third_party/socket_wrapper/socket_wrapper.c ... fd-passing simple
authorStefan Metzmacher <metze@samba.org>
Mon, 29 Jun 2020 16:28:56 +0000 (18:28 +0200)
committerStefan Metzmacher <metze@samba.org>
Mon, 5 Oct 2020 12:12:40 +0000 (14:12 +0200)
third_party/socket_wrapper/socket_wrapper.c

index ffdd31a51bfdec2b1ce4fa5a8be2cf175fc55543..fdabc111b67e5f17185f545a1cc54734d0fbdf8b 100644 (file)
@@ -268,6 +268,7 @@ struct socket_info
        int pktinfo;
        int tcp_nodelay;
        int listening;
+       int fd_passed;
 
        /* The unix path so we can unlink it on close() */
        struct sockaddr_un un_addr;
@@ -1779,7 +1780,7 @@ static int find_socket_info_index(int fd)
        return socket_fds_idx[fd];
 }
 
-static int swrap_add_socket_info(struct socket_info *si_input)
+static int swrap_add_socket_info(const struct socket_info *si_input)
 {
        struct socket_info *si = NULL;
        int si_index = -1;
@@ -1822,6 +1823,7 @@ static int swrap_create_socket(struct socket_info *si, int fd)
                          "trying to add %d",
                          socket_fds_max,
                          fd);
+               errno = EMFILE;
                return -1;
        }
 
@@ -2932,7 +2934,7 @@ static int swrap_pcap_get_fd(const char *fname)
                file_hdr.link_type      = 0x0065; /* 101 RAW IP */
 
                if (write(fd, &file_hdr, sizeof(file_hdr)) != sizeof(file_hdr)) {
-                       close(fd);
+                       libc_close(fd);
                        fd = -1;
                }
                return fd;
@@ -3437,6 +3439,9 @@ static int swrap_socket(int family, int type, int protocol)
 
        ret = swrap_create_socket(si, fd);
        if (ret == -1) {
+               int saved_errno = errno;
+               libc_close(fd);
+               errno = saved_errno;
                return -1;
        }
 
@@ -3607,7 +3612,7 @@ static int swrap_accept(int s,
                                       &in_addr.sa_socklen);
        if (ret == -1) {
                SWRAP_UNLOCK_SI(parent_si);
-               close(fd);
+               libc_close(fd);
                return ret;
        }
 
@@ -3639,7 +3644,7 @@ static int swrap_accept(int s,
                               &un_my_addr.sa.s,
                               &un_my_addr.sa_socklen);
        if (ret == -1) {
-               close(fd);
+               libc_close(fd);
                return ret;
        }
 
@@ -3650,7 +3655,7 @@ static int swrap_accept(int s,
                                       &in_my_addr.sa.s,
                                       &in_my_addr.sa_socklen);
        if (ret == -1) {
-               close(fd);
+               libc_close(fd);
                return ret;
        }
 
@@ -3665,7 +3670,9 @@ static int swrap_accept(int s,
 
        idx = swrap_create_socket(&new_si, fd);
        if (idx == -1) {
-               close (fd);
+               int saved_errno = errno;
+               libc_close(fd);
+               errno = saved_errno;
                return -1;
        }
 
@@ -4959,16 +4966,21 @@ static int swrap_msghdr_add_socket_info(struct socket_info *si,
        return rc;
 }
 
-static int swrap_sendmsg_copy_cmsg(struct cmsghdr *cmsg,
+static int swrap_sendmsg_copy_cmsg(const struct cmsghdr *cmsg,
                                   uint8_t **cm_data,
                                   size_t *cm_data_space);
-static int swrap_sendmsg_filter_cmsg_socket(struct cmsghdr *cmsg,
-                                           uint8_t **cm_data,
-                                           size_t *cm_data_space);
-
-static int swrap_sendmsg_filter_cmsghdr(struct msghdr *msg,
+static int swrap_sendmsg_filter_cmsg_ipproto_ip(const struct cmsghdr *cmsg,
+                                               uint8_t **cm_data,
+                                               size_t *cm_data_space);
+static int swrap_sendmsg_filter_cmsg_sol_socket(const struct cmsghdr *cmsg,
+                                               uint8_t **cm_data,
+                                               size_t *cm_data_space);
+
+static int swrap_sendmsg_filter_cmsghdr(const struct msghdr *_msg,
                                        uint8_t **cm_data,
-                                       size_t *cm_data_space) {
+                                       size_t *cm_data_space)
+{
+       struct msghdr *msg = discard_const_p(struct msghdr, _msg);
        struct cmsghdr *cmsg;
        int rc = -1;
 
@@ -4982,9 +4994,14 @@ static int swrap_sendmsg_filter_cmsghdr(struct msghdr *msg,
             cmsg = CMSG_NXTHDR(msg, cmsg)) {
                switch (cmsg->cmsg_level) {
                case IPPROTO_IP:
-                       rc = swrap_sendmsg_filter_cmsg_socket(cmsg,
-                                                             cm_data,
-                                                             cm_data_space);
+                       rc = swrap_sendmsg_filter_cmsg_ipproto_ip(cmsg,
+                                                                 cm_data,
+                                                                 cm_data_space);
+                       break;
+               case SOL_SOCKET:
+                       rc = swrap_sendmsg_filter_cmsg_sol_socket(cmsg,
+                                                                 cm_data,
+                                                                 cm_data_space);
                        break;
                default:
                        rc = swrap_sendmsg_copy_cmsg(cmsg,
@@ -4992,12 +5009,19 @@ static int swrap_sendmsg_filter_cmsghdr(struct msghdr *msg,
                                                     cm_data_space);
                        break;
                }
+               if (rc < 0) {
+                       int saved_errno = errno;
+                       SAFE_FREE(*cm_data);
+                       *cm_data_space = 0;
+                       errno = saved_errno;
+                       return rc;
+               }
        }
 
        return rc;
 }
 
-static int swrap_sendmsg_copy_cmsg(struct cmsghdr *cmsg,
+static int swrap_sendmsg_copy_cmsg(const struct cmsghdr *cmsg,
                                   uint8_t **cm_data,
                                   size_t *cm_data_space)
 {
@@ -5020,14 +5044,14 @@ static int swrap_sendmsg_copy_cmsg(struct cmsghdr *cmsg,
        return 0;
 }
 
