From: Sergey Bugaev <bugaevc@gmail.com>
To: Siddhesh Poyarekar <siddhesh@gotplt.org>
Cc: libc-alpha@sourceware.org
Subject: Re: [RFC PATCH 1/1] io: Add FORTIFY_SOURCE check for fcntl arguments
Date: Tue, 23 May 2023 23:01:23 +0300 [thread overview]
Message-ID: <CAN9u=HcwrjrTSgrdfON_eDpo0wtPmX1M5OHcHLkV6CUK+3neOw@mail.gmail.com> (raw)
In-Reply-To: <be0c6485-b43a-256e-41f9-71181a0b17b1@gotplt.org>
Hello,
On Tue, May 23, 2023 at 10:15 PM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
> *_chk but I don't want to block this good work on that. The overall
> direction is good IMO
Yay, thanks!
> - manual/contrib.texi should be updated to mention fcntl
Do you mean manual/maint.texi? manual/contrib.texi seems to contain a
list of contributors.
> - Internal users end up calling __libc_fcntl (see dup2.c or grantpt.c
> for example), which will essentially bypass any fortification. This is
> not a problem today since we don't build glibc with fortification, but
> Frederic Berat[1] has been experimenting with that and we're hoping to
> get at least a subset of glibc fortified for 2.38. It would be a shame
> to miss fortifying glibc itself. This is again not a problem that would
> block this patch, but something to be aware of.
Yes, I've thought of this, but I don't know what I could change in
this patch to make it friendlier to in-glibc fortification. I've
generally done things the same way as the open* fortification does; so
I don't think this would be adding any new complications compared to
what's already in there.
> Given that this will error out at compile time, do we even need this
> __fcntl64_2 call?
Same as for the open* fortification: this call will only fail at
compile time if the cmd is a compile-time constant. If it's not (which
is a rare, but valid case), we need to do the check at runtime. Note
that if cmd _is_ a compile-time constant and does not require the 3rd
arg, this will call the regular fcntl, not the _2 version; the _2
version is only for non-compile-time-const cmd-s.
Sergey
next prev parent reply other threads:[~2023-05-23 20:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-19 21:30 [RFC PATCH 0/1] Attempt to detect missing fcntl argument at compile time Sergey Bugaev
2023-05-19 21:30 ` [RFC PATCH 1/1] io: Add FORTIFY_SOURCE check for fcntl arguments Sergey Bugaev
2023-05-19 21:55 ` Joseph Myers
2023-05-20 11:46 ` Sergey Bugaev
2023-05-20 18:21 ` [RFC PATCH] debug: Add tests for fortified fcntl () Sergey Bugaev
2023-05-23 18:40 ` Adhemerval Zanella Netto
2023-05-23 19:19 ` Sergey Bugaev
2023-05-23 19:48 ` Adhemerval Zanella Netto
2023-05-24 7:15 ` Sergey Bugaev
2023-05-24 12:15 ` Adhemerval Zanella Netto
2023-05-23 19:09 ` [RFC PATCH 1/1] io: Add FORTIFY_SOURCE check for fcntl arguments Adhemerval Zanella Netto
2023-05-23 19:43 ` Sergey Bugaev
2023-05-23 19:56 ` Adhemerval Zanella Netto
2023-05-23 20:24 ` Sergey Bugaev
2023-05-23 20:44 ` Sergey Bugaev
2023-05-24 12:04 ` Adhemerval Zanella Netto
2023-05-23 19:15 ` Siddhesh Poyarekar
2023-05-23 20:01 ` Sergey Bugaev [this message]
2023-05-23 20:06 ` Sergey Bugaev
2023-05-23 21:46 ` Florian Weimer
2023-05-24 7:31 ` Sergey Bugaev
2023-05-24 8:29 ` Florian Weimer
2023-05-24 10:51 ` Sergey Bugaev
2023-05-24 11:18 ` Florian Weimer
2023-05-24 11:46 ` Siddhesh Poyarekar
2023-05-24 12:12 ` Andreas Schwab
2023-05-24 12:18 ` Florian Weimer
2023-05-24 12:37 ` Sergey Bugaev
2023-05-24 12:45 ` Florian Weimer
2023-05-24 13:02 ` Sergey Bugaev
2023-05-24 13:18 ` Florian Weimer
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