* [PATCH v2] tracing/boot: Replace strlcpy with strscpy
@ 2023-06-15 18:04 Azeem Shaikh
2023-06-18 22:30 ` Masami Hiramatsu
2023-06-20 20:28 ` Kees Cook
0 siblings, 2 replies; 6+ messages in thread
From: Azeem Shaikh @ 2023-06-15 18:04 UTC (permalink / raw)
To: Steven Rostedt, Masami Hiramatsu, Kees Cook, Eric Biggers
Cc: linux-hardening, Azeem Shaikh, 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().
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
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
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v2] tracing/boot: Replace strlcpy with strscpy
2023-06-15 18:04 [PATCH v2] tracing/boot: Replace strlcpy with strscpy Azeem Shaikh
@ 2023-06-18 22:30 ` Masami Hiramatsu
2023-06-20 20:28 ` Kees Cook
1 sibling, 0 replies; 6+ messages in thread
From: Masami Hiramatsu @ 2023-06-18 22:30 UTC (permalink / raw)
To: Azeem Shaikh
Cc: Steven Rostedt, Kees Cook, Eric Biggers, linux-hardening,
linux-kernel, linux-trace-kernel
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>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] tracing/boot: Replace strlcpy with strscpy
2023-06-15 18:04 [PATCH v2] tracing/boot: Replace strlcpy with strscpy Azeem Shaikh
2023-06-18 22:30 ` Masami Hiramatsu
@ 2023-06-20 20:28 ` Kees Cook
2023-06-20 20:33 ` Steven Rostedt
1 sibling, 1 reply; 6+ messages in thread
From: Kees Cook @ 2023-06-20 20:28 UTC (permalink / raw)
To: mhiramat, ebiggers, rostedt, azeemshaikh38
Cc: Kees Cook, linux-trace-kernel, linux-hardening, linux-kernel
On Thu, 15 Jun 2023 18:04:20 +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().
>
> [...]
Applied to for-next/hardening, thanks!
[1/1] tracing/boot: Replace strlcpy with strscpy
https://git.kernel.org/kees/c/b1c38314f756
--
Kees Cook
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] tracing/boot: Replace strlcpy with strscpy
2023-06-20 20:28 ` Kees Cook
@ 2023-06-20 20:33 ` Steven Rostedt
2023-06-20 20:35 ` Kees Cook
0 siblings, 1 reply; 6+ messages in thread
From: Steven Rostedt @ 2023-06-20 20:33 UTC (permalink / raw)
To: Kees Cook
Cc: mhiramat, ebiggers, azeemshaikh38, linux-trace-kernel,
linux-hardening, linux-kernel
On Tue, 20 Jun 2023 13:28:26 -0700
Kees Cook <keescook@chromium.org> wrote:
> On Thu, 15 Jun 2023 18:04:20 +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().
> >
> > [...]
>
> Applied to for-next/hardening, thanks!
>
> [1/1] tracing/boot: Replace strlcpy with strscpy
> https://git.kernel.org/kees/c/b1c38314f756
>
I was going to add this to my queue.
-- Steve
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] tracing/boot: Replace strlcpy with strscpy
2023-06-20 20:33 ` Steven Rostedt
@ 2023-06-20 20:35 ` Kees Cook
2023-07-04 13:42 ` Steven Rostedt
0 siblings, 1 reply; 6+ messages in thread
From: Kees Cook @ 2023-06-20 20:35 UTC (permalink / raw)
To: Steven Rostedt
Cc: mhiramat, ebiggers, azeemshaikh38, linux-trace-kernel,
linux-hardening, linux-kernel
On Tue, Jun 20, 2023 at 04:33:25PM -0400, Steven Rostedt wrote:
> On Tue, 20 Jun 2023 13:28:26 -0700
> Kees Cook <keescook@chromium.org> wrote:
>
> > On Thu, 15 Jun 2023 18:04:20 +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().
> > >
> > > [...]
> >
> > Applied to for-next/hardening, thanks!
> >
> > [1/1] tracing/boot: Replace strlcpy with strscpy
> > https://git.kernel.org/kees/c/b1c38314f756
> >
>
> I was going to add this to my queue.
Ah, okay, no worries. I will drop it from mine.
--
Kees Cook
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] tracing/boot: Replace strlcpy with strscpy
2023-06-20 20:35 ` Kees Cook
@ 2023-07-04 13:42 ` Steven Rostedt
0 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2023-07-04 13:42 UTC (permalink / raw)
To: Kees Cook
Cc: mhiramat, ebiggers, azeemshaikh38, linux-trace-kernel,
linux-hardening, linux-kernel
On Tue, 20 Jun 2023 13:35:14 -0700
Kees Cook <keescook@chromium.org> wrote:
> > > Applied to for-next/hardening, thanks!
> > >
> > > [1/1] tracing/boot: Replace strlcpy with strscpy
> > > https://git.kernel.org/kees/c/b1c38314f756
> > >
> >
> > I was going to add this to my queue.
>
> Ah, okay, no worries. I will drop it from mine.
Maybe I should have let you take it. I had v1 in my queue, and pushed
that one :-p
I'll fix it later.
Thanks,
-- Steve
^ permalink raw reply [flat|nested] 6+ messages in thread
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2023-06-15 18:04 [PATCH v2] tracing/boot: Replace strlcpy with strscpy Azeem Shaikh
2023-06-18 22:30 ` Masami Hiramatsu
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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