1# HG changeset patch
2# User Petr Písař <ppisar@redhat.com>
3# Date 1560182231 25200
4#      Mon Jun 10 08:57:11 2019 -0700
5# Branch SDL-1.2
6# Node ID a8afedbcaea0e84921dc770195c4699bda3ccdc5
7# Parent  faf9abbcfb5fe0d0ca23c4bf0394aa226ceccf02
8CVE-2019-7572: Fix a buffer overwrite in IMA_ADPCM_decode
9If data chunk was longer than expected based on a WAV format
10definition, IMA_ADPCM_decode() tried to write past the output
11buffer. This patch fixes it.
12
13Based on patch from
14<https://bugzilla.libsdl.org/show_bug.cgi?id=4496>.
15
16CVE-2019-7572
17https://bugzilla.libsdl.org/show_bug.cgi?id=4495
18
19Signed-off-by: Petr Písař <ppisar@redhat.com>
20
21# HG changeset patch
22# User Petr Písař <ppisar@redhat.com>
23# Date 1560041863 25200
24#      Sat Jun 08 17:57:43 2019 -0700
25# Branch SDL-1.2
26# Node ID e52413f5258600878f9a10d2f92605a729aa8976
27# Parent  4e73be7b47877ae11d2279bd916910d469d18f8e
28CVE-2019-7572: Fix a buffer overread in IMA_ADPCM_nibble
29If an IMA ADPCM block contained an initial index out of step table
30range (loaded in IMA_ADPCM_decode()), IMA_ADPCM_nibble() blindly used
31this bogus value and that lead to a buffer overread.
32
33This patch fixes it by moving clamping the index value at the
34beginning of IMA_ADPCM_nibble() function instead of the end after
35an update.
36
37CVE-2019-7572
38https://bugzilla.libsdl.org/show_bug.cgi?id=4495
39
40Signed-off-by: Petr Písař <ppisar@redhat.com>
41
42CVE: CVE-2019-7572
43Upstream-Status: Backport
44Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
45
46diff -r faf9abbcfb5f -r a8afedbcaea0 src/audio/SDL_wave.c
47--- a/src/audio/SDL_wave.c	Mon Jun 10 08:54:29 2019 -0700
48+++ b/src/audio/SDL_wave.c	Mon Jun 10 08:57:11 2019 -0700
49@@ -346,7 +346,7 @@
50 static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
51 {
52 	struct IMA_ADPCM_decodestate *state;
53-	Uint8 *freeable, *encoded, *encoded_end, *decoded;
54+	Uint8 *freeable, *encoded, *encoded_end, *decoded, *decoded_end;
55 	Sint32 encoded_len, samplesleft;
56 	unsigned int c, channels;
57
58@@ -373,6 +373,7 @@
59 		return(-1);
60 	}
61 	decoded = *audio_buf;
62+	decoded_end = decoded + *audio_len;
63
64 	/* Get ready... Go! */
65 	while ( encoded_len >= IMA_ADPCM_state.wavefmt.blockalign ) {
66@@ -392,6 +393,7 @@
67 			}
68
69 			/* Store the initial sample we start with */
70+			if (decoded + 2 > decoded_end) goto invalid_size;
71 			decoded[0] = (Uint8)(state[c].sample&0xFF);
72 			decoded[1] = (Uint8)(state[c].sample>>8);
73 			decoded += 2;
74@@ -402,6 +404,8 @@
75 		while ( samplesleft > 0 ) {
76 			for ( c=0; c<channels; ++c ) {
77 				if (encoded + 4 > encoded_end) goto invalid_size;
78+				if (decoded + 4 * 4 * channels > decoded_end)
79+					goto invalid_size;
80 				Fill_IMA_ADPCM_block(decoded, encoded,
81 						c, channels, &state[c]);
82 				encoded += 4;
83
84diff -r 4e73be7b4787 -r e52413f52586 src/audio/SDL_wave.c
85--- a/src/audio/SDL_wave.c	Sat Jun 01 18:27:46 2019 +0100
86+++ b/src/audio/SDL_wave.c	Sat Jun 08 17:57:43 2019 -0700
87@@ -264,6 +264,14 @@
88 	};
89 	Sint32 delta, step;
90
91+	/* Clamp index value. The inital value can be invalid. */
92+	if ( state->index > 88 ) {
93+		state->index = 88;
94+	} else
95+	if ( state->index < 0 ) {
96+		state->index = 0;
97+	}
98+
99 	/* Compute difference and new sample value */
100 	step = step_table[state->index];
101 	delta = step >> 3;
102@@ -275,12 +283,6 @@
103
104 	/* Update index value */
105 	state->index += index_table[nybble];
106-	if ( state->index > 88 ) {
107-		state->index = 88;
108-	} else
109-	if ( state->index < 0 ) {
110-		state->index = 0;
111-	}
112
113 	/* Clamp output sample */
114 	if ( state->sample > max_audioval ) {
115