| Message ID | 20190819161449.30248-1-mark.rutland@arm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [PATCHv2] lib/test_kasan: add roundtrip tests | expand |
On 8/19/19 7:14 PM, Mark Rutland wrote: > In several places we need to be able to operate on pointers which have > gone via a roundtrip: > > virt -> {phys,page} -> virt > > With KASAN_SW_TAGS, we can't preserve the tag for SLUB objects, and the > {phys,page} -> virt conversion will use KASAN_TAG_KERNEL. > > This patch adds tests to ensure that this works as expected, without > false positives which have recently been spotted [1,2] in testing. > > [1] https://lore.kernel.org/linux-arm-kernel/20190819114420.2535-1-walter-zh.wu@mediatek.com/ > [2] https://lore.kernel.org/linux-arm-kernel/20190819132347.GB9927@lakrids.cambridge.arm.com/ > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Reviewed-by: Andrey Konovalov <andreyknvl@google.com> > Tested-by: Andrey Konovalov <andreyknvl@google.com> > Cc: Alexander Potapenko <glider@google.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> > Cc: Dmitry Vyukov <dvyukov@google.com> > Cc: Will Deacon <will.deacon@arm.com> > --- Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
On Mon, 19 Aug 2019 17:14:49 +0100 Mark Rutland <mark.rutland@arm.com> wrote: > In several places we need to be able to operate on pointers which have > gone via a roundtrip: > > virt -> {phys,page} -> virt > > With KASAN_SW_TAGS, we can't preserve the tag for SLUB objects, and the > {phys,page} -> virt conversion will use KASAN_TAG_KERNEL. > > This patch adds tests to ensure that this works as expected, without > false positives which have recently been spotted [1,2] in testing. > > [1] https://lore.kernel.org/linux-arm-kernel/20190819114420.2535-1-walter-zh.wu@mediatek.com/ > [2] https://lore.kernel.org/linux-arm-kernel/20190819132347.GB9927@lakrids.cambridge.arm.com/ > > > ... > The only change I'm seeing from v1 is: --- a/lib/test_kasan.c~lib-test_kasan-add-roundtrip-tests-v2 +++ a/lib/test_kasan.c @@ -19,7 +19,6 @@ #include <linux/string.h> #include <linux/uaccess.h> -#include <asm/io.h> #include <asm/page.h> /* which is really kinda wrong. We should strictly include linux/io.h for things like virt_to_phys(). So I think I'll stick with v1 plus my fixlet: --- a/lib/test_kasan.c~lib-test_kasan-add-roundtrip-tests-checkpatch-fixes +++ a/lib/test_kasan.c @@ -18,8 +18,8 @@ #include <linux/slab.h> #include <linux/string.h> #include <linux/uaccess.h> +#include <linux/io.h> -#include <asm/io.h> #include <asm/page.h> /* > Since v1: > * Spin as a separate patch > * Fix typo > * Note examples in commit message. So I'm not sure what happened to these things. Did you send the correct patch?
Hi Andrew, On Thu, Aug 22, 2019 at 04:48:57PM -0700, Andrew Morton wrote: > On Mon, 19 Aug 2019 17:14:49 +0100 Mark Rutland <mark.rutland@arm.com> wrote: > > > In several places we need to be able to operate on pointers which have > > gone via a roundtrip: > > > > virt -> {phys,page} -> virt > > > > With KASAN_SW_TAGS, we can't preserve the tag for SLUB objects, and the > > {phys,page} -> virt conversion will use KASAN_TAG_KERNEL. > > > > This patch adds tests to ensure that this works as expected, without > > false positives which have recently been spotted [1,2] in testing. > > > > [1] https://lore.kernel.org/linux-arm-kernel/20190819114420.2535-1-walter-zh.wu@mediatek.com/ > > [2] https://lore.kernel.org/linux-arm-kernel/20190819132347.GB9927@lakrids.cambridge.arm.com/ > > > > > > ... > > > > The only change I'm seeing from v1 is: > > --- a/lib/test_kasan.c~lib-test_kasan-add-roundtrip-tests-v2 > +++ a/lib/test_kasan.c > @@ -19,7 +19,6 @@ > #include <linux/string.h> > #include <linux/uaccess.h> > > -#include <asm/io.h> > #include <asm/page.h> I think you've confused v1 with v3 (which was the first version to include <asm/io.h>). v1: https://lore.kernel.org/linux-arm-kernel/20190819150341.GC9927@lakrids.cambridge.arm.com/ v3: https://lore.kernel.org/linux-arm-kernel/20190819150341.GC9927@lakrids.cambridge.arm.com/ I guess as v1 was part of a reply (without the mail subject matching) that might have confused things? Sorry about that if so! > > /* > > which is really kinda wrong. We should strictly include linux/io.h for > things like virt_to_phys(). > > So I think I'll stick with v1 plus my fixlet: > > --- a/lib/test_kasan.c~lib-test_kasan-add-roundtrip-tests-checkpatch-fixes > +++ a/lib/test_kasan.c > @@ -18,8 +18,8 @@ > #include <linux/slab.h> > #include <linux/string.h> > #include <linux/uaccess.h> > +#include <linux/io.h> > > -#include <asm/io.h> > #include <asm/page.h> > > /* > Assuming that you mean *v3* with that fix, that looks good to me! Thanks, Mark.
