Commit 38638ffa authored by Azeem Shaikh's avatar Azeem Shaikh Committed by Steven Rostedt (Google)
Browse files

tracing/boot: Replace strlcpy with strscpy 

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 -E2BIG
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

Link: https://lore.kernel.org/linux-trace-kernel/20230613004125.3539934-1-azeemshaikh38@gmail.com



Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarAzeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent e88ed227

kernel/trace/trace_boot.c

+4 −4
Original line number Diff line number Diff line
@@ -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)) == -E2BIG) {

			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)) == -E2BIG) {

			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)) == -E2BIG)

			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)) == -E2BIG)

				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);