Messages in this thread | | | Date | Tue, 17 Apr 2012 23:19:16 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [PATCH c/r -mm] c/r: prctl: Simplify PR_SET_MM on mm::code/data assignment |
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On Tue, Apr 17, 2012 at 11:22:06AM -0700, Kees Cook wrote: > On Mon, Apr 16, 2012 at 3:55 PM, Cyrill Gorcunov <gorcunov@openvz.org> wrote: > > The mm::start_code, end_code, start_data, end_data members > > are set during startup of executable file and are not changed > > after. > > > > But the program itself might map new executable or/and data areas in > > time so the original values written into mm fields mentioned above > > might not have correspond VMA area at all, thus if one try to > > use this prctl codes without underlied VMA, the error will be > > returned. > > > > Drop this requirement. This shrinks the code and eliminates > > redundant calls to vma_flags_mismatch. The worst thing one can > > do (if say to write some bad values here) -- the weird results > > will be shown in /proc/$pid/statm or in /proc/pid/stat. > > > > Still, assignement of data on stack (such as command line and > > environment variables) requires the underlied VMA to exist. > > > > Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> > > Since this is CAP_SYS_RESOURCE, and mmap_min_addr is CAP_SYS_RAWIO, > how about a lower-bounds check against mmap_min_addr? (We're already > doing the TASK_SIZE upper check, so this additional sanity checking > seems reasonable to me.)
I think this is good idea, thanks Kees. I'll check it out.
Cyrill
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