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Commit cd1231d7 authored by Madhavan Srinivasan's avatar Madhavan Srinivasan Committed by Michael Ellerman
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powerpc/perf: Prevent kernel address leak via perf_get_data_addr() 



Sampled Data Address Register (SDAR) is a 64-bit register that
contains the effective address of the storage operand of an
instruction that was being executed, possibly out-of-order, at or
around the time that the Performance Monitor alert occurred.

In certain scenario SDAR happen to contain the kernel address even for
userspace only sampling. Add checks to prevent it.

Signed-off-by: default avatarMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent bb19af81

arch/powerpc/perf/core-book3s.c

+4 −0
Original line number Diff line number Diff line
@@ -198,6 +198,10 @@ static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp) 


	if (!(mmcra & MMCRA_SAMPLE_ENABLE) || sdar_valid)

		*addrp = mfspr(SPRN_SDAR);



	if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN) &&

		is_kernel_addr(mfspr(SPRN_SDAR)))

		*addrp = 0;

}



static bool regs_sihv(struct pt_regs *regs)