openssh/uidswap.c
Damien Miller 6536c7d3c9 - OpenBSD CVS Updates:
- markus@cvs.openbsd.org  2000/06/18 18:50:11
     [auth2.c compat.c compat.h sshconnect2.c]
     make userauth+pubkey interop with ssh.com-2.2.0
   - markus@cvs.openbsd.org  2000/06/18 20:56:17
     [dsa.c]
     mem leak + be more paranoid in dsa_verify.
   - markus@cvs.openbsd.org  2000/06/18 21:29:50
     [key.c]
     cleanup fingerprinting, less hardcoded sizes
   - markus@cvs.openbsd.org  2000/06/19 19:39:45
     [atomicio.c auth-options.c auth-passwd.c auth-rh-rsa.c auth-rhosts.c]
     [auth-rsa.c auth-skey.c authfd.c authfd.h authfile.c bufaux.c bufaux.h]
     [buffer.c buffer.h canohost.c channels.c channels.h cipher.c cipher.h]
     [clientloop.c compat.c compat.h compress.c compress.h crc32.c crc32.h]
     [deattack.c dispatch.c dsa.c fingerprint.c fingerprint.h getput.h hmac.c]
     [kex.c log-client.c log-server.c login.c match.c mpaux.c mpaux.h nchan.c]
     [nchan.h packet.c packet.h pty.c pty.h readconf.c readconf.h readpass.c]
     [rsa.c rsa.h scp.c servconf.c servconf.h ssh-add.c ssh-keygen.c ssh.c]
     [ssh.h tildexpand.c ttymodes.c ttymodes.h uidswap.c xmalloc.c xmalloc.h]
     OpenBSD tag
   - markus@cvs.openbsd.org  2000/06/21 10:46:10
     sshconnect2.c missing free; nuke old comment
2000-06-22 21:32:31 +10:00

89 lines
2.4 KiB
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("$OpenBSD: uidswap.c,v 1.7 2000/06/20 01:39:45 markus 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
/* 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 %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));
}