mirror of
git://anongit.mindrot.org/openssh.git
synced 2024-12-16 23:24:38 +00:00
96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/*
|
|
|
|
uidswap.c
|
|
|
|
Author: Tatu Ylonen <ylo@cs.hut.fi>
|
|
|
|
Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
|
|
All rights reserved
|
|
|
|
Created: Sat Sep 9 01:56:14 1995 ylo
|
|
|
|
Code for uid-swapping.
|
|
|
|
*/
|
|
|
|
#include "includes.h"
|
|
RCSID("$Id: uidswap.c,v 1.1 1999/10/27 03:42:46 damien Exp $");
|
|
|
|
#include "ssh.h"
|
|
#include "uidswap.h"
|
|
|
|
/* Note: all these functions must work in all of the following cases:
|
|
|
|
1. euid=0, ruid=0
|
|
2. euid=0, ruid!=0
|
|
3. euid!=0, ruid!=0
|
|
|
|
Additionally, they must work regardless of whether the system has
|
|
POSIX saved uids or not. */
|
|
|
|
#ifdef _POSIX_SAVED_IDS
|
|
/* Lets assume that posix saved ids also work with seteuid, even though that
|
|
is not part of the posix specification. */
|
|
#define SAVED_IDS_WORK_WITH_SETEUID
|
|
#endif /* _POSIX_SAVED_IDS */
|
|
|
|
/* Saved effective uid. */
|
|
static uid_t saved_euid = 0;
|
|
|
|
/* Temporarily changes to the given uid. If the effective user id is not
|
|
root, this does nothing. This call cannot be nested. */
|
|
|
|
void temporarily_use_uid(uid_t uid)
|
|
{
|
|
#ifdef SAVED_IDS_WORK_WITH_SETEUID
|
|
|
|
/* Save the current euid. */
|
|
saved_euid = geteuid();
|
|
|
|
/* Set the effective uid to the given (unprivileged) uid. */
|
|
if (seteuid(uid) == -1)
|
|
debug("seteuid %d: %.100s", (int)uid, strerror(errno));
|
|
|
|
#else /* SAVED_IDS_WORK_WITH_SETUID */
|
|
|
|
/* Propagate the privileged uid to all of our uids. */
|
|
if (setuid(geteuid()) < 0)
|
|
debug("setuid %d: %.100s", (int)geteuid(), strerror(errno));
|
|
|
|
/* Set the effective uid to the given (unprivileged) uid. */
|
|
if (seteuid(uid) == -1)
|
|
debug("seteuid %d: %.100s", (int)uid, strerror(errno));
|
|
|
|
#endif /* SAVED_IDS_WORK_WITH_SETEUID */
|
|
|
|
}
|
|
|
|
/* Restores to the original uid. */
|
|
|
|
void restore_uid()
|
|
{
|
|
#ifdef SAVED_IDS_WORK_WITH_SETEUID
|
|
|
|
/* Set the effective uid back to the saved uid. */
|
|
if (seteuid(saved_euid) < 0)
|
|
debug("seteuid %d: %.100s", (int)saved_euid, strerror(errno));
|
|
|
|
#else /* SAVED_IDS_WORK_WITH_SETEUID */
|
|
|
|
/* We are unable to restore the real uid to its unprivileged value. */
|
|
/* Propagate the real uid (usually more privileged) to effective uid
|
|
as well. */
|
|
setuid(getuid());
|
|
|
|
#endif /* SAVED_IDS_WORK_WITH_SETEUID */
|
|
}
|
|
|
|
/* Permanently sets all uids to the given uid. This cannot be called while
|
|
temporarily_use_uid is effective. */
|
|
|
|
void permanently_set_uid(uid_t uid)
|
|
{
|
|
if (setuid(uid) < 0)
|
|
debug("setuid %d: %.100s", (int)uid, strerror(errno));
|
|
}
|