'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. Fixes: f404da6e1d46 ("tracing: Add 'last error' error facility for hist triggers") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- 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 4f027642ceef..8357f36d7a1e 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); } -- 2.9.0
Hi Arnd,
On Wed, 2018-03-28 at 16:09 +0200, Arnd Bergmann wrote:
> '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.
>
> Fixes: f404da6e1d46 ("tracing: Add 'last error' error facility for hist triggers")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> 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 4f027642ceef..8357f36d7a1e 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);
> }
Yes, thanks for finding this, and for the patch!
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
On Wed, 28 Mar 2018 16:09:10 +0200 Arnd Bergmann <arnd@arndb.de> wrote: > '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. > > Fixes: f404da6e1d46 ("tracing: Add 'last error' error facility for hist triggers") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Thanks! I pulled this in and will push it to git after testing has succeeded. -- Steve > --- > 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 4f027642ceef..8357f36d7a1e 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); > }