resource, kunit: fix user-after-free in resource_test_region_intersects()

In resource_test_insert_resource(), the pointer is used in error message
after kfree().  This is user-after-free.  To fix this, we need to call
kunit_add_action_or_reset() to schedule memory freeing after usage.  But
kunit_add_action_or_reset() itself may fail and free the memory.  So, its
return value should be checked and abort the test for failure.  Then, we
found that other usage of kunit_add_action_or_reset() in
resource_test_region_intersects() needs to be fixed too.  We fix all these
user-after-free bugs in this patch.

Link: https://lkml.kernel.org/r/20240930070611.353338-1-ying.huang@intel.com
Fixes: 99185c10d5d9 ("resource, kunit: add test case for region_intersects()")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reported-by: Kees Bakker <kees@ijzerbout.nl>
Closes: https://lore.kernel.org/lkml/87ldzaotcg.fsf@yhuang6-desk2.ccr.corp.intel.com/
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/resource_kunit.c b/kernel/resource_kunit.c
index 42d2d8d20f5d54e868d344c1a73835977bc84a39..b8ef75b99eb2f788b518ba71fc1b35248595377f 100644 (file)
--- a/kernel/resource_kunit.c
+++ b/kernel/resource_kunit.c
@@ -169,6 +169,8 @@ static void resource_test_intersection(struct kunit *test)
 #define RES_TEST_RAM3_SIZE     SZ_1M
 #define RES_TEST_TOTAL_SIZE    ((RES_TEST_WIN1_OFFSET + RES_TEST_WIN1_SIZE))
 
+KUNIT_DEFINE_ACTION_WRAPPER(kfree_wrapper, kfree, const void *);
+
 static void remove_free_resource(void *ctx)
 {
        struct resource *res = (struct resource *)ctx;
@@ -177,6 +179,14 @@ static void remove_free_resource(void *ctx)
        kfree(res);
 }
 
+static void resource_test_add_action_or_abort(
+       struct kunit *test, void (*action)(void *), void *ctx)
+{
+       KUNIT_ASSERT_EQ_MSG(test, 0,
+                           kunit_add_action_or_reset(test, action, ctx),
+                           "Fail to add action");
+}
+
 static void resource_test_request_region(struct kunit *test, struct resource *parent,
                                         resource_size_t start, resource_size_t size,
                                         const char *name, unsigned long flags)
@@ -185,7 +195,7 @@ static void resource_test_request_region(struct kunit *test, struct resource *pa
 
        res = __request_region(parent, start, size, name, flags);
        KUNIT_ASSERT_NOT_NULL(test, res);
-       kunit_add_action_or_reset(test, remove_free_resource, res);
+       resource_test_add_action_or_abort(test, remove_free_resource, res);
 }
 
 static void resource_test_insert_resource(struct kunit *test, struct resource *parent,
@@ -202,11 +212,11 @@ static void resource_test_insert_resource(struct kunit *test, struct resource *p
        res->end = start + size - 1;
        res->flags = flags;
        if (insert_resource(parent, res)) {
-               kfree(res);
+               resource_test_add_action_or_abort(test, kfree_wrapper, res);
                KUNIT_FAIL_AND_ABORT(test, "Fail to insert resource %pR\n", res);
        }
 
-       kunit_add_action_or_reset(test, remove_free_resource, res);
+       resource_test_add_action_or_abort(test, remove_free_resource, res);
 }
 
 static void resource_test_region_intersects(struct kunit *test)
@@ -220,7 +230,7 @@ static void resource_test_region_intersects(struct kunit *test)
                                       "test resources");
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
        start = parent->start;
-       kunit_add_action_or_reset(test, remove_free_resource, parent);
+       resource_test_add_action_or_abort(test, remove_free_resource, parent);
 
        resource_test_request_region(test, parent, start + RES_TEST_RAM0_OFFSET,
                                     RES_TEST_RAM0_SIZE, "Test System RAM 0", flags);