- markus@cvs.openbsd.org 2006/06/08 14:45:49

[readpass.c sshconnect.c sshconnect2.c uidswap.c uidswap.h]
     do not set the gid, noted by solar; ok djm

ChangeLog

@@ -42,6 +42,9 @@
      [readpass.c sshconnect.c sshconnect.h sshconnect2.c uidswap.c]
      replace remaining setuid() calls with permanently_set_uid() and
      check seteuid() return values; report Marcus Meissner; ok dtucker djm
+   - markus@cvs.openbsd.org 2006/06/08 14:45:49
+     [readpass.c sshconnect.c sshconnect2.c uidswap.c uidswap.h]
+     do not set the gid, noted by solar; ok djm
 
 20060521
  - (dtucker) [auth.c monitor.c] Now that we don't log from both the monitor
@@ -4675,4 +4678,4 @@
    - (djm) Trim deprecated options from INSTALL. Mention UsePAM
    - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
 
-$Id: ChangeLog,v 1.4341 2006/06/13 03:05:15 djm Exp $
+$Id: ChangeLog,v 1.4342 2006/06/13 03:10:00 djm Exp $

readpass.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: readpass.c,v 1.38 2006/06/06 10:20:20 markus Exp $ */
+/* $OpenBSD: readpass.c,v 1.39 2006/06/08 14:45:49 markus Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -61,7 +61,7 @@ ssh_askpass(char *askpass, const char *msg)
 		return NULL;
 	}
 	if (pid == 0) {
-		permanently_set_uid(getpwuid(getuid()));
+		permanently_drop_suid(getuid());
 		close(p[0]);
 		if (dup2(p[1], STDOUT_FILENO) < 0)
 			fatal("ssh_askpass: dup2: %s", strerror(errno));

sshconnect.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect.c,v 1.183 2006/06/06 10:20:20 markus Exp $ */
+/* $OpenBSD: sshconnect.c,v 1.184 2006/06/08 14:45:49 markus Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -97,7 +97,7 @@ ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
 		char *argv[10];
 
 		/* Child.  Permanently give up superuser privileges. */
-		permanently_set_uid(getpwuid(original_real_uid));
+		permanently_drop_suid(original_real_uid);
 
 		/* Redirect stdin and stdout. */
 		close(pin[1]);

sshconnect2.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.154 2006/06/06 10:20:20 markus Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.155 2006/06/08 14:45:49 markus Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -1253,7 +1253,7 @@ ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
 		return -1;
 	}
 	if (pid == 0) {
-		permanently_set_uid(getpwuid(getuid()));
+		permanently_drop_suid(getuid());
 		close(from[0]);
 		if (dup2(from[1], STDOUT_FILENO) < 0)
 			fatal("ssh_keysign: dup2: %s", strerror(errno));

uidswap.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: uidswap.c,v 1.28 2006/06/06 10:20:20 markus Exp $ */
+/* $OpenBSD: uidswap.c,v 1.29 2006/06/08 14:45:49 markus Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -123,6 +123,41 @@ temporarily_use_uid(struct passwd *pw)
 		    strerror(errno));
 }
 
+void
+permanently_drop_suid(uid_t uid)
+{
+	uid_t old_uid = getuid();
+
+	debug("permanently_drop_suid: %u", (u_int)uid);
+#if defined(HAVE_SETRESUID) && !defined(BROKEN_SETRESUID)
+	if (setresuid(uid, uid, uid) < 0)
+		fatal("setresuid %u: %.100s", (u_int)uid, strerror(errno));
+#elif defined(HAVE_SETREUID) && !defined(BROKEN_SETREUID)
+	if (setreuid(uid, uid) < 0)
+		fatal("setreuid %u: %.100s", (u_int)uid, strerror(errno));
+#else
+# ifndef SETEUID_BREAKS_SETUID
+	if (seteuid(uid) < 0)
+		fatal("seteuid %u: %.100s", (u_int)uid, strerror(errno));
+# endif
+	if (setuid(uid) < 0)
+		fatal("setuid %u: %.100s", (u_int)uid, strerror(errno));
+#endif
+
+#ifndef HAVE_CYGWIN
+	/* Try restoration of UID if changed (test clearing of saved uid) */
+	if (old_uid != uid &&
+	    (setuid(old_uid) != -1 || seteuid(old_uid) != -1))
+		fatal("%s: was able to restore old [e]uid", __func__);
+#endif
+
+	/* Verify UID drop was successful */
+	if (getuid() != uid || geteuid() != uid) {
+		fatal("%s: euid incorrect uid:%u euid:%u (should be %u)",
+		    __func__, (u_int)getuid(), (u_int)geteuid(), (u_int)uid);
+	}
+}
+
 /*
  * Restores to the original (privileged) uid.
  */

uidswap.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: uidswap.h,v 1.10 2006/03/25 22:22:43 djm Exp $ */
+/* $OpenBSD: uidswap.h,v 1.11 2006/06/08 14:45:49 markus Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -18,5 +18,6 @@
 void	 temporarily_use_uid(struct passwd *);
 void	 restore_uid(void);
 void	 permanently_set_uid(struct passwd *);
+void	 permanently_drop_suid(uid_t);
 
 #endif				/* UIDSWAP_H */