[PATCH v2] tracing: Replace all non-returning strlcpy with strscpy

[Azeem Shaikh]

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 with strlcpy 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@xxxxxxxxx>
---
v1: https://lore.kernel.org/all/20230516043943.5234-1-azeemshaikh38@xxxxxxxxx/
Changes from v1:
 - Removed subsystem specific files.
 - Minor update to commit log.

 kernel/trace/trace.c               |    8 ++++----
 kernel/trace/trace_events.c        |    4 ++--
 kernel/trace/trace_events_inject.c |    4 ++--
 kernel/trace/trace_kprobe.c        |    2 +-
 kernel/trace/trace_probe.c         |    2 +-
 5 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ebc59781456a..28ccd0c9bdf0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -196,7 +196,7 @@ static int boot_snapshot_index;
 
 static int __init set_cmdline_ftrace(char *str)
 {
-	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
+	strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
 	default_bootup_tracer = bootup_tracer_buf;
 	/* We are using ftrace early, expand it */
 	ring_buffer_expanded = true;
@@ -281,7 +281,7 @@ static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
 
 static int __init set_trace_boot_options(char *str)
 {
-	strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
+	strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
 	return 1;
 }
 __setup("trace_options=", set_trace_boot_options);
@@ -291,7 +291,7 @@ static char *trace_boot_clock __initdata;
 
 static int __init set_trace_boot_clock(char *str)
 {
-	strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
+	strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
 	trace_boot_clock = trace_boot_clock_buf;
 	return 1;
 }
@@ -2521,7 +2521,7 @@ static void __trace_find_cmdline(int pid, char comm[])
 	if (map != NO_CMDLINE_MAP) {
 		tpid = savedcmd->map_cmdline_to_pid[map];
 		if (tpid == pid) {
-			strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
+			strscpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
 			return;
 		}
 	}
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 654ffa40457a..dc83a259915b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2831,7 +2831,7 @@ static __init int setup_trace_triggers(char *str)
 	char *buf;
 	int i;
 
-	strlcpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
+	strscpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
 	ring_buffer_expanded = true;
 	disable_tracing_selftest("running event triggers");
 
@@ -3621,7 +3621,7 @@ static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
 
 static __init int setup_trace_event(char *str)
 {
-	strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
+	strscpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
 	ring_buffer_expanded = true;
 	disable_tracing_selftest("running event tracing");
 
diff --git a/kernel/trace/trace_events_inject.c b/kernel/trace/trace_events_inject.c
index d6b4935a78c0..abe805d471eb 100644
--- a/kernel/trace/trace_events_inject.c
+++ b/kernel/trace/trace_events_inject.c
@@ -217,7 +217,7 @@ static int parse_entry(char *str, struct trace_event_call *call, void **pentry)
 			char *addr = (char *)(unsigned long) val;
 
 			if (field->filter_type == FILTER_STATIC_STRING) {
-				strlcpy(entry + field->offset, addr, field->size);
+				strscpy(entry + field->offset, addr, field->size);
 			} else if (field->filter_type == FILTER_DYN_STRING ||
 				   field->filter_type == FILTER_RDYN_STRING) {
 				int str_len = strlen(addr) + 1;
@@ -232,7 +232,7 @@ static int parse_entry(char *str, struct trace_event_call *call, void **pentry)
 				}
 				entry = *pentry;
 
-				strlcpy(entry + (entry_size - str_len), addr, str_len);
+				strscpy(entry + (entry_size - str_len), addr, str_len);
 				str_item = (u32 *)(entry + field->offset);
 				if (field->filter_type == FILTER_RDYN_STRING)
 					str_loc -= field->offset + field->size;
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 59cda19a9033..1b3fa7b854aa 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -30,7 +30,7 @@ static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
 
 static int __init set_kprobe_boot_events(char *str)
 {
-	strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
+	strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
 	disable_tracing_selftest("running kprobe events");
 
 	return 1;
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 2d2616678295..73055ba8d8ef 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -254,7 +254,7 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 			trace_probe_log_err(offset, GROUP_TOO_LONG);
 			return -EINVAL;
 		}
-		strlcpy(buf, event, slash - event + 1);
+		strscpy(buf, event, slash - event + 1);
 		if (!is_good_system_name(buf)) {
 			trace_probe_log_err(offset, BAD_GROUP_NAME);
 			return -EINVAL;
-- 
2.40.1.606.ga4b1b128d6-goog