From 42c54ff9d5e8733ec76f53b52ce2a7cbd6870763 Mon Sep 17 00:00:00 2001
From: Fred Wright <fw@fwright.net>
Date: Thu, 7 Nov 2024 17:27:22 -0800
Subject: [PATCH] test_realpath: Add nonexistent path case.
Although more thorough testing of various path cases would be useful,
this one, which just tests a simple nonexistent relative path, is
sufficient to demonstrate a bug in the 10.6 non-POSIX realpath(),
which returns "success" via an unsafe pointer to an internal buffer.
TESTED:
Fails in known bad case without the fix; passes in all cases with the
fix.
---
test/test_realpath.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/test/test_realpath.c b/test/test_realpath.c
index ec890dc..cf14745 100644
--- a/test/test_realpath.c
+++ b/test/test_realpath.c
@@ -37,6 +37,7 @@ typedef struct { strfunc_t realpath; } rpf_t;
#include <assert.h>
#include <libgen.h>
+#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -44,6 +45,17 @@ typedef struct { strfunc_t realpath; } rpf_t;
#include <sys/param.h>
+/*
+ * Beginning in the 15.x SDK, including malloc.h doesn't work when
+ * _POSIX_C_SOURCE is defined, which we need for the "nonext" version.
+ * So we avoid the official include and declare malloc_size() directly.
+ *
+ * #include <malloc/malloc.h>
+ */
+extern size_t malloc_size(const void *ptr);
+
+#define NONEX_PATH "4981a2d5a4c7bea88154c434b4708045"
+
/*
* Allow testing the legacy compatibility entry.
* We use a simple argless macro and disable the fancier tests.
@@ -85,6 +97,20 @@ main(int argc, char *argv[])
if (verbose) printf("realpath(path, NULL) supported.\n");
free((void*)q);
+ /*
+ * Test nonexistent path with no supplied buffer.
+ * In some cases (10.6 non-POSIX) this may "succeed" with a bad
+ * returned buffer address. We accept either failure or success
+ * with a valid buffer.
+ */
+ q = realpath(NONEX_PATH, NULL);
+ assert((!q || malloc_size(q)) \
+ && "realpath(_nonexpath, NULL) returned bad address");
+ if (verbose) {
+ printf("realpath(nonex_path, NULL) %s.\n", q ? "succeeds" : "fails");
+ }
+ if (q && malloc_size(q)) free((void*)q);
+
#ifndef TEST_MACPORTS_LEGACY_REALPATH
/* Test with name (reference) only */
f = realpath;
--
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