From 9b2eee24768889378032077423cb6a3221a8ad18 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= Date: Thu, 14 Feb 2019 15:41:47 +0100 Subject: [PATCH] CVE-2019-7574: Fix a buffer overread in IMA_ADPCM_decode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Písař --- src/audio/SDL_wave.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/src/audio/SDL_wave.c b/src/audio/SDL_wave.c index b6c49de..2968b3d 100644 --- a/src/audio/SDL_wave.c +++ b/src/audio/SDL_wave.c @@ -334,7 +334,7 @@ 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; @@ -350,6 +350,7 @@ 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* @@ -365,6 +366,7 @@ 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 encoded_end) goto invalid_size; /* Fill the state information for this block */ state[c].sample = ((encoded[1]<<8)|encoded[0]); encoded += 2; @@ -387,6 +389,7 @@ 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 encoded_end) goto invalid_size; Fill_IMA_ADPCM_block(decoded, encoded, c, channels, &state[c]); encoded += 4; @@ -398,6 +401,10 @@ 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, -- 2.20.1