Re: [PATCH ] powerpc/pkeys: Detach execute_only key on !PROT_EXEC
From: Thiago Jung Bauermann <hidden>
Date: 2018-05-22 01:42:40
Ram Pai [off-list ref] writes:
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.
cc: Shakeel Butt <redacted>
Reported-by: Shakeel Butt <redacted>
Fixes 5586cf6 ("powerpc: introduce execute-only pkey") ^
Missing a colon here.
quoted hunk ↗ jump to hunk
Signed-off-by: Ram Pai <redacted> --- arch/powerpc/mm/pkeys.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index e81d59e..fdeb9f5 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c@@ -425,9 +425,9 @@ 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; /*
I think I'm slow today. It took me a while to figure out why this is buggy. It will leave the VMA with the execute-only pkey if prot = 0. Other bit combinations work fine IIUC. Reviewed-by: Thiago Jung Bauermann <redacted> -- Thiago Jung Bauermann IBM Linux Technology Center