X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/a3626e1226c8eecce855a2bc4a500d6939cbdf4c..58df878930fd736fb8b09c870ef970b9a53dddc3:/uidswap.c

diff --git a/uidswap.c b/uidswap.c
index e2979014..cc91fcf2 100644
--- a/uidswap.c
+++ b/uidswap.c
@@ -12,7 +12,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: uidswap.c,v 1.16 2001/04/20 16:32:22 markus Exp $");
+RCSID("$OpenBSD: uidswap.c,v 1.18 2001/08/08 21:34:19 markus Exp $");
 
 #include "log.h"
 #include "uidswap.h"
@@ -26,17 +26,21 @@ RCSID("$OpenBSD: uidswap.c,v 1.16 2001/04/20 16:32:22 markus Exp $");
  * 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;
+static gid_t	saved_egid = 0;
+#endif
+
 /* Saved effective uid. */
 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.
@@ -44,42 +48,59 @@ static int	saved_egroupslen = -1, user_groupslen = -1;
 void
 temporarily_use_uid(struct passwd *pw)
 {
- 	/* 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;
+	/* Save the current euid, and egroups. */
+#ifdef SAVED_IDS_WORK_WITH_SETEUID
+	saved_euid = geteuid();
 	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. */
+	debug("temporarily_use_uid: %d/%d (e=%d)",
+	    pw->pw_uid, pw->pw_gid, saved_euid);
+	if (saved_euid != 0) {
+		privileged = 0;
+		return;
+	}
+#else
+	if (geteuid() != 0) {
+		privileged = 0;
+		return;
+	}
+#endif /* SAVED_IDS_WORK_WITH_SETEUID */
+
+	privileged = 1;
+	temporarily_use_uid_effective = 1;
+	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));
+	}
+#ifndef HAVE_CYGWIN
+	/* 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;
+#endif /* !HAVE_CYWIN */
+#ifndef SAVED_IDS_WORK_WITH_SETEUID
+	/* Propagate the privileged gid to all of our gids. */
+	if (setgid(getegid()) < 0)
+		debug("setgid %u: %.100s", (u_int) getegid(), strerror(errno));
+	/* Propagate the privileged uid to all of our uids. */
+	if (setuid(geteuid()) < 0)
+		debug("setuid %u: %.100s", (u_int) geteuid(), strerror(errno));
+#endif /* SAVED_IDS_WORK_WITH_SETEUID */
 	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));
+		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 (privileged) uid.
  */
@@ -92,13 +113,28 @@ restore_uid(void)
 		return;
 	if (!temporarily_use_uid_effective)
 		fatal("restore_uid: temporarily_use_uid not effective");
+
+#ifdef SAVED_IDS_WORK_WITH_SETEUID
 	/* 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));
+	if (setegid(saved_egid) < 0)
+		fatal("setegid %u: %.100s", (u_int) saved_egid, 
+		    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());
+	setgid(getgid());
+#endif /* SAVED_IDS_WORK_WITH_SETEUID */
+
+#ifndef HAVE_CYGWIN
 	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));
+#endif /* !HAVE_CYGWIN */
 	temporarily_use_uid_effective = 0;
 }