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The code declares variables as:

	char path[FILENAME_MAX];
	char buf_pname[FILENAME_MAX];
	char buf_cwd[FILENAME_MAX];

and on a coredump provided by an user, buf_cwd
has a sane value (it has a smaller value, thus
not overwritten), but buf_pname is pointing to
a very large shell script, having written more
than 16k bytes before the crash. The code looks
like:

	while (c != EOF) {
		c = fgetc(f);
		if ((c != EOF) && (c != '\0')) {
			buf_pname[len] = c;
			len++;
			continue;
		}
		buf_pname[len] = '\0';

from gdb I also see:
(gdb) p pname_status
$28 = 0x102b3e0 "sh"

so, I believe the crash was caused by some variant
of a logic like:

$ /bin/sh -c "$(cat /some/really/large/script)"

where contents of /some/really/large/script will be
in /proc/$PID/cmdline.

  The pseudo patch to prevent the crash would be:

-		if ((c != EOF) && (c != '\0')) {
+		if ((c != EOF) && (c != '\0') && len < 4095) {

another possible cause would be a corrupted
/proc/$PID/cmdline, but the above description
looks a lot more likely the crash condition.

Created attachment 1212848 [details]
Simple python reproducer

Created attachment 1212849 [details]
api.c: fix potential buffer overflow

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2017-0583.html