1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
https://bugs.gentoo.org/974283
https://gstreamer.freedesktop.org/security/sa-2026-0014.html
https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/11245
From 6dfb6e2e8c26477fa3cba0ef439ae0011318319c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Thu, 26 Mar 2026 18:45:57 +0200
Subject: [PATCH 2/8] typefind: Avoid signed 32 bit integer overflow when
parsing AV1 LEB128 values
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/work_items/4994
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/11245>
--- a/gst/typefind/gsttypefindfunctions.c
+++ b/gst/typefind/gsttypefindfunctions.c
@@ -6881,7 +6881,7 @@ av1_leb128 (const guint8 * data, guint32 * retval, gint * read_bytes)
for (i = 0; i < 8; i++) {
leb128_byte = data[i];
- value |= (((gint) leb128_byte & 0x7f) << (i * 7));
+ value |= (((guint64) leb128_byte & 0x7f) << (i * 7));
if (!(leb128_byte & 0x80))
break;
--
GitLab
From f7835ad222a176a51c84d81cdee3456dd3dfec52 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Thu, 26 Mar 2026 18:59:11 +0200
Subject: [PATCH 4/8] typefind: Use a byte reader for parsing AV1 bitstreams
And make sure to use appropriate bounds checks.
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/work_items/4993
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/11245>
--- a/gst/typefind/gsttypefindfunctions.c
+++ b/gst/typefind/gsttypefindfunctions.c
@@ -6870,17 +6870,17 @@ av1_is_valid_obu_type (guint obu_type)
}
static gboolean
-av1_leb128 (const guint8 * data, guint32 * retval, gint * read_bytes)
+av1_leb128 (GstByteReader * br, guint32 * retval)
{
guint8 leb128_byte = 0;
guint64 value = 0;
gint i;
*retval = 0;
- *read_bytes = 0;
for (i = 0; i < 8; i++) {
- leb128_byte = data[i];
+ if (!gst_byte_reader_get_uint8 (br, &leb128_byte))
+ return FALSE;
value |= (((guint64) leb128_byte & 0x7f) << (i * 7));
if (!(leb128_byte & 0x80))
break;
@@ -6895,7 +6895,6 @@ av1_leb128 (const guint8 * data, guint32 * retval, gint * read_bytes)
/* check for bitstream conformance see chapter 4.10.5 */
if (value < G_MAXUINT32) {
*retval = (guint32) value;
- *read_bytes = i + 1;
return TRUE;
}
@@ -6903,44 +6902,44 @@ av1_leb128 (const guint8 * data, guint32 * retval, gint * read_bytes)
}
static gboolean
-av1_is_valid_obu (const guint8 * data, guint * obu_type, gint * read_bytes)
+av1_is_valid_obu (GstByteReader * br, guint * obu_type)
{
gboolean obu_forbidden_bit;
gboolean obu_extension_flag;
gboolean obu_has_size_field;
gboolean obu_reserved_1bit;
- int offset = 1;
+ guint8 b;
*obu_type = 0;
- *read_bytes = 0;
+
+ if (!gst_byte_reader_get_uint8 (br, &b))
+ return FALSE;
/* Detect OBU header */
- obu_forbidden_bit = !!(data[0] & 0x80);
+ obu_forbidden_bit = !!(b & 0x80);
if (obu_forbidden_bit)
return FALSE;
- *obu_type = (data[0] & 0x78) >> 3;
- obu_extension_flag = !!(data[0] & 0x4);
- obu_has_size_field = !!(data[0] & 0x2);
- obu_reserved_1bit = !!(data[0] & 0x1);
+ *obu_type = (b & 0x78) >> 3;
+ obu_extension_flag = !!(b & 0x4);
+ obu_has_size_field = !!(b & 0x2);
+ obu_reserved_1bit = !!(b & 0x1);
/* if obu_extension_flag is set temporal_id (3 bits)
