Don't look up env variables until we know we'll trust them. Otherwise,

just delete them without looking.

ok millert@

1 files changed, 21 insertions, 32 deletions

diff --git a/libexec/ld.so/loader.c b/libexec/ld.so/loader.c
index bf62da51bbe..f63825ff231 100644
--- a/libexec/ld.so/loader.c
+++ b/libexec/ld.so/loader.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: loader.c,v 1.189 2019/12/11 18:27:54 millert Exp $ */
+/*	$OpenBSD: loader.c,v 1.190 2019/12/17 03:16:07 guenther Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -262,46 +262,35 @@ _dl_dopreload(char *paths)
 void
 _dl_setup_env(const char *argv0, char **envp)
 {
-	char *libpath;
 	static char progname_storage[NAME_MAX+1] = "";
 
 	/*
-	 * Get paths to various things we are going to use.
-	 */
-	_dl_debug = _dl_getenv("LD_DEBUG", envp) != NULL;
-	libpath = _dl_getenv("LD_LIBRARY_PATH", envp);
-	_dl_preload = _dl_getenv("LD_PRELOAD", envp);
-	_dl_bindnow = _dl_getenv("LD_BIND_NOW", envp) != NULL;
-	_dl_traceld = _dl_getenv("LD_TRACE_LOADED_OBJECTS", envp) != NULL;
-	_dl_tracefmt1 = _dl_getenv("LD_TRACE_LOADED_OBJECTS_FMT1", envp);
-	_dl_tracefmt2 = _dl_getenv("LD_TRACE_LOADED_OBJECTS_FMT2", envp);
-	_dl_traceprog = _dl_getenv("LD_TRACE_LOADED_OBJECTS_PROGNAME", envp);
-
-	/*
 	 * Don't allow someone to change the search paths if he runs
 	 * a suid program without credentials high enough.
 	 */
 	_dl_trust = !_dl_issetugid();
 	if (!_dl_trust) {	/* Zap paths if s[ug]id... */
-		if (libpath) {
-			libpath = NULL;
-			_dl_unsetenv("LD_LIBRARY_PATH", envp);
-		}
-		if (_dl_preload) {
-			_dl_preload = NULL;
-			_dl_unsetenv("LD_PRELOAD", envp);
-		}
-		if (_dl_bindnow) {
-			_dl_bindnow = 0;
-			_dl_unsetenv("LD_BIND_NOW", envp);
-		}
-		if (_dl_debug) {
-			_dl_debug = 0;
-			_dl_unsetenv("LD_DEBUG", envp);
-		}
+		_dl_unsetenv("LD_DEBUG", envp);
+		_dl_unsetenv("LD_LIBRARY_PATH", envp);
+		_dl_unsetenv("LD_PRELOAD", envp);
+		_dl_unsetenv("LD_BIND_NOW", envp);
+	} else {
+		/*
+		 * Get paths to various things we are going to use.
+		 */
+		_dl_debug = _dl_getenv("LD_DEBUG", envp) != NULL;
+		_dl_libpath = _dl_split_path(_dl_getenv("LD_LIBRARY_PATH",
+		    envp));
+		_dl_preload = _dl_getenv("LD_PRELOAD", envp);
+		_dl_bindnow = _dl_getenv("LD_BIND_NOW", envp) != NULL;
 	}
-	if (libpath)
-		_dl_libpath = _dl_split_path(libpath);
+
+	/* these are usable even in setugid processes */
+	_dl_traceld = _dl_getenv("LD_TRACE_LOADED_OBJECTS", envp) != NULL;
+	_dl_tracefmt1 = _dl_getenv("LD_TRACE_LOADED_OBJECTS_FMT1", envp);
+	_dl_tracefmt2 = _dl_getenv("LD_TRACE_LOADED_OBJECTS_FMT2", envp);
+	_dl_traceprog = _dl_getenv("LD_TRACE_LOADED_OBJECTS_PROGNAME", envp);
+
 	environ = envp;
 
 	_dl_trace_setup(envp);