From 22eb3dc56d8cb71af2c2d413ae587cc401704780 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Wed, 18 May 2022 11:24:37 +0300
Subject: [PATCH 2/4] matroskademux: Fix integer overflows in zlib/bz2/etc
decompression code
Various variables were of smaller types than needed and there were no
checks for any overflows when doing additions on the sizes. This is all
checked now.
In addition the size of the decompressed data is limited to 120MB now as
any larger sizes are likely pathological and we can avoid out of memory
situations in many cases like this.
Also fix a bug where the available output size on the next iteration in
the zlib/bz2 decompression code was provided too large and could
potentially lead to out of bound writes.
Thanks to Adam Doupe for analyzing and reporting the issue.
CVE: CVE-2022-1922, CVE-2022-1923, CVE-2022-1924, CVE-2022-1925
https://gstreamer.freedesktop.org/security/sa-2022-0002.html
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1225
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2610>
---
gst/matroska/matroska-read-common.c | 76 +++++++++++++++++++++++------
1 file changed, 61 insertions(+), 15 deletions(-)
diff --git a/gst/matroska/matroska-read-common.c b/gst/matroska/matroska-read-common.c
index 90d6e38e17..0ee9a787a4 100644
--- a/gst/matroska/matroska-read-common.c
+++ b/gst/matroska/matroska-read-common.c
@@ -70,6 +70,10 @@ typedef struct
gboolean audio_only;
} TargetTypeContext;
+/* 120MB as maximum decompressed data size. Anything bigger is likely
+ * pathological, and like this we avoid out of memory situations in many cases
+ */
+#define MAX_DECOMPRESS_SIZE (120 * 1024 * 1024)
static gboolean
gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
@@ -77,19 +81,23 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
GstMatroskaTrackCompressionAlgorithm algo)
{
guint8 *new_data = NULL;
- guint new_size = 0;
+ gsize new_size = 0;
guint8 *data = *data_out;
- guint size = *size_out;
+ const gsize size = *size_out;
gboolean ret = TRUE;
+ if (size > G_MAXUINT32) {
+ GST_WARNING ("too large compressed data buffer.");
+ ret = FALSE;
+ goto out;
+ }
+
if (algo == GST_MATROSKA_TRACK_COMPRESSION_ALGORITHM_ZLIB) {
#ifdef HAVE_ZLIB
/* zlib encoded data */
z_stream zstream;
- guint orig_size;
int result;
- orig_size = size;
zstream.zalloc = (alloc_func) 0;
zstream.zfree = (free_func) 0;
zstream.opaque = (voidpf) 0;
@@ -99,8 +107,8 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
goto out;
}
zstream.next_in = (Bytef *) data;
- zstream.avail_in = orig_size;
- new_size = orig_size;
+ zstream.avail_in = size;
+ new_size = size;
new_data = g_malloc (new_size);
zstream.avail_out = new_size;
zstream.next_out = (Bytef *) new_data;
@@ -114,10 +122,18 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
break;
}
+ if (new_size > G_MAXSIZE - 4096 || new_size + 4096 > MAX_DECOMPRESS_SIZE) {
+ GST_WARNING ("too big decompressed data");
+ result = Z_MEM_ERROR;
+ break;
+ }
+
new_size += 4096;
new_data = g_realloc (new_data, new_size);
zstream.next_out = (Bytef *) (new_data + zstream.total_out);
- zstream.avail_out += 4096;
+ /* avail_out is an unsigned int */
+ g_assert (new_size - zstream.total_out <= G_MAXUINT);
+ zstream.avail_out = new_size - zstream.total_out;
} while (zstream.avail_in > 0);
if (result != Z_STREAM_END) {
@@ -137,13 +153,11 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
#ifdef HAVE_BZ2
/* bzip2 encoded data */
bz_stream bzstream;
- guint orig_size;
int result;
bzstream.bzalloc = NULL;
bzstream.bzfree = NULL;
bzstream.opaque = NULL;
- orig_size = size;
if (BZ2_bzDecompressInit (&bzstream, 0, 0) != BZ_OK) {
GST_WARNING ("bzip2 initialization failed.");
@@ -152,8 +166,8 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
}
bzstream.next_in = (char *) data;
- bzstream.avail_in = orig_size;
- new_size = orig_size;
+ bzstream.avail_in = size;
+ new_size = size;
new_data = g_malloc (new_size);
bzstream.avail_out = new_size;
bzstream.next_out = (char *) new_data;
@@ -167,17 +181,31 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
break;
}
+ if (new_size > G_MAXSIZE - 4096 || new_size + 4096 > MAX_DECOMPRESS_SIZE) {
+ GST_WARNING ("too big decompressed data");
+ result = BZ_MEM_ERROR;
+ break;
+ }
+
new_size += 4096;
new_data = g_realloc (new_data, new_size);
- bzstream.next_out = (char *) (new_data + bzstream.total_out_lo32);
- bzstream.avail_out += 4096;
+ bzstream.next_out =
+ (char *) (new_data + ((guint64) bzstream.total_out_hi32 << 32) +
+ bzstream.total_out_lo32);
+ /* avail_out is an unsigned int */
+ g_assert (new_size - ((guint64) bzstream.total_out_hi32 << 32) +
+ bzstream.total_out_lo32 <= G_MAXUINT);
+ bzstream.avail_out =
+ new_size - ((guint64) bzstream.total_out_hi32 << 32) +
+ bzstream.total_out_lo32;
} while (bzstream.avail_in > 0);
if (result != BZ_STREAM_END) {
ret = FALSE;
g_free (new_data);
} else {
- new_size = bzstream.total_out_lo32;
+ new_size =
+ ((guint64) bzstream.total_out_hi32 << 32) + bzstream.total_out_lo32;
}
BZ2_bzDecompressEnd (&bzstream);
@@ -189,7 +217,13 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
} else if (algo == GST_MATROSKA_TRACK_COMPRESSION_ALGORITHM_LZO1X) {
/* lzo encoded data */
int result;
- int orig_size, out_size;
+ gint orig_size, out_size;
+
+ if (size > G_MAXINT) {
+ GST_WARNING ("too large compressed data buffer.");
+ ret = FALSE;
+ goto out;
+ }
orig_size = size;
out_size = size;
@@ -203,6 +237,11 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
result = lzo1x_decode (new_data, &out_size, data, &orig_size);
if (orig_size > 0) {
+ if (new_size > G_MAXINT - 4096 || new_size + 4096 > MAX_DECOMPRESS_SIZE) {
+ GST_WARNING ("too big decompressed data");
+ result = LZO_ERROR;
+ break;
+ }
new_size += 4096;
new_data = g_realloc (new_data, new_size);
}
@@ -221,6 +260,13 @@ gst_matroska_decompress_data (GstMatroskaTrackEncoding * enc,
} else if (algo == GST_MATROSKA_TRACK_COMPRESSION_ALGORITHM_HEADERSTRIP) {
/* header stripped encoded data */
if (enc->comp_settings_length > 0) {
+ if (size > G_MAXSIZE - enc->comp_settings_length
+ || size + enc->comp_settings_length > MAX_DECOMPRESS_SIZE) {
+ GST_WARNING ("too big decompressed data");
+ ret = FALSE;
+ goto out;
+ }
+
new_data = g_malloc (size + enc->comp_settings_length);
new_size = size + enc->comp_settings_length;
--
2.38.1