From: Samuel Thibault <samuel.thibault@gnu.org>
To: Florian Weimer <fw@deneb.enyo.de>
Cc: bug-hurd@gnu.org, commit-hurd@gnu.org, libc-alpha@sourceware.org
Subject: Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
Date: Sat, 1 Jan 2022 19:58:36 +0100 [thread overview]
Message-ID: <20220101185836.qwzd3af5ojjyjspl@begin> (raw)
In-Reply-To: <87mtkfuway.fsf@mid.deneb.enyo.de>
Florian Weimer, le sam. 01 janv. 2022 19:48:21 +0100, a ecrit:
> * Samuel Thibault via Libc-alpha:
> >> > + if (&__trivfs_server_name && __trivfs_server_name
> >> > + && __trivfs_server_name[0] == 'r'
> >> > + && __trivfs_server_name[1] == 'a'
> >> > + && __trivfs_server_name[2] == 'n'
> >> > + && __trivfs_server_name[3] == 'd'
> >> > + && __trivfs_server_name[4] == 'o'
> >> > + && __trivfs_server_name[5] == 'm'
> >> > + && __trivfs_server_name[6] == '\0')
> >> > /* We are random, don't try to read ourselves! */
> >> > return length;
> >>
> >> How does this work? It's a new synbol name, so there's no definition,
> >> so the weak reference is always null.
> >
> > It is peeking it from the program.
> >
> > Basically the problem is that the random translator uses glibc, whose
> > malloc implementation started using /dev/random in glibc 2.34, thus
> > reading itself.
>
> I still don't understand. Why isn't the condition always false?
The definition is in the random translator, which exports it in its
dynamic symbol table.
Samuel
next prev parent reply other threads:[~2022-01-01 18:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-01 16:53 Samuel Thibault
2022-01-01 17:27 ` Florian Weimer
2022-01-01 17:41 ` Samuel Thibault
2022-01-01 18:48 ` Florian Weimer
2022-01-01 18:58 ` Samuel Thibault [this message]
2022-01-01 19:02 ` Florian Weimer
2022-01-01 19:11 ` Samuel Thibault
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