Support chroot on unix-family platforms

Nick Kew · Nick Kew · commit ca4f206d2f60 · 2008-01-12T21:16:27.000Z
PR 43596 (Dimitar Pashev) git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@611483 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/CHANGES b/CHANGES
@@ -2,6 +2,9 @@
 Changes with Apache 2.3.0
 [ When backported to 2.2.x, remove entry from this file ]
 
+  *) Support chroot on Unix-family platforms
+     PR 43596 [Dimitar Pashev <mitko banksoft-bg.com>]
+
   *) Don't add bogus duplicate Content-Language entries
      PR 11035 [Davi Arnaut]
 
diff --git a/os/unix/unixd.c b/os/unix/unixd.c
@@ -117,6 +117,30 @@ AP_DECLARE(int) unixd_setup_child(void)
     if (set_group_privs()) {
         return -1;
     }
+
+    if (NULL != unixd_config.chroot_dir) {
+        if (geteuid()) {
+            ap_log_error(APLOG_MARK, APLOG_ALERT, errno, NULL,
+                         "Cannot chroot when not started as root");
+            return -1;
+        }
+        if (chdir(unixd_config.chroot_dir) != 0) {
+            ap_log_error(APLOG_MARK, APLOG_ALERT, errno, NULL,
+                         "Can't chdir to %s", unixd_config.chroot_dir);
+            return -1;
+        }
+        if (chroot(unixd_config.chroot_dir) != 0) {
+            ap_log_error(APLOG_MARK, APLOG_ALERT, errno, NULL,
+                         "Can't chroot to %s", unixd_config.chroot_dir);
+            return -1;
+        }
+        if (chdir("/") != 0) {
+            ap_log_error(APLOG_MARK, APLOG_ALERT, errno, NULL,
+                         "Can't chdir to new root");
+            return -1;
+        }
+    }
+
 #ifdef MPE
     /* Only try to switch if we're running as MANAGER.SYS */
     if (geteuid() == 1 && unixd_config.user_id > 1) {
@@ -198,6 +222,20 @@ AP_DECLARE(const char *) unixd_set_group(cmd_parms *cmd, void *dummy,
 
     return NULL;
 }
+AP_DECLARE(const char *) unixd_set_chroot_dir(cmd_parms *cmd, void *dummy,
+                                              const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+    if (!ap_is_directory(cmd->pool, arg)) {
+        return "ChrootDir must be a valid directory";
+    }
+
+    unixd_config.chroot_dir = arg;
+    return NULL;
+}
 
 AP_DECLARE(void) unixd_pre_config(apr_pool_t *ptemp)
 {
@@ -206,6 +244,8 @@ AP_DECLARE(void) unixd_pre_config(apr_pool_t *ptemp)
     unixd_config.user_name = DEFAULT_USER;
     unixd_config.user_id = ap_uname2id(DEFAULT_USER);
     unixd_config.group_id = ap_gname2id(DEFAULT_GROUP);
+    
+    unixd_config.chroot_dir = NULL; /* none */
 
     /* Check for suexec */
     unixd_config.suexec_enabled = 0;
diff --git a/os/unix/unixd.h b/os/unix/unixd.h
@@ -76,6 +76,7 @@ typedef struct {
     uid_t user_id;
     gid_t group_id;
     int suexec_enabled;
+    const char *chroot_dir;
 } unixd_config_rec;
 AP_DECLARE_DATA extern unixd_config_rec unixd_config;
 
@@ -85,6 +86,9 @@ AP_DECLARE(const char *) unixd_set_user(cmd_parms *cmd, void *dummy,
                                         const char *arg);
 AP_DECLARE(const char *) unixd_set_group(cmd_parms *cmd, void *dummy, 
                                          const char *arg);
+AP_DECLARE(const char *) unixd_set_chroot_dir(cmd_parms *cmd, void *dummy, 
+                                              const char *arg);
+					 
 #if defined(RLIMIT_CPU) || defined(RLIMIT_DATA) || defined(RLIMIT_VMEM) || defined(RLIMIT_NPROC) || defined(RLIMIT_AS)
 AP_DECLARE(void) unixd_set_rlimit(cmd_parms *cmd, struct rlimit **plimit,
                            const char *arg, const char * arg2, int type);
@@ -115,7 +119,9 @@ AP_DECLARE(apr_status_t) unixd_accept(void **accepted, ap_listen_rec *lr, apr_po
 AP_INIT_TAKE1("User", unixd_set_user, NULL, RSRC_CONF, \
   "Effective user id for this server"), \
 AP_INIT_TAKE1("Group", unixd_set_group, NULL, RSRC_CONF, \
-  "Effective group id for this server")
+  "Effective group id for this server"), \
+AP_INIT_TAKE1("ChrootDir", unixd_set_chroot_dir, NULL, RSRC_CONF, \
+    "The directory to chroot(2) into")
 
 #ifdef __cplusplus
 }
