[ntpsec commit] Forward-port bug fix for [Bug 2866] segmentation fault at initgroups()

[Eric S. Raymond]

Module:    ntpsec
Branch:    master
Commit:    e8eae9a7beefa1c45c7497cd2a1a8be24d2c4f4a
Changeset: http://git.ntpsec.org/ntpsec/commit/?id=e8eae9a7beefa1c45c7497cd2a1a8be24d2c4f4a

Author:    Eric S. Raymond <esr at thyrsus.com>
Date:      Thu Oct 22 17:13:57 2015 -0400

Forward-port bug fix for [Bug 2866] segmentation fault at initgroups()

---

 NEWS               |  1 +
 ntpd/ntp_sandbox.c | 15 +++++++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/NEWS b/NEWS
index 5bb74dd..05daa2a 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,7 @@ on user-visible changes.
   later fixes for parser support and reporting leap smear in the REFID.
 * [Bug 2859] Improve raw DCF77 robustness decoding.  Frank Kardel.
 * [Bug 2860] ntpq ifstats sanity check is too stringent.  Frank Kardel.
+* [Bug 2866] segmentation fault at initgroups().  Harlan Stenn.
 * [Bug 2867] ntpd with autokey active crashed by 'ntpq -crv'
 
 // end
diff --git a/ntpd/ntp_sandbox.c b/ntpd/ntp_sandbox.c
index b22e5f1..0ecab3e 100644
--- a/ntpd/ntp_sandbox.c
+++ b/ntpd/ntp_sandbox.c
@@ -166,10 +166,17 @@ getgroup:
 			msyslog(LOG_ERR, "Cannot setegid() to group `%s': %m", group);
 			exit (-1);
 		}
-		if (group)
-			setgroups(1, &sw_gid);
-		else
-			initgroups(pw->pw_name, pw->pw_gid);
+		if (group) {
+			if (0 != setgroups(1, &sw_gid)) {
+				msyslog(LOG_ERR, "setgroups(1, %d) failed: %m", sw_gid);
+				exit (-1);
+			}
+		}
+		else if (pw)
+			if (0 != initgroups(pw->pw_name, pw->pw_gid)) {
+				msyslog(LOG_ERR, "initgroups(<%s>, %d) filed: %m", pw->pw_name, pw->pw_gid);
+				exit (-1);
+			}
 		if (user && setuid(sw_uid)) {
 			msyslog(LOG_ERR, "Cannot setuid() to user `%s': %m", user);
 			exit (-1);