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charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: EDC0A40017 X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: uiiy7csjhcspr78mtptr7954q5w8e9i4 X-HE-Tag: 1761768669-775863 X-HE-Meta: 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 dqCuevB8 iXPWFXwLua51YPtskdtKlXLZHpjSS24Al9HPJnHLWrhHSofXGeVFJoHWzdWC/1qcMWqc8jchGeBqFpt9IH0MHEYzEeL2Hbn9bDIrU54fGY5Gaf+SpK0tPUpUYOaIdnvULj2kM8W1gQBAzK8c4rNaOBjTUbI6VtoETiknWL+b2dTztAFxTj6ebVbQ6ByxPEJenMR96NeDPmFkMQb849Sm/8rFnogiOazAzu3OJ3X8+FzdV8TKIea0mxeGTXmj80cdOLwfaObwaCw9Y0b24xX2YEZCK30+cCnowOBBCnkkbBzE//lt5b+wiQM0/GBpYNyfQWOgTUJHNuSW9D0kUM1U/fzmQYZTzDkgUAbfY+cXbTiFuK1ZmxwtITySsTJQ6VbsGSTXzD6R5WM2sf+0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Maciej Wieczor-Retman While generally tag-based KASAN adopts an arithemitc bit shift to convert a memory address to a shadow memory address, it doesn't work for all cases on x86. Testing different shadow memory offsets proved that either 4 or 5 level paging didn't work correctly or inline mode ran into issues. Thus the best working scheme is the logical bit shift and non-canonical shadow offset that x86 uses for generic KASAN, of course adjusted for the increased granularity from 8 to 16 bytes. Add an arch specific implementation of kasan_mem_to_shadow() that uses the logical bit shift. The non-canonical hook tries to calculate whether an address came from kasan_mem_to_shadow(). First it checks whether this address fits into the legal set of values possible to output from the mem to shadow function. Tie both generic and tag-based x86 KASAN modes to the address range check associated with generic KASAN. Signed-off-by: Maciej Wieczor-Retman --- Changelog v4: - Add this patch to the series. arch/x86/include/asm/kasan.h | 7 +++++++ mm/kasan/report.c | 5 +++-- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kasan.h b/arch/x86/include/asm/kasan.h index 375651d9b114..2372397bc3e5 100644 --- a/arch/x86/include/asm/kasan.h +++ b/arch/x86/include/asm/kasan.h @@ -49,6 +49,13 @@ #include =20 #ifdef CONFIG_KASAN_SW_TAGS +static inline void *__kasan_mem_to_shadow(const void *addr) +{ +=09return (void *)((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT) +=09=09+ KASAN_SHADOW_OFFSET; +} + +#define kasan_mem_to_shadow(addr)=09__kasan_mem_to_shadow(addr) #define __tag_shifted(tag)=09=09FIELD_PREP(GENMASK_ULL(60, 57), tag) #define __tag_reset(addr)=09=09(sign_extend64((u64)(addr), 56)) #define __tag_get(addr)=09=09=09((u8)FIELD_GET(GENMASK_ULL(60, 57), (u64)a= ddr)) diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 50d487a0687a..fd8fe004b0c0 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -642,13 +642,14 @@ void kasan_non_canonical_hook(unsigned long addr) =09const char *bug_type; =20 =09/* -=09 * For Generic KASAN, kasan_mem_to_shadow() uses the logical right shif= t +=09 * For Generic KASAN and Software Tag-Based mode on the x86 +=09 * architecture, kasan_mem_to_shadow() uses the logical right shift =09 * and never overflows with the chosen KASAN_SHADOW_OFFSET values (on =09 * both x86 and arm64). Thus, the possible shadow addresses (even for =09 * bogus pointers) belong to a single contiguous region that is the =09 * result of kasan_mem_to_shadow() applied to the whole address space. =09 */ -=09if (IS_ENABLED(CONFIG_KASAN_GENERIC)) { +=09if (IS_ENABLED(CONFIG_KASAN_GENERIC) || IS_ENABLED(CONFIG_X86_64)) { =09=09if (addr < (unsigned long)kasan_mem_to_shadow((void *)(0UL)) || =09=09 addr > (unsigned long)kasan_mem_to_shadow((void *)(~0UL))) =09=09=09return; --=20 2.51.0