fix CVE-2021-3700

0001-CVE-2021-3700.patch

@@ -0,0 +1,72 @@
+From 03c519ff5831ba75120e00ebebbf1d5a1f7220ab Mon Sep 17 00:00:00 2001
+From: Michael Hanselmann <public@hansmi.ch>
+Date: Sun, 8 Aug 2021 15:35:58 +0200
+Subject: [PATCH] Avoid use-after-free in serialization
+
+Serializing parsers with large amounts of buffered write data (e.g. in case of
+a slow or blocked write destination) would cause "serialize_data" to reallocate
+the state buffer whose default size is 64kB (USBREDIRPARSER_SERIALIZE_BUF_SIZE).
+The pointer to the position for the write buffer count would then point to
+a location outside the buffer where the number of write buffers would be written
+as a 32-bit value.
+
+As of QEMU 5.2.0 the serializer is invoked for migrations. Serializations for
+migrations may happen regularily such as when using the COLO feature[1].
+Serialization happens under QEMU's I/O lock. The guest can't control the state
+while the serialization is happening. The value written is the number of
+outstanding buffers which would be suceptible to timing and host system system
+load. The guest would have to continously groom the write buffers. A useful
+value needs to be allocated in the exact position freed during the buffer size
+increase, but before the buffer count is written. The author doesn't consider it
+realistic to exploit this use-after-free reliably.
+
+[1] https://wiki.qemu.org/Features/COLO
+
+Signed-off-by: Michael Hanselmann <public@hansmi.ch>
+---
+ usbredirparser/usbredirparser.c | 8 +++++---
+ 1 file changed, 5 insertions(+), 3 deletions(-)
+
+diff --git a/usbredirparser/usbredirparser.c b/usbredirparser/usbredirparser.c
+index d1f9850..dc5f5a4 100644
+--- a/usbredirparser/usbredirparser.c
++++ b/usbredirparser/usbredirparser.c
+@@ -20,6 +20,7 @@
+ */
+ #include "config.h"
+ 
++#include <stddef.h>
+ #include <stdio.h>
+ #include <stdlib.h>
+ #include <stdarg.h>
+@@ -1580,8 +1581,9 @@ int usbredirparser_serialize(struct usbredirparser *parser_pub,
+     struct usbredirparser_priv *parser =
+         (struct usbredirparser_priv *)parser_pub;
+     struct usbredirparser_buf *wbuf;
+-    uint8_t *write_buf_count_pos, *state = NULL, *pos = NULL;
++    uint8_t *state = NULL, *pos = NULL;
+     uint32_t write_buf_count = 0, len, remain = 0;
++    ptrdiff_t write_buf_count_pos;
+ 
+     *state_dest = NULL;
+     *state_len = 0;
+@@ -1626,7 +1628,7 @@ int usbredirparser_serialize(struct usbredirparser *parser_pub,
+                        parser->data, parser->data_read, "packet-data"))
+         return -1;
+ 
+-    write_buf_count_pos = pos;
++    write_buf_count_pos = pos - state;
+     /* To be replaced with write_buf_count later */
+     if (serialize_int(parser, &state, &pos, &remain, 0, "write_buf_count"))
+         return -1;
+@@ -1641,7 +1643,7 @@ int usbredirparser_serialize(struct usbredirparser *parser_pub,
+         wbuf = wbuf->next;
+     }
+     /* Patch in write_buf_count */
+-    memcpy(write_buf_count_pos, &write_buf_count, sizeof(int32_t));
++    memcpy(state + write_buf_count_pos, &write_buf_count, sizeof(int32_t));
+ 
+     /* Patch in length */
+     len = pos - state;
+-- 
+2.23.0

usbredir.spec

@@ -1,6 +1,6 @@
 Name:           usbredir
 Version:        0.8.0
-Release:        6
+Release:        7
 Summary:        network protocol libraries for sending USB device traffic
 License:        LGPLv2+ and GPLv2+
 URL:            https://www.spice-space.org/usbredir.html
@@ -11,6 +11,8 @@ BuildRequires:  libusb1-devel >= 1.0.9 gcc
 Provides:       %{name}-server
 Obsoletes:      %{name}-server
 
+Patch1:      0001-CVE-2021-3700.patch
+
 %description
 usbredir is the name of a network protocol for sending USB device traffic over
 a network connection. It is also the name of the software package offering a parsing
@@ -66,6 +68,9 @@ make %{?_smp_mflags} V=1
 
 
 %changelog
+* Thu Sep 23 2021 yanglongkang <yanglongkang@huawei.com> - 0.8.0-7
+- fix CVE-2021-3700
+
 * Fri Jul 30 2021 chenyanpanHW <chenyanpan@huawei.com> - 0.8.0-6
 - DESC: delete -S git from %autosetup, and delete BuildRequires git