sockets: check that the named file descriptor is a socket

The SocketAddress struct has an "fd" type, which references the name of a
file descriptor passed over the monitor using the "getfd" command. We
currently blindly assume the FD is a socket, which can lead to hard to
diagnose errors later. This adds an explicit check that the FD is actually
a socket to improve the error diagnosis.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrange 2017-12-22 11:08:49 +00:00 committed by Daniel P. Berrangé
parent 58dc31f1a7
commit 30bdb3c56d
2 changed files with 105 additions and 2 deletions

View File

@ -23,6 +23,7 @@
#include "qemu/sockets.h"
#include "qapi/error.h"
#include "socket-helpers.h"
#include "monitor/monitor.h"
static void test_fd_is_socket_bad(void)
{
@ -49,6 +50,90 @@ static void test_fd_is_socket_good(void)
close(fd);
}
static int mon_fd = -1;
static const char *mon_fdname;
int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp)
{
g_assert(cur_mon);
g_assert(mon == cur_mon);
if (mon_fd == -1 || !g_str_equal(mon_fdname, fdname)) {
error_setg(errp, "No fd named %s", fdname);
return -1;
}
return dup(mon_fd);
}
/* Syms in libqemustub.a are discarded at .o file granularity.
* To replace monitor_get_fd() we must ensure everything in
* stubs/monitor.c is defined, to make sure monitor.o is discarded
* otherwise we get duplicate syms at link time.
*/
Monitor *cur_mon;
void monitor_init(Chardev *chr, int flags) {}
static void test_socket_fd_pass_good(void)
{
SocketAddress addr;
int fd;
cur_mon = g_malloc(1); /* Fake a monitor */
mon_fdname = "myfd";
mon_fd = qemu_socket(AF_INET, SOCK_STREAM, 0);
g_assert_cmpint(mon_fd, >, STDERR_FILENO);
addr.type = SOCKET_ADDRESS_TYPE_FD;
addr.u.fd.str = g_strdup(mon_fdname);
fd = socket_connect(&addr, &error_abort);
g_assert_cmpint(fd, !=, -1);
g_assert_cmpint(fd, !=, mon_fd);
close(fd);
fd = socket_listen(&addr, &error_abort);
g_assert_cmpint(fd, !=, -1);
g_assert_cmpint(fd, !=, mon_fd);
close(fd);
g_free(addr.u.fd.str);
mon_fdname = NULL;
close(mon_fd);
mon_fd = -1;
g_free(cur_mon);
cur_mon = NULL;
}
static void test_socket_fd_pass_bad(void)
{
SocketAddress addr;
Error *err = NULL;
int fd;
cur_mon = g_malloc(1); /* Fake a monitor */
mon_fdname = "myfd";
mon_fd = dup(STDOUT_FILENO);
g_assert_cmpint(mon_fd, >, STDERR_FILENO);
addr.type = SOCKET_ADDRESS_TYPE_FD;
addr.u.fd.str = g_strdup(mon_fdname);
fd = socket_connect(&addr, &err);
g_assert_cmpint(fd, ==, -1);
error_free_or_abort(&err);
fd = socket_listen(&addr, &err);
g_assert_cmpint(fd, ==, -1);
error_free_or_abort(&err);
g_free(addr.u.fd.str);
mon_fdname = NULL;
close(mon_fd);
mon_fd = -1;
g_free(cur_mon);
cur_mon = NULL;
}
int main(int argc, char **argv)
{
bool has_ipv4, has_ipv6;
@ -71,6 +156,10 @@ int main(int argc, char **argv)
test_fd_is_socket_bad);
g_test_add_func("/util/socket/is-socket/good",
test_fd_is_socket_good);
g_test_add_func("/socket/fd-pass/good",
test_socket_fd_pass_good);
g_test_add_func("/socket/fd-pass/bad",
test_socket_fd_pass_bad);
}
return g_test_run();

View File

@ -1042,6 +1042,20 @@ fail:
return NULL;
}
static int socket_get_fd(const char *fdstr, Error **errp)
{
int fd = monitor_get_fd(cur_mon, fdstr, errp);
if (fd < 0) {
return -1;
}
if (!fd_is_socket(fd)) {
error_setg(errp, "File descriptor '%s' is not a socket", fdstr);
close(fd);
return -1;
}
return fd;
}
int socket_connect(SocketAddress *addr, Error **errp)
{
int fd;
@ -1056,7 +1070,7 @@ int socket_connect(SocketAddress *addr, Error **errp)
break;
case SOCKET_ADDRESS_TYPE_FD:
fd = monitor_get_fd(cur_mon, addr->u.fd.str, errp);
fd = socket_get_fd(addr->u.fd.str, errp);
break;
case SOCKET_ADDRESS_TYPE_VSOCK:
@ -1083,7 +1097,7 @@ int socket_listen(SocketAddress *addr, Error **errp)
break;
case SOCKET_ADDRESS_TYPE_FD:
fd = monitor_get_fd(cur_mon, addr->u.fd.str, errp);
fd = socket_get_fd(addr->u.fd.str, errp);
break;
case SOCKET_ADDRESS_TYPE_VSOCK: