Commit 993c670a authored Feb 26, 2020 by Nicholas Piggin Committed by Michael Ellerman Apr 01, 2020

powerpc/64/syscall: Zero volatile registers when returning



Kernel addresses and potentially other sensitive data could be leaked
in volatile registers after a syscall.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200225173541.1549955-27-npiggin@gmail.com

parent 68b34588

arch/powerpc/kernel/entry_64.S

+13 −0

Original line number	Diff line number	Diff line
		@@ -141,6 +141,19 @@ END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)

		cmpdi r3,0
		bne .Lsyscall_restore_regs
		/* Zero volatile regs that may contain sensitive kernel data */
		li r0,0
		li r4,0
		li r5,0
		li r6,0
		li r7,0
		li r8,0
		li r9,0
		li r10,0
		li r11,0
		li r12,0
		mtctr r0
		mtspr SPRN_XER,r0
		.Lsyscall_restore_regs_cont:

		BEGIN_FTR_SECTION

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