Re-arrange repository structure

1 files changed, 361 insertions, 0 deletions

diff --git a/operations.c b/operations.c
new file mode 100644
index 0000000..0327e57
--- /dev/null
+++ b/operations.c
@@ -0,0 +1,361 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright 2023 Red Hat GmbH
+ * Author: Alice Frosi <afrosi@redhat.com>
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sched.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <linux/seccomp.h>
+#include <linux/filter.h>
+#include <linux/audit.h>
+#include <errno.h>
+
+#include "gluten.h"
+#include "operations.h"
+
+static bool is_cookie_valid(int notifyFd, uint64_t id)
+{
+	return ioctl(notifyFd, SECCOMP_IOCTL_NOTIF_ID_VALID, &id) == 0;
+}
+
+static int send_target(const struct seccomp_notif_resp *resp, int notifyfd)
+{
+	if (!is_cookie_valid(notifyfd, resp->id)) {
+		fprintf(stderr,
+			"the response id isn't valid\ncheck if the targets has already terminated\n");
+		return -1;
+	}
+	if (ioctl(notifyfd, SECCOMP_IOCTL_NOTIF_SEND, resp) < 0) {
+		if (errno != EINPROGRESS) {
+			perror("sending the response");
+			return -1;
+		}
+	}
+	return 0;
+}
+
+static int send_inject_target(const struct seccomp_notif_addfd *resp,
+			      int notifyfd)
+{
+	if (!is_cookie_valid(notifyfd, resp->id)) {
+		fprintf(stderr,
+			"the response id isn't valid\ncheck if the targets has already terminated\n");
+		return -1;
+	}
+	if (ioctl(notifyfd, SECCOMP_IOCTL_NOTIF_ADDFD, resp) < 0) {
+		if (errno != EINPROGRESS) {
+			perror("sending the response");
+			return -1;
+		}
+	}
+	return 0;
+}
+
+static void proc_ns_name(unsigned i, char *ns)
+{
+	switch (i) {
+	case NS_CGROUP:
+		snprintf(ns, PATH_MAX + 1, "cgroup");
+		break;
+	case NS_IPC:
+		snprintf(ns, PATH_MAX + 1, "ipc");
+		break;
+	case NS_NET:
+		snprintf(ns, PATH_MAX + 1, "net");
+		break;
+	case NS_MOUNT:
+		snprintf(ns, PATH_MAX + 1, "mnt");
+		break;
+	case NS_PID:
+		snprintf(ns, PATH_MAX + 1, "pid");
+		break;
+	case NS_USER:
+		snprintf(ns, PATH_MAX + 1, "user");
+		break;
+	case NS_UTS:
+		snprintf(ns, PATH_MAX + 1, "uts");
+		break;
+	case NS_TIME:
+		snprintf(ns, PATH_MAX + 1, "time");
+		break;
+	default:
+		fprintf(stderr, "unrecognized namespace index %d\n", i);
+	}
+}
+
+static int set_namespaces(const struct op_call *a, int tpid)
+{
+	char path[PATH_MAX + 1];
+	char ns_name[PATH_MAX / 2];
+	struct ns_spec ns;
+	int fd;
+	unsigned int i;
+
+	for (i = 0, ns = (a->context).ns[i]; i < sizeof(enum ns_type);
+	     i++, ns = (a->context).ns[i]) {
+		proc_ns_name(i, ns_name);
+		switch (ns.type) {
+		case NS_NONE:
+			continue;
+		case NS_SPEC_TARGET:
+			snprintf(path, sizeof(path), "/proc/%d/ns/%s", tpid,
+				 ns_name);
+			break;
+		case NS_SPEC_PID:
+			snprintf(path, sizeof(path), "/proc/%d/ns/%s", ns.pid,
+				 ns_name);
+			break;
+		case NS_SPEC_PATH:
+			snprintf(path, sizeof(path), "%s", ns.path);
+			break;
+		}
+
+		if ((fd = open(path, O_CLOEXEC)) < 0) {
