openssh/uidswap.c
Damien Miller e4340be5b3 - (djm) Merge OpenBSD changes:
- markus@cvs.openbsd.org  2000/09/05 02:59:57
     [session.c]
     print hostname (not hushlogin)
   - markus@cvs.openbsd.org  2000/09/05 13:18:48
     [authfile.c ssh-add.c]
     enable ssh-add -d for DSA keys
   - markus@cvs.openbsd.org  2000/09/05 13:20:49
     [sftp-server.c]
     cleanup
   - markus@cvs.openbsd.org  2000/09/06 03:46:41
     [authfile.h]
     prototype
   - deraadt@cvs.openbsd.org 2000/09/07 14:27:56
     [ALL]
     cleanup copyright notices on all files.  I have attempted to be
     accurate with the details.  everything is now under Tatu's licence
     (which I copied from his readme), and/or the core-sdi bsd-ish thing
     for deattack, or various openbsd developers under a 2-term bsd
     licence.  We're not changing any rules, just being accurate.
   - markus@cvs.openbsd.org  2000/09/07 14:40:30
     [channels.c channels.h clientloop.c serverloop.c ssh.c]
     cleanup window and packet sizes for ssh2 flow control; ok niels
   - markus@cvs.openbsd.org  2000/09/07 14:53:00
     [scp.c]
     typo
   - markus@cvs.openbsd.org  2000/09/07 15:13:37
     [auth-options.c auth-options.h auth-rh-rsa.c auth-rsa.c auth.c]
     [authfile.h canohost.c channels.h compat.c hostfile.h log.c match.h]
     [pty.c readconf.c]
     some more Copyright fixes
   - markus@cvs.openbsd.org  2000/09/08 03:02:51
     [README.openssh2]
     bye bye
   - deraadt@cvs.openbsd.org 2000/09/11 18:38:33
     [LICENCE cipher.c]
     a few more comments about it being ARC4 not RC4
   - markus@cvs.openbsd.org  2000/09/12 14:53:11
     [log-client.c log-server.c log.c ssh.1 ssh.c ssh.h sshd.8 sshd.c]
     multiple debug levels
   - markus@cvs.openbsd.org  2000/09/14 14:25:15
     [clientloop.c]
     typo
   - deraadt@cvs.openbsd.org 2000/09/15 01:13:51
     [ssh-agent.c]
     check return value for setenv(3) for failure, and deal appropriately
2000-09-16 13:29:08 +11:00

105 lines
2.9 KiB
C

/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* Code for uid-swapping.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*/
#include "includes.h"
RCSID("$OpenBSD: uidswap.c,v 1.9 2000/09/07 20:27:55 deraadt Exp $");
#include "ssh.h"
#include "uidswap.h"
#ifdef WITH_IRIX_AUDIT
#include <sat.h>
#endif /* WITH_IRIX_AUDIT */
/*
* 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
/* Saved effective uid. */
static uid_t saved_euid = 0;
#endif /* _POSIX_SAVED_IDS */
/*
* 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 %u: %.100s", (u_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 %u: %.100s", (u_int) geteuid(), strerror(errno));
/* Set the effective uid to the given (unprivileged) uid. */
if (seteuid(uid) == -1)
debug("seteuid %u: %.100s", (u_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 %u: %.100s", (u_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)
{
#ifdef WITH_IRIX_AUDIT
if (sysconf(_SC_AUDIT)) {
debug("Setting sat id to %d", (int) uid);
if (satsetid(uid))
debug("error setting satid: %.100s", strerror(errno));
}
#endif /* WITH_IRIX_AUDIT */
if (setuid(uid) < 0)
debug("setuid %u: %.100s", (u_int) uid, strerror(errno));
}