From 30bdb3c56ddd911ab2b1629faa4ce6e883b80e2a Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Fri, 22 Dec 2017 11:08:49 +0000 Subject: [PATCH] sockets: check that the named file descriptor is a socket MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Marc-André Lureau Signed-off-by: Daniel P. Berrange --- tests/test-util-sockets.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++ util/qemu-sockets.c | 18 ++++++++-- 2 files changed, 105 insertions(+), 2 deletions(-) diff --git a/tests/test-util-sockets.c b/tests/test-util-sockets.c index 65190e0530..06eb0e4a28 100644 --- a/tests/test-util-sockets.c +++ b/tests/test-util-sockets.c @@ -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(); diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c index fa79471647..6dc4613855 100644 --- a/util/qemu-sockets.c +++ b/util/qemu-sockets.c @@ -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: -- 2.11.4.GIT