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path: root/drivers/misc/lkdtm/heap.c
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Diffstat (limited to 'drivers/misc/lkdtm/heap.c')
-rw-r--r--drivers/misc/lkdtm/heap.c72
1 files changed, 72 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c
index 65026d7de130..3c5cec85edce 100644
--- a/drivers/misc/lkdtm/heap.c
+++ b/drivers/misc/lkdtm/heap.c
@@ -7,6 +7,10 @@
#include <linux/slab.h>
#include <linux/sched.h>
+static struct kmem_cache *double_free_cache;
+static struct kmem_cache *a_cache;
+static struct kmem_cache *b_cache;
+
/*
* This tries to stay within the next largest power-of-2 kmalloc cache
* to avoid actually overwriting anything important if it's not detected
@@ -146,3 +150,71 @@ void lkdtm_READ_BUDDY_AFTER_FREE(void)
kfree(val);
}
+
+void lkdtm_SLAB_FREE_DOUBLE(void)
+{
+ int *val;
+
+ val = kmem_cache_alloc(double_free_cache, GFP_KERNEL);
+ if (!val) {
+ pr_info("Unable to allocate double_free_cache memory.\n");
+ return;
+ }
+
+ /* Just make sure we got real memory. */
+ *val = 0x12345678;
+ pr_info("Attempting double slab free ...\n");
+ kmem_cache_free(double_free_cache, val);
+ kmem_cache_free(double_free_cache, val);
+}
+
+void lkdtm_SLAB_FREE_CROSS(void)
+{
+ int *val;
+
+ val = kmem_cache_alloc(a_cache, GFP_KERNEL);
+ if (!val) {
+ pr_info("Unable to allocate a_cache memory.\n");
+ return;
+ }
+
+ /* Just make sure we got real memory. */
+ *val = 0x12345679;
+ pr_info("Attempting cross-cache slab free ...\n");
+ kmem_cache_free(b_cache, val);
+}
+
+void lkdtm_SLAB_FREE_PAGE(void)
+{
+ unsigned long p = __get_free_page(GFP_KERNEL);
+
+ pr_info("Attempting non-Slab slab free ...\n");
+ kmem_cache_free(NULL, (void *)p);
+ free_page(p);
+}
+
+/*
+ * We have constructors to keep the caches distinctly separated without
+ * needing to boot with "slab_nomerge".
+ */
+static void ctor_double_free(void *region)
+{ }
+static void ctor_a(void *region)
+{ }
+static void ctor_b(void *region)
+{ }
+
+void __init lkdtm_heap_init(void)
+{
+ double_free_cache = kmem_cache_create("lkdtm-heap-double_free",
+ 64, 0, 0, ctor_double_free);
+ a_cache = kmem_cache_create("lkdtm-heap-a", 64, 0, 0, ctor_a);
+ b_cache = kmem_cache_create("lkdtm-heap-b", 64, 0, 0, ctor_b);
+}
+
+void __exit lkdtm_heap_exit(void)
+{
+ kmem_cache_destroy(double_free_cache);
+ kmem_cache_destroy(a_cache);
+ kmem_cache_destroy(b_cache);
+}