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# HG changeset patch
# User Petr Písař <ppisar@redhat.com>
# Date 1560182051 25200
# Mon Jun 10 08:54:11 2019 -0700
# Branch SDL-1.2
# Node ID 416136310b88cbeeff8773e573e90ac1e22b3526
# Parent a6e3d2f5183e1cc300ad993e10e9ce077e13bd9c
CVE-2019-7577: Fix a buffer overread in MS_ADPCM_decode
If RIFF/WAV data chunk length is shorter then expected for an audio
format defined in preceeding RIFF/WAV format headers, a buffer
overread can happen.
This patch fixes it by checking a MS ADPCM data to be decoded are not
past the initialized buffer.
CVE-2019-7577
Reproducer: https://bugzilla.libsdl.org/show_bug.cgi?id=4492
Signed-off-by: Petr Písař <ppisar@redhat.com>
# HG changeset patch
# User Petr Písař <ppisar@redhat.com>
# Date 1560182069 25200
# Mon Jun 10 08:54:29 2019 -0700
# Branch SDL-1.2
# Node ID faf9abbcfb5fe0d0ca23c4bf0394aa226ceccf02
# Parent 416136310b88cbeeff8773e573e90ac1e22b3526
CVE-2019-7577: Fix a buffer overread in MS_ADPCM_nibble and MS_ADPCM_decode
If a chunk of RIFF/WAV file with MS ADPCM encoding contains an invalid
predictor (a valid predictor's value is between 0 and 6 inclusive),
a buffer overread can happen when the predictor is used as an index
into an array of MS ADPCM coefficients.
The overead happens when indexing MS_ADPCM_state.aCoeff[] array in
MS_ADPCM_decode() and later when dereferencing a coef pointer in
MS_ADPCM_nibble().
This patch fixes it by checking the MS ADPCM predictor values fit
into the valid range.
CVE-2019-7577
Reproducer: https://bugzilla.libsdl.org/show_bug.cgi?id=4492
Signed-off-by: Petr Písař <ppisar@redhat.com>
CVE: CVE-2019-7577
Upstream-Status: Backport
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
diff -r a6e3d2f5183e -r 416136310b88 src/audio/SDL_wave.c
--- a/src/audio/SDL_wave.c Mon Jun 10 08:50:59 2019 -0700
+++ b/src/audio/SDL_wave.c Mon Jun 10 08:54:11 2019 -0700
@@ -115,7 +115,7 @@
static int MS_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
{
struct MS_ADPCM_decodestate *state[2];
- Uint8 *freeable, *encoded, *decoded;
+ Uint8 *freeable, *encoded, *encoded_end, *decoded;
Sint32 encoded_len, samplesleft;
Sint8 nybble, stereo;
Sint16 *coeff[2];
@@ -124,6 +124,7 @@
/* 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/MS_ADPCM_state.wavefmt.blockalign) *
MS_ADPCM_state.wSamplesPerBlock*
@@ -141,6 +142,7 @@
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;
state[0]->hPredictor = *encoded++;
if ( stereo ) {
state[1]->hPredictor = *encoded++;
@@ -188,6 +190,8 @@
samplesleft = (MS_ADPCM_state.wSamplesPerBlock-2)*
MS_ADPCM_state.wavefmt.channels;
while ( samplesleft > 0 ) {
+ if (encoded + 1 > encoded_end) goto too_short;
+
nybble = (*encoded)>>4;
new_sample = MS_ADPCM_nibble(state[0],nybble,coeff[0]);
decoded[0] = new_sample&0xFF;
@@ -209,6 +213,10 @@
}
SDL_free(freeable);
return(0);
+too_short:
+ SDL_SetError("Too short chunk for a MS ADPCM decoder");
+ SDL_free(freeable);
+ return(-1);
}
struct IMA_ADPCM_decodestate {
diff -r 416136310b88 -r faf9abbcfb5f src/audio/SDL_wave.c
--- a/src/audio/SDL_wave.c Mon Jun 10 08:54:11 2019 -0700
+++ b/src/audio/SDL_wave.c Mon Jun 10 08:54:29 2019 -0700
@@ -147,6 +147,9 @@
if ( stereo ) {
state[1]->hPredictor = *encoded++;
}
+ if (state[0]->hPredictor >= 7 || state[1]->hPredictor >= 7) {
+ goto invalid_predictor;
+ }
state[0]->iDelta = ((encoded[1]<<8)|encoded[0]);
encoded += sizeof(Sint16);
if ( stereo ) {
@@ -217,6 +220,10 @@
SDL_SetError("Too short chunk for a MS ADPCM decoder");
SDL_free(freeable);
return(-1);
+invalid_predictor:
+ SDL_SetError("Invalid predictor value for a MS ADPCM decoder");
+ SDL_free(freeable);
+ return(-1);
}
struct IMA_ADPCM_decodestate {
|
