- (dtucker) [session.c openbsd-compat/bsd-cygwin_util.h] Move Cygwin

[openssh.git] / uidswap.c

diff --git a/uidswap.c b/uidswap.c
index db6253259ba58d1e65472eaa584e0ba5b28bf039..e517da21d3266e38c02d92c6fe8b75f05f4488db 100644 (file)
--- a/uidswap.c
+++ b/uidswap.c
@@ -143,16 +143,63 @@ 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)
+       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)
+       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)
+       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)
+       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);
+       }
+
+       /* 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__);
+
+       /* 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);
+       }
 }