72 lines
2.6 KiB
Diff
72 lines
2.6 KiB
Diff
From 9b2eee24768889378032077423cb6a3221a8ad18 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
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Date: Thu, 14 Feb 2019 15:41:47 +0100
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Subject: [PATCH] CVE-2019-7574: Fix a buffer overread in IMA_ADPCM_decode
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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If data chunk was shorter than expected based on a WAV format
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definition, IMA_ADPCM_decode() tried to read past the data chunk
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buffer. This patch fixes it.
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CVE-2019-7574
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https://bugzilla.libsdl.org/show_bug.cgi?id=4496
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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src/audio/SDL_wave.c | 9 ++++++++-
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1 file changed, 8 insertions(+), 1 deletion(-)
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diff --git a/src/audio/SDL_wave.c b/src/audio/SDL_wave.c
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index b6c49de..2968b3d 100644
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--- a/src/audio/SDL_wave.c
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+++ b/src/audio/SDL_wave.c
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@@ -334,7 +334,7 @@ static void Fill_IMA_ADPCM_block(Uint8 *decoded, Uint8 *encoded,
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static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
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{
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struct IMA_ADPCM_decodestate *state;
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- Uint8 *freeable, *encoded, *decoded;
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+ Uint8 *freeable, *encoded, *encoded_end, *decoded;
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Sint32 encoded_len, samplesleft;
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unsigned int c, channels;
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@@ -350,6 +350,7 @@ static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
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/* Allocate the proper sized output buffer */
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encoded_len = *audio_len;
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encoded = *audio_buf;
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+ encoded_end = encoded + encoded_len;
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freeable = *audio_buf;
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*audio_len = (encoded_len/IMA_ADPCM_state.wavefmt.blockalign) *
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IMA_ADPCM_state.wSamplesPerBlock*
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@@ -365,6 +366,7 @@ static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
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while ( encoded_len >= IMA_ADPCM_state.wavefmt.blockalign ) {
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/* Grab the initial information for this block */
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for ( c=0; c<channels; ++c ) {
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+ if (encoded + 4 > encoded_end) goto invalid_size;
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/* Fill the state information for this block */
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state[c].sample = ((encoded[1]<<8)|encoded[0]);
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encoded += 2;
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@@ -387,6 +389,7 @@ static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
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samplesleft = (IMA_ADPCM_state.wSamplesPerBlock-1)*channels;
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while ( samplesleft > 0 ) {
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for ( c=0; c<channels; ++c ) {
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+ if (encoded + 4 > encoded_end) goto invalid_size;
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Fill_IMA_ADPCM_block(decoded, encoded,
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c, channels, &state[c]);
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encoded += 4;
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@@ -398,6 +401,10 @@ static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
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}
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SDL_free(freeable);
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return(0);
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+invalid_size:
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+ SDL_SetError("Unexpected chunk length for an IMA ADPCM decoder");
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+ SDL_free(freeable);
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+ return(-1);
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}
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SDL_AudioSpec * SDL_LoadWAV_RW (SDL_RWops *src, int freesrc,
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--
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2.20.1
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