- markus@cvs.openbsd.org 2001/04/06 21:00:17
[auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth2.c channels.c session.c
ssh.c sshconnect.c sshconnect.h uidswap.c uidswap.h]
do gid/groups-swap in addition to uid-swap, should help if /home/group
is chmod 750 + chgrp grp /home/group/, work be deraadt and me, thanks
to olar@openwall.com is comments. we had many requests for this.
diff --git a/uidswap.c b/uidswap.c
index bdfa484..7cfacd4 100644
--- a/uidswap.c
+++ b/uidswap.c
@@ -12,7 +12,7 @@
*/
#include "includes.h"
-RCSID("$OpenBSD: uidswap.c,v 1.13 2001/01/21 19:06:01 markus Exp $");
+RCSID("$OpenBSD: uidswap.c,v 1.14 2001/04/06 21:00:16 markus Exp $");
#include "log.h"
#include "uidswap.h"
@@ -26,57 +26,80 @@
* POSIX saved uids or not.
*/
-#if defined(_POSIX_SAVED_IDS) && !defined(BROKEN_SAVED_UIDS)
/* 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
-
+static int privileged = 0;
+static int temporarily_use_uid_effective = 0;
+static uid_t saved_euid = 0;
+static gid_t saved_egid;
+static gid_t saved_egroups[NGROUPS_MAX], user_groups[NGROUPS_MAX];
+static int saved_egroupslen = -1, user_groupslen = -1;
+
/*
* 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)
+temporarily_use_uid(struct passwd *pw)
{
-#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_SETEUID */
- /* 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 */
+ /* Save the current euid, and egroups. */
+ saved_euid = geteuid();
+ debug("temporarily_use_uid: %d/%d (e=%d)",
+ pw->pw_uid, pw->pw_gid, saved_euid);
+ if (saved_euid != 0) {
+ privileged = 0;
+ return;
+ }
+ privileged = 1;
+ temporarily_use_uid_effective = 1;
+ saved_egid = getegid();
+ saved_egroupslen = getgroups(NGROUPS_MAX, saved_egroups);
+ if (saved_egroupslen < 0)
+ fatal("getgroups: %.100s", strerror(errno));
+
+ /* set and save the user's groups */
+ if (user_groupslen == -1) {
+ if (initgroups(pw->pw_name, pw->pw_gid) < 0)
+ fatal("initgroups: %s: %.100s", pw->pw_name,
+ strerror(errno));
+ user_groupslen = getgroups(NGROUPS_MAX, user_groups);
+ if (user_groupslen < 0)
+ fatal("getgroups: %.100s", strerror(errno));
+ }
+ /* Set the effective uid to the given (unprivileged) uid. */
+ if (setgroups(user_groupslen, user_groups) < 0)
+ fatal("setgroups: %.100s", strerror(errno));
+ pw->pw_gid = pw->pw_gid;
+ if (setegid(pw->pw_gid) < 0)
+ fatal("setegid %u: %.100s", (u_int) pw->pw_gid,
+ strerror(errno));
+ if (seteuid(pw->pw_uid) == -1)
+ fatal("seteuid %u: %.100s", (u_int) pw->pw_uid,
+ strerror(errno));
}
-
+
/*
* Restores to the original uid.
*/
void
restore_uid(void)
{
-#ifdef SAVED_IDS_WORK_WITH_SETEUID
+ debug("restore_uid");
+ /* it's a no-op unless privileged */
+ if (!privileged)
+ return;
+ if (!temporarily_use_uid_effective)
+ fatal("restore_uid: temporarily_use_uid not effective");
/* 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 */
+ fatal("seteuid %u: %.100s", (u_int) saved_euid, strerror(errno));
+ if (setgroups(saved_egroupslen, saved_egroups) < 0)
+ fatal("setgroups: %.100s", strerror(errno));
+ if (setegid(saved_egid) < 0)
+ fatal("setegid %u: %.100s", (u_int) saved_egid, strerror(errno));
+ temporarily_use_uid_effective = 0;
}
/*
@@ -84,8 +107,12 @@
* called while temporarily_use_uid is effective.
*/
void
-permanently_set_uid(uid_t uid)
+permanently_set_uid(struct passwd *pw)
{
- if (setuid(uid) < 0)
- debug("setuid %u: %.100s", (u_int) uid, strerror(errno));
+ if (temporarily_use_uid_effective)
+ fatal("restore_uid: temporarily_use_uid effective");
+ if (setuid(pw->pw_uid) < 0)
+ fatal("setuid %u: %.100s", (u_int) pw->pw_uid, strerror(errno));
+ if (setgid(pw->pw_gid) < 0)
+ fatal("setgid %u: %.100s", (u_int) pw->pw_gid, strerror(errno));
}