remove capability logic

It was only barely beneficial anyway, since some crucial
capabilities were never permanently dropped.

diff --git a/runtime/staprun/cap.c b/runtime/staprun/cap.c
deleted file mode 100644 (file)
index 6ac6701..0000000
--- a/runtime/staprun/cap.c
+++ /dev/null
@@ -1,166 +0,0 @@
-/* -*- linux-c -*-
- *
- * cap.c - staprun capabilities functions
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) 2007 Red Hat, Inc.
- *
- */
-
-#include "staprun.h"
-#include <sys/prctl.h>
-
-static int _stp_no_caps = 0;
-
-/* like perror, but exits */
-#define ferror(msg) {                                            \
-               _perr(msg);                                       \
-               exit(1);                                          \
-       }                                                         \
-
-/*
- * init_cap() sets up the initial capabilities for staprun. Then
- * it calls prctl( PR_SET_KEEPCAPS) to arrrange to keep these capabilities
- * even when not running as root. Next it resets the real, effective, and 
- * saved uid and gid back to the normal user.
- *
- * There are two sets of capabilities we are concerned with; permitted
- * and effective. The permitted capabilities are all the capabilities
- * that this process is ever permitted to have. They are defined in init_cap()
- * and may be permanently removed with drop_cap().
- *
- * Effective capabilities are the capabilities from the permitted set
- * that are currently enabled. A good practice would be to only enable 
- * capabilities when necessary and to delete or drop them as soon as possible.
- *
- * Capabilities we might use include:
- *
- * CAP_SYS_MODULE - insert and remove kernel modules
- * CAP_SYS_ADMIN - misc, including mounting and unmounting
- * CAP_SYS_NICE - setpriority()
- * CAP_SETUID - allows setuid
- * CAP_SETGID - allows setgid
- * CAP_CHOWN - allows chown
- */
-
-void init_cap(void)
-{
-       cap_t caps = cap_init();
-       cap_value_t capv[] = { CAP_SYS_MODULE, CAP_SYS_ADMIN, CAP_SYS_NICE, CAP_SETUID, CAP_SETGID, CAP_DAC_OVERRIDE };
-       const int numcaps = sizeof(capv) / sizeof(capv[0]);
-       uid_t uid = getuid();
-       gid_t gid = getgid();
-
-       cap_clear(caps);
-       if (caps == NULL)
-               ferror("cap_init");
-
-       if (cap_set_flag(caps, CAP_PERMITTED, numcaps, capv, CAP_SET) < 0)
-               ferror("cap_set_flag");
-
-       if (cap_set_proc(caps) < 0) {
-               dbug(1, "Setting capabilities failed. Capabilities disabled.\n");
-               _stp_no_caps = 1;
-               return;
-       }
-
-       cap_free(caps);
-
-       if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) < 0)
-               ferror("prctl");
-
-       if (setresuid(uid, uid, uid) < 0)
-               ferror("setresuid");
-
-       if (setresgid(gid, gid, gid) < 0)
-               ferror("setresgid");
-}
-
-void print_cap(char *text)
-{
-       int p;
-       cap_t caps = cap_get_proc();
-       uid_t uid, euid, suid;
-       gid_t gid, egid, sgid;
-
-       if (caps == NULL) {
-               perr("cap_get_proc");
-               return;
-       }
-
-       getresuid(&uid, &euid, &suid);
-       getresgid(&gid, &egid, &sgid);
-
-       printf("***** %s\n", text);
-
-       if ((p = prctl(PR_GET_KEEPCAPS, 0, 0, 0, 0)) < 0)
-               perr("Couldn't get PR_SET_KEEPCAPS flag value");
-       else
-               printf("KEEPCAPS: %d\n", p);
-
-       printf("uid: %d, euid: %d, suid: %d\ngid: %d. egid: %d, sgid: %d\n", uid, euid, suid, gid, egid, sgid);
-       printf("Caps: %s\n", cap_to_text(caps, NULL));
-       cap_free(caps);
-       printf("*****\n\n");
-}
-
-/* drop_cap() permanently removes a capability from the permitted set. There is
- * no way to recover the capability after this.  You do not need to remove
- * it from the effective set before calling this.
- */
-void drop_cap(cap_value_t cap)
-{
-       if (_stp_no_caps == 0) {
-               cap_t caps = cap_get_proc();
-               if (caps == NULL)
-                       ferror("cap_get_proc failed");
-               if (cap_set_flag(caps, CAP_PERMITTED, 1, &cap, CAP_CLEAR) < 0)
-                       ferror("Could not clear effective capabilities");
-               if (cap_set_proc(caps) < 0)
-                       ferror("Could not apply capability set");
-               cap_free(caps);
-       }
-}
-
-/* add_cap() adds a permitted capability to the effective set. */
-void add_cap(cap_value_t cap)
-{
-       if (_stp_no_caps == 0) {
-               cap_t caps = cap_get_proc();
-               if (caps == NULL)
-                       ferror("cap_get_proc failed");
-               if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap, CAP_SET) < 0)
-                       ferror("Could not set effective capabilities");
-               if (cap_set_proc(caps) < 0)
-                       ferror("Could not apply capability set");
-               cap_free(caps);
-       }
-}
-
-/* del_cap() deletes a permitted capability from the effective set. */
-void del_cap(cap_value_t cap)
-{
-       if (_stp_no_caps == 0) {
-               cap_t caps = cap_get_proc();
-               if (caps == NULL)
-                       ferror("cap_get_proc failed");
-               if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap, CAP_CLEAR) < 0)
-                       ferror("Could not clear effective capabilities");
-               if (cap_set_proc(caps) < 0)
-                       ferror("Could not apply capability set");
-               cap_free(caps);
-       }
-}