diff options
Diffstat (limited to 'src/kms/kms_client.c')
| -rw-r--r-- | src/kms/kms_client.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/src/kms/kms_client.c b/src/kms/kms_client.c new file mode 100644 index 0000000..ededbe9 --- /dev/null +++ b/src/kms/kms_client.c @@ -0,0 +1,234 @@ +#include "../../include/kms/kms_client.h" +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <errno.h> +#include <unistd.h> +#include <signal.h> +#include <limits.h> +#include <sys/socket.h> +#include <sys/un.h> +#include <sys/wait.h> +#include <sys/capability.h> + +static int send_msg_to_server(int server_fd, gsr_kms_request *request) { + struct iovec iov; + iov.iov_base = request; + iov.iov_len = sizeof(*request); + + struct msghdr request_message = {0}; + request_message.msg_iov = &iov; + request_message.msg_iovlen = 1; + + return sendmsg(server_fd, &request_message, 0); +} + +static int recv_msg_from_server(int server_fd, gsr_kms_response *response) { + struct iovec iov; + iov.iov_base = response; + iov.iov_len = sizeof(*response); + + struct msghdr response_message = {0}; + response_message.msg_iov = &iov; + response_message.msg_iovlen = 1; + + char cmsgbuf[CMSG_SPACE(sizeof(int))]; + memset(cmsgbuf, 0, sizeof(cmsgbuf)); + response_message.msg_control = cmsgbuf; + response_message.msg_controllen = sizeof(cmsgbuf); + + int res = recvmsg(server_fd, &response_message, MSG_WAITALL); + if(res <= 0) + return res; + + if(response->result == KMS_RESULT_OK) + response->data.fd.fd = 0; + + struct cmsghdr *cmsg = CMSG_FIRSTHDR(&response_message); + if(cmsg) { + fprintf(stderr, "got cmsg, %d\n", cmsg->cmsg_type); + if(cmsg->cmsg_type == SCM_RIGHTS) { + int kms_fd = 0; + memcpy(&kms_fd, CMSG_DATA(cmsg), sizeof(int)); + fprintf(stderr, "kms fd: %d\n", kms_fd); + response->data.fd.fd = kms_fd; + } + } + + return res; +} + +int gsr_kms_client_init(gsr_kms_client *self, const char *card_path, const char *program_dir) { + self->kms_server_pid = -1; + self->card_path = NULL; + self->socket_fd = -1; + self->client_fd = -1; + self->socket_path[0] = '\0'; + struct sockaddr_un local_addr = {0}; + struct sockaddr_un remote_addr = {0}; + + // TODO: Check if gsr-kms-server is installed + // TODO: Check if pkexec is installed + + char server_filepath[PATH_MAX]; + snprintf(server_filepath, sizeof(server_filepath), "%s/%s", program_dir, "gsr-kms-server"); + + int has_perm = 0; + cap_t kms_server_cap = cap_get_file(server_filepath); + if(kms_server_cap) { + cap_flag_value_t res = 0; + cap_get_flag(kms_server_cap, CAP_SYS_ADMIN, CAP_PERMITTED, &res); + if(res == CAP_SET) { + //fprintf(stderr, "has permission!\n"); + has_perm = 1; + } else { + //fprintf(stderr, "No permission:(\n"); + } + cap_free(kms_server_cap); + } else { + if(errno == ENODATA) + fprintf(stderr, "gsr info: gsr_kms_client_init: gsr-kms-server is missing sys_admin cap and will require root authentication. To bypass this automatically, run: sudo setcap cap_sys_admin+ep '%s'\n", server_filepath); + else + fprintf(stderr, "failed to get cap\n"); + } + + self->card_path = strdup(card_path); + if(!self->card_path) { + fprintf(stderr, "gsr error: gsr_kms_client_init: failed to duplicate card_path\n"); + goto err; + } + + strcpy(self->socket_path, "/tmp/gsr-kms-socket-XXXXXX"); + if(!tmpnam(self->socket_path)) { + fprintf(stderr, "gsr error: gsr_kms_client_init: mkstemp failed, error: %s\n", strerror(errno)); + goto err; + } + + self->socket_fd = socket(AF_UNIX, SOCK_STREAM, 0); + if(self->socket_fd == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_init: socket failed, error: %s\n", strerror(errno)); + goto