1# HG changeset patch
2# User Petr Písař <ppisar@redhat.com>
3# Date 1560181859 25200
4#      Mon Jun 10 08:50:59 2019 -0700
5# Branch SDL-1.2
6# Node ID a6e3d2f5183e1cc300ad993e10e9ce077e13bd9c
7# Parent  388987dff7bf8f1e214e69c2e4f1aa31e06396b5
8CVE-2019-7574: Fix a buffer overread in IMA_ADPCM_decode
9If data chunk was shorter than expected based on a WAV format
10definition, IMA_ADPCM_decode() tried to read past the data chunk
11buffer. This patch fixes it.
12
13CVE-2019-7574
14https://bugzilla.libsdl.org/show_bug.cgi?id=4496
15
16Signed-off-by: Petr Písař <ppisar@redhat.com>
17
18CVE: CVE-2019-7574
19Upstream-Status: Backport
20Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
21
22diff -r 388987dff7bf -r a6e3d2f5183e src/audio/SDL_wave.c
23--- a/src/audio/SDL_wave.c	Sat Jun 08 18:02:09 2019 -0700
24+++ b/src/audio/SDL_wave.c	Mon Jun 10 08:50:59 2019 -0700
25@@ -331,7 +331,7 @@
26 static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
27 {
28 	struct IMA_ADPCM_decodestate *state;
29-	Uint8 *freeable, *encoded, *decoded;
30+	Uint8 *freeable, *encoded, *encoded_end, *decoded;
31 	Sint32 encoded_len, samplesleft;
32 	unsigned int c, channels;
33
34@@ -347,6 +347,7 @@
35 	/* Allocate the proper sized output buffer */
36 	encoded_len = *audio_len;
37 	encoded = *audio_buf;
38+	encoded_end = encoded + encoded_len;
39 	freeable = *audio_buf;
40 	*audio_len = (encoded_len/IMA_ADPCM_state.wavefmt.blockalign) *
41 				IMA_ADPCM_state.wSamplesPerBlock*
42@@ -362,6 +363,7 @@
43 	while ( encoded_len >= IMA_ADPCM_state.wavefmt.blockalign ) {
44 		/* Grab the initial information for this block */
45 		for ( c=0; c<channels; ++c ) {
46+			if (encoded + 4 > encoded_end) goto invalid_size;
47 			/* Fill the state information for this block */
48 			state[c].sample = ((encoded[1]<<8)|encoded[0]);
49 			encoded += 2;
50@@ -384,6 +386,7 @@
51 		samplesleft = (IMA_ADPCM_state.wSamplesPerBlock-1)*channels;
52 		while ( samplesleft > 0 ) {
53 			for ( c=0; c<channels; ++c ) {
54+				if (encoded + 4 > encoded_end) goto invalid_size;
55 				Fill_IMA_ADPCM_block(decoded, encoded,
56 						c, channels, &state[c]);
57 				encoded += 4;
58@@ -395,6 +398,10 @@
59 	}
60 	SDL_free(freeable);
61 	return(0);
62+invalid_size:
63+	SDL_SetError("Unexpected chunk length for an IMA ADPCM decoder");
64+	SDL_free(freeable);
65+	return(-1);
66 }
67
68 SDL_AudioSpec * SDL_LoadWAV_RW (SDL_RWops *src, int freesrc,
69