From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Azeem Shaikh <azeemshaikh38@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
linux-hardening@vger.kernel.org,
Mark Rutland <mark.rutland@arm.com>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH] ftrace: Replace all non-returning strlcpy with strscpy
Date: Thu, 18 May 2023 07:28:15 +0900 [thread overview]
Message-ID: <20230518072815.53fd9f67a3423d85f133d98b@kernel.org> (raw)
In-Reply-To: <20230517145323.1522010-1-azeemshaikh38@gmail.com>
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>
next prev parent reply other threads:[~2023-05-17 22:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
2023-05-26 17:45 ` Kees Cook
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