From 86dc79030d4aaee7682a9cd22ae69907e91ed68a Mon Sep 17 00:00:00 2001
From: zodiac <zodiac@0da03de8-d603-11dd-86c2-0f8696b7b6f9>
Date: Sat, 28 Feb 2009 04:15:34 +0000
Subject: [PATCH] Work-around for systems that don't define a "nogroup" group.

git-svn-id: https://shellinabox.googlecode.com/svn/trunk@72 0da03de8-d603-11dd-86c2-0f8696b7b6f9
---
 ChangeLog                |  2 ++
 config.h                 |  2 +-
 shellinabox/privileges.c | 28 +++++++++++++++++++++++-----
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3481d81..04ec7ad 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2009-02-27  Markus Gutschke  <markus@shellinabox.com>
 
+	* Work-around for systems that don't define a "nogroup" group.
+
 	* Remove the dependency on fdopendir, which does not exist
 	everywhere.
 
diff --git a/config.h b/config.h
index b919999..4b8d18f 100644
--- a/config.h
+++ b/config.h
@@ -95,7 +95,7 @@
 #define STDC_HEADERS 1
 
 /* Most recent revision number in the version control system */
-#define VCS_REVISION "71"
+#define VCS_REVISION "72"
 
 /* Version number of package */
 #define VERSION "2.4"
diff --git a/shellinabox/privileges.c b/shellinabox/privileges.c
index f018163..161a508 100644
--- a/shellinabox/privileges.c
+++ b/shellinabox/privileges.c
@@ -227,12 +227,30 @@ const char *getGroupName(gid_t gid) {
 gid_t getGroupId(const char *name) {
   struct group grbuf, *gr;
   char *buf;
-  int len   = sysconf(_SC_GETGR_R_SIZE_MAX);
-  if (len <= 0) {
-    len     = 4096;
+  int gr_len      = sysconf(_SC_GETGR_R_SIZE_MAX);
+  if (gr_len <= 0) {
+    gr_len        = 4096;
   }
-  check(buf = malloc(len));
-  if (getgrnam_r(name, &grbuf, buf, len, &gr) || !gr) {
+  check(buf       = malloc(gr_len));
+  if (getgrnam_r(name, &grbuf, buf, gr_len, &gr) || !gr) {
+    // Maybe, this system does not have a "nogroup" group. Substitute the
+    // group of the "nobody" user.
+    if (!strcmp(name, "nogroup")) {
+      struct passwd pwbuf, *pw;
+      int pw_len  = sysconf(_SC_GETPW_R_SIZE_MAX);
+      if (pw_len <= 0) {
+        pw_len    = 4096;
+      }
+      if (pw_len > gr_len) {
+        check(buf = realloc(buf, pw_len));
+      }
+      if (!getpwnam_r("nobody", &pwbuf, buf, pw_len, &pw) && pw) {
+        debug("Substituting \"nobody's\" primary group for \"nogroup\"");
+        gid_t gid = pw->pw_gid;
+        free(buf);
+        return gid;
+      }
+    }
     fatal("Cannot look up group \"%s\"", name);
   }
   gid_t gid = gr->gr_gid;