Add 3 new tests for tag-based KASAN modes:
1. Check that match-all pointer tag is not assigned randomly.
2. Check that 0xff works as a match-all pointer tag.
3. Check that there are no match-all memory tags.
Note, that test #3 causes a significant number (255) of KASAN reports
to be printed during execution for the SW_TAGS mode.
Signed-off-by: Andrey Konovalov <[email protected]>
Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
---
lib/test_kasan.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
mm/kasan/kasan.h | 6 ++++
2 files changed, 99 insertions(+)
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 46e578c8e842..f1eda0bcc780 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -13,6 +13,7 @@
#include <linux/mman.h>
#include <linux/module.h>
#include <linux/printk.h>
+#include <linux/random.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/uaccess.h>
@@ -790,6 +791,95 @@ static void vmalloc_oob(struct kunit *test)
vfree(area);
}
+/*
+ * Check that match-all pointer tag is not assigned randomly for
+ * tag-based modes.
+ */
+static void match_all_not_assigned(struct kunit *test)
+{
+ char *ptr;
+ struct page *pages;
+ int i, size, order;
+
+ for (i = 0; i < 256; i++) {
+ size = get_random_int() % KMALLOC_MAX_SIZE;
+ ptr = kmalloc(128, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+ kfree(ptr);
+ }
+
+ for (i = 0; i < 256; i++) {
+ order = get_random_int() % 4;
+ pages = alloc_pages(GFP_KERNEL, order);
+ ptr = page_address(pages);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+ free_pages((unsigned long)ptr, order);
+ }
+}
+
+/* Check that 0xff works as a match-all pointer tag for tag-based modes. */
+static void match_all_ptr_tag(struct kunit *test)
+{
+ char *ptr;
+ u8 tag;
+
+ if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+ kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
+ return;
+ }
+
+ ptr = kmalloc(128, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+
+ /* Backup the assigned tag. */
+ tag = get_tag(ptr);
+ KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL);
+
+ /* Reset the tag to 0xff.*/
+ ptr = set_tag(ptr, KASAN_TAG_KERNEL);
+
+ /* This access shouldn't trigger a KASAN report. */
+ *ptr = 0;
+
+ /* Recover the pointer tag and free. */
+ ptr = set_tag(ptr, tag);
+ kfree(ptr);
+}
+
+/* Check that there are no match-all memory tags for tag-based modes. */
+static void match_all_mem_tag(struct kunit *test)
+{
+ char *ptr;
+ int tag;
+
+ if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+ kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
+ return;
+ }
+
+ ptr = kmalloc(128, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+
+ /* For each possible tag value not matching the pointer tag. */
+ for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) {
+ if (tag == get_tag(ptr))
+ continue;
+
+ /* Mark the first memory granule with the chosen memory tag. */
+ kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag);
+
+ /* This access must cause a KASAN report. */
+ KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0);
+ }
+
+ /* Recover the memory tag and free. */
+ kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr));
+ kfree(ptr);
+}
+
static struct kunit_case kasan_kunit_test_cases[] = {
KUNIT_CASE(kmalloc_oob_right),
KUNIT_CASE(kmalloc_oob_left),
@@ -829,6 +919,9 @@ static struct kunit_case kasan_kunit_test_cases[] = {
KUNIT_CASE(kasan_bitops_tags),
KUNIT_CASE(kmalloc_double_kzfree),
KUNIT_CASE(vmalloc_oob),
+ KUNIT_CASE(match_all_not_assigned),
+ KUNIT_CASE(match_all_ptr_tag),
+ KUNIT_CASE(match_all_mem_tag),
{}
};
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 3b38baddec47..c3fb9bf241d3 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -36,6 +36,12 @@ extern bool kasan_flag_panic __ro_after_init;
#define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */
#define KASAN_TAG_MAX 0xFD /* maximum value for random tags */
+#ifdef CONFIG_KASAN_HW_TAGS
+#define KASAN_TAG_MIN 0xF0 /* mimimum value for random tags */
+#else
+#define KASAN_TAG_MIN 0x00 /* mimimum value for random tags */
+#endif
+
#ifdef CONFIG_KASAN_GENERIC
#define KASAN_FREE_PAGE 0xFF /* page was freed */
#define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */
--
2.29.2.729.g45daf8777d-goog
On Tue, Jan 05, 2021 at 07:27PM +0100, Andrey Konovalov wrote:
> Add 3 new tests for tag-based KASAN modes:
>
> 1. Check that match-all pointer tag is not assigned randomly.