-static int swrap_sendmsg_filter_cmsg_pktinfo(struct cmsghdr *cmsg,
+static int swrap_sendmsg_filter_cmsg_pktinfo(const struct cmsghdr *cmsg,
                                            uint8_t **cm_data,
                                            size_t *cm_data_space);
 
 
-static int swrap_sendmsg_filter_cmsg_socket(struct cmsghdr *cmsg,
-                                           uint8_t **cm_data,
-                                           size_t *cm_data_space)
+static int swrap_sendmsg_filter_cmsg_ipproto_ip(const struct cmsghdr *cmsg,
+                                               uint8_t **cm_data,
+                                               size_t *cm_data_space)
 {
        int rc = -1;
 
@@ -5053,7 +5077,7 @@ static int swrap_sendmsg_filter_cmsg_socket(struct cmsghdr *cmsg,
        return rc;
 }
 
-static int swrap_sendmsg_filter_cmsg_pktinfo(struct cmsghdr *cmsg,
+static int swrap_sendmsg_filter_cmsg_pktinfo(const struct cmsghdr *cmsg,
                                             uint8_t **cm_data,
                                             size_t *cm_data_space)
 {
@@ -5067,7 +5091,816 @@ static int swrap_sendmsg_filter_cmsg_pktinfo(struct cmsghdr *cmsg,
         */
        return 0;
 }
+
+static int swrap_sendmsg_filter_cmsg_sol_socket(const struct cmsghdr *cmsg,
+                                               uint8_t **cm_data,
+                                               size_t *cm_data_space)
+{
+       int rc = -1;
+
+       switch (cmsg->cmsg_type) {
+       case SCM_RIGHTS:
+               SWRAP_LOG(SWRAP_LOG_TRACE,
+                         "Ignoring SCM_RIGHTS on inet socket!");
+               rc = 0;
+               break;
+#ifdef SCM_CREDENTIALS
+       case SCM_CREDENTIALS:
+               SWRAP_LOG(SWRAP_LOG_TRACE,
+                         "Ignoring SCM_CREDENTIALS on inet socket!");
+               rc = 0;
+               break;
+#endif /* SCM_CREDENTIALS */
+       default:
+               rc = swrap_sendmsg_copy_cmsg(cmsg,
+                                            cm_data,
+                                            cm_data_space);
+               break;
+       }
+
+       return rc;
+}
+
+#if 0
+#define __STRUCT_WITH_MAGIC(__magic_string_var, __magic_size_var, __payload_definition, __main_definition) \
+static const char *__magic_string_var = ## __payload_definition; \
+static const size_t __magic_size_var = sizeof(## __payload_definition); \
+__payload_definition; \
+__main_definition;
+#define __STRUCT_WITH_MAGIC(__magic_string_var, __magic_size_var, __payload_definition, __main_definition) \
+extern const char *__magic_string_var; \
+const char *__magic_string_var = # __payload_definition; \
+extern const size_t __magic_size_var; \
+const size_t __magic_size_var = sizeof(# __payload_definition); \
+__payload_definition; \
+__main_definition;
+
+__STRUCT_WITH_MAGIC(
+swrap_unix_scm_rights_payload_magic_string, \
+swrap_unix_scm_rights_payload_magic_size, \
+
+#endif
+
+#define SWRAP_MAX_PASSED_FDS ((size_t)8)
+#define SWRAP_MAX_PASSED_SOCKET_INFO ((size_t)8)
+struct swrap_unix_scm_rights_payload { \
+       uint8_t num_idxs; \
+       int8_t idxs[SWRAP_MAX_PASSED_FDS]; \
+       struct socket_info infos[SWRAP_MAX_PASSED_SOCKET_INFO]; \
+};
+struct swrap_unix_scm_rights { \
+       uint32_t full_size;
+       uint32_t payload_size;
+//     char payload_definition[sizeof(# __payload_definition)];
+       struct swrap_unix_scm_rights_payload payload;
+};
+
+static void swrap_dec_fd_passed_array(size_t num, struct socket_info **array)
+{
+       int saved_errno = errno;
+       size_t i;
+
+       for (i = 0; i < num; i++) {
+               struct socket_info *si = array[i];
+               if (si == NULL) {
+                       continue;
+               }
+
+               SWRAP_LOCK_SI(si);
+               swrap_dec_refcount(si);
+               if (si->fd_passed > 0) {
+                       si->fd_passed -= 1;
+               }
+               SWRAP_UNLOCK_SI(si);
+               array[i] = NULL;
+       }
+
+       errno = saved_errno;
+}
+
+static void swrap_undo_si_idx_array(size_t num, int *array)
+{
+       int saved_errno = errno;
+       size_t i;
+
+       swrap_mutex_lock(&first_free_mutex);
+
+       for (i = 0; i < num; i++) {
+               struct socket_info *si = NULL;
+
+               if (array[i] == -1) {
+                       continue;
+               }
+
+               si = swrap_get_socket_info(array[i]);
+               if (si == NULL) {
+                       continue;
+               }
+
+               SWRAP_LOCK_SI(si);
+               swrap_dec_refcount(si);
+               SWRAP_UNLOCK_SI(si);
+
+               swrap_set_next_free(si, first_free);
+               first_free = array[i];
+               array[i] = -1;
+       }
+
+       swrap_mutex_unlock(&first_free_mutex);
+       errno = saved_errno;
+}
+
+static void swrap_close_fd_array(size_t num, const int *array)
+{
+       int saved_errno = errno;
+       size_t i;
+
+       for (i = 0; i < num; i++) {
+               if (array[i] == -1) {
+                       continue;
+               }
+               libc_close(array[i]);
+       }
+
+       errno = saved_errno;
+}
+
+union __swrap_fds {
+       const uint8_t *p;
+       int *fds;
+};
+
+union __swrap_cmsghdr {
+       const uint8_t *p;
+       struct cmsghdr *cmsg;
+};
+
+static int swrap_sendmsg_unix_scm_rights(const struct cmsghdr *cmsg,
+                                        uint8_t **cm_data,
+                                        size_t *cm_data_space,
+                                        int *scm_rights_pipe_fd)
+{
+       struct swrap_unix_scm_rights info;
+       struct swrap_unix_scm_rights_payload *payload = NULL;
+       int si_idx_array[SWRAP_MAX_PASSED_FDS];
+       struct socket_info *si_array[SWRAP_MAX_PASSED_FDS] = { NULL, };
+       size_t info_idx = 0;
+       size_t size_fds_in;
+       size_t num_fds_in;
+       union __swrap_fds __fds_in = { .p = NULL, };
