Commit 3ed86b9a authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Catalin Marinas

kasan, arm64: fix pointer tags in KASAN reports

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.

Fixes: dceec3ff ("arm64: expose FAR_EL1 tag bits in siginfo")
Fixes: 4291e9ee ("kasan, arm64: print report from tag fault handler")
Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://linux-review.googlesource.com/id/I9ced973866036d8679e8f4ae325de547eb969649
Link: https://lore.kernel.org/r/ff30b0afe6005fd046f9ac72bfb71822aedccd89.1610731872.git.andreyknvl@google.comSigned-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 3a57a643
...@@ -709,10 +709,11 @@ static int do_tag_check_fault(unsigned long far, unsigned int esr, ...@@ -709,10 +709,11 @@ static int do_tag_check_fault(unsigned long far, unsigned int esr,
struct pt_regs *regs) struct pt_regs *regs)
{ {
/* /*
* The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN for tag * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN
* check faults. Mask them out now so that userspace doesn't see them. * 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); do_bad_area(far, esr, regs);
return 0; return 0;
} }
......
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