> 2. Check that 0xff works as a match-all pointer tag.
> 3. Check that there are no match-all memory tags.
>
> Note, that test #3 causes a significant number (255) of KASAN reports
> to be printed during execution for the SW_TAGS mode.
>
> Signed-off-by: Andrey Konovalov <[email protected]>
> Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
> ---
> lib/test_kasan.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
> mm/kasan/kasan.h | 6 ++++
> 2 files changed, 99 insertions(+)
>
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index 46e578c8e842..f1eda0bcc780 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -13,6 +13,7 @@
> #include <linux/mman.h>
> #include <linux/module.h>
> #include <linux/printk.h>
> +#include <linux/random.h>
> #include <linux/slab.h>
> #include <linux/string.h>
> #include <linux/uaccess.h>
> @@ -790,6 +791,95 @@ static void vmalloc_oob(struct kunit *test)
> vfree(area);
> }
>
> +/*
> + * Check that match-all pointer tag is not assigned randomly for
> + * tag-based modes.
> + */
> +static void match_all_not_assigned(struct kunit *test)
> +{
> + char *ptr;
> + struct page *pages;
> + int i, size, order;
> +
> + for (i = 0; i < 256; i++) {
> + size = get_random_int() % KMALLOC_MAX_SIZE;
size appears to be unused?
> + ptr = kmalloc(128, GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> + kfree(ptr);
> + }
> +
> + for (i = 0; i < 256; i++) {
> + order = get_random_int() % 4;
> + pages = alloc_pages(GFP_KERNEL, order);
> + ptr = page_address(pages);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> + free_pages((unsigned long)ptr, order);
> + }
> +}
> +
> +/* Check that 0xff works as a match-all pointer tag for tag-based modes. */
> +static void match_all_ptr_tag(struct kunit *test)
> +{
> + char *ptr;
> + u8 tag;
> +
> + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
> + kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
> + return;
> + }
> +
> + ptr = kmalloc(128, GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> +
> + /* Backup the assigned tag. */
> + tag = get_tag(ptr);
> + KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL);
> +
> + /* Reset the tag to 0xff.*/
> + ptr = set_tag(ptr, KASAN_TAG_KERNEL);
> +
> + /* This access shouldn't trigger a KASAN report. */
> + *ptr = 0;
> +
> + /* Recover the pointer tag and free. */
> + ptr = set_tag(ptr, tag);
> + kfree(ptr);
> +}
> +
> +/* Check that there are no match-all memory tags for tag-based modes. */
> +static void match_all_mem_tag(struct kunit *test)
> +{
> + char *ptr;
> + int tag;
> +
> + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
> + kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
> + return;
> + }
> +
> + ptr = kmalloc(128, GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> +
> + /* For each possible tag value not matching the pointer tag. */
> + for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) {
> + if (tag == get_tag(ptr))
> + continue;
> +
> + /* Mark the first memory granule with the chosen memory tag. */
> + kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag);
> +
> + /* This access must cause a KASAN report. */
> + KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0);
> + }
> +
> + /* Recover the memory tag and free. */
> + kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr));
> + kfree(ptr);
> +}
> +
> static struct kunit_case kasan_kunit_test_cases[] = {
> KUNIT_CASE(kmalloc_oob_right),
> KUNIT_CASE(kmalloc_oob_left),
> @@ -829,6 +919,9 @@ static struct kunit_case kasan_kunit_test_cases[] = {
> KUNIT_CASE(kasan_bitops_tags),
> KUNIT_CASE(kmalloc_double_kzfree),
> KUNIT_CASE(vmalloc_oob),
> + KUNIT_CASE(match_all_not_assigned),
> + KUNIT_CASE(match_all_ptr_tag),
> + KUNIT_CASE(match_all_mem_tag),
> {}
> };
>
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 3b38baddec47..c3fb9bf241d3 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -36,6 +36,12 @@ extern bool kasan_flag_panic __ro_after_init;
> #define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */
> #define KASAN_TAG_MAX 0xFD /* maximum value for random tags */
>
> +#ifdef CONFIG_KASAN_HW_TAGS
> +#define KASAN_TAG_MIN 0xF0 /* mimimum value for random tags */
> +#else
> +#define KASAN_TAG_MIN 0x00 /* mimimum value for random tags */
> +#endif
> +
> #ifdef CONFIG_KASAN_GENERIC
> #define KASAN_FREE_PAGE 0xFF /* page was freed */
> #define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */
> --
> 2.29.2.729.g45daf8777d-goog
>
On Tue, Jan 12, 2021 at 2:17 PM Marco Elver <[email protected]> wrote:
>
> On Tue, Jan 05, 2021 at 07:27PM +0100, Andrey Konovalov wrote:
> > Add 3 new tests for tag-based KASAN modes:
> >
> > 1. Check that match-all pointer tag is not assigned randomly.
