Fix libbpf-tools/sigsnoop segment fault (iovisor#4228)

Running without -n: [rongtao@RT-NUC libbpf-tools]$ sudo ./sigsnoop TIME PID COMM SIG TPID RESULT ... 16:32:48 0 swapper/1 34 2658 0 Running with -n, access sig_name[34] cause SEGV, this patch fix it, check that whether sig_name access is OOB, if yes, print signal number instead: [rongtao@RT-NUC libbpf-tools]$ sudo ./sigsnoop -n TIME PID COMM SIG TPID RESULT 19:01:38 0 swapper/11 34 2658 0 19:01:46 50019 id SIGCHLD 50018 0 Signed-off-by: Rong Tao <[email protected]>
weibang6liu · Sep 9, 2022 · a92c2bd · a92c2bd
1 parent c30c418
commit a92c2bd
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/libbpf-tools/sigsnoop.c b/libbpf-tools/sigsnoop.c
@@ -19,6 +19,7 @@
 #define PERF_BUFFER_PAGES 16
 #define PERF_POLL_TIMEOUT_MS 100
 #define warn(...) fprintf(stderr, __VA_ARGS__)
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 
 static volatile sig_atomic_t exiting = 0;
 
@@ -165,7 +166,7 @@ static void handle_event(void *ctx, int cpu, void *data, __u32 data_sz)
  time(&t);
  tm = localtime(&t);
  strftime(ts, sizeof(ts), "%H:%M:%S", tm);
- if (signal_name)
+ if (signal_name && e->sig < ARRAY_SIZE(sig_name))
  printf("%-8s %-7d %-16s %-9s %-7d %-6d\n",
  ts, e->pid, e->comm, sig_name[e->sig], e->tpid, e->ret);
  else