Merge tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull kernel hardening updates from Kees Cook:

 - Convert flexible array members, fix -Wstringop-overflow warnings, and
   fix KCFI function type mismatches that went ignored by maintainers
   (Gustavo A. R. Silva, Nathan Chancellor, Kees Cook)

 - Remove the remaining side-effect users of ksize() by converting
   dma-buf, btrfs, and coredump to using kmalloc_size_roundup(), add
   more __alloc_size attributes, and introduce full testing of all
   allocator functions. Finally remove the ksize() side-effect so that
   each allocation-aware checker can finally behave without exceptions

 - Introduce oops_limit (default 10,000) and warn_limit (default off) to
   provide greater granularity of control for panic_on_oops and
   panic_on_warn (Jann Horn, Kees Cook)

 - Introduce overflows_type() and castable_to_type() helpers for cleaner
   overflow checking

 - Improve code generation for strscpy() and update str*() kern-doc

 - Convert strscpy and sigphash tests to KUnit, and expand memcpy tests

 - Always use a non-NULL argument for prepare_kernel_cred()

 - Disable structleak plugin in FORTIFY KUnit test (Anders Roxell)

 - Adjust orphan linker section checking to respect CONFIG_WERROR (Xin
   Li)

 - Make sure siginfo is cleared for forced SIGKILL (haifeng.xu)

 - Fix um vs FORTIFY warnings for always-NULL arguments

* tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (31 commits)
  ksmbd: replace one-element arrays with flexible-array members
  hpet: Replace one-element array with flexible-array member
  um: virt-pci: Avoid GCC non-NULL warning
  signal: Initialize the info in ksignal
  lib: fortify_kunit: build without structleak plugin
  panic: Expose "warn_count" to sysfs
  panic: Introduce warn_limit
  panic: Consolidate open-coded panic_on_warn checks
  exit: Allow oops_limit to be disabled
  exit: Expose "oops_count" to sysfs
  exit: Put an upper limit on how often we can oops
  panic: Separate sysctl logic from CONFIG_SMP
  mm/pgtable: Fix multiple -Wstringop-overflow warnings
  mm: Make ksize() a reporting-only function
  kunit/fortify: Validate __alloc_size attribute results
  drm/sti: Fix return type of sti_{dvo,hda,hdmi}_connector_mode_valid()
  drm/fsl-dcu: Fix return type of fsl_dcu_drm_connector_mode_valid()
  driver core: Add __alloc_size hint to devm allocators
  overflow: Introduce overflows_type() and castable_to_type()
  coredump: Proactively round up to kmalloc bucket size
  ...

2 files changed, 15 insertions, 8 deletions

diff --git a/mm/kasan/kasan_test.c b/mm/kasan/kasan_test.c
index d1439669d6bc..74cd80c12b25 100644
--- a/mm/kasan/kasan_test.c
+++ b/mm/kasan/kasan_test.c
@@ -825,23 +825,30 @@ static void kasan_global_oob_left(struct kunit *test)
 	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
 }
 
-/* Check that ksize() makes the whole object accessible. */
+/* Check that ksize() does NOT unpoison whole object. */
 static void ksize_unpoisons_memory(struct kunit *test)
 {
 	char *ptr;
-	size_t size = 123, real_size;
+	size_t size = 128 - KASAN_GRANULE_SIZE - 5;
+	size_t real_size;
 
 	ptr = kmalloc(size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+
 	real_size = ksize(ptr);
+	KUNIT_EXPECT_GT(test, real_size, size);
 
 	OPTIMIZER_HIDE_VAR(ptr);
 
-	/* This access shouldn't trigger a KASAN report. */
-	ptr[size] = 'x';
+	/* These accesses shouldn't trigger a KASAN report. */
+	ptr[0] = 'x';
+	ptr[size - 1] = 'x';
 
-	/* This one must. */
-	KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[real_size]);
+	/* These must trigger a KASAN report. */
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
+		KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
+	KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size + 5]);
+	KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[real_size - 1]);
 
 	kfree(ptr);
 }
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index f2db8605ee0f..1d02757e90a3 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -186,8 +186,8 @@ static void end_report(unsigned long *flags, void *addr)
 				       (unsigned long)addr);
 	pr_err("==================================================================\n");
 	spin_unlock_irqrestore(&report_lock, *flags);
-	if (panic_on_warn && !test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
-		panic("panic_on_warn set ...\n");
+	if (!test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
+		check_panic_on_warn("KASAN");
 	if (kasan_arg_fault == KASAN_ARG_FAULT_PANIC)
 		panic("kasan.fault=panic set ...\n");
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);