> > 2. Check that 0xff works as a match-all pointer tag.
> > 3. Check that there are no match-all memory tags.
> >
> > Note, that test #3 causes a significant number (255) of KASAN reports
> > to be printed during execution for the SW_TAGS mode.
> >
> > Signed-off-by: Andrey Konovalov <[email protected]>
> > Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
> > ---
> > lib/test_kasan.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
> > mm/kasan/kasan.h | 6 ++++
> > 2 files changed, 99 insertions(+)
> >
> > diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> > index 46e578c8e842..f1eda0bcc780 100644
> > --- a/lib/test_kasan.c
> > +++ b/lib/test_kasan.c
> > @@ -13,6 +13,7 @@
> > #include <linux/mman.h>
> > #include <linux/module.h>
> > #include <linux/printk.h>
> > +#include <linux/random.h>
> > #include <linux/slab.h>
> > #include <linux/string.h>
> > #include <linux/uaccess.h>
> > @@ -790,6 +791,95 @@ static void vmalloc_oob(struct kunit *test)
> > vfree(area);
> > }
> >
> > +/*
> > + * Check that match-all pointer tag is not assigned randomly for
> > + * tag-based modes.
> > + */
> > +static void match_all_not_assigned(struct kunit *test)
> > +{
> > + char *ptr;
> > + struct page *pages;
> > + int i, size, order;
> > +
> > + for (i = 0; i < 256; i++) {
> > + size = get_random_int() % KMALLOC_MAX_SIZE;
>
> size appears to be unused?
Indeed, will fix in v2, thanks!
>
> > + ptr = kmalloc(128, GFP_KERNEL);
> > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> > + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> > + kfree(ptr);
> > + }
> > +
> > + for (i = 0; i < 256; i++) {
> > + order = get_random_int() % 4;
> > + pages = alloc_pages(GFP_KERNEL, order);
> > + ptr = page_address(pages);
> > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> > + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> > + free_pages((unsigned long)ptr, order);
> > + }
> > +}
> > +
> > +/* Check that 0xff works as a match-all pointer tag for tag-based modes. */
> > +static void match_all_ptr_tag(struct kunit *test)
> > +{
> > + char *ptr;
> > + u8 tag;
> > +
> > + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
> > + kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
> > + return;
> > + }
> > +
> > + ptr = kmalloc(128, GFP_KERNEL);
> > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> > +
> > + /* Backup the assigned tag. */
> > + tag = get_tag(ptr);
> > + KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL);
> > +
> > + /* Reset the tag to 0xff.*/
> > + ptr = set_tag(ptr, KASAN_TAG_KERNEL);
> > +
> > + /* This access shouldn't trigger a KASAN report. */
> > + *ptr = 0;
> > +
> > + /* Recover the pointer tag and free. */
> > + ptr = set_tag(ptr, tag);
> > + kfree(ptr);
> > +}
> > +
> > +/* Check that there are no match-all memory tags for tag-based modes. */
> > +static void match_all_mem_tag(struct kunit *test)
> > +{
> > + char *ptr;
> > + int tag;
> > +
> > + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
> > + kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
> > + return;
> > + }
> > +
> > + ptr = kmalloc(128, GFP_KERNEL);
> > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> > + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
> > +
> > + /* For each possible tag value not matching the pointer tag. */
> > + for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) {
> > + if (tag == get_tag(ptr))
> > + continue;
> > +
> > + /* Mark the first memory granule with the chosen memory tag. */
> > + kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag);
> > +
> > + /* This access must cause a KASAN report. */
> > + KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0);
> > + }
> > +
> > + /* Recover the memory tag and free. */
> > + kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr));
> > + kfree(ptr);
> > +}
> > +
> > static struct kunit_case kasan_kunit_test_cases[] = {
> > KUNIT_CASE(kmalloc_oob_right),
> > KUNIT_CASE(kmalloc_oob_left),
