Fix unchecked return value of initgroups() (#11855)

* Fix unchecked return value of initgroups()

Signed-off-by: Jeffrey Bencteux <[email protected]>

* clang-format

---------

Signed-off-by: Jeffrey Bencteux <[email protected]>
Co-authored-by: Jeffrey Bencteux <[email protected]>
(cherry picked from commit ae63809)

Author: 2 people

src/tscore/ink_cap.cc

@@ -160,7 +160,9 @@ impersonate(const struct passwd *pwd, ImpersonationLevel level)
 #endif
 
   // Always repopulate the supplementary group list for the new user.
-  initgroups(pwd->pw_name, pwd->pw_gid);
+  if (initgroups(pwd->pw_name, pwd->pw_gid) != 0) {
+    Fatal("switching to user %s, failed to initialize supplementary groups ID %ld", pwd->pw_name, (long)pwd->pw_gid);
+  }
 
   switch (level) {
   case IMPERSONATE_PERMANENT: