| Message ID | 20241007135126.873234-1-leo.yan@arm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tracing: Consider the NULL character when validating the event length | expand |
On Mon, 7 Oct 2024 14:51:26 +0100 Leo Yan <leo.yan@arm.com> wrote: > strlen() returns a string length excluding the null byte. This commit > adds 1 to account for the NULL terminating character when checking if an > event string is within the maximum length. > > Fixes: dec65d79fd26 ("tracing/probe: Check event name length correctly") > Signed-off-by: Leo Yan <leo.yan@arm.com> > --- > kernel/trace/trace_probe.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > index 39877c80d6cb..376ba56c3680 100644 > --- a/kernel/trace/trace_probe.c > +++ b/kernel/trace/trace_probe.c > @@ -276,7 +276,7 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup, > } > trace_probe_log_err(offset, NO_EVENT_NAME); > return -EINVAL; > - } else if (len > MAX_EVENT_NAME_LEN) { > + } else if (len + 1 > MAX_EVENT_NAME_LEN) { Usually, the check is: } else if (len >= MAX_EVENT_NAME_LEN) { Which is a better way to check max length. -- Steve > trace_probe_log_err(offset, EVENT_TOO_LONG); > return -EINVAL; > }
On 10/7/24 15:22, Steven Rostedt wrote: > Warning: EXTERNAL SENDER, use caution when opening links or attachments. > > > On Mon, 7 Oct 2024 14:51:26 +0100 > Leo Yan <leo.yan@arm.com> wrote: > >> strlen() returns a string length excluding the null byte. This commit >> adds 1 to account for the NULL terminating character when checking if an >> event string is within the maximum length. >> >> Fixes: dec65d79fd26 ("tracing/probe: Check event name length correctly") >> Signed-off-by: Leo Yan <leo.yan@arm.com> >> --- >> kernel/trace/trace_probe.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c >> index 39877c80d6cb..376ba56c3680 100644 >> --- a/kernel/trace/trace_probe.c >> +++ b/kernel/trace/trace_probe.c >> @@ -276,7 +276,7 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup, >> } >> trace_probe_log_err(offset, NO_EVENT_NAME); >> return -EINVAL; >> - } else if (len > MAX_EVENT_NAME_LEN) { >> + } else if (len + 1 > MAX_EVENT_NAME_LEN) { > > Usually, the check is: > > } else if (len >= MAX_EVENT_NAME_LEN) { > > Which is a better way to check max length. Will update. Thanks for suggestion. Leo
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 39877c80d6cb..376ba56c3680 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -276,7 +276,7 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup, } trace_probe_log_err(offset, NO_EVENT_NAME); return -EINVAL; - } else if (len > MAX_EVENT_NAME_LEN) { + } else if (len + 1 > MAX_EVENT_NAME_LEN) { trace_probe_log_err(offset, EVENT_TOO_LONG); return -EINVAL; }
strlen() returns a string length excluding the null byte. This commit adds 1 to account for the NULL terminating character when checking if an event string is within the maximum length. Fixes: dec65d79fd26 ("tracing/probe: Check event name length correctly") Signed-off-by: Leo Yan <leo.yan@arm.com> --- kernel/trace/trace_probe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)