[PATCH 1/6] tracing: Avoid string overflow

From: Steven Rostedt
Date: Thu Jul 05 2018 - 21:07:13 EST


From: Arnd Bergmann <arnd@xxxxxxxx>

'err' is used as a NUL-terminated string, but using strncpy() with the length
equal to the buffer size may result in lack of the termination:

kernel/trace/trace_events_hist.c: In function 'hist_err_event':
kernel/trace/trace_events_hist.c:396:3: error: 'strncpy' specified bound 256 equals destination size [-Werror=stringop-truncation]
strncpy(err, var, MAX_FILTER_STR_VAL);

This changes it to use the safer strscpy() instead.

Link: http://lkml.kernel.org/r/20180328140920.2842153-1-arnd@xxxxxxxx

Cc: stable@xxxxxxxxxxxxxxx
Fixes: f404da6e1d46 ("tracing: Add 'last error' error facility for hist triggers")
Acked-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace_events_hist.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 046c716a6536..aae18af94c94 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -393,7 +393,7 @@ static void hist_err_event(char *str, char *system, char *event, char *var)
else if (system)
snprintf(err, MAX_FILTER_STR_VAL, "%s.%s", system, event);
else
- strncpy(err, var, MAX_FILTER_STR_VAL);
+ strscpy(err, var, MAX_FILTER_STR_VAL);

hist_err(str, err);
}
--
2.17.1