luck/tmp_suning_uos_patched
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[PATCH] uml: fix fault handler on write

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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 <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Paolo 'Blaisorblade' Giarrusso 2005-09-10 19:44:57 +02:00 committed by Linus Torvalds
parent d99c4022f6
commit d129f31236
1 changed files with 2 additions and 1 deletions
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3
arch/um/kernel/trap_kern.c
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@ -57,7 +57,8 @@ int handle_page_fault(unsigned long address, unsigned long ip,
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 {