+       const int *fds_in = NULL;
+       size_t num_fds_out;
+       size_t size_fds_out;
+       union __swrap_fds __fds_out = { .p = NULL, };
+       int *fds_out = NULL;
+       size_t cmsg_len;
+       size_t cmsg_space;
+       size_t new_cm_data_space;
+       union __swrap_cmsghdr __new_cmsg = { .p = NULL, };
+       struct cmsghdr *new_cmsg = NULL;
+       uint8_t *p = NULL;
+       size_t i;
+       int pipefd[2] = { -1, -1 };
+       int rc;
+       ssize_t sret;
+
+       /*
+        * We pass this a bufer to the kernel make sure any padding
+        * is also cleared.
+        */
+       ZERO_STRUCT(info);
+       info.full_size = sizeof(info);
+       info.payload_size = sizeof(info.payload);
+       payload = &info.payload;
+
+       if (*scm_rights_pipe_fd != -1) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "Two SCM_RIGHTS headers are not supported by socket_wrapper");
+               errno = EINVAL;
+               return -1;
+       }
+
+       if (cmsg->cmsg_len < CMSG_LEN(0)) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "cmsg->cmsg_len=%zu < CMSG_LEN(0)=%zu",
+                         (size_t)cmsg->cmsg_len,
+                         CMSG_LEN(0));
+               errno = EINVAL;
+               return -1;
+       }
+       size_fds_in = cmsg->cmsg_len - CMSG_LEN(0);
+       if ((size_fds_in % sizeof(int)) != 0) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "cmsg->cmsg_len=%zu => (size_fds_in=%zu %% sizeof(int)=%zu) != 0",
+                         (size_t)cmsg->cmsg_len,
+                         size_fds_in,
+                         sizeof(int));
+               errno = EINVAL;
+               return -1;
+       }
+       num_fds_in = size_fds_in / sizeof(int);
+       if (num_fds_in > SWRAP_MAX_PASSED_FDS) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "cmsg->cmsg_len=%zu,size_fds_in=%zu => "
+                         "num_fds_in=%zu > "
+                         "SWRAP_MAX_PASSED_FDS(%zu)",
+                         (size_t)cmsg->cmsg_len,
+                         size_fds_in,
+                         num_fds_in,
+                         SWRAP_MAX_PASSED_FDS);
+               errno = EINVAL;
+               return -1;
+       }
+       if (num_fds_in == 0) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "cmsg->cmsg_len=%zu,size_fds_in=%zu => "
+                         "num_fds_in=%zu",
+                         (size_t)cmsg->cmsg_len,
+                         size_fds_in,
+                         num_fds_in);
+               errno = EINVAL;
+               return -1;
+       }
+       __fds_in.p = CMSG_DATA(cmsg);
+       fds_in = __fds_in.fds;
+       num_fds_out = num_fds_in + 1;
+
+       SWRAP_LOG(SWRAP_LOG_TRACE,
+                 "num_fds_in=%zu num_fds_out=%zu",
+                 num_fds_in, num_fds_out);
+
+       size_fds_out = sizeof(int) * num_fds_out;
+       cmsg_len = CMSG_LEN(size_fds_out);
+       cmsg_space = CMSG_SPACE(size_fds_out);
+
+       new_cm_data_space = *cm_data_space + cmsg_space;
+
+       p = realloc((*cm_data), new_cm_data_space);
+       if (p == NULL) {
+               return -1;
+       }
+       (*cm_data) = p;
+       p = (*cm_data) + (*cm_data_space);
+       memset(p, 0, cmsg_space);
+       __new_cmsg.p = p;
+       new_cmsg = __new_cmsg.cmsg;
+       *new_cmsg = *cmsg;
+       __fds_out.p = CMSG_DATA(new_cmsg);
+       fds_out = __fds_out.fds;
+       memcpy(fds_out, fds_in, size_fds_out);
+       new_cmsg->cmsg_len = cmsg->cmsg_len;
+
+       for (i = 0; i < num_fds_in; i++) {
+               size_t j;
+
+               payload->idxs[i] = -1;
+               payload->num_idxs++;
+
+               si_idx_array[i] = find_socket_info_index(fds_in[i]);
+               if (si_idx_array[i] == -1) {
+                       continue;
+               }
+
+               si_array[i] = swrap_get_socket_info(si_idx_array[i]);
+               if (si_array[i] == NULL) {
+                       SWRAP_LOG(SWRAP_LOG_ERROR,
+                                 "fds_in[%zu]=%d si_idx_array[%zu]=%d missing!",
+                                 i, fds_in[i], i, si_idx_array[i]);
+                       errno = EINVAL;
+                       return -1;
+               }
+
+               for (j = 0; j < i; j++) {
+                       if (si_array[j] == si_array[i]) {
+                               payload->idxs[i] = payload->idxs[j];
+                               break;
+                       }
+               }
+               if (payload->idxs[i] == -1) {
+                       if (info_idx >= SWRAP_MAX_PASSED_SOCKET_INFO) {
+                               SWRAP_LOG(SWRAP_LOG_ERROR,
+                                         "fds_in[%zu]=%d,si_idx_array[%zu]=%d: "
+                                         "info_idx=%zu >= SWRAP_MAX_PASSED_FDS(%zu)!",
+                                         i, fds_in[i], i, si_idx_array[i],
+                                         info_idx,
+                                         SWRAP_MAX_PASSED_SOCKET_INFO);
+                               errno = EINVAL;
+                               return -1;
+                       }
+                       payload->idxs[i] = info_idx;
+                       info_idx += 1;
+                       continue;
+               }
+       }
+
+       for (i = 0; i < num_fds_in; i++) {
+               struct socket_info *si = si_array[i];
+
+               if (si == NULL) {
+                       SWRAP_LOG(SWRAP_LOG_TRACE,
+                                 "fds_in[%zu]=%d not an inet socket",
+                                 i, fds_in[i]);
+                       continue;
+               }
+
+               SWRAP_LOG(SWRAP_LOG_TRACE,
+                         "fds_in[%zu]=%d si_idx_array[%zu]=%d "
+                         "passing as info.idxs[%zu]=%d!",
+                         i, fds_in[i],
+                         i, si_idx_array[i],
+                         i, payload->idxs[i]);
