Re: [PATCH 2/3] uprobes: Change valid_vma() to demand VM_MAYEXECrather than VM_EXEC

[Srikar Dronamraju]

* Oleg Nesterov <oleg@xxxxxxxxxx> [2012-09-16 19:52:46]:

> uprobe_register() or uprobe_mmap() requires VM_READ | VM_EXEC, this
> is not right. An apllication can do mprotect(PROT_EXEC) later and
> execute this code.
> 
> Change valid_vma(is_register => true) to check VM_MAYEXEC instead.
> No need to check VM_MAYREAD, it is always set.
> 
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>

> ---
>  kernel/events/uprobes.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index fa1579a..b9b50dd 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -106,8 +106,8 @@ static bool valid_vma(struct vm_area_struct *vma, bool is_register)
>  	if (!is_register)
>  		return true;
> 
> -	if ((vma->vm_flags & (VM_HUGETLB|VM_READ|VM_WRITE|VM_EXEC|VM_SHARED))
> -				== (VM_READ|VM_EXEC))
> +	if ((vma->vm_flags & (VM_HUGETLB | VM_WRITE | VM_MAYEXEC | VM_SHARED))
> +				== VM_MAYEXEC)
>  		return true;
> 
>  	return false;
> -- 
> 1.5.5.1
> 

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