Messages in this thread | | | Date | Fri, 12 Jul 2019 23:17:03 +0200 (CEST) | From | Jakub Jankowski <> | Subject | Re: [PATCH] proc: Fix uninitialized byte read in get_mm_cmdline() |
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On 2019-07-12, Alexey Izbyshev wrote:
> On 7/12/19 8:46 PM, Alexey Dobriyan wrote: >> The proper fix to all /proc/*/cmdline problems is to revert >> >> f5b65348fd77839b50e79bc0a5e536832ea52d8d >> proc: fix missing final NUL in get_mm_cmdline() rewrite >> >> 5ab8271899658042fabc5ae7e6a99066a210bc0e >> fs/proc: simplify and clarify get_mm_cmdline() function >> > Should this be interpreted as an actual suggestion to revert the patches, > fix the conflicts, test and submit them, or is this more like thinking out > loud? In the former case, will it be OK for long term branches? > > get_mm_cmdline() does seem easier to read for me before 5ab8271899658042. > But it also has different semantics in corner cases, for example: > > - If there is no NUL at arg_end-1, it reads only the first string in > the combined arg/env block, and doesn't terminate it with NUL. > > - If there is any problem with access_remote_vm() or copy_to_user(), > it returns -EFAULT even if some data were copied to userspace. > > On the other hand, 5ab8271899658042 was merged not too long ago (about a year), > so it's possible that the current semantics isn't heavily relied upon.
I posted this (corner?) case ~3 months ago, unfortunately it wasn't picked up by anyone: https://lkml.org/lkml/2019/4/5/825 You can treat it as another datapoint in this discussion.
Regards, Jakub
-- Jakub Jankowski|shasta@toxcorp.com|https://toxcorp.com/
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