* [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
@ 2022-01-01 16:53 Samuel Thibault
2022-01-01 17:27 ` Florian Weimer
0 siblings, 1 reply; 7+ messages in thread
From: Samuel Thibault @ 2022-01-01 16:53 UTC (permalink / raw)
To: libc-alpha; +Cc: Samuel Thibault, commit-hurd
The latter violates namespace contraints
---
sysdeps/mach/hurd/getrandom.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/sysdeps/mach/hurd/getrandom.c b/sysdeps/mach/hurd/getrandom.c
index 24f9ac60f7..76f2e900d2 100644
--- a/sysdeps/mach/hurd/getrandom.c
+++ b/sysdeps/mach/hurd/getrandom.c
@@ -21,7 +21,7 @@
#include <unistd.h>
#include <not-cancel.h>
-extern char *trivfs_server_name __attribute__((weak));
+extern char *__trivfs_server_name __attribute__((weak));
/* Write up to LENGTH bytes of randomness starting at BUFFER.
Return the number of bytes written, or -1 on error. */
@@ -33,14 +33,14 @@ __getrandom (void *buffer, size_t length, unsigned int flags)
size_t amount_read;
int fd;
- 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')
+ 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;
--
2.34.1
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
2022-01-01 16:53 [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name Samuel Thibault
@ 2022-01-01 17:27 ` Florian Weimer
2022-01-01 17:41 ` Samuel Thibault
0 siblings, 1 reply; 7+ messages in thread
From: Florian Weimer @ 2022-01-01 17:27 UTC (permalink / raw)
To: Samuel Thibault; +Cc: libc-alpha, commit-hurd
* Samuel Thibault:
> The latter violates namespace contraints
> ---
> sysdeps/mach/hurd/getrandom.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/sysdeps/mach/hurd/getrandom.c b/sysdeps/mach/hurd/getrandom.c
> index 24f9ac60f7..76f2e900d2 100644
> --- a/sysdeps/mach/hurd/getrandom.c
> +++ b/sysdeps/mach/hurd/getrandom.c
> @@ -21,7 +21,7 @@
> #include <unistd.h>
> #include <not-cancel.h>
>
> -extern char *trivfs_server_name __attribute__((weak));
> +extern char *__trivfs_server_name __attribute__((weak));
>
> /* Write up to LENGTH bytes of randomness starting at BUFFER.
> Return the number of bytes written, or -1 on error. */
> @@ -33,14 +33,14 @@ __getrandom (void *buffer, size_t length, unsigned int flags)
> size_t amount_read;
> int fd;
>
> - 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')
> + 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.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
2022-01-01 17:27 ` Florian Weimer
@ 2022-01-01 17:41 ` Samuel Thibault
2022-01-01 18:48 ` Florian Weimer
0 siblings, 1 reply; 7+ messages in thread
From: Samuel Thibault @ 2022-01-01 17:41 UTC (permalink / raw)
To: bug-hurd; +Cc: commit-hurd, libc-alpha
Florian Weimer, le sam. 01 janv. 2022 18:27:49 +0100, a ecrit:
> > @@ -33,14 +33,14 @@ __getrandom (void *buffer, size_t length, unsigned int flags)
> > size_t amount_read;
> > int fd;
> >
> > - 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')
> > + 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.
Samuel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
2022-01-01 17:41 ` Samuel Thibault
@ 2022-01-01 18:48 ` Florian Weimer
2022-01-01 18:58 ` Samuel Thibault
0 siblings, 1 reply; 7+ messages in thread
From: Florian Weimer @ 2022-01-01 18:48 UTC (permalink / raw)
To: bug-hurd; +Cc: commit-hurd, libc-alpha
* Samuel Thibault via Libc-alpha:
> Florian Weimer, le sam. 01 janv. 2022 18:27:49 +0100, a ecrit:
>> > @@ -33,14 +33,14 @@ __getrandom (void *buffer, size_t length, unsigned int flags)
>> > size_t amount_read;
>> > int fd;
>> >
>> > - 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')
>> > + 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?
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
2022-01-01 18:48 ` Florian Weimer
@ 2022-01-01 18:58 ` Samuel Thibault
2022-01-01 19:02 ` Florian Weimer
0 siblings, 1 reply; 7+ messages in thread
From: Samuel Thibault @ 2022-01-01 18:58 UTC (permalink / raw)
To: Florian Weimer; +Cc: bug-hurd, commit-hurd, libc-alpha
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
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
2022-01-01 18:58 ` Samuel Thibault
@ 2022-01-01 19:02 ` Florian Weimer
2022-01-01 19:11 ` Samuel Thibault
0 siblings, 1 reply; 7+ messages in thread
From: Florian Weimer @ 2022-01-01 19:02 UTC (permalink / raw)
To: bug-hurd; +Cc: commit-hurd, libc-alpha
* 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?
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name
2022-01-01 19:02 ` Florian Weimer
@ 2022-01-01 19:11 ` Samuel Thibault
0 siblings, 0 replies; 7+ messages in thread
From: Samuel Thibault @ 2022-01-01 19:11 UTC (permalink / raw)
To: Florian Weimer; +Cc: bug-hurd, commit-hurd, libc-alpha
Florian Weimer, le sam. 01 janv. 2022 20:02:12 +0100, a ecrit:
> * 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?
Yes, it's there:
http://git.savannah.gnu.org/cgit/hurd/hurd.git/commit/?id=8c5eb657ff196a31a3230652823221f3fe805d73
Samuel
^ permalink raw reply [flat|nested] 7+ messages in thread
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2022-01-01 16:53 [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name 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
2022-01-01 19:11 ` Samuel Thibault
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