Merge branch 'tor-github/pr/690'

changes/bug29150

+  o Minor bugfixes (linux seccomp sandbox):
+    - Fix startup crash when experimental sandbox support is enabled.
+      Fixes bug 29150; bugfix on 0.4.0.1-alpha. Patch by Peter Gerber.

src/lib/sandbox/sandbox.c

@@ -832,6 +832,12 @@ sb_getsockopt(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
   if (rc)
     return rc;
 
+  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt),
+      SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET),
+      SCMP_CMP(2, SCMP_CMP_EQ, SO_ACCEPTCONN));
+  if (rc)
+    return rc;
+
 #ifdef HAVE_SYSTEMD
   rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt),
       SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET),