commands: partially backport seccomp notify

This backports seccomp notify into various parts of the codebase as a pure nop
to make maintenance easier.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/af_unix.c b/src/lxc/af_unix.c
index 3b00d64fb531c616e084bbc41fdb79a67d77cb56..06700fac1ead675980f66c19facd61e8930d1fcc 100644 (file)
--- a/src/lxc/af_unix.c
+++ b/src/lxc/af_unix.c
@@ -201,7 +201,8 @@ int lxc_abstract_unix_recv_fds(int fd, int *recvfds, int num_recvfds,
        struct iovec iov;
        struct cmsghdr *cmsg = NULL;
        char buf[1] = {0};
-       size_t cmsgbufsize = CMSG_SPACE(num_recvfds * sizeof(int));
+       size_t cmsgbufsize = CMSG_SPACE(sizeof(struct ucred)) +
+                            CMSG_SPACE(num_recvfds * sizeof(int));
 
        memset(&msg, 0, sizeof(msg));
        memset(&iov, 0, sizeof(iov));
@@ -224,12 +225,20 @@ int lxc_abstract_unix_recv_fds(int fd, int *recvfds, int num_recvfds,
        if (ret <= 0)
                goto out;
 
-       cmsg = CMSG_FIRSTHDR(&msg);
-
-       memset(recvfds, -1, num_recvfds * sizeof(int));
-       if (cmsg && cmsg->cmsg_len == CMSG_LEN(num_recvfds * sizeof(int)) &&
-           cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
-               memcpy(recvfds, CMSG_DATA(cmsg), num_recvfds * sizeof(int));
+       /*
+        * If SO_PASSCRED is set we will always get a ucred message.
+        */
+       for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+               if (cmsg->cmsg_type != SCM_RIGHTS)
+                       continue;
+
+               memset(recvfds, -1, num_recvfds * sizeof(int));
+               if (cmsg &&
+                   cmsg->cmsg_len == CMSG_LEN(num_recvfds * sizeof(int)) &&
+                   cmsg->cmsg_level == SOL_SOCKET)
+                       memcpy(recvfds, CMSG_DATA(cmsg), num_recvfds * sizeof(int));
+               break;
+       }
 
 out:
        return ret;

diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index f2a1339d3f61c0469cf2c061c49f2515e388cba3..554a3f9574c18f137054fd6196d50ee4dc80d39e 100644 (file)
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -853,7 +853,9 @@ static int attach_child_main(struct attach_clone_payload *payload)
 
        if (init_ctx->container && init_ctx->container->lxc_conf &&
            init_ctx->container->lxc_conf->seccomp) {
-               ret = lxc_seccomp_load(init_ctx->container->lxc_conf);
+               struct lxc_conf *conf = init_ctx->container->lxc_conf;
+
+               ret = lxc_seccomp_load(conf);
                if (ret < 0)
                        goto on_error;
 

diff --git a/src/lxc/commands.c b/src/lxc/commands.c
index ad2c578e14944dcd85d7825911c7ce7e53dbadbf..ca1cde4533ae06d9fd9a51602296896edf4b5a71 100644 (file)
--- a/src/lxc/commands.c
+++ b/src/lxc/commands.c
@@ -47,6 +47,7 @@
 #include "log.h"
 #include "lxc.h"
 #include "lxclock.h"
+#include "lxcseccomp.h"
 #include "mainloop.h"
 #include "memory_utils.h"
 #include "monitor.h"
@@ -97,6 +98,7 @@ static const char *lxc_cmd_str(lxc_cmd_t cmd)
                [LXC_CMD_ADD_STATE_CLIENT]    = "add_state_client",
                [LXC_CMD_CONSOLE_LOG]         = "console_log",
                [LXC_CMD_SERVE_STATE_CLIENTS] = "serve_state_clients",
+               [LXC_CMD_SECCOMP_NOTIFY_ADD_LISTENER] = "seccomp_notify_add_listener",
        };
 
        if (cmd >= LXC_CMD_MAX)
@@ -244,14 +246,21 @@ static int lxc_cmd_send(const char *name, struct lxc_cmd_rr *cmd,
        if (ret < 0 || (size_t)ret != sizeof(cmd->req))
                return -1;
 
-       if (cmd->req.datalen <= 0)
-               return move_fd(client_fd);
+       if (cmd->req.cmd == LXC_CMD_SECCOMP_NOTIFY_ADD_LISTENER) {
+               int notify_fd = PTR_TO_INT(cmd->req.data);
+               ret = lxc_abstract_unix_send_fds(client_fd, &notify_fd, 1, NULL, 0);
+               if (ret <= 0)
+                       return -1;
+       } else {
+               if (cmd->req.datalen <= 0)
+                       return move_fd(client_fd);
 
-       errno = EMSGSIZE;
-       ret = lxc_send_nointr(client_fd, (void *)cmd->req.data,
-                             cmd->req.datalen, MSG_NOSIGNAL);
-       if (ret < 0 || ret != (ssize_t)cmd->req.datalen)
-               return -1;
+               errno = EMSGSIZE;
+               ret = lxc_send_nointr(client_fd, (void *)cmd->req.data,
+                                     cmd->req.datalen, MSG_NOSIGNAL);
+               if (ret < 0 || ret != (ssize_t)cmd->req.datalen)
+                       return -1;
+       }
 
        return move_fd(client_fd);
 }
@@ -373,7 +382,8 @@ pid_t lxc_cmd_get_init_pid(const char *name, const char *lxcpath)
 }
 
 static int lxc_cmd_get_init_pid_callback(int fd, struct lxc_cmd_req *req,
-                                        struct lxc_handler *handler)
+                                        struct lxc_handler *handler,
+                                        struct lxc_epoll_descr *descr)
 {
        intmax_t pid = handler->pid;
 
@@ -407,7 +417,8 @@ int lxc_cmd_get_clone_flags(const char *name, const char *lxcpath)
 }
 
 static int lxc_cmd_get_clone_flags_callback(int fd, struct lxc_cmd_req *req,
-                                           struct lxc_handler *handler)
+                                           struct lxc_handler *handler,
+                                           struct lxc_epoll_descr *descr)
 {
        struct lxc_cmd_rsp rsp = { .data = INT_TO_PTR(handler->ns_clone_flags) };
 
@@ -457,7 +468,8 @@ char *lxc_cmd_get_cgroup_path(const char *name, const char *lxcpath,
 }
 
 static int lxc_cmd_get_cgroup_callback(int fd, struct lxc_cmd_req *req,
-                                      struct lxc_handler *handler)
+                                      struct lxc_handler *handler,
+                                      struct lxc_epoll_descr *descr)
 {
        const char *path;
        struct lxc_cmd_rsp rsp;
@@ -509,7 +521,8 @@ char *lxc_cmd_get_config_item(const char *name, const char *item,
 }
 
 static int lxc_cmd_get_config_item_callback(int fd, struct lxc_cmd_req *req,
-                                           struct lxc_handler *handler)
+                                           struct lxc_handler *handler,
+                                           struct lxc_epoll_descr *descr)
 {
        __do_free char *cidata = NULL;
        int cilen;
@@ -575,7 +588,8 @@ int lxc_cmd_get_state(const char *name, const char *lxcpath)
 }
 
 static int lxc_cmd_get_state_callback(int fd, struct lxc_cmd_req *req,
-                                     struct lxc_handler *handler)
+                                     struct lxc_handler *handler,
+                                     struct lxc_epoll_descr *descr)
 {
        struct lxc_cmd_rsp rsp = { .data = INT_TO_PTR(handler->state) };
 
