Messages in this thread | | | Subject | Re: [RFC PATCH] ima: verify mprotect change is consistent with mmap policy | From | Mimi Zohar <> | Date | Tue, 05 May 2020 10:16:44 -0400 |
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Hi Jann,
On Tue, 2020-05-05 at 02:15 +0200, Jann Horn wrote: > On Mon, May 4, 2020 at 11:18 PM Mimi Zohar <zohar@linux.ibm.com> wrote: > > Files can be mmap'ed read/write and later changed to execute to circumvent > > IMA's mmap appraise policy rules. Due to locking issues (mmap semaphore > > would be taken prior to i_mutex), files can not be measured or appraised at > > this point. Eliminate this integrity gap, by denying the mprotect > > PROT_EXECUTE change, if an mmap appraise policy rule exists. > > Just keep in mind that there are other ways to create executable > mappings containing controlled code; e.g. PROT_EXEC with > MAP_ANONYMOUS, or writing to /proc/self/mem (which is a debugging API > that works entirely without ever making the VMA writable - I had an > old series to provide LSM hooks for that stuff at > <https://lore.kernel.org/lkml/1478142286-18427-3-git-send-email-jann@thejh.net/>, > but I guess I must have forgotten about it or something...).
Sure. These sound like memory attacks, which should be closed, but are probably out of scope for IMA.
thanks,
Mimi
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