err; + } + + local_addr.sun_family = AF_UNIX; + strncpy(local_addr.sun_path, self->socket_path, sizeof(local_addr.sun_path)); + if(bind(self->socket_fd, (struct sockaddr*)&local_addr, sizeof(local_addr.sun_family) + strlen(local_addr.sun_path)) == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_init: failed to bind socket, error: %s\n", strerror(errno)); + goto err; + } + + if(listen(self->socket_fd, 1) == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_init: failed to listen on socket, error: %s\n", strerror(errno)); + goto err; + } + + pid_t pid = fork(); + if(pid == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_init: fork failed, error: %s\n", strerror(errno)); + goto err; + } else if(pid == 0) { /* child */ + if(has_perm) { + const char *args[] = { server_filepath, self->socket_path, NULL }; + execvp(args[0], (char *const*)args); + } else { + const char *args[] = { "pkexec", server_filepath, self->socket_path, NULL }; + execvp(args[0], (char *const*)args); + } + perror("execvp"); + _exit(127); + } else { /* parent */ + self->kms_server_pid = pid; + } + + fprintf(stderr, "gsr info: gsr_kms_client_init: waiting for client to connect\n"); + for(;;) { + struct timeval tv; + fd_set rfds; + FD_ZERO(&rfds); + FD_SET(self->socket_fd, &rfds); + + tv.tv_sec = 0; + tv.tv_usec = 100 * 1000; // 100 ms + + int select_res = select(1 + self->socket_fd, &rfds, NULL, NULL, &tv); + if(select_res > 0) { + socklen_t sock_len = 0; + self->client_fd = accept(self->socket_fd, (struct sockaddr*)&remote_addr, &sock_len); + if(self->client_fd == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_init: accept failed on socket, error: %s\n", strerror(errno)); + goto err; + } + break; + } else { + int status; + int wait_result = waitpid(self->kms_server_pid, &status, WNOHANG); + if(wait_result > 0) { + fprintf(stderr, "gsr error: gsr_kms_client_init: waitpid failed on kms server, error: %s\n", strerror(errno)); + goto err; + } else if(wait_result > 0) { + fprintf(stderr, "gsr error: gsr_kms_client_init: kms server died\n"); + goto err; + } + } + } + fprintf(stderr, "gsr info: gsr_kms_client_init: client connected\n"); + + return 0; + + err: + gsr_kms_client_deinit(self); + return -1; +} + +void gsr_kms_client_deinit(gsr_kms_client *self) { + if(self->card_path) { + free(self->card_path); + self->card_path = NULL; + } + + if(self->client_fd != -1) { + close(self->client_fd); + self->client_fd = -1; + } + + if(self->socket_fd != -1) { + close(self->socket_fd); + self->socket_fd = -1; + } + + if(self->kms_server_pid != -1) { + kill(self->kms_server_pid, SIGINT); + int status; + waitpid(self->kms_server_pid, &status, 0); + self->kms_server_pid = -1; + } + + if(self->socket_path[0] != '\0') { + remove(self->socket_path); + self->socket_path[0] = '\0'; + } +} + +int gsr_kms_client_get_kms(gsr_kms_client *self, gsr_kms_response *response) { + response->result = KMS_RESULT_FAILED_TO_SEND; + strcpy(response->data.err_msg, "failed to send"); + + gsr_kms_request request; + request.type = KMS_REQUEST_TYPE_GET_KMS; + strcpy(request.data.card_path, self->card_path); + if(send_msg_to_server(self->client_fd, &request) == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_get_kms: failed to send request message to server\n"); + return -1; + } + + const int recv_res = recv_msg_from_server(self->client_fd, response); + if(recv_res == 0) { + fprintf(stderr, "gsr warning: gsr_kms_client_get_kms: kms server shut down\n"); + return -1; + } else if(recv_res == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_get_kms: failed to receive response\n"); + return -1; + } + + return 0; +} |