+
+               SWRAP_LOCK_SI(si);
+               si->fd_passed += 1;
+               payload->infos[payload->idxs[i]] = *si;
+               payload->infos[payload->idxs[i]].fd_passed = 0;
+               SWRAP_UNLOCK_SI(si);
+       }
+
+       rc = pipe(pipefd);
+       if (rc == -1) {
+               int saved_errno = errno;
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "pipe() failed - %d %s",
+                         saved_errno,
+                         strerror(saved_errno));
+               swrap_dec_fd_passed_array(num_fds_in, si_array);
+               errno = saved_errno;
+               return -1;
+       }
+
+       sret = write(pipefd[1], &info, sizeof(info));
+       if (sret != sizeof(info)) {
+               int saved_errno = errno;
+               if (sret != -1) {
+                       saved_errno = EINVAL;
+               }
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "write() failed - sret=%zd - %d %s",
+                         sret, saved_errno,
+                         strerror(saved_errno));
+               swrap_dec_fd_passed_array(num_fds_in, si_array);
+               libc_close(pipefd[1]);
+               libc_close(pipefd[0]);
+               errno = saved_errno;
+               return -1;
+       }
+       libc_close(pipefd[1]);
+
+       /*
+        * Add the pipe read end to the end of the passed fd array
+        */
+       fds_out[num_fds_in] = pipefd[0];
+       new_cmsg->cmsg_len = cmsg_len;
+
+       /* we're done ... */
+       *scm_rights_pipe_fd = pipefd[0];
+       *cm_data_space = new_cm_data_space;
+
+       return 0;
+}
+
+static int swrap_sendmsg_unix_sol_socket(const struct cmsghdr *cmsg,
+                                        uint8_t **cm_data,
+                                        size_t *cm_data_space,
+                                        int *scm_rights_pipe_fd)
+{
+       int rc = -1;
+
+       switch (cmsg->cmsg_type) {
+       case SCM_RIGHTS:
+               rc = swrap_sendmsg_unix_scm_rights(cmsg,
+                                                  cm_data,
+                                                  cm_data_space,
+                                                  scm_rights_pipe_fd);
+               break;
+       default:
+               rc = swrap_sendmsg_copy_cmsg(cmsg,
+                                            cm_data,
+                                            cm_data_space);
+               break;
+       }
+
+       return rc;
+}
+
+static int swrap_recvmsg_unix_scm_rights(const struct cmsghdr *cmsg,
+                                        uint8_t **cm_data,
+                                        size_t *cm_data_space)
+{
+       int scm_rights_pipe_fd = -1;
+       struct swrap_unix_scm_rights info;
+       struct swrap_unix_scm_rights_payload *payload = NULL;
+       int si_idx_array[SWRAP_MAX_PASSED_FDS];
+       size_t size_fds_in;
+       size_t num_fds_in;
+       union __swrap_fds __fds_in = { .p = NULL, };
+       const int *fds_in = NULL;
+       size_t num_fds_out;
+       size_t size_fds_out;
+       union __swrap_fds __fds_out = { .p = NULL, };
+       int *fds_out = NULL;
+       size_t cmsg_len;
+       size_t cmsg_space;
+       size_t new_cm_data_space;
+       union __swrap_cmsghdr __new_cmsg = { .p = NULL, };
+       struct cmsghdr *new_cmsg = NULL;
+       uint8_t *p = NULL;
+       size_t i;
+       ssize_t sret;
+
+       if (cmsg->cmsg_len < CMSG_LEN(0)) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "cmsg->cmsg_len=%zu < CMSG_LEN(0)=%zu",
+                         (size_t)cmsg->cmsg_len,
+                         CMSG_LEN(0));
+               errno = EINVAL;
+               return -1;
+       }
+       size_fds_in = cmsg->cmsg_len - CMSG_LEN(0);
+       if ((size_fds_in % sizeof(int)) != 0) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "cmsg->cmsg_len=%zu => (size_fds_in=%zu %% sizeof(int)=%zu) != 0",
+                         (size_t)cmsg->cmsg_len,
+                         size_fds_in,
+                         sizeof(int));
+               errno = EINVAL;
+               return -1;
+       }
+       num_fds_in = size_fds_in / sizeof(int);
+       if (num_fds_in > (SWRAP_MAX_PASSED_FDS + 1)) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "cmsg->cmsg_len=%zu,size_fds_in=%zu => "
+                         "num_fds_in=%zu > SWRAP_MAX_PASSED_FDS+1(%zu)",
+                         (size_t)cmsg->cmsg_len,
+                         size_fds_in,
+                         num_fds_in,
+                         SWRAP_MAX_PASSED_FDS+1);
+               errno = EINVAL;
+               return -1;
+       }
+       if (num_fds_in <= 1) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "cmsg->cmsg_len=%zu,size_fds_in=%zu => "
+                         "num_fds_in=%zu",
+                         (size_t)cmsg->cmsg_len,
+                         size_fds_in,
+                         num_fds_in);
+               errno = EINVAL;
+               return -1;
+       }
+       __fds_in.p = CMSG_DATA(cmsg);
+       fds_in = __fds_in.fds;
+       num_fds_out = num_fds_in - 1;
+
+       SWRAP_LOG(SWRAP_LOG_TRACE,
+                 "num_fds_in=%zu num_fds_out=%zu",
+                 num_fds_in, num_fds_out);
+
+       for (i = 0; i < num_fds_in; i++) {
+               /* Check if we have a stale fd and remove it */
+               swrap_remove_stale(fds_in[i]);
+       }
+
+       scm_rights_pipe_fd = fds_in[num_fds_out];
+       size_fds_out = sizeof(int) * num_fds_out;
+       cmsg_len = CMSG_LEN(size_fds_out);
+       cmsg_space = CMSG_SPACE(size_fds_out);
+
+       new_cm_data_space = *cm_data_space + cmsg_space;
+
+       p = realloc((*cm_data), new_cm_data_space);
+       if (p == NULL) {
+               swrap_close_fd_array(num_fds_in, fds_in);
+               return -1;
+       }
+       (*cm_data) = p;
+       p = (*cm_data) + (*cm_data_space);
+       memset(p, 0, cmsg_space);
+       __new_cmsg.p = p;
