From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Azeem Shaikh <azeemshaikh38@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Kees Cook <keescook@chromium.org>,
Eric Biggers <ebiggers@kernel.org>,
linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH v2] tracing/boot: Replace strlcpy with strscpy
Date: Mon, 19 Jun 2023 07:30:01 +0900 [thread overview]
Message-ID: <20230619073001.ed0058623b238bb1f2069c88@kernel.org> (raw)
In-Reply-To: <20230615180420.400769-1-azeemshaikh38@gmail.com>
On Thu, 15 Jun 2023 18:04:20 +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().
>
> Direct replacement is safe here since return value of -errno
> is used to check for truncation instead of sizeof(dest).
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
>
Looks good to me.
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Thanks!
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
> ---
> v2:
> * Use "< 0" instead of -E2BIG.
>
> v1:
> * https://lore.kernel.org/all/20230613004125.3539934-1-azeemshaikh38@gmail.com/
>
> kernel/trace/trace_boot.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
> index 778200dd8ede..7ccc7a8e155b 100644
> --- a/kernel/trace/trace_boot.c
> +++ b/kernel/trace/trace_boot.c
> @@ -31,7 +31,7 @@ trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
>
> /* Common ftrace options */
> xbc_node_for_each_array_value(node, "options", anode, p) {
> - if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
> + if (strscpy(buf, p, ARRAY_SIZE(buf)) < 0) {
> pr_err("String is too long: %s\n", p);
> continue;
> }
> @@ -87,7 +87,7 @@ trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
> const char *p;
>
> xbc_node_for_each_array_value(node, "events", anode, p) {
> - if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
> + if (strscpy(buf, p, ARRAY_SIZE(buf)) < 0) {
> pr_err("String is too long: %s\n", p);
> continue;
> }
> @@ -486,7 +486,7 @@ trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
>
> p = xbc_node_find_value(enode, "filter", NULL);
> if (p && *p != '\0') {
> - if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
> + if (strscpy(buf, p, ARRAY_SIZE(buf)) < 0)
> pr_err("filter string is too long: %s\n", p);
> else if (apply_event_filter(file, buf) < 0)
> pr_err("Failed to apply filter: %s\n", buf);
> @@ -494,7 +494,7 @@ trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
>
> if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) {
> xbc_node_for_each_array_value(enode, "actions", anode, p) {
> - if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
> + if (strscpy(buf, p, ARRAY_SIZE(buf)) < 0)
> pr_err("action string is too long: %s\n", p);
> else if (trigger_process_regex(file, buf) < 0)
> pr_err("Failed to apply an action: %s\n", p);
> --
> 2.41.0.162.gfafddb0af9-goog
>
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2023-06-18 22:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-15 18:04 [PATCH v2] tracing/boot: Replace strlcpy with strscpy Azeem Shaikh
2023-06-18 22:30 ` Masami Hiramatsu [this message]
2023-06-20 20:28 ` Kees Cook
2023-06-20 20:33 ` Steven Rostedt
2023-06-20 20:35 ` Kees Cook
2023-07-04 13:42 ` Steven Rostedt
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