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char: fix use-after-free with dup chardev & reconnect

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With a reconnect socket, qemu_char_open() will start a background
thread. It should keep a reference on the chardev.

Fixes invalid read:
READ of size 8 at 0x6040000ac858 thread T7
    #0 0x5555598d37b8 in unix_connect_saddr /home/elmarco/src/qq/util/qemu-sockets.c:954
    #1 0x5555598d4751 in socket_connect /home/elmarco/src/qq/util/qemu-sockets.c:1109
    #2 0x555559707c34 in qio_channel_socket_connect_sync /home/elmarco/src/qq/io/channel-socket.c:145
    #3 0x5555596adebb in tcp_chr_connect_client_task /home/elmarco/src/qq/chardev/char-socket.c:1104
    #4 0x555559723d55 in qio_task_thread_worker /home/elmarco/src/qq/io/task.c:123
    #5 0x5555598a6731 in qemu_thread_start /home/elmarco/src/qq/util/qemu-thread-posix.c:519
    #6 0x7ffff40d4431 in start_thread (/lib64/libpthread.so.0+0x9431)
    #7 0x7ffff40029d2 in __clone (/lib64/libc.so.6+0x1019d2)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200420112012.567284-1-marcandre.lureau@redhat.com>
This commit is contained in:
Marc-André Lureau 2020-04-20 13:20:12 +02:00
parent 14a7a20306
commit 6806601969
2 changed files with 54 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
chardev/char-socket.c
View File

@ -1129,7 +1129,8 @@ static void tcp_chr_connect_client_async(Chardev *chr)
*/
s->connect_task = qio_task_new(OBJECT(sioc),
qemu_chr_socket_connected,
chr, NULL);
object_ref(OBJECT(chr)),
(GDestroyNotify)object_unref);
qio_task_run_in_thread(s->connect_task,
tcp_chr_connect_client_task,
s->addr,

54
tests/test-char.c
View File

@ -904,6 +904,52 @@ typedef struct {
char_socket_cb event_cb;
} CharSocketClientTestConfig;
static void char_socket_client_dupid_test(gconstpointer opaque)
{
const CharSocketClientTestConfig *config = opaque;
QIOChannelSocket *ioc;
char *optstr;
Chardev *chr1, *chr2;
SocketAddress *addr;
QemuOpts *opts;
Error *local_err = NULL;
/*
* Setup a listener socket and determine get its address
* so we know the TCP port for the client later
*/
ioc = qio_channel_socket_new();
g_assert_nonnull(ioc);
qio_channel_socket_listen_sync(ioc, config->addr, 1, &error_abort);
addr = qio_channel_socket_get_local_address(ioc, &error_abort);
g_assert_nonnull(addr);
/*
* Populate the chardev address based on what the server
* is actually listening on
*/
optstr = char_socket_addr_to_opt_str(addr,
config->fd_pass,
config->reconnect,
false);
opts = qemu_opts_parse_noisily(qemu_find_opts("chardev"),
optstr, true);
g_assert_nonnull(opts);
chr1 = qemu_chr_new_from_opts(opts, NULL, &error_abort);
g_assert_nonnull(chr1);
chr2 = qemu_chr_new_from_opts(opts, NULL, &local_err);
g_assert_null(chr2);
error_free_or_abort(&local_err);
object_unref(OBJECT(ioc));
qemu_opts_del(opts);
object_unparent(OBJECT(chr1));
qapi_free_SocketAddress(addr);
g_free(optstr);
}
static void char_socket_client_test(gconstpointer opaque)
{
const CharSocketClientTestConfig *config = opaque;
@ -1456,7 +1502,7 @@ int main(int argc, char **argv)
#define SOCKET_CLIENT_TEST(name, addr) \
static CharSocketClientTestConfig client1 ## name = \
{ addr, NULL, false, false, char_socket_event}; \
{ addr, NULL, false, false, char_socket_event }; \
static CharSocketClientTestConfig client2 ## name = \
{ addr, NULL, true, false, char_socket_event }; \
static CharSocketClientTestConfig client3 ## name = \
@ -1470,6 +1516,8 @@ int main(int argc, char **argv)
static CharSocketClientTestConfig client7 ## name = \
{ addr, ",reconnect=1", true, false, \
char_socket_event_with_error }; \
static CharSocketClientTestConfig client8 ## name = \
{ addr, ",reconnect=1", false, false, char_socket_event }; \
g_test_add_data_func("/char/socket/client/mainloop/" # name, \
&client1 ##name, char_socket_client_test); \
g_test_add_data_func("/char/socket/client/wait-conn/" # name, \
@ -1483,7 +1531,9 @@ int main(int argc, char **argv)
g_test_add_data_func("/char/socket/client/wait-conn-fdpass/" # name, \
&client6 ##name, char_socket_client_test); \
g_test_add_data_func("/char/socket/client/reconnect-error/" # name, \
&client7 ##name, char_socket_client_test)
&client7 ##name, char_socket_client_test); \
g_test_add_data_func("/char/socket/client/dupid-reconnect/" # name, \
&client8 ##name, char_socket_client_dupid_test)
if (has_ipv4) {
SOCKET_SERVER_TEST(tcp, &tcpaddr);