+       new_cmsg = __new_cmsg.cmsg;
+       *new_cmsg = *cmsg;
+       __fds_out.p = CMSG_DATA(new_cmsg);
+       fds_out = __fds_out.fds;
+       memcpy(fds_out, fds_in, size_fds_out);
+       new_cmsg->cmsg_len = cmsg_len;
+
+       sret = read(scm_rights_pipe_fd, &info, sizeof(info));
+       if (sret != sizeof(info)) {
+               int saved_errno = errno;
+               if (sret != -1) {
+                       saved_errno = EINVAL;
+               }
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "read() failed - sret=%zd - %d %s",
+                         sret, saved_errno,
+                         strerror(saved_errno));
+               swrap_close_fd_array(num_fds_in, fds_in);
+               errno = saved_errno;
+               return -1;
+       }
+       libc_close(scm_rights_pipe_fd);
+       payload = &info.payload;
+
+       if (payload->num_idxs != num_fds_out) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "info.num_idxs=%u != num_fds_out=%zu",
+                         payload->num_idxs, num_fds_out);
+               swrap_close_fd_array(num_fds_out, fds_out);
+               errno = EINVAL;
+               return -1;
+       }
+
+       for (i = 0; i < num_fds_out; i++) {
+               size_t j;
+
+               si_idx_array[i] = -1;
+
+               if (payload->idxs[i] == -1) {
+                       SWRAP_LOG(SWRAP_LOG_TRACE,
+                                 "fds_out[%zu]=%d not an inet socket",
+                                 i, fds_out[i]);
+                       continue;
+               }
+
+               if (payload->idxs[i] < 0) {
+                       SWRAP_LOG(SWRAP_LOG_ERROR,
+                                 "fds_out[%zu]=%d info.idxs[%zu]=%d < 0!",
+                                 i, fds_out[i], i, payload->idxs[i]);
+                       swrap_close_fd_array(num_fds_out, fds_out);
+                       errno = EINVAL;
+                       return -1;
+               }
+
+               if (payload->idxs[i] >= payload->num_idxs) {
+                       SWRAP_LOG(SWRAP_LOG_ERROR,
+                                 "fds_out[%zu]=%d info.idxs[%zu]=%d >= %u!",
+                                 i, fds_out[i], i, payload->idxs[i],
+                                 payload->num_idxs);
+                       swrap_close_fd_array(num_fds_out, fds_out);
+                       errno = EINVAL;
+                       return -1;
+               }
+
+               if ((size_t)fds_out[i] >= socket_fds_max) {
+                       SWRAP_LOG(SWRAP_LOG_ERROR,
+                                 "The max socket index limit of %zu has been reached, "
+                                 "trying to add %d",
+                                 socket_fds_max,
+                                 fds_out[i]);
+                       swrap_close_fd_array(num_fds_out, fds_out);
+                       errno = EMFILE;
+                       return -1;
+               }
+
+               SWRAP_LOG(SWRAP_LOG_TRACE,
+                         "fds_in[%zu]=%d "
+                         "received as info.idxs[%zu]=%d!",
+                         i, fds_out[i],
+                         i, payload->idxs[i]);
+
+               for (j = 0; j < i; j++) {
+                       if (payload->idxs[j] == -1) {
+                               continue;
+                       }
+                       if (payload->idxs[j] == payload->idxs[i]) {
+                               si_idx_array[i] = si_idx_array[j];
+                       }
+               }
+               if (si_idx_array[i] == -1) {
+                       const struct socket_info *si = &payload->infos[payload->idxs[i]];
+
+                       si_idx_array[i] = swrap_add_socket_info(si);
+                       if (si_idx_array[i] == -1) {
+                               int saved_errno = errno;
+                               SWRAP_LOG(SWRAP_LOG_ERROR,
+                                         "The max socket index limit of %zu has been reached, "
+                                         "trying to add %d",
+                                         socket_fds_max,
+                                         fds_out[i]);
+                               swrap_undo_si_idx_array(i, si_idx_array);
+                               swrap_close_fd_array(num_fds_out, fds_out);
+                               errno = saved_errno;
+                               return -1;
+                       }
+                       SWRAP_LOG(SWRAP_LOG_TRACE,
+                                 "Imported %s socket for protocol %s, fd=%d",
+                                 si->family == AF_INET ? "IPv4" : "IPv6",
+                                 si->type == SOCK_DGRAM ? "UDP" : "TCP",
+                                 fds_out[i]);
+               }
+       }
+
+       for (i = 0; i < num_fds_out; i++) {
+               if (si_idx_array[i] == -1) {
+                       continue;
+               }
+               set_socket_info_index(fds_out[i], si_idx_array[i]);
+       }
+
+#if 0
+       si->family = family;
+
+       /* however, the rest of the socket_wrapper code expects just
+        * the type, not the flags */
+       si->type = real_type;
+       si->protocol = protocol;
+
+       ret = swrap_create_socket(si, fd);
+       if (ret == -1) {
+               return -1;
+       }
+
+       SWRAP_LOG(SWRAP_LOG_TRACE,
+                 "Created %s socket for protocol %s, fd=%d",
+                 family == AF_INET ? "IPv4" : "IPv6",
+                 real_type == SOCK_DGRAM ? "UDP" : "TCP",
+                 fd);
+
+               si_array[i] = swrap_get_socket_info(info.idxs[i]);
+               if (si_array[i] == NULL) {
+                       SWRAP_LOG(SWRAP_LOG_ERROR,
+                                 "fds_out[%zu]=%d info.idxs[%zu]=%d missing!",
+                                 i, fds_out[i], i, info.idxs[i]);
+                       swrap_close_fd_array(num_fds_out, fds_out);