@@ -622,7 +636,8 @@ int lxc_cmd_stop(const char *name, const char *lxcpath)
 }
 
 static int lxc_cmd_stop_callback(int fd, struct lxc_cmd_req *req,
-                                struct lxc_handler *handler)
+                                struct lxc_handler *handler,
+                                struct lxc_epoll_descr *descr)
 {
        struct lxc_cmd_rsp rsp;
        int stopsignal = SIGKILL;
@@ -665,7 +680,8 @@ int lxc_cmd_terminal_winch(const char *name, const char *lxcpath)
 }
 
 static int lxc_cmd_terminal_winch_callback(int fd, struct lxc_cmd_req *req,
-                                          struct lxc_handler *handler)
+                                          struct lxc_handler *handler,
+                                          struct lxc_epoll_descr *descr)
 {
        /* should never be called */
        return -1;
@@ -720,7 +736,8 @@ int lxc_cmd_console(const char *name, int *ttynum, int *fd, const char *lxcpath)
 }
 
 static int lxc_cmd_console_callback(int fd, struct lxc_cmd_req *req,
-                                   struct lxc_handler *handler)
+                                   struct lxc_handler *handler,
+                                   struct lxc_epoll_descr *descr)
 {
        int masterfd, ret;
        struct lxc_cmd_rsp rsp;
@@ -773,7 +790,8 @@ char *lxc_cmd_get_name(const char *hashed_sock_name)
 }
 
 static int lxc_cmd_get_name_callback(int fd, struct lxc_cmd_req *req,
-                                    struct lxc_handler *handler)
+                                    struct lxc_handler *handler,
+                                    struct lxc_epoll_descr *descr)
 {
        struct lxc_cmd_rsp rsp;
 
@@ -811,7 +829,8 @@ char *lxc_cmd_get_lxcpath(const char *hashed_sock_name)
 }
 
 static int lxc_cmd_get_lxcpath_callback(int fd, struct lxc_cmd_req *req,
-                                       struct lxc_handler *handler)
+                                       struct lxc_handler *handler,
+                                       struct lxc_epoll_descr *descr)
 {
        struct lxc_cmd_rsp rsp;
 
@@ -872,7 +891,8 @@ int lxc_cmd_add_state_client(const char *name, const char *lxcpath,
 }
 
 static int lxc_cmd_add_state_client_callback(int fd, struct lxc_cmd_req *req,
-                                            struct lxc_handler *handler)
+                                            struct lxc_handler *handler,
+                                            struct lxc_epoll_descr *descr)
 {
        int ret;
        struct lxc_cmd_rsp rsp = {0};
@@ -943,7 +963,8 @@ int lxc_cmd_console_log(const char *name, const char *lxcpath,
 }
 
 static int lxc_cmd_console_log_callback(int fd, struct lxc_cmd_req *req,
-                                       struct lxc_handler *handler)
+                                       struct lxc_handler *handler,
+                                       struct lxc_epoll_descr *descr)
 {
        struct lxc_cmd_rsp rsp;
        uint64_t buffer_size = handler->conf->console.buffer_size;
@@ -1002,7 +1023,8 @@ int lxc_cmd_serve_state_clients(const char *name, const char *lxcpath,
 }
 
 static int lxc_cmd_serve_state_clients_callback(int fd, struct lxc_cmd_req *req,
-                                               struct lxc_handler *handler)
+                                               struct lxc_handler *handler,
+                                               struct lxc_epoll_descr *descr)
 {
        int ret;
        lxc_state_t state = PTR_TO_INT(req->data);
@@ -1025,62 +1047,97 @@ reap_client_fd:
        return 1;
 }
 
