From d129f31236c241c07e583e8bc695c382365d02ce Mon Sep 17 00:00:00 2001 From: Paolo 'Blaisorblade' Giarrusso Date: Sat, 10 Sep 2005 19:44:57 +0200 Subject: [PATCH] [PATCH] uml: fix fault handler on write The UML fault handler was recently changed to enforce PROT_NONE protections, by requiring VM_READ or VM_EXEC on VMA's. However, by mistake, things were changed such that VM_READ is always checked, also on write faults; so a VMA mapped with only PROT_WRITE is not readable (unless it's prefaulted with MAP_POPULATE or with a write), which is different from i386. Discovered while testing remap_file_pages protection support. Signed-off-by: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Linus Torvalds --- arch/um/kernel/trap_kern.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/um/kernel/trap_kern.c b/arch/um/kernel/trap_kern.c index b5fc89f..d20361d 100644 --- a/arch/um/kernel/trap_kern.c +++ b/arch/um/kernel/trap_kern.c @@ -57,7 +57,8 @@ good_area: if(is_write && !(vma->vm_flags & VM_WRITE)) goto out; - if(!(vma->vm_flags & (VM_READ | VM_EXEC))) + /* Don't require VM_READ|VM_EXEC for write faults! */ + if(!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC))) goto out; do { -- 1.8.2.3