+			fprintf(stderr, "open for file %s: %s", path,
+				strerror(errno));
+			return -1;
+		}
+
+		if (setns(fd, 0) != 0) {
+			perror("setns");
+			return -1;
+		}
+	}
+	return 0;
+}
+
+static int execute_syscall(void *args)
+{
+	struct arg_clone *a = (struct arg_clone *)args;
+	const struct op_call *c = a->args;
+
+	if (set_namespaces(a->args, a->pid) < 0) {
+		exit(EXIT_FAILURE);
+	}
+	/* execute syscall */
+	a->ret = syscall(c->nr, c->args[0], c->args[1], c->args[2], c->args[3],
+			 c->args[4], c->args[5]);
+	a->err = errno;
+	if (a->ret < 0) {
+		perror("syscall");
+		exit(EXIT_FAILURE);
+	}
+	exit(0);
+}
+
+int copy_args(struct seccomp_notif *req, struct op_copy_args *copy, void *data,
+	      int notifier)
+{
+	char path[PATH_MAX];
+	unsigned int i;
+	ssize_t nread;
+	void *dest;
+	int fd;
+
+	snprintf(path, sizeof(path), "/proc/%d/mem", req->pid);
+	if ((fd = open(path, O_RDONLY | O_CLOEXEC)) < 0) {
+		perror("open mem");
+		return -1;
+	}
+
+	/*
+         * Avoid the TOCTOU and check if the read mappings are still valid
+         */
+	if (!is_cookie_valid(notifier, req->id)) {
+		fprintf(stderr, "the seccomp request isn't valid anymore\n");
+		return -1;
+	}
+	for (i = 0; i < 6; i++) {
+		if (copy->args[i].type == REFERENCE) {
+			dest = (uint16_t *)data + copy->args[i].args_off;
+			nread = pread(fd, dest, copy->args[i].size,
+				      req->data.args[i]);
+			if (nread < 0) {
+				perror("pread");
+				return -1;
+			}
+		} else {
+			memcpy((uint16_t *)data + copy->args[i].args_off,
+			       &req->data.args[i], copy->args[i].size);
+		}
+	}
+	close(fd);
+	return 0;
+}
+
+static int resolve_fd(void *data, struct op_resolvedfd *resfd, pid_t pid)
+{
+	char fdpath[PATH_MAX], buf[PATH_MAX];
+	char *path = (char *)((uint16_t *)data + resfd->path_off);
+	int *fd = (int *)((uint16_t *)data + resfd->fd_off);
+	ssize_t nbytes;
+
+	snprintf(fdpath, PATH_MAX, "/proc/%d/fd/%d", pid, *fd);
+	if ((nbytes = readlink(fdpath, buf, resfd->path_size)) < 0) {
+		fprintf(stderr, "error reading %s\n", fdpath);
+		perror("readlink");
+		return -1;
+	}
+	if (strcmp(path, buf) == 0)
+		return 0;
+	else
+		return 1;
+}
+
+int do_call(struct arg_clone *c)
+{
+	char stack[STACK_SIZE];
+	pid_t child;
+
+	c->ret = -1;
+	c->err = 0;
+
+	/* Create a process that will be moved to the namespace */
+	child = clone(execute_syscall, stack + sizeof(stack),
+		      CLONE_FILES | CLONE_VM | SIGCHLD, (void *)c);
+	if (child == -1) {
+		perror("clone");
+		return -1;
+	}
+	wait(NULL);
+	return 0;
+}
+
+static void set_inject_fields(uint64_t id, void *data, const struct op *a,
+			      struct seccomp_notif_addfd *resp)
+{
+	const struct fd_type *new = &(a->inj).newfd;
+	const struct fd_type *old = &(a->inj).oldfd;
+
+	resp->flags = SECCOMP_ADDFD_FLAG_SETFD;
+	resp->id = id;
+	if (new->type == IMMEDIATE)
+		resp->newfd = new->fd;
+	else
+		memcpy(&resp->srcfd, (uint16_t *)data + old->fd_off,
+		       sizeof(resp->srcfd));
