[Bug nptl/13724] New: pthread_setname_np segfault

[Bug nptl/13724] New: pthread_setname_np segfault

[law at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13724

             Bug #: 13724
           Summary: pthread_setname_np segfault
           Product: glibc
           Version: 2.15
            Status: NEW
          Severity: normal
          Priority: P2
         Component: nptl
        AssignedTo: unassigned@sourceware.org
        ReportedBy: law@redhat.com
                CC: drepper.fsp@gmail.com
    Classification: Unclassified


pthread_setname_np can segfault if passed a NULL pointer.

#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <string.h>

int
main(void)
{
  pthread_t thr = pthread_self ();
  int ret = pthread_setname_np (thr, NULL);
  printf ("pthread_setname_np: %s\n", strerror (ret));
  return 0;
}

The setname_np/getname_np have non-null attributes for the appropriate
arguments and one could make a case that this is ultimately a user error. 
However, given these are not performance critical routines, I believe we can
spare the cycles to do argument verification  to improve the quality of
implementation.

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[Bug nptl/13724] pthread_setname_np segfault

[yselkowitz at cygwin dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13724

Cygwin/X maintainer <yselkowitz at cygwin dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |yselkowitz at cygwin dot
                   |                            |com

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[Bug nptl/13724] pthread_setname_np segfault

[yselkowitz at cygwin dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13724

--- Comment #1 from Cygwin/X maintainer <yselkowitz at cygwin dot com> 2012-02-23 03:04:44 UTC ---
Since pthread_setname_np is undocumented, I'm not sure what the desired
solution is in this case:

1) Return EFAULT, just as pthread_getname_np (thr, NULL, 16).
2) Leave the nonnull attribute but treat NULL as "" just in case.
3) Remove the nonnull attribute and allow NULL as synonym for "".

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[Bug nptl/13724] pthread_setname_np segfault

[jakub at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13724

Jakub Jelinek <jakub at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at redhat dot com

--- Comment #2 from Jakub Jelinek <jakub at redhat dot com> 2012-02-23 07:09:57 UTC ---
When it isn't documented in man pages or info pages, the headers are the only
documentation.  And the headers clearly document that you must not call it with
NULL:

/* Get thread name visible in the kernel and its interfaces.  */
extern int pthread_getname_np (pthread_t __target_thread, char *__buf,
                               size_t __buflen)
     __THROW __nonnull ((2));

/* Set thread name visible in the kernel and its interfaces.  */
extern int pthread_setname_np (pthread_t __target_thread, __const char *__name)
     __THROW __nonnull ((2));

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[Bug nptl/13724] pthread_setname_np segfault

[yselkowitz at cygwin dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13724

--- Comment #3 from Cygwin/X maintainer <yselkowitz at cygwin dot com> 2012-02-23 07:25:39 UTC ---
(In reply to comment #2)
> When it isn't documented in man pages or info pages, the headers are the only
> documentation.  And the headers clearly document that you must not call it with
> NULL:

I understand that, but that doesn't necessarily mean it should segfault if NULL
is passed anyway.  pthread_getname_np(thr, NULL, 16) returns EFAULT, but
pthread_setname_np(thr, NULL) segfaults.  That inconsistency in a corresponding
pair of functions seems odd to me, hence the question if this is the intended
result.

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[Bug nptl/13724] pthread_setname_np segfault

[schwab@linux-m68k.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=13724

--- Comment #4 from Andreas Schwab <schwab@linux-m68k.org> 2012-02-23 10:01:49 UTC ---
It's consistently undefined behaviour.

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[Bug nptl/13724] pthread_setname_np segfault

[neleai at seznam dot cz]

https://sourceware.org/bugzilla/show_bug.cgi?id=13724

Ondrej Bilka <neleai at seznam dot cz> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |neleai at seznam dot cz
         Resolution|---                         |WONTFIX

--- Comment #5 from Ondrej Bilka <neleai at seznam dot cz> ---
In discussion at http://www.sourceware.org/ml/libc-alpha/2013-10/msg00111.html
we decided that crashing is better as error code will likely be ignored.

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[Bug nptl/13724] pthread_setname_np segfault

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=13724

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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