+                       errno = EINVAL;
+                       return -1;
+               }
+       }
+
+       for (i = 0; i < num_fds_in; i++) {
+               struct socket_info *si = si_array[i];
+
+               if (si == NULL) {
+                       SWRAP_LOG(SWRAP_LOG_TRACE,
+                                 "fds_out[%zu]=%d not an inet socket",
+                                 i, fds_in[i]);
+                       continue;
+               }
+
+               SWRAP_LOG(SWRAP_LOG_TRACE,
+                         "fds_out[%zu]=%d si_idx_array[%zu]=%d passed!",
+                         i, fds_in[i], i, info.idxs[i]);
+               set_socket_info_index(fds_out[i], info.idxs[i]);
+       }
+#endif
+
+       /* we're done ... */
+       *cm_data_space = new_cm_data_space;
+
+       return 0;
+}
+
+static int swrap_recvmsg_unix_sol_socket(const struct cmsghdr *cmsg,
+                                        uint8_t **cm_data,
+                                        size_t *cm_data_space)
+{
+       int rc = -1;
+
+       switch (cmsg->cmsg_type) {
+       case SCM_RIGHTS:
+               rc = swrap_recvmsg_unix_scm_rights(cmsg,
+                                                  cm_data,
+                                                  cm_data_space);
+               break;
+       default:
+               rc = swrap_sendmsg_copy_cmsg(cmsg,
+                                            cm_data,
+                                            cm_data_space);
+               break;
+       }
+
+       return rc;
+}
+
+#endif /* HAVE_STRUCT_MSGHDR_MSG_CONTROL */
+
+static int swrap_sendmsg_before_unix(const struct msghdr *_msg_in,
+                                    struct msghdr *msg_tmp,
+                                    int *scm_rights_pipe_fd)
+{
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+       struct msghdr *msg_in = discard_const_p(struct msghdr, _msg_in);
+       struct cmsghdr *cmsg = NULL;
+       uint8_t *cm_data = NULL;
+       size_t cm_data_space = 0;
+       int rc = -1;
+
+       *msg_tmp = *msg_in;
+       *scm_rights_pipe_fd = -1;
+
+       /* Nothing to do */
+       if (msg_in->msg_controllen == 0 || msg_in->msg_control == NULL) {
+               return 0;
+       }
+
+       for (cmsg = CMSG_FIRSTHDR(msg_in);
+            cmsg != NULL;
+            cmsg = CMSG_NXTHDR(msg_in, cmsg)) {
+               switch (cmsg->cmsg_level) {
+               case SOL_SOCKET:
+                       rc = swrap_sendmsg_unix_sol_socket(cmsg,
+                                                          &cm_data,
+                                                          &cm_data_space,
+                                                          scm_rights_pipe_fd);
+                       break;
+
+               default:
+                       rc = swrap_sendmsg_copy_cmsg(cmsg,
+                                                    &cm_data,
+                                                    &cm_data_space);
+                       break;
+               }
+               if (rc < 0) {
+                       int saved_errno = errno;
+                       SAFE_FREE(cm_data);
+                       errno = saved_errno;
+                       return rc;
+               }
+       }
+
+       msg_tmp->msg_controllen = cm_data_space;
+       msg_tmp->msg_control = cm_data;
+
+       return 0;
+#else /* HAVE_STRUCT_MSGHDR_MSG_CONTROL */
+       *msg_tmp = *_msg_in;
+       return 0;
+#endif /* ! HAVE_STRUCT_MSGHDR_MSG_CONTROL */
+}
+
+static ssize_t swrap_sendmsg_after_unix(struct msghdr *msg_tmp,
+                                       ssize_t ret,
+                                       int scm_rights_pipe_fd)
+{
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+       int saved_errno = errno;
+       SAFE_FREE(msg_tmp->msg_control);
+       if (scm_rights_pipe_fd != -1) {
+               libc_close(scm_rights_pipe_fd);
+       }
+       errno = saved_errno;
 #endif /* HAVE_STRUCT_MSGHDR_MSG_CONTROL */
+       return ret;
+}
+
+static int swrap_recvmsg_before_unix(struct msghdr *msg_in,
+                                    struct msghdr *msg_tmp)
+{
+       *msg_tmp = *msg_in;
+       return 0;
+}
+
+static ssize_t swrap_recvmsg_after_unix(struct msghdr *msg_tmp,
+                                       struct msghdr *msg_out,
+                                       ssize_t ret)
+{
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+       struct cmsghdr *cmsg = NULL;
+       uint8_t *cm_data = NULL;
+       size_t cm_data_space = 0;
+       int rc = -1;
+
+       /* Nothing to do */
+       if (msg_tmp->msg_controllen == 0 || msg_tmp->msg_control == NULL) {
+               goto done;
+       }
+
+       for (cmsg = CMSG_FIRSTHDR(msg_tmp);
+            cmsg != NULL;
+            cmsg = CMSG_NXTHDR(msg_tmp, cmsg)) {
+               switch (cmsg->cmsg_level) {
+               case SOL_SOCKET:
+                       rc = swrap_recvmsg_unix_sol_socket(cmsg,
+                                                          &cm_data,
+                                                          &cm_data_space);
+                       break;
+
+               default:
+                       rc = swrap_sendmsg_copy_cmsg(cmsg,
+                                                    &cm_data,
+                                                    &cm_data_space);
+                       break;
+               }
+               if (rc < 0) {
+                       int saved_errno = errno;
+                       SAFE_FREE(cm_data);
+                       errno = saved_errno;
+                       return rc;
+               }
+       }
+
+       /*
+        * msg_tmp->msg_control is still the buffer of the caller.
+        */
+       memcpy(msg_tmp->msg_control, cm_data, cm_data_space);
+       msg_tmp->msg_controllen = cm_data_space;
+       SAFE_FREE(cm_data);
+done:
+#endif /* ! HAVE_STRUCT_MSGHDR_MSG_CONTROL */
+       *msg_out = *msg_tmp;
+       return ret;
+}
 