On Fri, 23 Aug 2019 11:41:08 +0100 Mark Rutland <mark.rutland@arm.com> wrote: > > > > /* > > > > which is really kinda wrong. We should strictly include linux/io.h for > > things like virt_to_phys(). > > > > So I think I'll stick with v1 plus my fixlet: > > > > --- a/lib/test_kasan.c~lib-test_kasan-add-roundtrip-tests-checkpatch-fixes > > +++ a/lib/test_kasan.c > > @@ -18,8 +18,8 @@ > > #include <linux/slab.h> > > #include <linux/string.h> > > #include <linux/uaccess.h> > > +#include <linux/io.h> > > > > -#include <asm/io.h> > > #include <asm/page.h> > > > > /* > > > > Assuming that you mean *v3* with that fix, that looks good to me! Yes, that's what we have.
diff --git a/lib/test_kasan.c b/lib/test_kasan.c index b63b367a94e8..cf7b93f0d90c 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -19,6 +19,8 @@ #include <linux/string.h> #include <linux/uaccess.h> +#include <asm/page.h> + /* * Note: test functions are marked noinline so that their names appear in * reports. @@ -337,6 +339,42 @@ static noinline void __init kmalloc_uaf2(void) kfree(ptr2); } +static noinline void __init kfree_via_page(void) +{ + char *ptr; + size_t size = 8; + struct page *page; + unsigned long offset; + + pr_info("invalid-free false positive (via page)\n"); + ptr = kmalloc(size, GFP_KERNEL); + if (!ptr) { + pr_err("Allocation failed\n"); + return; + } + + page = virt_to_page(ptr); + offset = offset_in_page(ptr); + kfree(page_address(page) + offset); +} + +static noinline void __init kfree_via_phys(void) +{ + char *ptr; + size_t size = 8; + phys_addr_t phys; + + pr_info("invalid-free false positive (via phys)\n"); + ptr = kmalloc(size, GFP_KERNEL); + if (!ptr) { + pr_err("Allocation failed\n"); + return; + } + + phys = virt_to_phys(ptr); + kfree(phys_to_virt(phys)); +} + static noinline void __init kmem_cache_oob(void) { char *p; @@ -737,6 +775,8 @@ static int __init kmalloc_tests_init(void) kmalloc_uaf(); kmalloc_uaf_memset(); kmalloc_uaf2(); + kfree_via_page(); + kfree_via_phys(); kmem_cache_oob(); memcg_accounted_kmem_cache(); kasan_stack_oob();
In several places we need to be able to operate on pointers which have gone via a roundtrip: virt -> {phys,page} -> virt With KASAN_SW_TAGS, we can't preserve the tag for SLUB objects, and the {phys,page} -> virt conversion will use KASAN_TAG_KERNEL. This patch adds tests to ensure that this works as expected, without false positives which have recently been spotted [1,2] in testing. [1] https://lore.kernel.org/linux-arm-kernel/20190819114420.2535-1-walter-zh.wu@mediatek.com/ [2] https://lore.kernel.org/linux-arm-kernel/20190819132347.GB9927@lakrids.cambridge.arm.com/ Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Will Deacon <will.deacon@arm.com> --- lib/test_kasan.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) Since v1: * Spin as a separate patch * Fix typo * Note examples in commit message. Mark. -- 2.11.0