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-rw-r--r--kernel/bpf/bpf_lsm.c356
1 files changed, 356 insertions, 0 deletions
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
new file mode 100644
index 000000000..e6a76da4b
--- /dev/null
+++ b/kernel/bpf/bpf_lsm.c
@@ -0,0 +1,356 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2020 Google LLC.
+ */
+
+#include <linux/filter.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/binfmts.h>
+#include <linux/lsm_hooks.h>
+#include <linux/bpf_lsm.h>
+#include <linux/kallsyms.h>
+#include <linux/bpf_verifier.h>
+#include <net/bpf_sk_storage.h>
+#include <linux/bpf_local_storage.h>
+#include <linux/btf_ids.h>
+#include <linux/ima.h>
+#include <linux/bpf-cgroup.h>
+
+/* For every LSM hook that allows attachment of BPF programs, declare a nop
+ * function where a BPF program can be attached.
+ */
+#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
+noinline RET bpf_lsm_##NAME(__VA_ARGS__) \
+{ \
+ return DEFAULT; \
+}
+
+#include <linux/lsm_hook_defs.h>
+#undef LSM_HOOK
+
+#define LSM_HOOK(RET, DEFAULT, NAME, ...) BTF_ID(func, bpf_lsm_##NAME)
+BTF_SET_START(bpf_lsm_hooks)
+#include <linux/lsm_hook_defs.h>
+#undef LSM_HOOK
+BTF_SET_END(bpf_lsm_hooks)
+
+/* List of LSM hooks that should operate on 'current' cgroup regardless
+ * of function signature.
+ */
+BTF_SET_START(bpf_lsm_current_hooks)
+/* operate on freshly allocated sk without any cgroup association */
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_sk_alloc_security)
+BTF_ID(func, bpf_lsm_sk_free_security)
+#endif
+BTF_SET_END(bpf_lsm_current_hooks)
+
+/* List of LSM hooks that trigger while the socket is properly locked.
+ */
+BTF_SET_START(bpf_lsm_locked_sockopt_hooks)
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_sock_graft)
+BTF_ID(func, bpf_lsm_inet_csk_clone)
+BTF_ID(func, bpf_lsm_inet_conn_established)
+#endif
+BTF_SET_END(bpf_lsm_locked_sockopt_hooks)
+
+/* List of LSM hooks that trigger while the socket is _not_ locked,
+ * but it's ok to call bpf_{g,s}etsockopt because the socket is still
+ * in the early init phase.
+ */
+BTF_SET_START(bpf_lsm_unlocked_sockopt_hooks)
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_socket_post_create)
+BTF_ID(func, bpf_lsm_socket_socketpair)
+#endif
+BTF_SET_END(bpf_lsm_unlocked_sockopt_hooks)
+
+#ifdef CONFIG_CGROUP_BPF
+void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
+ bpf_func_t *bpf_func)
+{
+ const struct btf_param *args __maybe_unused;
+
+ if (btf_type_vlen(prog->aux->attach_func_proto) < 1 ||
+ btf_id_set_contains(&bpf_lsm_current_hooks,
+ prog->aux->attach_btf_id)) {
+ *bpf_func = __cgroup_bpf_run_lsm_current;
+ return;
+ }
+
+#ifdef CONFIG_NET
+ args = btf_params(prog->aux->attach_func_proto);
+
+ if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCKET])
+ *bpf_func = __cgroup_bpf_run_lsm_socket;
+ else if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCK])
+ *bpf_func = __cgroup_bpf_run_lsm_sock;
+ else
+#endif
+ *bpf_func = __cgroup_bpf_run_lsm_current;
+}
+#endif
+
+int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
+ const struct bpf_prog *prog)
+{
+ if (!prog->gpl_compatible) {
+ bpf_log(vlog,
+ "LSM programs must have a GPL compatible license\n");
+ return -EINVAL;
+ }
+
+ if (!btf_id_set_contains(&bpf_lsm_hooks, prog->aux->attach_btf_id)) {
+ bpf_log(vlog, "attach_btf_id %u points to wrong type name %s\n",
+ prog->aux->attach_btf_id, prog->aux->attach_func_name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/* Mask for all the currently supported BPRM option flags */
+#define BPF_F_BRPM_OPTS_MASK BPF_F_BPRM_SECUREEXEC
+
+BPF_CALL_2(bpf_bprm_opts_set, struct linux_binprm *, bprm, u64, flags)
+{
+ if (flags & ~BPF_F_BRPM_OPTS_MASK)
+ return -EINVAL;
+
+ bprm->secureexec = (flags & BPF_F_BPRM_SECUREEXEC);
+ return 0;
+}
+
+BTF_ID_LIST_SINGLE(bpf_bprm_opts_set_btf_ids, struct, linux_binprm)
