The patch titled
Subject: mm, kasan: instrument copy_from/to_kernel_nofault
has been added to the -mm mm-unstable branch. Its filename is
mm-instrument-copy_from-to_kernel_nofault.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-instrument-copy_from-to_kernel_nofault.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx>
Subject: mm, kasan: instrument copy_from/to_kernel_nofault
Date: Fri, 27 Sep 2024 20:14:38 +0500
Instrument copy_from_kernel_nofault(), copy_to_kernel_nofault() with
instrument_memcpy_before() for KASAN, KCSAN checks and
instrument_memcpy_after() for KMSAN.
Tested on x86_64 and arm64 with CONFIG_KASAN_SW_TAGS. On arm64 with
CONFIG_KASAN_HW_TAGS, kunit test currently fails. Need more clarification
on it - currently, disabled in kunit test.
Link: https://lkml.kernel.org/r/20240927151438.2143936-1-snovitoll@xxxxxxxxx
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx>
Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=210505
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kasan/kasan_test.c | 31 +++++++++++++++++++++++++++++++
mm/maccess.c | 8 ++++++--
2 files changed, 37 insertions(+), 2 deletions(-)
--- a/mm/kasan/kasan_test.c~mm-instrument-copy_from-to_kernel_nofault
+++ a/mm/kasan/kasan_test.c
@@ -1944,6 +1944,36 @@ static void match_all_mem_tag(struct kun
kfree(ptr);
}
+static void copy_from_to_kernel_nofault_oob(struct kunit *test)
+{
+ char *ptr;
+ char buf[128];
+ size_t size = sizeof(buf);
+
+ /* Not detecting fails currently with HW_TAGS */
+ KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_HW_TAGS);
+
+ ptr = kmalloc(size - KASAN_GRANULE_SIZE, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
+
+ if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) {
+ /* Check that the returned pointer is tagged. */
+ KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
+ KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+ }
+
+ KUNIT_EXPECT_KASAN_FAIL(test,
+ copy_from_kernel_nofault(&buf[0], ptr, size));
+ KUNIT_EXPECT_KASAN_FAIL(test,
+ copy_from_kernel_nofault(ptr, &buf[0], size));
+ KUNIT_EXPECT_KASAN_FAIL(test,
+ copy_to_kernel_nofault(&buf[0], ptr, size));
+ KUNIT_EXPECT_KASAN_FAIL(test,
+ copy_to_kernel_nofault(ptr, &buf[0], size));
+ kfree(ptr);
+}
+
static struct kunit_case kasan_kunit_test_cases[] = {
KUNIT_CASE(kmalloc_oob_right),
KUNIT_CASE(kmalloc_oob_left),
@@ -2017,6 +2047,7 @@ static struct kunit_case kasan_kunit_tes
KUNIT_CASE(match_all_not_assigned),
KUNIT_CASE(match_all_ptr_tag),
KUNIT_CASE(match_all_mem_tag),
+ KUNIT_CASE(copy_from_to_kernel_nofault_oob),
{}
};
--- a/mm/maccess.c~mm-instrument-copy_from-to_kernel_nofault
+++ a/mm/maccess.c
@@ -15,7 +15,7 @@ bool __weak copy_from_kernel_nofault_all
#define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \
while (len >= sizeof(type)) { \
- __get_kernel_nofault(dst, src, type, err_label); \
+ __get_kernel_nofault(dst, src, type, err_label); \
dst += sizeof(type); \
src += sizeof(type); \
len -= sizeof(type); \
@@ -32,6 +32,7 @@ long copy_from_kernel_nofault(void *dst,
return -ERANGE;
pagefault_disable();
+ instrument_memcpy_before(dst, src, size);
if (!(align & 7))
copy_from_kernel_nofault_loop(dst, src, size, u64, Efault);
if (!(align & 3))
@@ -39,6 +40,7 @@ long copy_from_kernel_nofault(void *dst,
if (!(align & 1))
copy_from_kernel_nofault_loop(dst, src, size, u16, Efault);
copy_from_kernel_nofault_loop(dst, src, size, u8, Efault);
+ instrument_memcpy_after(dst, src, size, 0);
pagefault_enable();
return 0;
Efault:
@@ -49,7 +51,7 @@ EXPORT_SYMBOL_GPL(copy_from_kernel_nofau
#define copy_to_kernel_nofault_loop(dst, src, len, type, err_label) \
while (len >= sizeof(type)) { \
- __put_kernel_nofault(dst, src, type, err_label); \
+ __put_kernel_nofault(dst, src, type, err_label); \
dst += sizeof(type); \
src += sizeof(type); \
len -= sizeof(type); \
@@ -63,6 +65,7 @@ long copy_to_kernel_nofault(void *dst, c
align = (unsigned long)dst | (unsigned long)src;
pagefault_disable();
+ instrument_memcpy_before(dst, src, size);
if (!(align & 7))
copy_to_kernel_nofault_loop(dst, src, size, u64, Efault);
if (!(align & 3))
@@ -70,6 +73,7 @@ long copy_to_kernel_nofault(void *dst, c
if (!(align & 1))
copy_to_kernel_nofault_loop(dst, src, size, u16, Efault);
copy_to_kernel_nofault_loop(dst, src, size, u8, Efault);
+ instrument_memcpy_after(dst, src, size, 0);
pagefault_enable();
return 0;
Efault:
_
Patches currently in -mm which might be from snovitoll@xxxxxxxxx are
mm-instrument-copy_from-to_kernel_nofault.patch
