FLAC: Fix a buffer read overrun

Buffer read overrun occurs when reading a FLAC file that switches
from 2 channels to one channel mid-stream. Only option is to
abort the read.

Change-Id: I56004d7e40f9d9a2ab8b4119e420d663e0e8326a
Closes: https://github.com/erikd/libsndfile/issues/230

diff --git a/src/common.h b/src/common.h
index 63eb785..3e51828 100644 (file)
--- a/src/common.h
+++ b/src/common.h
@@ -747,6 +747,7 @@ enum
        SFE_FLAC_INIT_DECODER,
        SFE_FLAC_LOST_SYNC,
        SFE_FLAC_BAD_SAMPLE_RATE,
+       SFE_FLAC_CHANNEL_COUNT_CHANGED,
        SFE_FLAC_UNKOWN_ERROR,
 
        SFE_WVE_NOT_WVE,

diff --git a/src/flac.c b/src/flac.c
index b74ada1..adc67f5 100644 (file)
--- a/src/flac.c
+++ b/src/flac.c
@@ -434,6 +434,19 @@ sf_flac_meta_callback (const FLAC__StreamDecoder * UNUSED (decoder), const FLAC_
 
        switch (metadata->type)
        {       case FLAC__METADATA_TYPE_STREAMINFO :
+                       if (psf->sf.channels > 0 && psf->sf.channels != (int) metadata->data.stream_info.channels)
+                       {       psf_log_printf (psf, "Error: FLAC stream changed from %d to %d channels\n"
+                                                                       "Nothing to be but to error out.\n" ,
+                                                                       psf->sf.channels, metadata->data.stream_info.channels) ;
+                               psf->error = SFE_FLAC_CHANNEL_COUNT_CHANGED ;
+                               return ;
+                               } ;
+
+                       if (psf->sf.channels > 0 && psf->sf.samplerate != (int) metadata->data.stream_info.sample_rate)
+                       {       psf_log_printf (psf, "Warning: FLAC stream changed sample rates from %d to %d.\n"
+                                                                       "Carrying on as if nothing happened.",
+                                                                       psf->sf.samplerate, metadata->data.stream_info.sample_rate) ;
+                               } ;
                        psf->sf.channels = metadata->data.stream_info.channels ;
                        psf->sf.samplerate = metadata->data.stream_info.sample_rate ;
                        psf->sf.frames = metadata->data.stream_info.total_samples ;

diff --git a/src/sndfile.c b/src/sndfile.c
index a4e7ca9..c028584 100644 (file)
--- a/src/sndfile.c
+++ b/src/sndfile.c
@@ -245,6 +245,7 @@ ErrorStruct SndfileErrors [] =
        {       SFE_FLAC_INIT_DECODER   , "Error : problem with initialization of the flac decoder." },
        {       SFE_FLAC_LOST_SYNC              , "Error : flac decoder lost sync." },
        {       SFE_FLAC_BAD_SAMPLE_RATE, "Error : flac does not support this sample rate." },
+       {       SFE_FLAC_CHANNEL_COUNT_CHANGED, "Error : flac channel changed mid stream." },
        {       SFE_FLAC_UNKOWN_ERROR   , "Error : unknown error in flac decoder." },
 
        {       SFE_WVE_NOT_WVE                 , "Error : not a WVE file." },