From 0eb76f6cabcffa2104e34c26e0f41e6de95356ff Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= Date: Fri, 15 Feb 2019 10:56:59 +0100 Subject: [PATCH] CVE-2019-7578: Fix a buffer overread in InitIMA_ADPCM MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If IMA ADPCM format chunk was too short, InitIMA_ADPCM() parsing it could read past the end of chunk data. This patch fixes it. CVE-2019-7578 https://bugzilla.libsdl.org/show_bug.cgi?id=4494 Signed-off-by: Petr Písař --- src/audio/SDL_wave.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/audio/SDL_wave.c b/src/audio/SDL_wave.c index 1d446ed..08f65cb 100644 --- a/src/audio/SDL_wave.c +++ b/src/audio/SDL_wave.c @@ -240,11 +240,12 @@ static struct IMA_ADPCM_decoder { struct IMA_ADPCM_decodestate state[2]; } IMA_ADPCM_state; -static int InitIMA_ADPCM(WaveFMT *format) +static int InitIMA_ADPCM(WaveFMT *format, int length) { - Uint8 *rogue_feel; + Uint8 *rogue_feel, *rogue_feel_end; /* Set the rogue pointer to the IMA_ADPCM specific data */ + if (length < sizeof(*format)) goto too_short; IMA_ADPCM_state.wavefmt.encoding = SDL_SwapLE16(format->encoding); IMA_ADPCM_state.wavefmt.channels = SDL_SwapLE16(format->channels); IMA_ADPCM_state.wavefmt.frequency = SDL_SwapLE32(format->frequency); @@ -253,11 +254,16 @@ static int InitIMA_ADPCM(WaveFMT *format) IMA_ADPCM_state.wavefmt.bitspersample = SDL_SwapLE16(format->bitspersample); rogue_feel = (Uint8 *)format+sizeof(*format); + rogue_feel_end = (Uint8 *)format + length; if ( sizeof(*format) == 16 ) { rogue_feel += sizeof(Uint16); } + if (rogue_feel + 2 > rogue_feel_end) goto too_short; IMA_ADPCM_state.wSamplesPerBlock = ((rogue_feel[1]<<8)|rogue_feel[0]); return(0); +too_short: + SDL_SetError("Unexpected length of a chunk with an IMA ADPCM format"); + return(-1); } static Sint32 IMA_ADPCM_nibble(struct IMA_ADPCM_decodestate *state,Uint8 nybble) @@ -500,7 +506,7 @@ SDL_AudioSpec * SDL_LoadWAV_RW (SDL_RWops *src, int freesrc, break; case IMA_ADPCM_CODE: /* Try to understand this */ - if ( InitIMA_ADPCM(format) < 0 ) { + if ( InitIMA_ADPCM(format, lenread) < 0 ) { was_error = 1; goto done; } -- 2.20.1