 static ssize_t swrap_sendmsg_before(int fd,
                                    struct socket_info *si,
@@ -5215,28 +6048,6 @@ static ssize_t swrap_sendmsg_before(int fd,
                goto out;
        }
 
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       if (msg->msg_controllen > 0 && msg->msg_control != NULL) {
-               uint8_t *cmbuf = NULL;
-               size_t cmlen = 0;
-
-               ret = swrap_sendmsg_filter_cmsghdr(msg, &cmbuf, &cmlen);
-               if (ret < 0) {
-                       free(cmbuf);
-                       goto out;
-               }
-
-               if (cmlen == 0) {
-                       msg->msg_controllen = 0;
-                       msg->msg_control = NULL;
-               } else if (cmlen < msg->msg_controllen && cmbuf != NULL) {
-                       memcpy(msg->msg_control, cmbuf, cmlen);
-                       msg->msg_controllen = cmlen;
-               }
-               free(cmbuf);
-       }
-#endif
-
        ret = 0;
 out:
        SWRAP_UNLOCK_SI(si);
@@ -6003,7 +6814,12 @@ static ssize_t swrap_recvmsg(int s, struct msghdr *omsg, int flags)
 
        si = find_socket_info(s);
        if (si == NULL) {
-               return libc_recvmsg(s, omsg, flags);
+               rc = swrap_recvmsg_before_unix(omsg, &msg);
+               if (rc < 0) {
+                       return rc;
+               }
+               ret = libc_recvmsg(s, &msg, flags);
+               return swrap_recvmsg_after_unix(&msg, omsg, ret);
        }
 
