Recherche avancée

Sur d’autres sites (4613)

• avcodec/wmavoice : sanity check block_align

  21 décembre 2019, par Michael Niedermayer

  avcodec/wmavoice : sanity check block_align
  This limit is roughly based on the bitreader limit, its likely a much tighter limit
  
  could be used
  Fixes : left shift of 1965039647 by 1 places cannot be represented in type 'int'
  
  Fixes : 19545/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMAVOICE_fuzzer-5695391899320320
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/wmavoice.c

• avutil/opt : Avoid av_strdup(NULL)

  25 mars 2024, par Andreas Rheinhardt

  avutil/opt : Avoid av_strdup(NULL)
  It is not documented to be safe and in any case it is nonsense :
  
  Currently av_strdup(NULL) returns NULL and in order to distinguish
  
  this from a genuine allocation failure, opt_copy_elem()
  
  checked afterwards whether src was actually NULL. But then one
  
  can simply check in advance whether one should call av_strdup()
  
  at all.
  
  set_string() was even worse and returned ENOMEM in case the value
  
  to be duplicated is NULL ; this only worked because
  
  av_opt_set_defaults2() does not check the return value at all
  
  (given that it can't propagate it).
  These two places account for 389114 of 390356 av_strdup(NULL)
  
  calls during one FATE run.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavutil/opt.c

• Weird cross platform support in ffmpeg

  31 mai 2022, par LmTinyToon

  I tried to build ffmpeg 4.4 library and link with it and I received multiple unresolved references. I came across on unusual architecture in ffmpeg for multiple platforms.The library has many places with code like this :

  


  void foo()
{
    // DO SOMETHING
    if (ARCH_MIPS) // maybe #if ARCH_MIPS (...) #endif should be used instead?
         foo_mips(...);
    if (ARCH_PPC)
        foo_ppc(c);
    if (ARCH_ARM)
         foo_arm(...);
    if (ARCH_AARCH64)
        foo_aarch64(...);
}


  


  This code leads to linker errors because there is no any stub methods for other platforms. I observed root MakeFile, it optionally includes platform dependent code for each library (path like $(LIB_SUBDIR)/$(ARCH)/MakeFile) where each foo_<arch></arch> is defined.

  


  So, how does it work ? In my opinion preprocessor directive #if should be used, otherwise we will receive unresolved reference on any platform. Maybe I missed something ? because this code appears frequently for example :

  


  

  1. utils.c : ff_yuv2rgb_init_tables_ppc

  


  2. swscale_unscaled.c : ff_get_unscaled_swscale_ppc, ff_get_unscaled_swscale_arm, ff_get_unscaled_swscale_aarch64

  


  3. cpu.c : ff_get_cpu_max_align_x86, ff_get_cpu_max_align_mips

  


  4. float_dsp.c : ff_float_dsp_init_aarch64, ff_float_dsp_init_ppc, ff_float_dsp_init_x86

  


  5. etc.