From: Andrey Konovalov <andreyknvl@google.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>
Cc: Will Deacon <will.deacon@arm.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Peter Collingbourne <pcc@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v3 2/2] kasan, arm64: fix pointer tags in KASAN reports
Date: Fri, 15 Jan 2021 18:41:53 +0100 [thread overview]
Message-ID: <ff30b0afe6005fd046f9ac72bfb71822aedccd89.1610731872.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1610731872.git.andreyknvl@google.com>
As of the "arm64: expose FAR_EL1 tag bits in siginfo" patch, the address
that is passed to report_tag_fault has pointer tags in the format of 0x0X,
while KASAN uses 0xFX format (note the difference in the top 4 bits).
Fix up the pointer tag for kernel pointers in do_tag_check_fault by
setting them to the same value as bit 55. Explicitly use __untagged_addr()
instead of untagged_addr(), as the latter doesn't affect TTBR1 addresses.
Link: https://linux-review.googlesource.com/id/I9ced973866036d8679e8f4ae325de547eb969649
Fixes: dceec3ff7807 ("arm64: expose FAR_EL1 tag bits in siginfo")
Fixes: 4291e9ee6189 ("kasan, arm64: print report from tag fault handler")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
arch/arm64/mm/fault.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 3c40da479899..35d75c60e2b8 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -709,10 +709,11 @@ static int do_tag_check_fault(unsigned long far, unsigned int esr,
struct pt_regs *regs)
{
/*
- * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN for tag
- * check faults. Mask them out now so that userspace doesn't see them.
+ * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN
+ * for tag check faults. Set them to corresponding bits in the untagged
+ * address.
*/
- far &= (1UL << 60) - 1;
+ far = (__untagged_addr(far) & ~MTE_TAG_MASK) | (far & MTE_TAG_MASK);
do_bad_area(far, esr, regs);
return 0;
}
--
2.30.0.284.gd98b1dd5eaa7-goog
next prev parent reply other threads:[~2021-01-15 17:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-15 17:41 [PATCH v3 0/2] kasan: fixes for 5.11-rc Andrey Konovalov
2021-01-15 17:41 ` [PATCH v3 1/2] kasan, mm: fix conflicts with init_on_alloc/free Andrey Konovalov
2021-01-15 17:41 ` Andrey Konovalov [this message]
2021-01-15 17:59 ` [PATCH v3 2/2] kasan, arm64: fix pointer tags in KASAN reports Catalin Marinas
2021-01-15 18:08 ` Andrey Konovalov
2021-01-15 18:03 ` Vincenzo Frascino
2021-01-18 18:31 ` [PATCH v3 0/2] kasan: fixes for 5.11-rc Catalin Marinas
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