| Message ID | 20210103171137.153834-1-lecopzer@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | arm64: kasan: support CONFIG_KASAN_VMALLOC | expand |
On Sun, Jan 3, 2021 at 6:12 PM Lecopzer Chen <lecopzer@gmail.com> wrote: > > Linux supports KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > ("kasan: support backing vmalloc space with real shadow memory") > > Acroding to how x86 ported it [1], they early allocated p4d and pgd, > but in arm64 I just simulate how KAsan supports MODULES_VADDR in arm64 > by not to populate the vmalloc area except for kimg address. > > Test environment: > 4G and 8G Qemu virt, > 39-bit VA + 4k PAGE_SIZE with 3-level page table, > test by lib/test_kasan.ko and lib/test_kasan_module.ko > > It also works in Kaslr with CONFIG_RANDOMIZE_MODULE_REGION_FULL, > but not test for HW_TAG(I have no proper device), thus keep > HW_TAG and KASAN_VMALLOC mutual exclusion until confirming > the functionality. > > > [1]: commit 0609ae011deb41c ("x86/kasan: support KASAN_VMALLOC") > > Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com> Hi Lecopzer, Thanks for working on this! Acked-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> for the series along with the other two patches minding the nit in patch #3. Will, Catalin, could you please take a look at the arm changes? Thanks!
On Sun, Jan 3, 2021 at 6:12 PM Lecopzer Chen <lecopzer@gmail.com> wrote: > > Linux supports KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > ("kasan: support backing vmalloc space with real shadow memory") > > Acroding to how x86 ported it [1], they early allocated p4d and pgd, > but in arm64 I just simulate how KAsan supports MODULES_VADDR in arm64 > by not to populate the vmalloc area except for kimg address. > > Test environment: > 4G and 8G Qemu virt, > 39-bit VA + 4k PAGE_SIZE with 3-level page table, > test by lib/test_kasan.ko and lib/test_kasan_module.ko > > It also works in Kaslr with CONFIG_RANDOMIZE_MODULE_REGION_FULL, > but not test for HW_TAG(I have no proper device), thus keep > HW_TAG and KASAN_VMALLOC mutual exclusion until confirming > the functionality. Re this: it makes sense to introduce vmalloc support one step a time and add SW_TAGS support before taking on HW_TAGS. SW_TAGS doesn't require any special hardware. Working on SW_TAGS first will also allow dealing with potential conflicts between vmalloc and tags without having MTE in the picture as well. Just FYI, no need to include that in this change.
On Fri, 8 Jan 2021 at 19:31, Andrey Konovalov <andreyknvl@google.com> wrote: > > On Sun, Jan 3, 2021 at 6:12 PM Lecopzer Chen <lecopzer@gmail.com> wrote: > > > > Linux supports KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > > ("kasan: support backing vmalloc space with real shadow memory") > > > > Acroding to how x86 ported it [1], they early allocated p4d and pgd, > > but in arm64 I just simulate how KAsan supports MODULES_VADDR in arm64 > > by not to populate the vmalloc area except for kimg address. > > > > Test environment: > > 4G and 8G Qemu virt, > > 39-bit VA + 4k PAGE_SIZE with 3-level page table, > > test by lib/test_kasan.ko and lib/test_kasan_module.ko > > > > It also works in Kaslr with CONFIG_RANDOMIZE_MODULE_REGION_FULL, > > but not test for HW_TAG(I have no proper device), thus keep > > HW_TAG and KASAN_VMALLOC mutual exclusion until confirming > > the functionality. > > > > > > [1]: commit 0609ae011deb41c ("x86/kasan: support KASAN_VMALLOC") > > > > Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com> > > Hi Lecopzer, > > Thanks for working on this! > > Acked-by: Andrey Konovalov <andreyknvl@google.com> > Tested-by: Andrey Konovalov <andreyknvl@google.com> > > for the series along with the other two patches minding the nit in patch #3. > > Will, Catalin, could you please take a look at the arm changes? > > Thanks! > If vmalloc can now be backed with real shadow memory, we no longer have to keep the module region in its default location when KASLR and KASAN are both enabled. So the check on line 164 in arch/arm64/kernel/kaslr.c should probably be updated to reflect this change.
