linux_kselftest-kunit-fixes-6.11-rc7

This kunit update for Linux 6.11-rc7 consist of one single fix to
 a use-after-free bug resulting from kunit_driver_create() failing
 to copy the driver name leaving it on the stack or freeing it.
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Merge tag 'linux_kselftest-kunit-fixes-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kunit fix fromShuah Khan:
 "One single fix to a use-after-free bug resulting from
  kunit_driver_create() failing to copy the driver name leaving it on
  the stack or freeing it"

* tag 'linux_kselftest-kunit-fixes-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: Device wrappers should also manage driver name

include/kunit/test.h

@@ -28,6 +28,7 @@
 #include <linux/types.h>
 
 #include <asm/rwonce.h>
+#include <asm/sections.h>
 
 /* Static key: true if any KUnit tests are currently running */
 DECLARE_STATIC_KEY_FALSE(kunit_running);
@@ -480,6 +481,53 @@ static inline void *kunit_kcalloc(struct kunit *test, size_t n, size_t size, gfp
 	return kunit_kmalloc_array(test, n, size, gfp | __GFP_ZERO);
 }
 
+
+/**
+ * kunit_kfree_const() - conditionally free test managed memory
+ * @x: pointer to the memory
+ *
+ * Calls kunit_kfree() only if @x is not in .rodata section.
+ * See kunit_kstrdup_const() for more information.
+ */
+void kunit_kfree_const(struct kunit *test, const void *x);
+
+/**
+ * kunit_kstrdup() - Duplicates a string into a test managed allocation.
+ *
+ * @test: The test context object.
+ * @str: The NULL-terminated string to duplicate.
+ * @gfp: flags passed to underlying kmalloc().
+ *
+ * See kstrdup() and kunit_kmalloc_array() for more information.
+ */
+static inline char *kunit_kstrdup(struct kunit *test, const char *str, gfp_t gfp)
+{
+	size_t len;
+	char *buf;
+
+	if (!str)
+		return NULL;
+
+	len = strlen(str) + 1;
+	buf = kunit_kmalloc(test, len, gfp);
+	if (buf)
+		memcpy(buf, str, len);
+	return buf;
+}
+
+/**
+ * kunit_kstrdup_const() - Conditionally duplicates a string into a test managed allocation.
+ *
+ * @test: The test context object.
+ * @str: The NULL-terminated string to duplicate.
+ * @gfp: flags passed to underlying kmalloc().
+ *
+ * Calls kunit_kstrdup() only if @str is not in the rodata section. Must be freed with
+ * kunit_kfree_const() -- not kunit_kfree().
+ * See kstrdup_const() and kunit_kmalloc_array() for more information.
+ */
+const char *kunit_kstrdup_const(struct kunit *test, const char *str, gfp_t gfp);
+
 /**
  * kunit_vm_mmap() - Allocate KUnit-tracked vm_mmap() area
  * @test: The test context object.

lib/kunit/device.c

@@ -89,7 +89,7 @@ struct device_driver *kunit_driver_create(struct kunit *test, const char *name)
 	if (!driver)
 		return ERR_PTR(err);
 
-	driver->name = name;
+	driver->name = kunit_kstrdup_const(test, name, GFP_KERNEL);
 	driver->bus = &kunit_bus_type;
 	driver->owner = THIS_MODULE;
 
@@ -192,8 +192,11 @@ void kunit_device_unregister(struct kunit *test, struct device *dev)
 	const struct device_driver *driver = to_kunit_device(dev)->driver;
 
 	kunit_release_action(test, device_unregister_wrapper, dev);
-	if (driver)
+	if (driver) {
+		const char *driver_name = driver->name;
 		kunit_release_action(test, driver_unregister_wrapper, (void *)driver);
+		kunit_kfree_const(test, driver_name);
+	}
 }
 EXPORT_SYMBOL_GPL(kunit_device_unregister);
 

lib/kunit/test.c

@@ -874,6 +874,25 @@ void kunit_kfree(struct kunit *test, const void *ptr)
 }
 EXPORT_SYMBOL_GPL(kunit_kfree);
 
+void kunit_kfree_const(struct kunit *test, const void *x)
+{
+#if !IS_MODULE(CONFIG_KUNIT)
+	if (!is_kernel_rodata((unsigned long)x))
+#endif
+		kunit_kfree(test, x);
+}
+EXPORT_SYMBOL_GPL(kunit_kfree_const);
+
+const char *kunit_kstrdup_const(struct kunit *test, const char *str, gfp_t gfp)
+{
+#if !IS_MODULE(CONFIG_KUNIT)
+	if (is_kernel_rodata((unsigned long)str))
+		return str;
+#endif
+	return kunit_kstrdup(test, str, gfp);
+}
+EXPORT_SYMBOL_GPL(kunit_kstrdup_const);
+
 void kunit_cleanup(struct kunit *test)
 {
 	struct kunit_resource *res;