Move kms client and server to separate directories

1 files changed, 245 insertions, 0 deletions

diff --git a/kms/client/kms_client.c b/kms/client/kms_client.c
new file mode 100644
index 0000000..2b59836
--- /dev/null
+++ b/kms/client/kms_client.c
@@ -0,0 +1,245 @@
+#include "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 <stdbool.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <sys/capability.h>
+
+static bool is_inside_flatpak(void) {
+    return getenv("FLATPAK_ID") != NULL;
+}
+
+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};
+
+    bool inside_flatpak = is_inside_flatpak();
+    char server_filepath[PATH_MAX];
+    snprintf(server_filepath, sizeof(server_filepath), "%s/%s", program_dir, "gsr-kms-server");
+    if(access(server_filepath, F_OK) != 0 || inside_flatpak)
+        snprintf(server_filepath, sizeof(server_filepath), "gsr-kms-server"); // Assume gsr-kms-server is in $PATH
+
+    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 = 0;
+            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(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");
+        }
+    }
+
+    fprintf(stderr, "gsr info: gsr server path: %s, exists: %s\n", server_filepath, access(server_filepath, F_OK) == 0 ? "yes" : "no");
+
+    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 if(inside_flatpak) {
+            const char *args[] = { "flatpak-spawn", "--host", "pkexec", 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: kms server died or never started, error: %s\n", strerror(errno));
+                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;
+}