Merge branch 'feature22976_squashed'

4 files changed, 22 insertions, 71 deletions

diff --git a/src/common/sandbox.c b/src/common/sandbox.c
index c06f9694b1..18beaabe14 100644
--- a/src/common/sandbox.c
+++ b/src/common/sandbox.c
@@ -289,37 +289,6 @@ sb_rt_sigaction(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
   return rc;
 }
 
-#if 0
-/**
- * Function responsible for setting up the execve syscall for
- * the seccomp filter sandbox.
- */
-static int
-sb_execve(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
-{
-  int rc;
-  sandbox_cfg_t *elem = NULL;
-
-  // for each dynamic parameter filters
-  for (elem = filter; elem != NULL; elem = elem->next) {
-    smp_param_t *param = elem->param;
-
-    if (param != NULL && param->prot == 1 && param->syscall
-        == SCMP_SYS(execve)) {
-      rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(execve),
-               SCMP_CMP_STR(0, SCMP_CMP_EQ, param->value));
-      if (rc != 0) {
-        log_err(LD_BUG,"(Sandbox) failed to add execve syscall, received "
-            "libseccomp error %d", rc);
-        return rc;
-      }
-    }
-  }
-
-  return 0;
-}
-#endif
-
 /**
  * Function responsible for setting up the time syscall for
  * the seccomp filter sandbox.
@@ -1063,9 +1032,6 @@ sb_stat64(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 static sandbox_filter_func_t filter_func[] = {
     sb_rt_sigaction,
     sb_rt_sigprocmask,
-#if 0
-    sb_execve,
-#endif
     sb_time,
     sb_accept4,
 #ifdef __NR_mmap2
@@ -1417,26 +1383,6 @@ sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file)
   return 0;
 }
 
-#if 0
-int
-sandbox_cfg_allow_execve(sandbox_cfg_t **cfg, const char *com)
-{
-  sandbox_cfg_t *elem = NULL;
-
-  elem = new_element(SCMP_SYS(execve), com);
-  if (!elem) {
-    log_err(LD_BUG,"(Sandbox) failed to register parameter!");
-    return -1;
-  }
-
-  elem->next = *cfg;
-  *cfg = elem;
-
-  return 0;
-}
-
-#endif
-
 /** Cache entry for getaddrinfo results; used when sandboxing is implemented
  * so that we can consult the cache when the sandbox prevents us from doing
  * getaddrinfo.
@@ -1910,15 +1856,6 @@ sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file)
   return 0;
 }
 
-#if 0
-int
-sandbox_cfg_allow_execve(sandbox_cfg_t **cfg, const char *com)
-{
-  (void)cfg; (void)com;
-  return 0;
-}
-#endif
-
 int
 sandbox_cfg_allow_stat_filename(sandbox_cfg_t **cfg, char *file)
 {
diff --git a/src/common/sandbox.h b/src/common/sandbox.h
index a6b83153af..55454eaa2b 100644
--- a/src/common/sandbox.h
+++ b/src/common/sandbox.h
@@ -156,14 +156,6 @@ int sandbox_cfg_allow_rename(sandbox_cfg_t **cfg, char *file1, char *file2);
  */
 int sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file);
 
-#if 0
-/**
- * Function used to add a execve allowed filename to a supplied configuration.
- * The (char*) specifies the path to the allowed file; that pointer is stolen.
- */
-int sandbox_cfg_allow_execve(sandbox_cfg_t **cfg, const char *com);
-#endif
-
 /**
  * Function used to add a stat/stat64 allowed filename to a configuration.
  * The (char*) specifies the path to the allowed file; that pointer is stolen.
diff --git a/src/common/util.c b/src/common/util.c
index 0858d17fe6..eff678d6a4 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -4142,6 +4142,20 @@ process_handle_waitpid_cb(int status, void *arg)
 #define CHILD_STATE_EXEC 8
 #define CHILD_STATE_FAILEXEC 9
 /** @} */
+/**
+ * Boolean.  If true, then Tor may call execve or CreateProcess via
+ * tor_spawn_background.
+ **/
+static int may_spawn_background_process = 1;
+/**
+ * Turn off may_spawn_background_process, so that all future calls to
+ * tor_spawn_background are guaranteed to fail.
+ **/
+void
+tor_disable_spawning_background_processes(void)
+{
+  may_spawn_background_process = 0;
+}
 /** Start a program in the background. If <b>filename</b> contains a '/', then
  * it will be treated as an absolute or relative path.  Otherwise, on
  * non-Windows systems, the system path will be searched for <b>filename</b>.
@@ -4166,6 +4180,12 @@ tor_spawn_background(const char *const filename, const char **argv,
                      process_environment_t *env,
                      process_handle_t **process_handle_out)
 {
+  if (BUG(may_spawn_background_process == 0)) {
+    /* We should never reach this point if we're forbidden to spawn
+     * processes. Instead we should have caught the attempt earlier. */
+    return PROCESS_STATUS_ERROR;
+  }
+
 #ifdef _WIN32
   HANDLE stdout_pipe_read = NULL;
   HANDLE stdout_pipe_write = NULL;
diff --git a/src/common/util.h b/src/common/util.h
index df581d2405..f50cf043a4 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -396,6 +396,8 @@ void tor_check_port_forwarding(const char *filename,
                                struct smartlist_t *ports_to_forward,
                                time_t now);
 
+void tor_disable_spawning_background_processes(void);
+
 typedef struct process_handle_t process_handle_t;
 typedef struct process_environment_t process_environment_t;
 int tor_spawn_background(const char *const filename, const char **argv,