Hi Andrey, > > On Sun, Jan 3, 2021 at 6:12 PM Lecopzer Chen <lecopzer@gmail.com> wrote: > > > > Linux supports KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > > ("kasan: support backing vmalloc space with real shadow memory") > > > > Acroding to how x86 ported it [1], they early allocated p4d and pgd, > > but in arm64 I just simulate how KAsan supports MODULES_VADDR in arm64 > > by not to populate the vmalloc area except for kimg address. > > > > Test environment: > > 4G and 8G Qemu virt, > > 39-bit VA + 4k PAGE_SIZE with 3-level page table, > > test by lib/test_kasan.ko and lib/test_kasan_module.ko > > > > It also works in Kaslr with CONFIG_RANDOMIZE_MODULE_REGION_FULL, > > but not test for HW_TAG(I have no proper device), thus keep > > HW_TAG and KASAN_VMALLOC mutual exclusion until confirming > > the functionality. > > Re this: it makes sense to introduce vmalloc support one step a time > and add SW_TAGS support before taking on HW_TAGS. SW_TAGS doesn't > require any special hardware. Working on SW_TAGS first will also allow > dealing with potential conflicts between vmalloc and tags without > having MTE in the picture as well. Just FYI, no need to include that > in this change. Thanks for the information and suggestion, so this serise I'll keep only for KASAN_GENERIC support :) BRs, Lecopzer
Hi Ard, > On Fri, 8 Jan 2021 at 19:31, Andrey Konovalov <andreyknvl@google.com> wrote: > > > > On Sun, Jan 3, 2021 at 6:12 PM Lecopzer Chen <lecopzer@gmail.com> wrote: > > > > > > Linux supports KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > > > ("kasan: support backing vmalloc space with real shadow memory") > > > > > > Acroding to how x86 ported it [1], they early allocated p4d and pgd, > > > but in arm64 I just simulate how KAsan supports MODULES_VADDR in arm64 > > > by not to populate the vmalloc area except for kimg address. > > > > > > Test environment: > > > 4G and 8G Qemu virt, > > > 39-bit VA + 4k PAGE_SIZE with 3-level page table, > > > test by lib/test_kasan.ko and lib/test_kasan_module.ko > > > > > > It also works in Kaslr with CONFIG_RANDOMIZE_MODULE_REGION_FULL, > > > but not test for HW_TAG(I have no proper device), thus keep > > > HW_TAG and KASAN_VMALLOC mutual exclusion until confirming > > > the functionality. > > > > > > > > > [1]: commit 0609ae011deb41c ("x86/kasan: support KASAN_VMALLOC") > > > > > > Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com> > > > > Hi Lecopzer, > > > > Thanks for working on this! > > > > Acked-by: Andrey Konovalov <andreyknvl@google.com> > > Tested-by: Andrey Konovalov <andreyknvl@google.com> > > > > for the series along with the other two patches minding the nit in patch #3. > > > > Will, Catalin, could you please take a look at the arm changes? > > > > Thanks! > > > > > If vmalloc can now be backed with real shadow memory, we no longer > have to keep the module region in its default location when KASLR and > KASAN are both enabled. > > So the check on line 164 in arch/arm64/kernel/kaslr.c should probably > be updated to reflect this change. > I've tested supporting module region randomized and It looks fine in some easy test(insmod some modules). I'll add this to patch v2, thanks for your suggestion. BRs, Lecopzer
Linux supports KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 ("kasan: support backing vmalloc space with real shadow memory") Acroding to how x86 ported it [1], they early allocated p4d and pgd, but in arm64 I just simulate how KAsan supports MODULES_VADDR in arm64 by not to populate the vmalloc area except for kimg address. Test environment: 4G and 8G Qemu virt, 39-bit VA + 4k PAGE_SIZE with 3-level page table, test by lib/test_kasan.ko and lib/test_kasan_module.ko It also works in Kaslr with CONFIG_RANDOMIZE_MODULE_REGION_FULL, but not test for HW_TAG(I have no proper device), thus keep HW_TAG and KASAN_VMALLOC mutual exclusion until confirming the functionality. [1]: commit 0609ae011deb41c ("x86/kasan: support KASAN_VMALLOC") Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com> Lecopzer Chen (3): arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC arm64: kasan: abstract _text and _end to KERNEL_START/END arm64: Kconfig: support CONFIG_KASAN_VMALLOC arch/arm64/Kconfig | 1 + arch/arm64/mm/kasan_init.c | 29 +++++++++++++++++++++-------- 2 files changed, 22 insertions(+), 8 deletions(-)