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SubjectRe: [PATCH v4 00/10] Function Granular KASLR
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On 8/3/20 1:45 PM, Kees Cook wrote:
> On Mon, Aug 03, 2020 at 02:39:32PM +0300, Evgenii Shatokhin wrote:
>> There are at least 2 places where high-order memory allocations might happen
>> during module loading. Such allocations may fail if memory is fragmented,
>> while physically contiguous memory areas are not really needed there. I
>> suggest to switch to kvmalloc/kvfree there.
>
> While this does seem to be the right solution for the extant problem, I
> do want to take a moment and ask if the function sections need to be
> exposed at all? What tools use this information, and do they just want
> to see the bounds of the code region? (i.e. the start/end of all the
> .text* sections) Perhaps .text.* could be excluded from the sysfs
> section list?
>

[[cc += FChE, see [0] for Evgenii's full mail ]]

It looks like debugging tools like systemtap [1], gdb [2] and its
add-symbol-file cmd, etc. peek at the /sys/module/<MOD>/section/ info.

But yeah, it would be preferable if we didn't export a long sysfs
representation if nobody actually needs it.


[0]
https://lore.kernel.org/lkml/e9c4d88b-86db-47e9-4299-3fac45a7e3fd@virtuozzo.com/
[1] https://fossies.org/linux/systemtap/staprun/staprun.c
[2]
https://www.oreilly.com/library/view/linux-device-drivers/0596005903/ch04.html#linuxdrive3-CHP-4-SECT-6.1

-- Joe

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