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• avfilter/formats : Fix double frees and memleaks on error

  7 août 2020, par Andreas Rheinhardt

  avfilter/formats : Fix double frees and memleaks on error
  The formats API deals with lists of channel layouts, sample rates,
  
  pixel formats and sample formats. These lists are refcounted in a way in
  
  which the list structure itself contains pointers to all of its owners.
  
  Furthermore, it is possible for a list to be not owned by anyone yet ;
  
  this status is temporary until the list has been attached to an owner.
  
  Adding an owner to a list involves reallocating the list's list of
  
  owners and can therefore fail.
  In order to reduce the amount of checks and cleanup code for the users
  
  of this API, the API is supposed to be lenient when faced with input
  
  lists that are NULL and it is supposed to clean up if adding an owner
  
  to a list fails, so that a simple use case like
  list = ff_make_format_list(foo_fmts) ;
  
  if ((ret = ff_formats_ref(list, &ctx->inputs[0]->out_formats)) < 0)
  
      return ret ;
  needn't check whether list could be successfully allocated
  
  (ff_formats_ref() return AVERROR(ENOMEM) if it couldn't) and it also
  
  needn't free list if ff_formats_ref() couldn't add an owner for it.
  But the cleaning up after itself was broken. The root cause was that
  
  the refcount was decremented during unreferencing whether or not the
  
  element to be unreferenced was actually an owner of the list or not.
  
  This means that if the above sample code is continued by
  if ((ret = ff_formats_ref(list, &ctx->inputs[1]->out_formats)) < 0)
  
      return ret ;
  and that if an error happens at the second ff_formats_ref() call, the
  
  automatic cleaning of list will decrement the refcount from 1 (the sole
  
  owner of list at this moment is ctx->input[0]->out_formats) to 0 and so
  
  the list will be freed ; yet ctx->input[0]->out_formats still points to
  
  the list and this will lead to a double free/use-after-free when
  
  ctx->input[0] is freed later.
  Presumably in order to work around such an issue, commit
  
  93afb338a405eac0f9e7b092bc26603378bfcca6 restricted unreferencing to
  
  lists with owners. This does not solve the root cause (the above example
  
  is not fixed by this) at all, but it solves some crashs.
  This commit fixes the API : The list's refcount is only decremented if
  
  an owner is removed from the list of owners and not if the
  
  unref-function is called with a pointer that is not among the owners of
  
  the list. Furtermore, the requirement for the list to have owners is
  
  dropped.
  This implies that if the first call to ff_formats_ref() in the above
  
  example fails, the refcount which is initially zero during unreferencing
  
  is not modified, so that the list will be freed automatically in said
  
  call to ff_formats_ref() as every list whose refcount reaches zero is.
  If on the other hand, the second call to ff_formats_ref() is the first
  
  to fail, the refcount would stay at one during the automatic
  
  unreferencing in ff_formats_ref(). The list would later be freed when
  
  its last (and in this case sole) owner (namely
  
  ctx->inputs[0]->out_formats) gets unreferenced.
  The issues described here for ff_formats_ref() also affected the other
  
  functions of this API. E.g. ff_add_format() failed to clean up after
  
  itself if adding an entry to an already existing list failed (the case
  
  of a freshly allocated list was handled specially and this commit also
  
  removes said code). E.g. ff_all_formats() inherited the flaw.
  Reviewed-by : Nicolas George <george@nsup.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/formats.c

• Anomalie #4049 (Nouveau) : Double authentification LDAP

  21 novembre 2017, par svpip -

  Version SPIP utilisée : 3.0.26 [23574]¶

  Lors d’une première authentification LDAP, l’utilisateur est amené à soumettre 2 fois son identité via le formulaire adhoc (#LOGIN_PUBLIC ou #LOGIN_PRIVE) pour valider son action, après un premier message indiquant "Erreur de mot de passe.".
  Lors d’une seconde authentification LDAP, ce même utilisateur, à présent référencé dans la table spip_auteurs, n’est soumis qu’à une seule demande de formulaire.
  Pour palier à cette anomalie "non bloquante" (la première), 2 solutions vérifiées :

  - soit peupler (si possible) en amont la base spip_auteurs
  - soit passer un parametre=valeur dans l’url lors de l’authentification qu’il convient de récupérer depuis config/ldap.php pour déclencher l’appel au LDAP.

