1# HG changeset patch
2# User Petr Písař <ppisar@redhat.com>
3# Date 1560042129 25200
4#      Sat Jun 08 18:02:09 2019 -0700
5# Branch SDL-1.2
6# Node ID 388987dff7bf8f1e214e69c2e4f1aa31e06396b5
7# Parent  e52413f5258600878f9a10d2f92605a729aa8976
8CVE-2019-7578: Fix a buffer overread in InitIMA_ADPCM
9If IMA ADPCM format chunk was too short, InitIMA_ADPCM() parsing it
10could read past the end of chunk data. This patch fixes it.
11
12CVE-2019-7578
13https://bugzilla.libsdl.org/show_bug.cgi?id=4494
14
15Signed-off-by: Petr Písař <ppisar@redhat.com>
16
17CVE: CVE-2019-7578
18Upstream-Status: Backport
19Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
20
21diff -r e52413f52586 -r 388987dff7bf src/audio/SDL_wave.c
22--- a/src/audio/SDL_wave.c	Sat Jun 08 17:57:43 2019 -0700
23+++ b/src/audio/SDL_wave.c	Sat Jun 08 18:02:09 2019 -0700
24@@ -222,11 +222,12 @@
25 	struct IMA_ADPCM_decodestate state[2];
26 } IMA_ADPCM_state;
27
28-static int InitIMA_ADPCM(WaveFMT *format)
29+static int InitIMA_ADPCM(WaveFMT *format, int length)
30 {
31-	Uint8 *rogue_feel;
32+	Uint8 *rogue_feel, *rogue_feel_end;
33
34 	/* Set the rogue pointer to the IMA_ADPCM specific data */
35+	if (length < sizeof(*format)) goto too_short;
36 	IMA_ADPCM_state.wavefmt.encoding = SDL_SwapLE16(format->encoding);
37 	IMA_ADPCM_state.wavefmt.channels = SDL_SwapLE16(format->channels);
38 	IMA_ADPCM_state.wavefmt.frequency = SDL_SwapLE32(format->frequency);
39@@ -235,11 +236,16 @@
40 	IMA_ADPCM_state.wavefmt.bitspersample =
41 					 SDL_SwapLE16(format->bitspersample);
42 	rogue_feel = (Uint8 *)format+sizeof(*format);
43+	rogue_feel_end = (Uint8 *)format + length;
44 	if ( sizeof(*format) == 16 ) {
45 		rogue_feel += sizeof(Uint16);
46 	}
47+	if (rogue_feel + 2 > rogue_feel_end) goto too_short;
48 	IMA_ADPCM_state.wSamplesPerBlock = ((rogue_feel[1]<<8)|rogue_feel[0]);
49 	return(0);
50+too_short:
51+	SDL_SetError("Unexpected length of a chunk with an IMA ADPCM format");
52+	return(-1);
53 }
54
55 static Sint32 IMA_ADPCM_nibble(struct IMA_ADPCM_decodestate *state,Uint8 nybble)
56@@ -471,7 +477,7 @@
57 			break;
58 		case IMA_ADPCM_CODE:
59 			/* Try to understand this */
60-			if ( InitIMA_ADPCM(format) < 0 ) {
61+			if ( InitIMA_ADPCM(format, lenread) < 0 ) {
62 				was_error = 1;
63 				goto done;
64 			}
65