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arm64: Don't walk page table for user faults in do_mem_abort 

Commit 42dbf54e88 ("arm64: consistently log ESR and page table")
dumps page table entries for user faults hitting do_bad entries in the
fault handler table. Whilst this shouldn't really happen in practice,
it's not beyond the realms of possibility if e.g. running an old kernel
on a new CPU.

Generally, we want to avoid exposing physical addresses under the control
of userspace (see commit bf396c09c2 ("arm64: mm: don't print out page
table entries on EL0 faults")), so walk the page tables only on exceptions
from EL1.

Reported-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2017-10-31 15:56:11 +00:00
parent c80ed088a5
commit 80b6eb04b5
1 changed files with 2 additions and 1 deletions
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3
arch/arm64/mm/fault.c
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@ -698,7 +698,8 @@ asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
mem_abort_decode(esr);
show_pte(addr);
if (!user_mode(regs))
show_pte(addr);
info.si_signo = inf->sig;
info.si_errno = 0;