diff options
Diffstat (limited to 'kms/client/kms_client.c')
| -rw-r--r-- | kms/client/kms_client.c | 426 |
1 files changed, 426 insertions, 0 deletions
diff --git a/kms/client/kms_client.c b/kms/client/kms_client.c new file mode 100644 index 0000000..57c6ccf --- /dev/null +++ b/kms/client/kms_client.c @@ -0,0 +1,426 @@ +#include "kms_client.h" +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <errno.h> +#include <unistd.h> +#include <signal.h> +#include <stdbool.h> +#include <fcntl.h> +#include <sys/socket.h> +#include <sys/un.h> +#include <sys/wait.h> +#include <sys/stat.h> +#include <sys/capability.h> + +#define GSR_SOCKET_PAIR_LOCAL 0 +#define GSR_SOCKET_PAIR_REMOTE 1 + +static void cleanup_socket(gsr_kms_client *self, bool kill_server); +static int gsr_kms_client_replace_connection(gsr_kms_client *self); + +static bool generate_random_characters(char *buffer, int buffer_size, const char *alphabet, size_t alphabet_size) { + int fd = open("/dev/urandom", O_RDONLY); + if(fd == -1) { + perror("/dev/urandom"); + return false; + } + + if(read(fd, buffer, buffer_size) < buffer_size) { + fprintf(stderr, "Failed to read %d bytes from /dev/urandom\n", buffer_size); + close(fd); + return false; + } + + for(int i = 0; i < buffer_size; ++i) { + unsigned char c = *(unsigned char*)&buffer[i]; + buffer[i] = alphabet[c % alphabet_size]; + } + + close(fd); + return true; +} + +static void close_fds(gsr_kms_response *response) { + for(int i = 0; i < response->num_fds; ++i) { + if(response->fds[i].fd > 0) + close(response->fds[i].fd); + response->fds[i].fd = 0; + } +} + +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 response_message = {0}; + response_message.msg_iov = &iov; + response_message.msg_iovlen = 1; + + char cmsgbuf[CMSG_SPACE(sizeof(int) * 1)]; + memset(cmsgbuf, 0, sizeof(cmsgbuf)); + + if(request->new_connection_fd > 0) { + response_message.msg_control = cmsgbuf; + response_message.msg_controllen = sizeof(cmsgbuf); + + struct cmsghdr *cmsg = CMSG_FIRSTHDR(&response_message); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + cmsg->cmsg_len = CMSG_LEN(sizeof(int) * 1); + + int *fds = (int*)CMSG_DATA(cmsg); + fds[0] = request->new_connection_fd; + + response_message.msg_controllen = cmsg->cmsg_len; + } + + return sendmsg(server_fd, &response_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) * GSR_KMS_MAX_PLANES)]; + 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->num_fds > 0) { + struct cmsghdr *cmsg = CMSG_FIRSTHDR(&response_message); + if(cmsg) { + int *fds = (int*)CMSG_DATA(cmsg); + for(int i = 0; i < response->num_fds; ++i) { + response->fds[i].fd = fds[i]; + } + } else { + close_fds(response); + } + } + + return res; +} + +/* We have to use $HOME because in flatpak there is no simple path that is accessible, read and write, that multiple flatpak instances can access */ +static bool create_socket_path(char *output_path, size_t output_path_size) { + const char *home = getenv("HOME"); + if(!home) + home = "/tmp"; + + char random_characters[11]; + random_characters[10] = '\0'; + if(!generate_random_characters(random_characters, 10, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", 62)) + return false; + + snprintf(output_path, output_path_size, "%s/.gsr-kms-socket-%s", home, random_characters); + return true; +} + +static void strncpy_safe(char *dst, const char *src, int len) { + int src_len = strlen(src); + int min_len = src_len; + if(len - 1 < min_len) + min_len = len - 1; + memcpy(dst, src, min_len); + dst[min_len] = '\0'; +} + +static bool find_program_in_path(const char *program_name, char *filepath, int filepath_len) { + const char *path = getenv("PATH"); + if(!path) + return false; + + int program_name_len = strlen(program_name); + const char *end = path + strlen(path); + while(path != end) { + const char *part_end = strchr(path, ':'); + const char *next = part_end; + if(part_end) { + next = part_end + 1; + } else { + part_end = end; + next = end; + } + + int len = part_end - path; + if(len + 1 + program_name_len < filepath_len) { + memcpy(filepath, path, len); + filepath[len] = '/'; + memcpy(filepath + len + 1, program_name, program_name_len); + filepath[len + 1 + program_name_len] = '\0'; + + if(access(filepath, F_OK) == 0) + return true; + } + + path = next; + } + + return false; +} + +int gsr_kms_client_init(gsr_kms_client *self, const char *card_path) { + int result = -1; + self->kms_server_pid = -1; + self->initial_socket_fd = -1; + self->initial_client_fd = -1; + self->initial_socket_path[0] = '\0'; + self->socket_pair[0] = -1; + self->socket_pair[1] = -1; + struct sockaddr_un local_addr = {0}; + struct sockaddr_un remote_addr = {0}; + + if(!create_socket_path(self->initial_socket_path, sizeof(self->initial_socket_path))) { + fprintf(stderr, "gsr error: gsr_kms_client_init: failed to create path to kms socket\n"); + return -1; + } + + char server_filepath[PATH_MAX]; + if(!find_program_in_path("gsr-kms-server", server_filepath, sizeof(server_filepath))) { + fprintf(stderr, "gsr error: gsr_kms_client_init: gsr-kms-server is not installed\n"); + return -1; + } + + const bool inside_flatpak = getenv("FLATPAK_ID") != NULL; + const char *home = getenv("HOME"); + if(!home) + home = "/tmp"; + + bool has_perm = 0; + if(geteuid() == 0) { + has_perm = true; + } else { + cap_t kms_server_cap = cap_get_file(server_filepath); + if(kms_server_cap) { + cap_flag_value_t res = CAP_CLEAR; + cap_get_flag(kms_server_cap, CAP_SYS_ADMIN, CAP_PERMITTED, &res); + if(res == CAP_SET) { + //fprintf(stderr, "has permission!\n"); + has_perm = true; + } else { + //fprintf(stderr, "No permission:(\n"); + } + cap_free(kms_server_cap); + } else if(!inside_flatpak) { + 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, "gsr info: gsr_kms_client_init: failed to get cap\n"); + } + } + + if(socketpair(AF_UNIX, SOCK_STREAM, 0, self->socket_pair) == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_init: socketpair failed, error: %s\n", strerror(errno)); + goto err; + } + + self->initial_socket_fd = socket(AF_UNIX, SOCK_STREAM, 0); + if(self->initial_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_safe(local_addr.sun_path, self->initial_socket_path, sizeof(local_addr.sun_path)); + + const mode_t prev_mask = umask(0000); + const int bind_res = bind(self->initial_socket_fd, (struct sockaddr*)&local_addr, sizeof(local_addr.sun_family) + strlen(local_addr.sun_path)); + umask(prev_mask); + + if(bind_res == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_init: failed to bind socket, error: %s\n", strerror(errno)); + goto err; + } + + if(listen(self->initial_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(inside_flatpak) { + const char *args[] = { "flatpak-spawn", "--host", "/var/lib/flatpak/app/com.dec05eba.gpu_screen_recorder/current/active/files/bin/kms-server-proxy", self->initial_socket_path, card_path, home, NULL }; + execvp(args[0], (char *const*)args); + } else if(has_perm) { + const char *args[] = { server_filepath, self->initial_socket_path, card_path, NULL }; + execvp(args[0], (char *const*)args); + } else { + const char *args[] = { "pkexec", server_filepath, self->initial_socket_path, card_path, NULL }; + execvp(args[0], (char *const*)args); + } + fprintf(stderr, "gsr error: gsr_kms_client_init: execvp failed, error: %s\n", strerror(errno)); + _exit(127); + } else { /* parent */ + self->kms_server_pid = pid; + } + + fprintf(stderr, "gsr info: gsr_kms_client_init: waiting for server to connect\n"); + for(;;) { + struct timeval tv; + fd_set rfds; + FD_ZERO(&rfds); + FD_SET(self->initial_socket_fd, &rfds); + + tv.tv_sec = 0; + tv.tv_usec = 100 * 1000; // 100 ms + + int select_res = select(1 + self->initial_socket_fd, &rfds, NULL, NULL, &tv); + if(select_res > 0) { + socklen_t sock_len = 0; + self->initial_client_fd = accept(self->initial_socket_fd, (struct sockaddr*)&remote_addr, &sock_len); + if(self->initial_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 = 0; + int wait_result = waitpid(self->kms_server_pid, &status, WNOHANG); + if(wait_result != 0) { + int exit_code = -1; + if(WIFEXITED(status)) + exit_code = WEXITSTATUS(status); + fprintf(stderr, "gsr