Skip to content
Permalink
Browse files
CVE-2019-7574: Fix a buffer overread in IMA_ADPCM_decode
If data chunk was shorter than expected based on a WAV format
definition, IMA_ADPCM_decode() tried to read past the data chunk
buffer. This patch fixes it.

CVE-2019-7574
https://bugzilla.libsdl.org/show_bug.cgi?id=4496

Signed-off-by: Petr P?sa? <ppisar@redhat.com>
  • Loading branch information
ppisar committed Jun 10, 2019
1 parent c4a9f00 commit 76871a1c52dc74b8ba2357b9d68c34d765ea9db3
Showing with 8 additions and 1 deletion.
  1. +8 −1 src/audio/SDL_wave.c
@@ -331,7 +331,7 @@ static void Fill_IMA_ADPCM_block(Uint8 *decoded, Uint8 *encoded,
static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
{
struct IMA_ADPCM_decodestate *state;
Uint8 *freeable, *encoded, *decoded;
Uint8 *freeable, *encoded, *encoded_end, *decoded;
Sint32 encoded_len, samplesleft;
unsigned int c, channels;

@@ -347,6 +347,7 @@ static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
/* Allocate the proper sized output buffer */
encoded_len = *audio_len;
encoded = *audio_buf;
encoded_end = encoded + encoded_len;
freeable = *audio_buf;
*audio_len = (encoded_len/IMA_ADPCM_state.wavefmt.blockalign) *
IMA_ADPCM_state.wSamplesPerBlock*
@@ -362,6 +363,7 @@ static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
while ( encoded_len >= IMA_ADPCM_state.wavefmt.blockalign ) {
/* Grab the initial information for this block */
for ( c=0; c<channels; ++c ) {
if (encoded + 4 > encoded_end) goto invalid_size;
/* Fill the state information for this block */
state[c].sample = ((encoded[1]<<8)|encoded[0]);
encoded += 2;
@@ -384,6 +386,7 @@ static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
samplesleft = (IMA_ADPCM_state.wSamplesPerBlock-1)*channels;
while ( samplesleft > 0 ) {
for ( c=0; c<channels; ++c ) {
if (encoded + 4 > encoded_end) goto invalid_size;
Fill_IMA_ADPCM_block(decoded, encoded,
c, channels, &state[c]);
encoded += 4;
@@ -395,6 +398,10 @@ static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
}
SDL_free(freeable);
return(0);
invalid_size:
SDL_SetError("Unexpected chunk length for an IMA ADPCM decoder");
SDL_free(freeable);
return(-1);
}

SDL_AudioSpec * SDL_LoadWAV_RW (SDL_RWops *src, int freesrc,

0 comments on commit 76871a1

Please sign in to comment.