> > @@ -829,6 +919,9 @@ static struct kunit_case kasan_kunit_test_cases[] = {
> > KUNIT_CASE(kasan_bitops_tags),
> > KUNIT_CASE(kmalloc_double_kzfree),
> > KUNIT_CASE(vmalloc_oob),
> > + KUNIT_CASE(match_all_not_assigned),
> > + KUNIT_CASE(match_all_ptr_tag),
> > + KUNIT_CASE(match_all_mem_tag),
> > {}
> > };
> >
> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> > index 3b38baddec47..c3fb9bf241d3 100644
> > --- a/mm/kasan/kasan.h
> > +++ b/mm/kasan/kasan.h
> > @@ -36,6 +36,12 @@ extern bool kasan_flag_panic __ro_after_init;
> > #define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */
> > #define KASAN_TAG_MAX 0xFD /* maximum value for random tags */
> >
> > +#ifdef CONFIG_KASAN_HW_TAGS
> > +#define KASAN_TAG_MIN 0xF0 /* mimimum value for random tags */
> > +#else
> > +#define KASAN_TAG_MIN 0x00 /* mimimum value for random tags */
> > +#endif
> > +
> > #ifdef CONFIG_KASAN_GENERIC
> > #define KASAN_FREE_PAGE 0xFF /* page was freed */
> > #define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */
> > --
> > 2.29.2.729.g45daf8777d-goog
> >
On Tue, Jan 5, 2021 at 7:28 PM Andrey Konovalov <[email protected]> wrote:
>
> Add 3 new tests for tag-based KASAN modes:
>
> 1. Check that match-all pointer tag is not assigned randomly.
> 2. Check that 0xff works as a match-all pointer tag.
> 3. Check that there are no match-all memory tags.
>
> Note, that test #3 causes a significant number (255) of KASAN reports
> to be printed during execution for the SW_TAGS mode.
>
> Signed-off-by: Andrey Konovalov <[email protected]>
> Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
> ---
> lib/test_kasan.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
> mm/kasan/kasan.h | 6 ++++
> 2 files changed, 99 insertions(+)
>
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index 46e578c8e842..f1eda0bcc780 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -13,6 +13,7 @@
> #include <linux/mman.h>
> #include <linux/module.h>
> #include <linux/printk.h>
> +#include <linux/random.h>
> #include <linux/slab.h>
> #include <linux/string.h>
> #include <linux/uaccess.h>
> @@ -790,6 +791,95 @@ static void vmalloc_oob(struct kunit *test)
> vfree(area);
> }
>
> +/*
> + * Check that match-all pointer tag is not assigned randomly for
> + * tag-based modes.
> + */
> +static void match_all_not_assigned(struct kunit *test)
> +{
Do we want to run this test in non-tag-based modes? Probably not?
On Tue, Jan 12, 2021 at 9:05 AM Alexander Potapenko <[email protected]> wrote:
>
> On Tue, Jan 5, 2021 at 7:28 PM Andrey Konovalov <[email protected]> wrote:
> >
> > Add 3 new tests for tag-based KASAN modes:
> >
> > 1. Check that match-all pointer tag is not assigned randomly.
> > 2. Check that 0xff works as a match-all pointer tag.
> > 3. Check that there are no match-all memory tags.
> >
> > Note, that test #3 causes a significant number (255) of KASAN reports
> > to be printed during execution for the SW_TAGS mode.
> >
> > Signed-off-by: Andrey Konovalov <[email protected]>
> > Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
> > ---
> > lib/test_kasan.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
> > mm/kasan/kasan.h | 6 ++++
> > 2 files changed, 99 insertions(+)
> >
> > diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> > index 46e578c8e842..f1eda0bcc780 100644
> > --- a/lib/test_kasan.c
> > +++ b/lib/test_kasan.c
> > @@ -13,6 +13,7 @@
> > #include <linux/mman.h>
> > #include <linux/module.h>
> > #include <linux/printk.h>
> > +#include <linux/random.h>
> > #include <linux/slab.h>
> > #include <linux/string.h>
> > #include <linux/uaccess.h>
> > @@ -790,6 +791,95 @@ static void vmalloc_oob(struct kunit *test)
> > vfree(area);
> > }
> >
> > +/*
> > + * Check that match-all pointer tag is not assigned randomly for
> > + * tag-based modes.
> > + */
> > +static void match_all_not_assigned(struct kunit *test)
> > +{
>
> Do we want to run this test in non-tag-based modes? Probably not?
Will fix in v2, thanks!