[PATCH] tracing: Fix misuse of strncpy to copy boot params

[Frederic Weisbecker]

While copying ftrace string boot parameters into buffers, we
use strncpy by passing the whole buffer size instead of the max
strlen the buffers can host (which is buffer size - 1), this might
lead to non-null terminated strings.

Fix that by simply using strlcpy instead.

Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
---
 kernel/trace/ftrace.c |    4 ++--
 kernel/trace/trace.c  |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 37ba67e..0f4803f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2300,14 +2300,14 @@ static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
 
 static int __init set_ftrace_notrace(char *str)
 {
-	strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
+	strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_notrace=", set_ftrace_notrace);
 
 static int __init set_ftrace_filter(char *str)
 {
-	strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
+	strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_filter=", set_ftrace_filter);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4506826..621d81e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -131,7 +131,7 @@ static char *default_bootup_tracer;
 
 static int __init set_ftrace(char *str)
 {
-	strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
+	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
 	default_bootup_tracer = bootup_tracer_buf;
 	/* We are using ftrace early, expand it */
 	ring_buffer_expanded = 1;
-- 
1.6.2.3


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