pgrep: Initialize the cmd*[] stack buffers.

Otherwise (for example), if the (undocumented) opt_echo is set, but not
opt_long, and not opt_longlong, and not opt_pattern, there is a call to
xstrdup(cmdoutput) but cmdoutput was never initialized:

sleep 60 & echo "$!" > pidfile
env -i LD_DEBUG=`perl -e 'print "A" x 131000'` pkill -e -c -F pidfile | xxd
...
000001c0: 4141 4141 4141 4141 4141 4141 4141 4141  AAAAAAAAAAAAAAAA
000001d0: 4141 4141 4141 4141 fcd4 e6bd e47f 206b  AAAAAAAA...... k
000001e0: 696c 6c65 6420 2870 6964 2031 3230 3931  illed (pid 12091
000001f0: 290a 310a                                ).1.
[1]+  Terminated              sleep 60

(the LD_DEBUG is just a trick to fill the initial stack with non-null
bytes, to show that there is uninitialized data from the stack in the
output; here, an address "fcd4 e6bd e47f")

diff --git a/pgrep.c b/pgrep.c
index e37678b2ea532d86f37c7bb6a3f39d2809aec0e3..4199ac44d5226e010032a3d962638f39b2a07374 100644 (file)
--- a/pgrep.c
+++ b/pgrep.c
@@ -497,9 +497,9 @@ static struct el * select_procs (int *num)
        regex_t *preg;
        pid_t myself = getpid();
        struct el *list = NULL;
-       char cmdline[CMDSTRSIZE];
-       char cmdsearch[CMDSTRSIZE];
-       char cmdoutput[CMDSTRSIZE];
+       char cmdline[CMDSTRSIZE] = "";
+       char cmdsearch[CMDSTRSIZE] = "";
+       char cmdoutput[CMDSTRSIZE] = "";
        proc_t ns_task;
 
        ptp = do_openproc();