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ee4ae0e7ad
This can be used to get the uid we changed away from when we gained root privileges Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>
94 lines
2.5 KiB
C
94 lines
2.5 KiB
C
/*
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Unix SMB/CIFS implementation.
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gain/lose root privileges
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Copyright (C) Andrew Tridgell 2004
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "includes.h"
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#include "system/passwd.h"
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#include "../lib/util/unix_privs.h"
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#if defined(UID_WRAPPER)
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#if !defined(UID_WRAPPER_REPLACE) && !defined(UID_WRAPPER_NOT_REPLACE)
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#define UID_WRAPPER_REPLACE
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#include "../uid_wrapper/uid_wrapper.h"
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#endif
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#else
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#define uwrap_enabled() 0
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#endif
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/**
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* @file
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* @brief Gaining/losing root privileges
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*/
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/*
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there are times when smbd needs to temporarily gain root privileges
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to do some operation. To do this you call root_privileges(), which
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returns a talloc handle. To restore your previous privileges
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talloc_free() this pointer.
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Note that this call is considered successful even if it does not
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manage to gain root privileges, but it will call smb_abort() if it
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fails to restore the privileges afterwards. The logic is that
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failing to gain root access can be caught by whatever operation
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needs to be run as root failing, but failing to lose the root
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privileges is dangerous.
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This also means that this code is safe to be called from completely
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unprivileged processes.
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*/
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struct saved_state {
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uid_t uid;
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};
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static int privileges_destructor(struct saved_state *s)
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{
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if (geteuid() != s->uid &&
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seteuid(s->uid) != 0) {
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smb_panic("Failed to restore privileges");
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}
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return 0;
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}
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/**
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* Obtain root privileges for the current process.
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*
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* The privileges can be dropped by talloc_free()-ing the
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* token returned by this function
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*/
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void *root_privileges(void)
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{
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struct saved_state *s;
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s = talloc(NULL, struct saved_state);
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if (!s) return NULL;
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s->uid = geteuid();
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if (s->uid != 0) {
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seteuid(0);
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}
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talloc_set_destructor(s, privileges_destructor);
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return s;
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}
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uid_t root_privileges_original_uid(void *s)
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{
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struct saved_state *saved = talloc_get_type_abort(s, struct saved_state);
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return saved->uid;
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}
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