatsu, linux-hardening, Mark Rutland,
	linux-kernel, linux-trace-kernel

On Wed, May 17, 2023 at 02:53:23PM +0000, Azeem Shaikh wrote:
> 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@gmail.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] ftrace: Replace all non-returning strlcpy with strscpy
  2023-05-17 14:53 [PATCH] ftrace: Replace all non-returning strlcpy with strscpy Azeem Shaikh
  2023-05-17 19:14 ` Kees Cook
@ 2023-05-17 22:28 ` Masami Hiramatsu
  2023-05-26 17:45 ` Kees Cook
  2 siblings, 0 replies; 4+ messages in thread
From: Masami Hiramatsu @ 2023-05-17 22:28 UTC (permalink / raw)
  To: Azeem Shaikh
  Cc: Steven Rostedt, linux-hardening, Mark Rutland, linux-kernel,
	linux-trace-kernel

On Wed, 17 May 2023 14:53:23 +0000
Azeem Shaikh <azeemshaikh38@gmail.com> wrote:

> 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@gmail.com>

Looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks!

> ---
>  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;
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] ftrace: Replace all non-returning strlcpy with strscpy
  2023-05-17 14:53 [PATCH] ftrace: Replace all non-returning strlcpy with strscpy Azeem Shaikh
  2023-05-17 19:14 ` Kees Cook
  2023-05-17 22:28 ` Masami Hiramatsu
@ 2023-05-26 17:45 ` Kees Cook
  2 siblings, 0 replies; 4+ messages in thread
From: Kees Cook @ 2023-05-26 17:45 UTC (permalink / raw)
  To: mhiramat, rostedt, azeemshaikh38
  Cc: Kees Cook, linux-hardening, linux-trace-kernel, linux-kernel,
	mark.rutland

On Wed, 17 May 2023 14:53:23 +0000, Azeem Shaikh wrote:
> 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.
> 
> [...]

Applied to for-next/hardening, thanks!

[1/1] ftrace: Replace all non-returning strlcpy with strscpy
      https://git.kernel.org/kees/c/bd35ef4f612f

-- 
Kees Cook


^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-05-26 17:45 UTC | newest]

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2023-05-17 14:53 [PATCH] ftrace: Replace all non-returning strlcpy with strscpy Azeem Shaikh
2023-05-17 19:14 ` Kees Cook
2023-05-17 22:28 ` Masami Hiramatsu
2023-05-26 17:45 ` Kees Cook

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