error: gsr_kms_client_init: kms server died or never started, exit code: %d\n", exit_code); + self->kms_server_pid = -1; + if(exit_code != 0) + result = exit_code; + goto err; + } + } + } + fprintf(stderr, "gsr info: gsr_kms_client_init: server connected\n"); + + fprintf(stderr, "gsr info: replacing file-backed unix domain socket with socketpair\n"); + if(gsr_kms_client_replace_connection(self) != 0) + goto err; + + cleanup_socket(self, false); + fprintf(stderr, "gsr info: using socketpair\n"); + + return 0; + + err: + gsr_kms_client_deinit(self); + return result; +} + +void cleanup_socket(gsr_kms_client *self, bool kill_server) { + if(self->initial_client_fd != -1) { + close(self->initial_client_fd); + self->initial_client_fd = -1; + } + + if(self->initial_socket_fd != -1) { + close(self->initial_socket_fd); + self->initial_socket_fd = -1; + } + + if(kill_server) { + for(int i = 0; i < 2; ++i) { + if(self->socket_pair[i] > 0) { + close(self->socket_pair[i]); + self->socket_pair[i] = -1; + } + } + } + + if(kill_server && self->kms_server_pid != -1) { + kill(self->kms_server_pid, SIGKILL); + //int status; + //waitpid(self->kms_server_pid, &status, 0); + self->kms_server_pid = -1; + } + + if(self->initial_socket_path[0] != '\0') { + remove(self->initial_socket_path); + self->initial_socket_path[0] = '\0'; + } +} + +void gsr_kms_client_deinit(gsr_kms_client *self) { + cleanup_socket(self, true); +} + +int gsr_kms_client_replace_connection(gsr_kms_client *self) { + gsr_kms_response response; + response.version = 0; + response.result = KMS_RESULT_FAILED_TO_SEND; + response.err_msg[0] = '\0'; + + gsr_kms_request request; + request.version = GSR_KMS_PROTOCOL_VERSION; + request.type = KMS_REQUEST_TYPE_REPLACE_CONNECTION; + request.new_connection_fd = self->socket_pair[GSR_SOCKET_PAIR_REMOTE]; + if(send_msg_to_server(self->initial_client_fd, &request) == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_replace_connection: failed to send request message to server\n"); + return -1; + } + + const int recv_res = recv_msg_from_server(self->socket_pair[GSR_SOCKET_PAIR_LOCAL], &response); + if(recv_res == 0) { + fprintf(stderr, "gsr warning: gsr_kms_client_replace_connection: kms server shut down\n"); + return -1; + } else if(recv_res == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_replace_connection: failed to receive response\n"); + return -1; + } + + if(response.version != GSR_KMS_PROTOCOL_VERSION) { + fprintf(stderr, "gsr error: gsr_kms_client_replace_connection: expected gsr-kms-server protocol version to be %u, but it's %u\n", GSR_KMS_PROTOCOL_VERSION, response.version); + /*close_fds(response);*/ + return -1; + } + + return 0; +} + +int gsr_kms_client_get_kms(gsr_kms_client *self, gsr_kms_response *response) { + response->version = 0; + response->result = KMS_RESULT_FAILED_TO_SEND; + response->err_msg[0] = '\0'; + + gsr_kms_request request; + request.version = GSR_KMS_PROTOCOL_VERSION; + request.type = KMS_REQUEST_TYPE_GET_KMS; + request.new_connection_fd = 0; + if(send_msg_to_server(self->socket_pair[GSR_SOCKET_PAIR_LOCAL], &request) == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_get_kms: failed to send request message to server\n"); + strcpy(response->err_msg, "failed to send"); + return -1; + } + + const int recv_res = recv_msg_from_server(self->socket_pair[GSR_SOCKET_PAIR_LOCAL], response); + if(recv_res == 0) { + fprintf(stderr, "gsr warning: gsr_kms_client_get_kms: kms server shut down\n"); + strcpy(response->err_msg, "failed to receive"); + return -1; + } else if(recv_res == -1) { + fprintf(stderr, "gsr error: gsr_kms_client_get_kms: failed to receive response\n"); + strcpy(response->err_msg, "failed to receive"); + return -1; + } + + if(response->version != GSR_KMS_PROTOCOL_VERSION) { + fprintf(stderr, "gsr error: gsr_kms_client_get_kms: expected gsr-kms-server protocol version to be %u, but it's %u\n", GSR_KMS_PROTOCOL_VERSION, response->version); + /*close_fds(response);*/ + strcpy(response->err_msg, "mismatching protocol version"); + return -1; + } + + return 0; +} |