[patch 2/2] fs, proc: Introduce the /proc/<pid>/map_files/ directory v6

Vasiliy Kulikov segoon at openwall.com
Wed Aug 31 02:06:12 PDT 2011


Hi,

On Wed, Aug 31, 2011 at 11:58 +0400, Cyrill Gorcunov wrote:
> From: Pavel Emelyanov <xemul at parallels.com>
> 
> This one behaves similarly to the /proc/<pid>/fd/ one - it contains symlinks
> one for each mapping with file, the name of a symlink is "vma->vm_start-vma->vm_end",
> the target is the file. Opening a symlink results in a file that point exactly
> to the same inode as them vma's one.

I'm late noting it before the RFCv6 :)  Besides checking
ptrace_may_access() on ->lookup and ->readdir you also should define
->stat, otherwise you can bypass ptrace checks if there is a
corresponding dentry in the cache.  The same issue existed in fd* handlers:

http://www.openwall.com/lists/kernel-hardening/2011/08/29/1

Thanks,

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments


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