+int lxc_cmd_seccomp_notify_add_listener(const char *name, const char *lxcpath,
+                                       int fd,
+                                       /* unused */ unsigned int command,
+                                       /* unused */ unsigned int flags)
+{
+       return minus_one_set_errno(ENOSYS);
+}
+
+static int lxc_cmd_seccomp_notify_add_listener_callback(int fd,
+                                                       struct lxc_cmd_req *req,
+                                                       struct lxc_handler *handler,
+                                                       struct lxc_epoll_descr *descr)
+{
+       struct lxc_cmd_rsp rsp = {
+           .ret = -ENOSYS,
+       };
+       int ret;
+
+       ret = lxc_cmd_rsp_send(fd, &rsp);
+       if (ret < 0)
+               goto reap_client_fd;
+
+       return 0;
+
+reap_client_fd:
+       /* Special indicator to lxc_cmd_handler() to close the fd and do
+        * related cleanup.
+        */
+       return 1;
+}
+
 static int lxc_cmd_process(int fd, struct lxc_cmd_req *req,
-                          struct lxc_handler *handler)
+                          struct lxc_handler *handler,
+                          struct lxc_epoll_descr *descr)
 {
-       typedef int (*callback)(int, struct lxc_cmd_req *, struct lxc_handler *);
+       typedef int (*callback)(int, struct lxc_cmd_req *, struct lxc_handler *,
+                               struct lxc_epoll_descr *);
 
        callback cb[LXC_CMD_MAX] = {
-               [LXC_CMD_CONSOLE]             = lxc_cmd_console_callback,
-               [LXC_CMD_TERMINAL_WINCH]      = lxc_cmd_terminal_winch_callback,
-               [LXC_CMD_STOP]                = lxc_cmd_stop_callback,
-               [LXC_CMD_GET_STATE]           = lxc_cmd_get_state_callback,
-               [LXC_CMD_GET_INIT_PID]        = lxc_cmd_get_init_pid_callback,
-               [LXC_CMD_GET_CLONE_FLAGS]     = lxc_cmd_get_clone_flags_callback,
-               [LXC_CMD_GET_CGROUP]          = lxc_cmd_get_cgroup_callback,
-               [LXC_CMD_GET_CONFIG_ITEM]     = lxc_cmd_get_config_item_callback,
-               [LXC_CMD_GET_NAME]            = lxc_cmd_get_name_callback,
-               [LXC_CMD_GET_LXCPATH]         = lxc_cmd_get_lxcpath_callback,
-               [LXC_CMD_ADD_STATE_CLIENT]    = lxc_cmd_add_state_client_callback,
-               [LXC_CMD_CONSOLE_LOG]         = lxc_cmd_console_log_callback,
-               [LXC_CMD_SERVE_STATE_CLIENTS] = lxc_cmd_serve_state_clients_callback,
+               [LXC_CMD_CONSOLE]                     = lxc_cmd_console_callback,
+               [LXC_CMD_TERMINAL_WINCH]              = lxc_cmd_terminal_winch_callback,
+               [LXC_CMD_STOP]                        = lxc_cmd_stop_callback,
+               [LXC_CMD_GET_STATE]                   = lxc_cmd_get_state_callback,
+               [LXC_CMD_GET_INIT_PID]                = lxc_cmd_get_init_pid_callback,
+               [LXC_CMD_GET_CLONE_FLAGS]             = lxc_cmd_get_clone_flags_callback,
+               [LXC_CMD_GET_CGROUP]                  = lxc_cmd_get_cgroup_callback,
+               [LXC_CMD_GET_CONFIG_ITEM]             = lxc_cmd_get_config_item_callback,
+               [LXC_CMD_GET_NAME]                    = lxc_cmd_get_name_callback,
+               [LXC_CMD_GET_LXCPATH]                 = lxc_cmd_get_lxcpath_callback,
+               [LXC_CMD_ADD_STATE_CLIENT]            = lxc_cmd_add_state_client_callback,
+               [LXC_CMD_CONSOLE_LOG]                 = lxc_cmd_console_log_callback,
+               [LXC_CMD_SERVE_STATE_CLIENTS]         = lxc_cmd_serve_state_clients_callback,
+               [LXC_CMD_SECCOMP_NOTIFY_ADD_LISTENER] = lxc_cmd_seccomp_notify_add_listener_callback,
        };
 
