Merge tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into char-misc-next

Kees writes:

lkdtm updates for -next

- Test for new usercopy memory regions
- avoid GCC 12 warnings
- update expected CONFIGs for selftests

* tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lkdtm/heap: Hide allocation size from -Warray-bounds
  selftests/lkdtm: Add configs for stackleak and "after free" tests
  lkdtm/usercopy: Check vmalloc and >0-order folios
  lkdtm/usercopy: Rename "heap" to "slab"
  lkdtm: cfi: Fix type width for masking PAC bits

2 files changed, 99 insertions, 15 deletions

diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c
index 5d3b92cd23bd..62516078a619 100644
--- a/drivers/misc/lkdtm/heap.c
+++ b/drivers/misc/lkdtm/heap.c
@@ -56,6 +56,7 @@ static void lkdtm_SLAB_LINEAR_OVERFLOW(void)
 		return;
 
 	pr_info("Attempting slab linear overflow ...\n");
+	OPTIMIZER_HIDE_VAR(data);
 	data[1024 / sizeof(u32)] = 0x12345678;
 	kfree(data);
 }
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index 7852b9fc7c47..6215ec995cd3 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -5,6 +5,7 @@
  */
 #include "lkdtm.h"
 #include <linux/slab.h>
+#include <linux/highmem.h>
 #include <linux/vmalloc.h>
 #include <linux/sched/task_stack.h>
 #include <linux/mman.h>
@@ -130,7 +131,7 @@ free_user:
  * This checks for whole-object size validation with hardened usercopy,
  * with or without usercopy whitelisting.
  */
-static void do_usercopy_heap_size(bool to_user)
+static void do_usercopy_slab_size(bool to_user)
 {
 	unsigned long user_addr;
 	unsigned char *one, *two;
@@ -196,9 +197,9 @@ free_kernel:
 
 /*
  * This checks for the specific whitelist window within an object. If this
- * test passes, then do_usercopy_heap_size() tests will pass too.
+ * test passes, then do_usercopy_slab_size() tests will pass too.
  */
-static void do_usercopy_heap_whitelist(bool to_user)
+static void do_usercopy_slab_whitelist(bool to_user)
 {
 	unsigned long user_alloc;
 	unsigned char *buf = NULL;
@@ -272,24 +273,24 @@ free_alloc:
 }
 
 /* Callable tests. */
-static void lkdtm_USERCOPY_HEAP_SIZE_TO(void)
+static void lkdtm_USERCOPY_SLAB_SIZE_TO(void)
 {
-	do_usercopy_heap_size(true);
+	do_usercopy_slab_size(true);
 }
 
-static void lkdtm_USERCOPY_HEAP_SIZE_FROM(void)
+static void lkdtm_USERCOPY_SLAB_SIZE_FROM(void)
 {
-	do_usercopy_heap_size(false);
+	do_usercopy_slab_size(false);
 }
 
-static void lkdtm_USERCOPY_HEAP_WHITELIST_TO(void)
+static void lkdtm_USERCOPY_SLAB_WHITELIST_TO(void)
 {
-	do_usercopy_heap_whitelist(true);
+	do_usercopy_slab_whitelist(true);
 }
 
-static void lkdtm_USERCOPY_HEAP_WHITELIST_FROM(void)
+static void lkdtm_USERCOPY_SLAB_WHITELIST_FROM(void)
 {
-	do_usercopy_heap_whitelist(false);
+	do_usercopy_slab_whitelist(false);
 }
 
 static void lkdtm_USERCOPY_STACK_FRAME_TO(void)
@@ -341,6 +342,86 @@ free_user:
 	vm_munmap(user_addr, PAGE_SIZE);
 }
 
+/*
+ * This expects "kaddr" to point to a PAGE_SIZE allocation, which means
+ * a more complete test that would include copy_from_user() would risk
+ * memory corruption. Just test copy_to_user() here, as that exercises
+ * almost exactly the same code paths.
+ */
+static void do_usercopy_page_span(const char *name, void *kaddr)
+{
+	unsigned long uaddr;
+
+	uaddr = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_WRITE,
+			MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (uaddr >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		return;
+	}
+
+	/* Initialize contents. */
+	memset(kaddr, 0xAA, PAGE_SIZE);
+
+	/* Bump the kaddr forward to detect a page-spanning overflow. */
+	kaddr += PAGE_SIZE / 2;
+
+	pr_info("attempting good copy_to_user() from kernel %s: %px\n",
+		name, kaddr);
+	if (copy_to_user((void __user *)uaddr, kaddr,
+			 unconst + (PAGE_SIZE / 2))) {
+		pr_err("copy_to_user() failed unexpectedly?!\n");
+		goto free_user;
+	}
+
+	pr_info("attempting bad copy_to_user() from kernel %s: %px\n",
+		name, kaddr);
+	if (copy_to_user((void __user *)uaddr, kaddr, unconst + PAGE_SIZE)) {
+		pr_warn("Good, copy_to_user() failed, but lacked Oops(?!)\n");
+		goto free_user;
+	}
+
+	pr_err("FAIL: bad copy_to_user() not detected!\n");
+	pr_expected_config_param(CONFIG_HARDENED_USERCOPY, "hardened_usercopy");
+
+free_user:
+	vm_munmap(uaddr, PAGE_SIZE);
+}
+
+static void lkdtm_USERCOPY_VMALLOC(void)
+{
+	void *addr;
+
+	addr = vmalloc(PAGE_SIZE);
+	if (!addr) {
+		pr_err("vmalloc() failed!?\n");
+		return;
+	}
+	do_usercopy_page_span("vmalloc", addr);
+	vfree(addr);
+}
+
+static void lkdtm_USERCOPY_FOLIO(void)
+{
+	struct folio *folio;
+	void *addr;
+
+	/*
+	 * FIXME: Folio checking currently misses 0-order allocations, so
+	 * allocate and bump forward to the last page.
+	 */
+	folio = folio_alloc(GFP_KERNEL | __GFP_ZERO, 1);
+	if (!folio) {
+		pr_err("folio_alloc() failed!?\n");
+		return;
+	}
+	addr = folio_address(folio);
+	if (addr)
+		do_usercopy_page_span("folio", addr + PAGE_SIZE);
+	else
+		pr_err("folio_address() failed?!\n");
+	folio_put(folio);
+}
+
 void __init lkdtm_usercopy_init(void)
 {
 	/* Prepare cache that lacks SLAB_USERCOPY flag. */
@@ -358,13 +439,15 @@ void __exit lkdtm_usercopy_exit(void)
 }
 
 static struct crashtype crashtypes[] = {
-	CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
-	CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
-	CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
-	CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
+	CRASHTYPE(USERCOPY_SLAB_SIZE_TO),
+	CRASHTYPE(USERCOPY_SLAB_SIZE_FROM),
+	CRASHTYPE(USERCOPY_SLAB_WHITELIST_TO),
+	CRASHTYPE(USERCOPY_SLAB_WHITELIST_FROM),
 	CRASHTYPE(USERCOPY_STACK_FRAME_TO),
 	CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
 	CRASHTYPE(USERCOPY_STACK_BEYOND),
+	CRASHTYPE(USERCOPY_VMALLOC),
+	CRASHTYPE(USERCOPY_FOLIO),
 	CRASHTYPE(USERCOPY_KERNEL),
 };