X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/fd7bc9fc046dbec78001a8a898f3097baa90e688..5486a45797557bd2ffca421ca5e7ad2441f4db59:/uidswap.c

diff --git a/uidswap.c b/uidswap.c
index 9377ca4b..4cabaa44 100644
--- a/uidswap.c
+++ b/uidswap.c
@@ -12,7 +12,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: uidswap.c,v 1.22 2002/05/28 21:24:00 stevesk Exp $");
+RCSID("$OpenBSD: uidswap.c,v 1.24 2003/05/29 16:58:45 deraadt Exp $");
 
 #include "log.h"
 #include "uidswap.h"
@@ -52,8 +52,9 @@ temporarily_use_uid(struct passwd *pw)
 #ifdef SAVED_IDS_WORK_WITH_SETEUID
 	saved_euid = geteuid();
 	saved_egid = getegid();
-	debug("temporarily_use_uid: %u/%u (e=%u)",
-	    (u_int)pw->pw_uid, (u_int)pw->pw_gid, (u_int)saved_euid);
+	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);
 	if (saved_euid != 0) {
 		privileged = 0;
 		return;
@@ -80,11 +81,9 @@ temporarily_use_uid(struct passwd *pw)
 		if (user_groupslen < 0)
 			fatal("getgroups: %.100s", strerror(errno));
 	}
-#ifndef HAVE_CYGWIN
 	/* Set the effective uid to the given (unprivileged) uid. */
 	if (setgroups(user_groupslen, user_groups) < 0)
 		fatal("setgroups: %.100s", strerror(errno));
-#endif /* !HAVE_CYGWIN */
 #ifndef SAVED_IDS_WORK_WITH_SETEUID
 	/* Propagate the privileged gid to all of our gids. */
 	if (setgid(getegid()) < 0)
@@ -107,14 +106,16 @@ temporarily_use_uid(struct passwd *pw)
 void
 restore_uid(void)
 {
-	debug("restore_uid");
 	/* it's a no-op unless privileged */
-	if (!privileged)
+	if (!privileged) {
+		debug("restore_uid: (unprivileged)");
 		return;
+	}
 	if (!temporarily_use_uid_effective)
 		fatal("restore_uid: temporarily_use_uid not effective");
 
 #ifdef SAVED_IDS_WORK_WITH_SETEUID
+	debug("restore_uid: %u/%u", (u_int)saved_euid, (u_int)saved_egid);
 	/* Set the effective uid back to the saved privileged uid. */
 	if (seteuid(saved_euid) < 0)
 		fatal("seteuid %u: %.100s", (u_int)saved_euid, strerror(errno));
@@ -130,10 +131,8 @@ restore_uid(void)
 	setgid(getgid());
 #endif /* SAVED_IDS_WORK_WITH_SETEUID */
 
-#ifndef HAVE_CYGWIN
 	if (setgroups(saved_egroupslen, saved_egroups) < 0)
 		fatal("setgroups: %.100s", strerror(errno));
-#endif /* !HAVE_CYGWIN */
 	temporarily_use_uid_effective = 0;
 }
 
@@ -144,10 +143,65 @@ restore_uid(void)
 void
 permanently_set_uid(struct passwd *pw)
 {
+	uid_t old_uid = getuid();
+	gid_t old_gid = getgid();
+
 	if (temporarily_use_uid_effective)
 		fatal("permanently_set_uid: temporarily_use_uid effective");
+	debug("permanently_set_uid: %u/%u", (u_int)pw->pw_uid,
+	    (u_int)pw->pw_gid);
+
+#if defined(HAVE_SETRESGID) && !defined(BROKEN_SETRESGID)
+	if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) < 0)
+		fatal("setresgid %u: %.100s", (u_int)pw->pw_gid, strerror(errno));
+#elif defined(HAVE_SETREGID) && !defined(BROKEN_SETREGID)
+	if (setregid(pw->pw_gid, pw->pw_gid) < 0)
+		fatal("setregid %u: %.100s", (u_int)pw->pw_gid, strerror(errno));
+#else
+	if (setegid(pw->pw_gid) < 0)
+		fatal("setegid %u: %.100s", (u_int)pw->pw_gid, strerror(errno));
 	if (setgid(pw->pw_gid) < 0)
 		fatal("setgid %u: %.100s", (u_int)pw->pw_gid, strerror(errno));
+#endif
+
+#if defined(HAVE_SETRESUID) && !defined(BROKEN_SETRESUID)
+	if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) < 0)
+		fatal("setresuid %u: %.100s", (u_int)pw->pw_uid, strerror(errno));
+#elif defined(HAVE_SETREUID) && !defined(BROKEN_SETREUID)
+	if (setreuid(pw->pw_uid, pw->pw_uid) < 0)
+		fatal("setreuid %u: %.100s", (u_int)pw->pw_uid, strerror(errno));
+#else
+# ifndef SETEUID_BREAKS_SETUID
+	if (seteuid(pw->pw_uid) < 0)
+		fatal("seteuid %u: %.100s", (u_int)pw->pw_uid, strerror(errno));
+# endif
 	if (setuid(pw->pw_uid) < 0)
 		fatal("setuid %u: %.100s", (u_int)pw->pw_uid, strerror(errno));
+#endif
+
+	/* Try restoration of GID if changed (test clearing of saved gid) */
+	if (old_gid != pw->pw_gid &&
+	    (setgid(old_gid) != -1 || setegid(old_gid) != -1))
+		fatal("%s: was able to restore old [e]gid", __func__);
+
+	/* Verify GID drop was successful */
+	if (getgid() != pw->pw_gid || getegid() != pw->pw_gid) {
+		fatal("%s: egid incorrect gid:%u egid:%u (should be %u)",
+		    __func__, (u_int)getgid(), (u_int)getegid(),
+		    (u_int)pw->pw_gid);
+	}
+
+#ifndef HAVE_CYGWIN
+	/* Try restoration of UID if changed (test clearing of saved uid) */
+	if (old_uid != pw->pw_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() != pw->pw_uid || geteuid() != pw->pw_uid) {
+		fatal("%s: euid incorrect uid:%u euid:%u (should be %u)",
+		    __func__, (u_int)getuid(), (u_int)geteuid(),
+		    (u_int)pw->pw_uid);
+	}
 }