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• avfilter/vf_showpalette : Fix double-free of AVFilterFormats on error

  7 août 2020, par Andreas Rheinhardt

  avfilter/vf_showpalette : Fix double-free of AVFilterFormats on error
  The query_formats function of the showpalette filter tries to allocate
  
  two lists of formats which on success are attached to more permanent objects
  
  (AVFilterLinks) for storage afterwards. If attaching a list to an
  
  AVFilterLink succeeds, the link becomes one (in this case the only one)
  
  of the owners of the list. Yet if attaching the first list to its link
  
  succeeds and attaching the second list fails, both lists were manually
  
  freed, which means that the first link's pointer to the first list
  
  becomes dangling and there will be a double-free when the first link is
  
  cleaned up automatically.
  This commit fixes this by removing the custom free code ; this will
  
  temporarily add a leaking codepath (if attaching a list to a link fails,
  
  the list will leak), but this will be fixed shortly by making sure that
  
  an AVFilterFormats without owner will be automatically freed when
  
  attaching it to an AVFilterLink fails. Notice at most one list leaks
  
  because as of this commit a new list is only allocated after the old list
  
  has been successfully attached to a link.
  Reviewed-by : Nicolas George <george@nsup.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/vf_showpalette.c

• lavc : add avcodec_free_context().

  5 avril 2014, par Anton Khirnov

  lavc : add avcodec_free_context().
  Right now, the caller has to manually manage some allocated
  
  AVCodecContext fields, like extradata or subtitle_header. This is
  
  fragile and prone to leaks, especially if we want to add more such
  
  fields in the future.
  The only reason for this behaviour is so that the AVStream codec context
  
  can be reused for decoding. Such reuse is discouraged anyway, so this
  
  commit is the first step to deprecating it.
  

  • [DH] doc/APIchanges
  • [DH] libavcodec/avcodec.h
  • [DH] libavcodec/options.c
  • [DH] libavcodec/version.h

• stream_decoder : fix memory leak after seek table read error

  14 juillet 2016, par Max Kellermann

  stream_decoder : fix memory leak after seek table read error
  When read_metadata_seektable_() fails, the has_seek_table flag is
  
  never set to true, and thus free() is never called.
  Example valgrind output :
   11,185,464 bytes in 1 blocks are definitely lost in loss record 62 of 62
  
      at 0x4C2BC0F : malloc (vg_replace_malloc.c:299)
  
      by 0x4C2DE6F : realloc (vg_replace_malloc.c:785)
  
      by 0x40A7880 : safe_realloc_ (alloc.h:159)
  
      by 0x40A7911 : safe_realloc_mul_2op_ (alloc.h:205)
  
      by 0x40AB6B5 : read_metadata_seektable_ (stream_decoder.c:1654)
  
      by 0x40AAB2D : read_metadata_ (stream_decoder.c:1422)
  
      by 0x40A9C79 : FLAC__stream_decoder_process_until_end_of_metadata (stream_decoder.c:1055)
  It is easy to craft a FLAC file which leaks megabytes of memory on
  
  every attempt to open the file.
  This patch fixes the problem by removing checks which are unnecessary
  
  (and harmful).  Checking the has_seek_table flag is not enough, as
  
  described above.  The NULL check is not harmful, but is not helpful
  
  either, because free(NULL) is documented to be legal.
  After running this code block, we’re in a well-known safe state, no
  
  matter how inconsistent pointer and flag may have been before, for
  
  whatever reasons.
  Signed-off-by : Erik de Castro Lopo <erikd@mega-nerd.com>
  

  • [DH] src/libFLAC/stream_decoder.c