        tmp.iov_base = NULL;
@@ -6126,7 +6942,15 @@ static ssize_t swrap_sendmsg(int s, const struct msghdr *omsg, int flags)
        int bcast = 0;
 
        if (!si) {
-               return libc_sendmsg(s, omsg, flags);
+               int scm_rights_pipe_fd = -1;
+
+               rc = swrap_sendmsg_before_unix(omsg, &msg,
+                                              &scm_rights_pipe_fd);
+               if (rc < 0) {
+                       return rc;
+               }
+               ret = libc_sendmsg(s, &msg, flags);
+               return swrap_sendmsg_after_unix(&msg, ret, scm_rights_pipe_fd);
        }
 
        ZERO_STRUCT(un_addr);
@@ -6148,20 +6972,32 @@ static ssize_t swrap_sendmsg(int s, const struct msghdr *omsg, int flags)
        SWRAP_UNLOCK_SI(si);
 
 #ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       if (msg.msg_controllen > 0 && msg.msg_control != NULL) {
-               /* omsg is a const so use a local buffer for modifications */
-               uint8_t cmbuf[omsg->msg_controllen];
+       if (omsg != NULL && omsg->msg_controllen > 0 && omsg->msg_control != NULL) {
+               uint8_t *cmbuf = NULL;
+               size_t cmlen = 0;
 
-               memcpy(cmbuf, omsg->msg_control, omsg->msg_controllen);
+               rc = swrap_sendmsg_filter_cmsghdr(omsg, &cmbuf, &cmlen);
+               if (rc < 0) {
+                       return rc;
+               }
 
-               msg.msg_control = cmbuf;       /* ancillary data, see below */
-               msg.msg_controllen = omsg->msg_controllen; /* ancillary data buffer len */
+               if (cmlen == 0) {
+                       msg.msg_controllen = 0;
+                       msg.msg_control = NULL;
+               } else {
+                       msg.msg_control = cmbuf;
+                       msg.msg_controllen = cmlen;
+               }
        }
        msg.msg_flags = omsg->msg_flags;           /* flags on received message */
 #endif
-
        rc = swrap_sendmsg_before(s, si, &msg, &tmp, &un_addr, &to_un, &to, &bcast);
        if (rc < 0) {
+               int saved_errno = errno;
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+               SAFE_FREE(msg.msg_control);
+#endif
+               errno = saved_errno;
                return -1;
        }
 
@@ -6187,6 +7023,11 @@ static ssize_t swrap_sendmsg(int s, const struct msghdr *omsg, int flags)
                /* we capture it as one single packet */
                buf = (uint8_t *)malloc(remain);
                if (!buf) {
+                       int saved_errno = errno;
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+                       SAFE_FREE(msg.msg_control);
+#endif
+                       errno = saved_errno;
                        return -1;
                }
 
@@ -6203,7 +7044,12 @@ static ssize_t swrap_sendmsg(int s, const struct msghdr *omsg, int flags)
 
                swrap_dir = socket_wrapper_dir();
                if (swrap_dir == NULL) {
-                       free(buf);
+                       int saved_errno = errno;
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+                       SAFE_FREE(msg.msg_control);
+#endif
+                       SAFE_FREE(buf);
+                       errno = saved_errno;
                        return -1;
                }
 
@@ -6234,6 +7080,14 @@ static ssize_t swrap_sendmsg(int s, const struct msghdr *omsg, int flags)
 
        swrap_sendmsg_after(s, si, &msg, to, ret);
 
+#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
+       {
+               int saved_errno = errno;
+               SAFE_FREE(msg.msg_control);
+               errno = saved_errno;
+       }
+#endif
+
        return ret;
 }
 
@@ -6385,6 +7239,10 @@ static int swrap_close(int fd)
                goto out;
        }
 
+       if (si->fd_passed) {
+               goto set_next_free;
+       }
+
        if (si->myname.sa_socklen > 0 && si->peername.sa_socklen > 0) {
                swrap_pcap_dump_packet(si, NULL, SWRAP_CLOSE_SEND, NULL, 0);
        }
@@ -6398,6 +7256,7 @@ static int swrap_close(int fd)
                unlink(si->un_addr.sun_path);
        }
 
+set_next_free:
        swrap_set_next_free(si, first_free);
        first_free = si_index;
 
@@ -6437,6 +7296,17 @@ static int swrap_dup(int fd)
                return -1;
        }
 
+       if ((size_t)dup_fd >= socket_fds_max) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "The max socket index limit of %zu has been reached, "
+                         "trying to add %d",
+                         socket_fds_max,
+                         dup_fd);
+               libc_close(dup_fd);
+               errno = EMFILE;
+               return -1;
+       }
+
        SWRAP_LOCK_SI(si);
 
        swrap_inc_refcount(si);
@@ -6482,6 +7352,16 @@ static int swrap_dup2(int fd, int newfd)
                return newfd;
        }
 
+       if ((size_t)newfd >= socket_fds_max) {
+               SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "The max socket index limit of %zu has been reached, "
+                         "trying to add %d",
+                         socket_fds_max,
+                         newfd);
+               errno = EMFILE;
+               return -1;
+       }
+
        if (find_socket_info(newfd)) {
                /* dup2() does an implicit close of newfd, which we
                 * need to emulate */
@@ -6539,14 +7419,26 @@ static int swrap_vfcntl(int fd, int cmd, va_list va)
                        return -1;
                }
 
+               /* Make sure we don't have an entry for the fd */
+               swrap_remove_stale(dup_fd);
+
+               if ((size_t)dup_fd >= socket_fds_max) {
+                       SWRAP_LOG(SWRAP_LOG_ERROR,
+                         "The max socket index limit of %zu has been reached, "
+                         "trying to add %d",
+                         socket_fds_max,
+                         dup_fd);
+                       libc_close(dup_fd);
+                       errno = EMFILE;
+                       return -1;
+               }
+
                SWRAP_LOCK_SI(si);
 
                swrap_inc_refcount(si);
 
                SWRAP_UNLOCK_SI(si);
 
-               /* Make sure we don't have an entry for the fd */
-               swrap_remove_stale(dup_fd);
 
                set_socket_info_index(dup_fd, idx);