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From: Florian Weimer <fw@deneb.enyo.de>
To: Rich Felker <dalias@libc.org>
Cc: musl@lists.openwall.com
Subject: Re: [musl] [PATCH] Add REL_COPY size change detection
Date: Wed, 26 Feb 2020 19:38:31 +0100	[thread overview]
Message-ID: <87a7556vo8.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20200226173621.GA11469@brightrain.aerifal.cx> (Rich Felker's message of "Wed, 26 Feb 2020 12:36:21 -0500")

* Rich Felker:

> At the very least I think we ought to catch and error on the case
> where def.sym->st_size>sym->st_size, since we can't honor it and
> failure to honor it can produce silent memory corruption. I'm less
> sure about what to do if def.sym->st_size<sym->st-size; this case
> seems safe and might be desirable not to break (I vaguely recall an
> intent that it be ok), but if you think there are reasons it's
> dangerous I'm ok with disallowing it too. I'm having a hard time now
> thinking of a reason it would really help to support that, anyway.

Unfortunately the Mozilla NSS people disagree that size mismatches for
global symbols are an ABI break.  I don't know if this is relevant in
the musl context, but it means that for glibc, we probably can't make
it a hard error.

I want to have better diagnostics for this in glibc, but the current
warning (which is poorly worded at that) is in the
architecture-specific code, and I got side-tracked when I tried to
clean this up the last time.

  reply	other threads:[~2020-02-26 18:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-26  5:24 Markus Wichmann
2020-02-26 17:36 ` Rich Felker
2020-02-26 18:38   ` Florian Weimer [this message]
2020-02-26 19:00     ` Rich Felker
2020-02-26 19:53       ` Florian Weimer
2020-02-26 22:48         ` Rich Felker
2020-02-27  5:00           ` Fangrui Song
2020-04-17 10:58           ` Florian Weimer
2020-02-26 20:12   ` Markus Wichmann
2020-02-26 22:02     ` Rich Felker

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