+
+static const struct bpf_func_proto bpf_bprm_opts_set_proto = {
+ .func = bpf_bprm_opts_set,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_BTF_ID,
+ .arg1_btf_id = &bpf_bprm_opts_set_btf_ids[0],
+ .arg2_type = ARG_ANYTHING,
+};
+
+BPF_CALL_3(bpf_ima_inode_hash, struct inode *, inode, void *, dst, u32, size)
+{
+ return ima_inode_hash(inode, dst, size);
+}
+
+static bool bpf_ima_inode_hash_allowed(const struct bpf_prog *prog)
+{
+ return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id);
+}
+
+BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode)
+
+static const struct bpf_func_proto bpf_ima_inode_hash_proto = {
+ .func = bpf_ima_inode_hash,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_BTF_ID,
+ .arg1_btf_id = &bpf_ima_inode_hash_btf_ids[0],
+ .arg2_type = ARG_PTR_TO_UNINIT_MEM,
+ .arg3_type = ARG_CONST_SIZE,
+ .allowed = bpf_ima_inode_hash_allowed,
+};
+
+BPF_CALL_3(bpf_ima_file_hash, struct file *, file, void *, dst, u32, size)
+{
+ return ima_file_hash(file, dst, size);
+}
+
+BTF_ID_LIST_SINGLE(bpf_ima_file_hash_btf_ids, struct, file)
+
+static const struct bpf_func_proto bpf_ima_file_hash_proto = {
+ .func = bpf_ima_file_hash,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_BTF_ID,
+ .arg1_btf_id = &bpf_ima_file_hash_btf_ids[0],
+ .arg2_type = ARG_PTR_TO_UNINIT_MEM,
+ .arg3_type = ARG_CONST_SIZE,
+ .allowed = bpf_ima_inode_hash_allowed,
+};
+
+BPF_CALL_1(bpf_get_attach_cookie, void *, ctx)
+{
+ struct bpf_trace_run_ctx *run_ctx;
+
+ run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
+ return run_ctx->bpf_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_attach_cookie_proto = {
+ .func = bpf_get_attach_cookie,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+};
+
+static const struct bpf_func_proto *
+bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+ const struct bpf_func_proto *func_proto;
+
+ if (prog->expected_attach_type == BPF_LSM_CGROUP) {
+ func_proto = cgroup_common_func_proto(func_id, prog);
+ if (func_proto)
+ return func_proto;
+ }
+
+ switch (func_id) {
+ case BPF_FUNC_inode_storage_get:
+ return &bpf_inode_storage_get_proto;
+ case BPF_FUNC_inode_storage_delete:
+ return &bpf_inode_storage_delete_proto;
+#ifdef CONFIG_NET
+ case BPF_FUNC_sk_storage_get:
+ return &bpf_sk_storage_get_proto;
+ case BPF_FUNC_sk_storage_delete:
+ return &bpf_sk_storage_delete_proto;
+#endif /* CONFIG_NET */
+ case BPF_FUNC_spin_lock:
+ return &bpf_spin_lock_proto;
+ case BPF_FUNC_spin_unlock:
+ return &bpf_spin_unlock_proto;
+ case BPF_FUNC_bprm_opts_set:
+ return &bpf_bprm_opts_set_proto;
+ case BPF_FUNC_ima_inode_hash:
+ return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL;
+ case BPF_FUNC_ima_file_hash:
+ return prog->aux->sleepable ? &bpf_ima_file_hash_proto : NULL;
+ case BPF_FUNC_get_attach_cookie:
+ return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto : NULL;
+#ifdef CONFIG_NET
+ case BPF_FUNC_setsockopt:
+ if (prog->expected_attach_type != BPF_LSM_CGROUP)
+ return NULL;
+ if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks,
+ prog->aux->attach_btf_id))
+ return &bpf_sk_setsockopt_proto;
+ if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks,
+ prog->aux->attach_btf_id))
+ return &bpf_unlocked_sk_setsockopt_proto;
+ return NULL;
+ case BPF_FUNC_getsockopt:
+ if (prog->expected_attach_type != BPF_LSM_CGROUP)
+ return NULL;
+ if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks,
+ prog->aux->attach_btf_id))
+ return &bpf_sk_getsockopt_proto;
+ if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks,
+ prog->aux->attach_btf_id))
+ return &bpf_unlocked_sk_getsockopt_proto;
+ return NULL;
+#endif
+ default:
+ return tracing_prog_func_proto(func_id, prog);
+ }
+}
+
+/* The set of hooks which are called without pagefaults disabled and are allowed
+ * to "sleep" and thus can be used for sleepable BPF programs.
