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# HG changeset patch
# User Petr Písař <ppisar@redhat.com>
# Date 1560181859 25200
# Mon Jun 10 08:50:59 2019 -0700
# Branch SDL-1.2
# Node ID a6e3d2f5183e1cc300ad993e10e9ce077e13bd9c
# Parent 388987dff7bf8f1e214e69c2e4f1aa31e06396b5
CVE-2019-7574: Fix a buffer overread in IMA_ADPCM_decode
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 <ppisar@redhat.com>
CVE: CVE-2019-7574
Upstream-Status: Backport
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
diff -r 388987dff7bf -r a6e3d2f5183e src/audio/SDL_wave.c
--- a/src/audio/SDL_wave.c Sat Jun 08 18:02:09 2019 -0700
+++ b/src/audio/SDL_wave.c Mon Jun 10 08:50:59 2019 -0700
@@ -331,7 +331,7 @@
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;
@@ -347,6 +347,7 @@
/* 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/IMA_ADPCM_state.wavefmt.blockalign) *
IMA_ADPCM_state.wSamplesPerBlock*
@@ -362,6 +363,7 @@
while ( encoded_len >= IMA_ADPCM_state.wavefmt.blockalign ) {
/* Grab the initial information for this block */
for ( c=0; c<channels; ++c ) {
+ if (encoded + 4 > encoded_end) goto invalid_size;
/* Fill the state information for this block */
state[c].sample = ((encoded[1]<<8)|encoded[0]);
encoded += 2;
@@ -384,6 +386,7 @@
samplesleft = (IMA_ADPCM_state.wSamplesPerBlock-1)*channels;
while ( samplesleft > 0 ) {
for ( c=0; c<channels; ++c ) {
+ if (encoded + 4 > encoded_end) goto invalid_size;
Fill_IMA_ADPCM_block(decoded, encoded,
c, channels, &state[c]);
encoded += 4;
@@ -395,6 +398,10 @@
}
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,
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