Commit eabdb8ca authored May 04, 2018 by Ram Pai Committed by Michael Ellerman Jun 05, 2018

powerpc/pkeys: Detach execute_only key on !PROT_EXEC



Disassociate the exec_key from a VMA if the VMA permission is not
PROT_EXEC anymore. Otherwise the exec_only key continues to be
associated with the vma, causing unexpected behavior.

The problem was reported on x86 by Shakeel Butt, which is also
applicable on powerpc.

Fixes: 5586cf61 ("powerpc: introduce execute-only pkey")
Cc: stable@vger.kernel.org # v4.16+
Reported-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

parent 75743649

arch/powerpc/mm/pkeys.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -383,9 +383,9 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot,
		{
		/*
		* If the currently associated pkey is execute-only, but the requested
		* protection requires read or write, move it back to the default pkey.
		* protection is not execute-only, move it back to the default pkey.
		*/
		if (vma_is_pkey_exec_only(vma) && (prot & (PROT_READ \| PROT_WRITE)))
		if (vma_is_pkey_exec_only(vma) && (prot != PROT_EXEC))
		return 0;

		/*