        if (req->cmd >= LXC_CMD_MAX) {
                ERROR("Undefined command id %d", req->cmd);
                return -1;
        }
-       return cb[req->cmd](fd, req, handler);
+       return cb[req->cmd](fd, req, handler, descr);
 }
 
 static void lxc_cmd_fd_cleanup(int fd, struct lxc_handler *handler,
-                              struct lxc_epoll_descr *descr,
-                              const lxc_cmd_t cmd)
+                              struct lxc_epoll_descr *descr, const lxc_cmd_t cmd)
 {
        struct lxc_list *cur, *next;
 
        lxc_terminal_free(handler->conf, fd);
        lxc_mainloop_del_handler(descr, fd);
-       if (cmd != LXC_CMD_ADD_STATE_CLIENT) {
-               close(fd);
-               return;
-       }
-
-       lxc_list_for_each_safe(cur, &handler->conf->state_clients, next) {
-               struct lxc_state_client *client = cur->elem;
 
-               if (client->clientfd != fd)
-                       continue;
-
-               /* kick client from list */
-               lxc_list_del(cur);
-               close(client->clientfd);
-               free(cur->elem);
-               free(cur);
-               /* No need to walk the whole list. If we found the state client
-                * fd there can't be a second one.
-                */
+       switch (cmd) {
+       case LXC_CMD_ADD_STATE_CLIENT:
+               lxc_list_for_each_safe(cur, &handler->conf->state_clients, next) {
+                       struct lxc_state_client *client = cur->elem;
+
+                       if (client->clientfd != fd)
+                               continue;
+
+                       /* kick client from list */
+                       lxc_list_del(cur);
+                       close(client->clientfd);
+                       free(cur->elem);
+                       free(cur);
+                       /* No need to walk the whole list. If we found the state
+                        * client fd there can't be a second one.
+                        */
+                       break;
+               }
                break;
+       default:
+               close(fd);
        }
 }
 
@@ -1139,7 +1196,7 @@ static int lxc_cmd_handler(int fd, uint32_t events, void *data,
                req.data = reqdata;
        }
 
-       ret = lxc_cmd_process(fd, &req, handler);
+       ret = lxc_cmd_process(fd, &req, handler, descr);
        if (ret) {
                /* This is not an error, but only a request to close fd. */
                ret = LXC_MAINLOOP_CONTINUE;

diff --git a/src/lxc/commands.h b/src/lxc/commands.h
index 2c024b65d124d4e70966512de71f6b4c09b94100..d7d0c6096aa2d77f24490a69f5ef13f96428dc51 100644 (file)
--- a/src/lxc/commands.h
+++ b/src/lxc/commands.h
@@ -46,6 +46,7 @@ typedef enum {
        LXC_CMD_ADD_STATE_CLIENT,
        LXC_CMD_CONSOLE_LOG,
        LXC_CMD_SERVE_STATE_CLIENTS,
+       LXC_CMD_SECCOMP_NOTIFY_ADD_LISTENER,
        LXC_CMD_MAX,
 } lxc_cmd_t;
 
@@ -124,5 +125,10 @@ extern int lxc_cmd_mainloop_add(const char *name, struct lxc_epoll_descr *descr,
 extern int lxc_try_cmd(const char *name, const char *lxcpath);
 extern int lxc_cmd_console_log(const char *name, const char *lxcpath,
                               struct lxc_console_log *log);
+extern int lxc_cmd_seccomp_notify_add_listener(const char *name,
+                                              const char *lxcpath,
+                                              int fd,
+                                              /* unused */ unsigned int command,
+                                              /* unused */ unsigned int flags);
 
 #endif /* __commands_h */

diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 88997f72b6a376db34727adfe30829c6e62091ce..a1b76e91b4effe6302e3cef41adafdef8dac9619 100644 (file)
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -4948,6 +4948,28 @@ out:
        return ret;
 }
 
