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From: Florian Weimer <fweimer@redhat.com>
To: Joel Molin via Libc-help <libc-help@sourceware.org>
Cc: Joel Molin <joelmolin@gmail.com>
Subject: Re: Why does _dl_protect_relro align the end address down?
Date: Tue, 17 Jan 2023 08:57:38 +0100	[thread overview]
Message-ID: <87zgah7fv1.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <CACXmTyJ7qtzNVBGBOn5bgsvV0VQZEquiP+5tMqAdxXxp3H48xg@mail.gmail.com> (Joel Molin via Libc-help's message of "Mon, 16 Jan 2023 13:26:28 -0800")

* Joel Molin via Libc-help:

> Since mprotect will protect entire pages anyway, wouldn't it make a lot
> more sense here to say `end = ALIGN_UP(...)`? Apart from feeling more
> intuitive, it also seems like it would avoid page size inconsistencies
> between runtime and link editing like the one above.

ALIGN_UP might make memory read-only that should not be.

There's some discussion about the alignment here:

  PT_GNU_RELRO is somewhat broken
  <https://sourceware.org/pipermail/libc-alpha/2022-May/138638.html>

I still think this is fairly broken, but there does not seem to be much
desire to fix it.

Thanks,
Florian


  reply	other threads:[~2023-01-17  7:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-16 21:26 Joel Molin
2023-01-17  7:57 ` Florian Weimer [this message]
2023-01-17 14:11   ` Adhemerval Zanella Netto
2023-01-17 14:16     ` Florian Weimer
2023-01-17 14:30       ` Adhemerval Zanella Netto
2023-01-17 15:48         ` H.J. Lu
2023-01-17 15:56           ` Joel Molin

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