diff options
| author | Petr Písař <ppisar@redhat.com> | 2019-06-10 09:25:05 -0700 |
|---|---|---|
| committer | Wim Taymans <wtaymans@redhat.com> | 2019-06-25 15:59:08 +0200 |
| commit | 730c8b917e7deecc3cdf9ac9eb20e2b7e6450356 (patch) | |
| tree | 321ddb8a9a02e7df9a0e2f093711dc7b5866a353 | |
| parent | 45ef356d8c01a3941286b35b90eb319959f20f2c (diff) | |
CVE-2019-7575: Fix a buffer overwrite in MS_ADPCM_decode
If a WAV format defines shorter audio stream and decoded MS ADPCM data chunk
is longer, decoding continued past the output audio buffer.
This fix is based on a patch from
<https://bugzilla.libsdl.org/show_bug.cgi?id=4492>.
https://bugzilla.libsdl.org/show_bug.cgi?id=4493
CVE-2019-7575
Signed-off-by: Petr Písař <ppisar@redhat.com>
--HG--
branch : SDL-1.2
| -rw-r--r-- | src/audio/SDL_wave.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/src/audio/SDL_wave.c b/src/audio/SDL_wave.c index 88ac2cca6b..5f9365147a 100644 --- a/src/audio/SDL_wave.c +++ b/src/audio/SDL_wave.c @@ -122,7 +122,7 @@ static Sint32 MS_ADPCM_nibble(struct MS_ADPCM_decodestate *state, static int MS_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len) { struct MS_ADPCM_decodestate *state[2]; - Uint8 *freeable, *encoded, *encoded_end, *decoded; + Uint8 *freeable, *encoded, *encoded_end, *decoded, *decoded_end; Sint32 encoded_len, samplesleft; Sint8 nybble, stereo; Sint16 *coeff[2]; @@ -142,6 +142,7 @@ static int MS_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len) return(-1); } decoded = *audio_buf; + decoded_end = decoded + *audio_len; /* Get ready... Go! */ stereo = (MS_ADPCM_state.wavefmt.channels == 2); @@ -149,7 +150,7 @@ static int MS_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len) state[1] = &MS_ADPCM_state.state[stereo]; while ( encoded_len >= MS_ADPCM_state.wavefmt.blockalign ) { /* Grab the initial information for this block */ - if (encoded + 7 + (stereo ? 7 : 0) > encoded_end) goto too_short; + if (encoded + 7 + (stereo ? 7 : 0) > encoded_end) goto invalid_size; state[0]->hPredictor = *encoded++; if ( stereo ) { state[1]->hPredictor = *encoded++; @@ -179,6 +180,7 @@ static int MS_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len) coeff[1] = MS_ADPCM_state.aCoeff[state[1]->hPredictor]; /* Store the two initial samples we start with */ + if (decoded + 4 + (stereo ? 4 : 0) > decoded_end) goto invalid_size; decoded[0] = state[0]->iSamp2&0xFF; decoded[1] = state[0]->iSamp2>>8; decoded += 2; @@ -200,7 +202,8 @@ static int MS_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len) samplesleft = (MS_ADPCM_state.wSamplesPerBlock-2)* MS_ADPCM_state.wavefmt.channels; while ( samplesleft > 0 ) { - if (encoded + 1 > encoded_end) goto too_short; + if (encoded + 1 > encoded_end) goto invalid_size; + if (decoded + 4 > decoded_end) goto invalid_size; nybble = (*encoded)>>4; new_sample = MS_ADPCM_nibble(state[0],nybble,coeff[0]); @@ -223,8 +226,8 @@ static int MS_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len) } SDL_free(freeable); return(0); -too_short: - SDL_SetError("Too short chunk for a MS ADPCM decoder"); +invalid_size: + SDL_SetError("Unexpected chunk length for a MS ADPCM decoder"); SDL_free(freeable); return(-1); invalid_predictor: |