From: Florian Weimer <fw@deneb.enyo.de>
To: bug-hurd@gnu.org
Cc: commit-hurd@gnu.org, libc-alpha@sourceware.org
Subject: Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
Date: Sat, 01 Jan 2022 20:02:12 +0100 [thread overview]
Message-ID: <87fsq7uvnv.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20220101185836.qwzd3af5ojjyjspl@begin> (Samuel Thibault's message of "Sat, 1 Jan 2022 19:58:36 +0100")
* Samuel Thibault:
> 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.
Oh, so there is a companion patch that is not reflected in the glibc
sources?
next prev parent reply other threads:[~2022-01-01 19:02 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
2022-01-01 19:02 ` Florian Weimer [this message]
2022-01-01 19:11 ` Samuel Thibault
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