+static int do_lxcapi_seccomp_notify(struct lxc_container *c, unsigned int cmd, int fd)
+{
+#if HAVE_DECL_SECCOMP_NOTIF_GET_FD
+       if (!c || !c->lxc_conf)
+               return minus_one_set_errno(-EINVAL);
+
+       switch (cmd) {
+       case LXC_SECCOMP_NOTIFY_GET_FD:
+               if (fd)
+                       return minus_one_set_errno(EINVAL);
+
+               return c->lxc_conf->seccomp_notify_fd;
+       }
+
+       return minus_one_set_errno(EINVAL);
+#else
+       return minus_one_set_errno(ENOSYS);
+#endif
+}
+
+WRAP_API_2(int, lxcapi_seccomp_notify, unsigned int, int)
+
 struct lxc_container *lxc_container_new(const char *name, const char *configpath)
 {
        struct lxc_container *c;

diff --git a/src/lxc/macro.h b/src/lxc/macro.h
index b83e4391159332d19d810bd6c697976700f88251..7df3b56f0300b84321a8264f49d9a52d475b90d3 100644 (file)
--- a/src/lxc/macro.h
+++ b/src/lxc/macro.h
@@ -407,4 +407,10 @@ enum {
                __internal_fd__;            \
        })
 
+#define minus_one_set_errno(__errno__) \
+       ({                             \
+               errno = __errno__;     \
+               -1;                    \
+       })
+
 #endif /* __LXC_MACRO_H */

diff --git a/src/lxc/start.c b/src/lxc/start.c
index 6bd799a326941877f771245c0d0d49da15f61a1c..4f1117c6d96bf68af80fb333325d2bf8bf4a381a 100644 (file)
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -1085,6 +1085,9 @@ void lxc_abort(const char *name, struct lxc_handler *handler)
 
 static int do_start(void *data)
 {
+       struct lxc_handler *handler = data;
+       __do_close_prot_errno int data_sock0 = handler->data_sock[0],
+                                 data_sock1 = handler->data_sock[1];
        int ret;
        char path[PATH_MAX];
        uid_t new_uid;
@@ -1093,7 +1096,6 @@ static int do_start(void *data)
        uid_t nsuid = 0;
        gid_t nsgid = 0;
        int devnull_fd = -1;
-       struct lxc_handler *handler = data;
 
        lxc_sync_fini_parent(handler);
 
@@ -1269,8 +1271,6 @@ static int do_start(void *data)
 
        /* Setup the container, ip, names, utsname, ... */
        ret = lxc_setup(handler);
-       close(handler->data_sock[1]);
-       close(handler->data_sock[0]);
        if (ret < 0) {
                ERROR("Failed to setup container \"%s\"", handler->name);
                goto out_warn_father;
@@ -1574,6 +1574,7 @@ static inline int do_share_ns(void *arg)
  */
 static int lxc_spawn(struct lxc_handler *handler)
 {
+       __do_close_prot_errno int data_sock0 = -EBADF, data_sock1 = -EBADF;
        int i, ret;
        char pidstr[20];
        bool wants_to_map_ids;
@@ -1606,6 +1607,8 @@ static int lxc_spawn(struct lxc_handler *handler)
                         handler->data_sock);
        if (ret < 0)
                goto out_sync_fini;
+       data_sock0 = handler->data_sock[0];
+       data_sock1 = handler->data_sock[1];
 
        ret = resolve_clone_flags(handler);
        if (ret < 0)
@@ -1962,11 +1965,6 @@ int __lxc_start(const char *name, struct lxc_handler *handler,
                ERROR("Failed to spawn container \"%s\"", name);
                goto out_detach_blockdev;
        }
-       /* close parent side of data socket */
-       close(handler->data_sock[0]);
-       handler->data_sock[0] = -1;
-       close(handler->data_sock[1]);
-       handler->data_sock[1] = -1;
 
        handler->conf->reboot = REBOOT_NONE;