tools lib traceevent: Fix buffer overflow in arg_eval

commit 7c5b019e3a638a5a290b0ec020f6ca83d2ec2aaa upstream.

Fix buffer overflow observed when running perf test.

The overflow is when trying to evaluate "1ULL << (64 - 1)" which is
resulting in -9223372036854775808 which overflows the 20 character
buffer.

If is possible this bug has been reported before but I still don't see
any fix checked in:

See: https://www.spinics.net/lists/linux-perf-users/msg07714.html

Reported-by: Michael Sartain <mikesart@fastmail.com>
Reported-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Tony Jones <tonyj@suse.de>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Fixes: f7d82350e597 ("tools/events: Add files to create libtraceevent.a")
Link: http://lkml.kernel.org/r/20190228015532.8941-1-tonyj@suse.de
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 6b8769a40acba81b50bc36fdfd9941fd6d3bfcfb..95b2df232d71d21a1c2013126ddda2ed83cdcf94 100644 (file)
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -2283,7 +2283,7 @@ static int arg_num_eval(struct print_arg *arg, long long *val)
 static char *arg_eval (struct print_arg *arg)
 {
        long long val;
-       static char buf[20];
+       static char buf[24];
 
        switch (arg->type) {
        case PRINT_ATOM: