+ kasan-unify-large-kfree-checks.patch added to -mm tree

* + kasan-unify-large-kfree-checks.patch added to -mm tree
@ 2021-02-05 21:18 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2021-02-05 21:18 UTC (permalink / raw)
  To: andreyknvl, aryabinin, Branislav.Rankov, catalin.marinas,
	dvyukov, elver, eugenis, glider, kevin.brodsky, mm-commits, pcc,
	vincenzo.frascino, will.deacon


The patch titled
     Subject: kasan: unify large kfree checks
has been added to the -mm tree.  Its filename is
     kasan-unify-large-kfree-checks.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/kasan-unify-large-kfree-checks.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/kasan-unify-large-kfree-checks.patch

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Andrey Konovalov <andreyknvl@google.com>
Subject: kasan: unify large kfree checks

Unify checks in kasan_kfree_large() and in kasan_slab_free_mempool() for
large allocations as it's done for small kfree() allocations.

With this change, kasan_slab_free_mempool() starts checking that the first
byte of the memory that's being freed is accessible.

Link: https://lkml.kernel.org/r/14ffc4cd867e0b1ed58f7527e3b748a1b4ad08aa.1612546384.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/kasan.h |   16 ++++++++--------
 mm/kasan/common.c     |   36 ++++++++++++++++++++++++++----------
 2 files changed, 34 insertions(+), 18 deletions(-)

--- a/include/linux/kasan.h~kasan-unify-large-kfree-checks
+++ a/include/linux/kasan.h
@@ -200,6 +200,13 @@ static __always_inline bool kasan_slab_f
 	return false;
 }
 
+void __kasan_kfree_large(void *ptr, unsigned long ip);
+static __always_inline void kasan_kfree_large(void *ptr)
+{
+	if (kasan_enabled())
+		__kasan_kfree_large(ptr, _RET_IP_);
+}
+
 void __kasan_slab_free_mempool(void *ptr, unsigned long ip);
 static __always_inline void kasan_slab_free_mempool(void *ptr)
 {
@@ -247,13 +254,6 @@ static __always_inline void * __must_che
 	return (void *)object;
 }
 
-void __kasan_kfree_large(void *ptr, unsigned long ip);
-static __always_inline void kasan_kfree_large(void *ptr)
-{
-	if (kasan_enabled())
-		__kasan_kfree_large(ptr, _RET_IP_);
-}
-
 /*
  * Unlike kasan_check_read/write(), kasan_check_byte() is performed even for
  * the hardware tag-based mode that doesn't rely on compiler instrumentation.
@@ -302,6 +302,7 @@ static inline bool kasan_slab_free(struc
 {
 	return false;
 }
+static inline void kasan_kfree_large(void *ptr) {}
 static inline void kasan_slab_free_mempool(void *ptr) {}
 static inline void *kasan_slab_alloc(struct kmem_cache *s, void *object,
 				   gfp_t flags)
@@ -322,7 +323,6 @@ static inline void *kasan_krealloc(const
 {
 	return (void *)object;
 }
-static inline void kasan_kfree_large(void *ptr) {}
 static inline bool kasan_check_byte(const void *address)
 {
 	return true;
--- a/mm/kasan/common.c~kasan-unify-large-kfree-checks
+++ a/mm/kasan/common.c
@@ -364,6 +364,31 @@ bool __kasan_slab_free(struct kmem_cache
 	return ____kasan_slab_free(cache, object, ip, true);
 }
 
+static bool ____kasan_kfree_large(void *ptr, unsigned long ip)
+{
+	if (ptr != page_address(virt_to_head_page(ptr))) {
+		kasan_report_invalid_free(ptr, ip);
+		return true;
+	}
+
+	if (!kasan_byte_accessible(ptr)) {
+		kasan_report_invalid_free(ptr, ip);
+		return true;
+	}
+
+	/*
+	 * The object will be poisoned by kasan_free_pages() or
+	 * kasan_slab_free_mempool().
+	 */
+
+	return false;
+}
+
+void __kasan_kfree_large(void *ptr, unsigned long ip)
+{
+	____kasan_kfree_large(ptr, ip);
+}
+
 void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
 {
 	struct page *page;
@@ -377,10 +402,8 @@ void __kasan_slab_free_mempool(void *ptr
 	 * KMALLOC_MAX_SIZE, and kmalloc falls back onto page_alloc.
 	 */
 	if (unlikely(!PageSlab(page))) {
-		if (ptr != page_address(page)) {
-			kasan_report_invalid_free(ptr, ip);
+		if (____kasan_kfree_large(ptr, ip))
 			return;
-		}
 		kasan_poison(ptr, page_size(page), KASAN_FREE_PAGE);
 	} else {
 		____kasan_slab_free(page->slab_cache, ptr, ip, false);
@@ -539,13 +562,6 @@ void * __must_check __kasan_krealloc(con
 		return ____kasan_kmalloc(page->slab_cache, object, size, flags);
 }
 
-void __kasan_kfree_large(void *ptr, unsigned long ip)
-{
-	if (ptr != page_address(virt_to_head_page(ptr)))
-		kasan_report_invalid_free(ptr, ip);
-	/* The object will be poisoned by kasan_free_pages(). */
-}
-
 bool __kasan_check_byte(const void *address, unsigned long ip)
 {
 	if (!kasan_byte_accessible(address)) {
_

Patches currently in -mm which might be from andreyknvl@google.com are

kasan-prefix-global-functions-with-kasan_.patch
kasan-clarify-hw_tags-impact-on-tbi.patch
kasan-clean-up-comments-in-tests.patch
kasan-add-macros-to-simplify-checking-test-constraints.patch
kasan-add-match-all-tag-tests.patch
kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
kasan-rename-config_test_kasan_module.patch
kasan-add-compiler-barriers-to-kunit_expect_kasan_fail.patch
kasan-adapt-kmalloc_uaf2-test-to-hw_tags-mode.patch
kasan-fix-memory-corruption-in-kasan_bitops_tags-test.patch
kasan-move-_ret_ip_-to-inline-wrappers.patch
kasan-fix-bug-detection-via-ksize-for-hw_tags-mode.patch
kasan-add-proper-page-allocator-tests.patch
kasan-add-a-test-for-kmem_cache_alloc-free_bulk.patch
kasan-dont-run-tests-when-kasan-is-not-enabled.patch
kfence-kasan-make-kfence-compatible-with-kasan-fix-2.patch
kasan-mm-dont-save-alloc-stacks-twice.patch
kasan-mm-optimize-kmalloc-poisoning.patch
kasan-optimize-large-kmalloc-poisoning.patch
kasan-clean-up-setting-free-info-in-kasan_slab_free.patch
kasan-unify-large-kfree-checks.patch
kasan-rework-krealloc-tests.patch
kasan-mm-fail-krealloc-on-freed-objects.patch
kasan-mm-optimize-krealloc-poisoning.patch
kasan-ensure-poisoning-size-alignment.patch
arm64-kasan-simplify-and-inline-mte-functions.patch
kasan-inline-hw_tags-helper-functions.patch
arm64-kasan-export-mte-symbols-for-kasan-tests.patch
kasan-clarify-that-only-first-bug-is-reported-in-hw_tags.patch


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