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    SubjectRe: [RFC][PATCH 11/11] security: AppArmor - Export namespace semaphore
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    On Thu, 2006-04-20 at 15:11 -0700, Linda A. Walsh wrote:
    > The *current* accepted way to get pathnames going into system
    > calls is to trap the syscall vector as audit currently does --
    > a method subject to race conditions. There is no way to implement
    > pathname-based security (or auditing) without providing hooks
    > in each of the relevant system calls after they have copied their
    > arguments from user space, safely into kernel space. Decoding
    > the arguments (including copying them from user space) twice allows
    > for a window during which the user-space arguments can still be
    > changed by a user-level process. You can't copy the arguments from
    > userspace, twice, and expect that the userspace memory will be
    > remain the same between the two "copies".

    They aren't being copied twice. Look at getname() in fs/namei.c, and
    note the call to audit_getname(). The native Linux 2.6 audit framework
    combines processing at entry/exit with certain hooks placed at key
    locations to collect the necessary information, without requiring the
    degree of invasiveness of the SGI CAPP auditing patches of long ago.

    --
    Stephen Smalley
    National Security Agency

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