* spatial_id (2 bits) and extension_header_reserved_3bits (3 bits)
* field are coded in the header so OBU size field is
* 1 byte after */
- if (obu_extension_flag)
- offset++;
-
- *read_bytes += offset;
+ if (obu_extension_flag) {
+ if (!gst_byte_reader_skip (br, 1))
+ return FALSE;
+ }
if (av1_is_valid_obu_type (*obu_type) && !obu_reserved_1bit) {
if (obu_has_size_field) {
guint32 obu_size;
- gint bytes;
- if (!av1_leb128 (data + offset, &obu_size, &bytes))
+ if (!av1_leb128 (br, &obu_size))
return FALSE;
- *read_bytes += bytes;
}
return TRUE;
@@ -6956,42 +6955,39 @@ av1_type_find (GstTypeFind * tf, gpointer unused)
guint32 frame_unit_size;
guint32 obu_length;
const guint8 *data;
+ GstByteReader br;
guint obu_type;
- gint read_bytes;
- gint offset = 0;
data = gst_type_find_peek (tf, 0, 25);
if (!data)
return;
- if (av1_is_valid_obu (data, &obu_type, &read_bytes)) {
+ gst_byte_reader_init (&br, data, 25);
+
+ if (av1_is_valid_obu (&br, &obu_type)) {
gst_type_find_suggest_simple (tf, GST_TYPE_FIND_MINIMUM, "video/x-av1",
"stream-format", G_TYPE_STRING, "obu-stream",
"alignment", G_TYPE_STRING, "none", NULL);
return;
}
- if (!av1_leb128 (data, &temporal_unit_size, &read_bytes))
+ if (!av1_leb128 (&br, &temporal_unit_size))
return;
- offset += read_bytes;
- if (!av1_leb128 (data + offset, &frame_unit_size, &read_bytes))
+ if (!av1_leb128 (&br, &frame_unit_size))
return;
- offset += read_bytes;
if (frame_unit_size > temporal_unit_size)
return;
- if (!av1_leb128 (data + offset, &obu_length, &read_bytes))
+ if (!av1_leb128 (&br, &obu_length))
return;
- offset += read_bytes;
if (obu_length > frame_unit_size)
return;
- if (!av1_is_valid_obu (data + offset, &obu_type, &read_bytes))
+ if (!av1_is_valid_obu (&br, &obu_type))
return;
- offset += read_bytes;
/* The first OBU must be a temporal delimiter */
if (obu_type == 2)
--
GitLab
From 30a18fc8dba3892f168008fe211f7c951465f26a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Thu, 26 Mar 2026 19:19:19 +0200
Subject: [PATCH 6/8] typefind: Allow G_MAXUINT32 as LEB128 encoded value when
parsing AV1 bitstreams
The spec states that any value less than or equal to (1<<32) - 1 should be
accepted but we were rejecting (1<<32) - 1.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/11245>
--- a/gst/typefind/gsttypefindfunctions.c
+++ b/gst/typefind/gsttypefindfunctions.c
@@ -6893,7 +6893,7 @@ av1_leb128 (GstByteReader * br, guint32 * retval)
return FALSE;
/* check for bitstream conformance see chapter 4.10.5 */
- if (value < G_MAXUINT32) {
+ if (value <= G_MAXUINT32) {
*retval = (guint32) value;
return TRUE;
}
--
GitLab
From 554e3ee6f2a353c0192b2af10f7b141e8cd32d85 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Thu, 26 Mar 2026 19:27:22 +0200
Subject: [PATCH 8/8] typefind: Remove dead code in AV1 LEB128 parser
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/11245>
--- a/gst/typefind/gsttypefindfunctions.c
+++ b/gst/typefind/gsttypefindfunctions.c
@@ -6889,9 +6889,6 @@ av1_leb128 (GstByteReader * br, guint32 * retval)
return FALSE;
}
- if (i == 8)
- return FALSE;
-
/* check for bitstream conformance see chapter 4.10.5 */
if (value <= G_MAXUINT32) {
*retval = (guint32) value;
--
GitLab
|