  Problème de la "double identification" évoqué sur forum SPIP :
  voir https://forum.spip.net/fr_263478.html?debut_forums=%40266046#forum266046

  ---

  Tests non réalisés sur SPIP :
  3.1.7 [23768]
  3.2.0 [23778]

  Ces versions comportent des erreurs natives concernant la gestion LDAP, qu’il est néanmoins possible de contourner facilement.
  Voir tickets :

  https://core.spip.net/issues/3918
  https://core.spip.net/issues/3919

• How can I reset the path of FFMPEG in the VideoExport library in Processing ?

  11 avril 2021, par bella

  Note : This question was originally titled "How can I reset the path of FFMPEG in Java ?" but, as it has been pointed out in the comments and the answer, the issue is not with Java, so I've changed the title to make it easier to find for others with the same issue.

  


  ---

  


  I accidentally set the path for FFMPEG to a different folder, and I can't change it back.

  


  I'm using Processing (the library and its IDE) and the user-created Video Export library to capture and write to an mp4 video file. The library required FFMPEG, so I downloaded and installed it. After I installed it, I ran the code, and the library called Java to request the path of FFMPEG. I wrongly set the path to a different folder (which I eventually deleted), and immediately realized my mistake. I ran the code again to see if I could trigger the prompt again to correct the path.

  


  ---

  


  The console response I received was : (I'm sure most of it doesn't have to do with the actual issue. However, I wanted to show all of it in case it somehow does.)

  


  


  Oct 24, 2016 10:23:25 PM java.util.prefs.WindowsPreferences 
WARNING : Could not open/create prefs root node Software\JavaSoft\Prefs
at root 0x80000002. Windows RegCreateKeyEx(...) returned error code 5.
java.io.IOException : Cannot run program
"C :...\Processing\Octree_Graphics\data\FFMPEG\ff-prompt.bat" :
CreateProcess error=2, The system cannot find the file specified at
java.lang.ProcessBuilder.start(ProcessBuilder.java:1048) at
com.hamoid.VideoExport.startFfmpeg(Unknown Source) at
com.hamoid.VideoExport.initialize(Unknown Source) at
com.hamoid.VideoExport.saveFrame(Unknown Source) at
Octree_Graphics.draw(Octree_Graphics.java:90) at
processing.core.PApplet.handleDraw(PApplet.java:2399) at
processing.opengl.PSurfaceJOGL$DrawListener.display(PSurfaceJOGL.java:731)
at
jogamp.opengl.GLDrawableHelper.displayImpl(GLDrawableHelper.java:692)
at jogamp.opengl.GLDrawableHelper.display(GLDrawableHelper.java:674)
at
jogamp.opengl.GLAutoDrawableBase$2.run(GLAutoDrawableBase.java:443)
at
jogamp.opengl.GLDrawableHelper.invokeGLImpl(GLDrawableHelper.java:1293)
at
jogamp.opengl.GLDrawableHelper.invokeGL(GLDrawableHelper.java:1147)
at com.jogamp.newt.opengl.GLWindow.display(GLWindow.java:759) at
com.jogamp.opengl.util.AWTAnimatorImpl.display(AWTAnimatorImpl.java:81)
at com.jogamp.opengl.util.AnimatorBase.display(AnimatorBase.java:452)
at
com.jogamp.opengl.util.FPSAnimator$MainTask.run(FPSAnimator.java:178)
at java.util.TimerThread.mainLoop(Timer.java:555) at
java.util.TimerThread.run(Timer.java:505) Caused by :
java.io.IOException : CreateProcess error=2, The system cannot find the
file specified at java.lang.ProcessImpl.create(Native Method) at
java.lang.ProcessImpl.(ProcessImpl.java:386) at
java.lang.ProcessImpl.start(ProcessImpl.java:137) at
java.lang.ProcessBuilder.start(ProcessBuilder.java:1029) ... 17 more
VideoExport error : Ffmpeg failed. Study
C :...\Processing\Octree_Graphics\basic.mp4.txt for more details.

  


  


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  I need to find a way to reset the path of FFMPEG that Java has. I have tried uninstalling and reinstalling the library, but I haven't tried Java (I don't want to mess with anything it has in its current state).