+	if (old->type == IMMEDIATE)
+		resp->srcfd = old->fd;
+	else
+		memcpy(&resp->srcfd, (uint16_t *)data + old->fd_off,
+		       sizeof(resp->srcfd));
+	resp->newfd_flags = 0;
+}
+
+int do_operations(void *data, struct op operations[], struct seccomp_notif *req,
+		  unsigned int n_operations, int pid, int notifyfd, uint64_t id)
+{
+	struct seccomp_notif_addfd resp_fd;
+	struct seccomp_notif_resp resp;
+	struct arg_clone c;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < n_operations; i++) {
+		switch (operations[i].type) {
+		case OP_CALL:
+			resp.id = id;
+			resp.val = 0;
+			resp.flags = 0;
+			c.args = &operations[i].call;
+			c.pid = pid;
+			if (do_call(&c) == -1) {
+				resp.error = -1;
+				if (send_target(&resp, notifyfd) == -1)
+					return -1;
+			}
+			if (c.err != 0) {
+				resp.error = -1;
+				if (send_target(&resp, notifyfd) == -1)
+					return c.err;
+			}
+			/*
+			 * The result of the call needs to be save as
+			 * reference
+			 */
+			if (operations[i].call.has_ret) {
+				memcpy((uint16_t *)data +
+					       operations[i].call.ret_off,
+				       &c.ret, sizeof(c.ret));
+			}
+			break;
+		case OP_BLOCK:
+			resp.id = id;
+			resp.val = 0;
+			resp.flags = 0;
+			resp.error = operations[i].block.error;
+			if (send_target(&resp, notifyfd) == -1)
+				return -1;
+			break;
+		case OP_RETURN:
+			resp.id = id;
+			resp.flags = 0;
+			resp.error = 0;
+			if (operations[i].ret.type == IMMEDIATE)
+				resp.val = operations[i].ret.value;
+			else
+				memcpy(&resp.val,
+				       (uint16_t *)data +
+					       operations[i].ret.value_off,
+				       sizeof(resp.val));
+
+			if (send_target(&resp, notifyfd) == -1)
+				return -1;
+			break;
+
+		case OP_CONT:
+			resp.id = id;
+			resp.flags = SECCOMP_USER_NOTIF_FLAG_CONTINUE;
+			resp.error = 0;
+			resp.val = 0;
+			if (send_target(&resp, notifyfd) == -1)
+				return -1;
+			break;
+		case OP_INJECT_A:
+			set_inject_fields(id, data, &operations[i], &resp_fd);
+			resp_fd.flags |= SECCOMP_ADDFD_FLAG_SEND;
+			if (send_inject_target(&resp_fd, notifyfd) == -1)
+				return -1;
+			break;
+		case OP_INJECT:
+			set_inject_fields(id, data, &operations[i], &resp_fd);
+			if (send_inject_target(&resp_fd, notifyfd) == -1)
+				return -1;
+			break;
+		case OP_COPY_ARGS:
+			if (copy_args(req, &operations[i].copy, data,
+				      notifyfd) < 0)
+				return -1;
+			break;
+		case OP_END:
+			return 0;
+		case OP_CMP:
+			if (memcmp((uint16_t *)data + operations[i].cmp.s1_off,
+				   (uint16_t *)data + operations[i].cmp.s2_off,
+				   operations[i].cmp.size) != 0) {
+				i = operations[i].cmp.jmp;
+			}
+			break;
+		case OP_RESOLVEDFD:
+			ret = resolve_fd(data, &operations[i].resfd, pid);
+			if (ret == -1)
+				return -1;
+			else if (ret == 1)
+				i = operations[i].resfd.jmp;
+			break;
+		default:
+			fprintf(stderr, "unknow operation %d \n",
+				operations[i].type);
+		}
+	}
+	return 0;
+}