X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/12408a1b16c3ce5b7e203bec879ceb3d67ae09a8..476861787f6e1b8a6c6af9307a15b9e57cb979dc:/openssh/uidswap.c

diff --git a/openssh/uidswap.c b/openssh/uidswap.c
index 4cabaa4..91d878c 100644
--- a/openssh/uidswap.c
+++ b/openssh/uidswap.c
@@ -1,3 +1,4 @@
+/* $OpenBSD: uidswap.c,v 1.35 2006/08/03 03:34:42 deraadt Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -12,10 +13,19 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: uidswap.c,v 1.24 2003/05/29 16:58:45 deraadt Exp $");
+
+#include <sys/param.h>
+#include <errno.h>
+#include <pwd.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdarg.h>
+
+#include <grp.h>
 
 #include "log.h"
 #include "uidswap.h"
+#include "xmalloc.h"
 
 /*
  * Note: all these functions must work in all of the following cases:
@@ -38,7 +48,7 @@ static gid_t	saved_egid = 0;
 /* Saved effective uid. */
 static int	privileged = 0;
 static int	temporarily_use_uid_effective = 0;
-static gid_t	saved_egroups[NGROUPS_MAX], user_groups[NGROUPS_MAX];
+static gid_t	*saved_egroups = NULL, *user_groups = NULL;
 static int	saved_egroupslen = -1, user_groupslen = -1;
 
 /*
@@ -55,10 +65,12 @@ temporarily_use_uid(struct passwd *pw)
 	debug("temporarily_use_uid: %u/%u (e=%u/%u)",
 	    (u_int)pw->pw_uid, (u_int)pw->pw_gid,
 	    (u_int)saved_euid, (u_int)saved_egid);
+#ifndef HAVE_CYGWIN
 	if (saved_euid != 0) {
 		privileged = 0;
 		return;
 	}
+#endif
 #else
 	if (geteuid() != 0) {
 		privileged = 0;
@@ -68,18 +80,38 @@ temporarily_use_uid(struct passwd *pw)
 
 	privileged = 1;
 	temporarily_use_uid_effective = 1;
-	saved_egroupslen = getgroups(NGROUPS_MAX, saved_egroups);
+
+	saved_egroupslen = getgroups(0, NULL);
 	if (saved_egroupslen < 0)
 		fatal("getgroups: %.100s", strerror(errno));
+	if (saved_egroupslen > 0) {
+		saved_egroups = xrealloc(saved_egroups,
+		    saved_egroupslen, sizeof(gid_t));
+		if (getgroups(saved_egroupslen, saved_egroups) < 0)
+			fatal("getgroups: %.100s", strerror(errno));
+	} else { /* saved_egroupslen == 0 */
+		if (saved_egroups != NULL)
+			xfree(saved_egroups);
+	}
 
 	/* 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);
+
+		user_groupslen = getgroups(0, NULL);
 		if (user_groupslen < 0)
 			fatal("getgroups: %.100s", strerror(errno));
+		if (user_groupslen > 0) {
+			user_groups = xrealloc(user_groups,
+			    user_groupslen, sizeof(gid_t));
+			if (getgroups(user_groupslen, user_groups) < 0)
+				fatal("getgroups: %.100s", strerror(errno));
+		} else { /* user_groupslen == 0 */
+			if (user_groups)
+				xfree(user_groups);
+		}
 	}
 	/* Set the effective uid to the given (unprivileged) uid. */
 	if (setgroups(user_groupslen, user_groups) < 0)
@@ -100,6 +132,41 @@ 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.
  */
@@ -146,6 +213,8 @@ permanently_set_uid(struct passwd *pw)
 	uid_t old_uid = getuid();
 	gid_t old_gid = getgid();
 
+	if (pw == NULL)
+		fatal("permanently_set_uid: no user given");
 	if (temporarily_use_uid_effective)
 		fatal("permanently_set_uid: temporarily_use_uid effective");
 	debug("permanently_set_uid: %u/%u", (u_int)pw->pw_uid,
@@ -179,10 +248,12 @@ permanently_set_uid(struct passwd *pw)
 		fatal("setuid %u: %.100s", (u_int)pw->pw_uid, strerror(errno));
 #endif
 
+#ifndef HAVE_CYGWIN
 	/* Try restoration of GID if changed (test clearing of saved gid) */
-	if (old_gid != pw->pw_gid &&
+	if (old_gid != pw->pw_gid && pw->pw_uid != 0 &&
 	    (setgid(old_gid) != -1 || setegid(old_gid) != -1))
 		fatal("%s: was able to restore old [e]gid", __func__);
+#endif
 
 	/* Verify GID drop was successful */
 	if (getgid() != pw->pw_gid || getegid() != pw->pw_gid) {