+ */
+BTF_SET_START(sleepable_lsm_hooks)
+BTF_ID(func, bpf_lsm_bpf)
+BTF_ID(func, bpf_lsm_bpf_map)
+BTF_ID(func, bpf_lsm_bpf_map_alloc_security)
+BTF_ID(func, bpf_lsm_bpf_map_free_security)
+BTF_ID(func, bpf_lsm_bpf_prog)
+BTF_ID(func, bpf_lsm_bprm_check_security)
+BTF_ID(func, bpf_lsm_bprm_committed_creds)
+BTF_ID(func, bpf_lsm_bprm_committing_creds)
+BTF_ID(func, bpf_lsm_bprm_creds_for_exec)
+BTF_ID(func, bpf_lsm_bprm_creds_from_file)
+BTF_ID(func, bpf_lsm_capget)
+BTF_ID(func, bpf_lsm_capset)
+BTF_ID(func, bpf_lsm_cred_prepare)
+BTF_ID(func, bpf_lsm_file_ioctl)
+BTF_ID(func, bpf_lsm_file_lock)
+BTF_ID(func, bpf_lsm_file_open)
+BTF_ID(func, bpf_lsm_file_receive)
+
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_inet_conn_established)
+#endif /* CONFIG_SECURITY_NETWORK */
+
+BTF_ID(func, bpf_lsm_inode_create)
+BTF_ID(func, bpf_lsm_inode_free_security)
+BTF_ID(func, bpf_lsm_inode_getattr)
+BTF_ID(func, bpf_lsm_inode_getxattr)
+BTF_ID(func, bpf_lsm_inode_mknod)
+BTF_ID(func, bpf_lsm_inode_need_killpriv)
+BTF_ID(func, bpf_lsm_inode_post_setxattr)
+BTF_ID(func, bpf_lsm_inode_readlink)
+BTF_ID(func, bpf_lsm_inode_rename)
+BTF_ID(func, bpf_lsm_inode_rmdir)
+BTF_ID(func, bpf_lsm_inode_setattr)
+BTF_ID(func, bpf_lsm_inode_setxattr)
+BTF_ID(func, bpf_lsm_inode_symlink)
+BTF_ID(func, bpf_lsm_inode_unlink)
+BTF_ID(func, bpf_lsm_kernel_module_request)
+BTF_ID(func, bpf_lsm_kernel_read_file)
+BTF_ID(func, bpf_lsm_kernfs_init_security)
+
+#ifdef CONFIG_KEYS
+BTF_ID(func, bpf_lsm_key_free)
+#endif /* CONFIG_KEYS */
+
+BTF_ID(func, bpf_lsm_mmap_file)
+BTF_ID(func, bpf_lsm_netlink_send)
+BTF_ID(func, bpf_lsm_path_notify)
+BTF_ID(func, bpf_lsm_release_secctx)
+BTF_ID(func, bpf_lsm_sb_alloc_security)
+BTF_ID(func, bpf_lsm_sb_eat_lsm_opts)
+BTF_ID(func, bpf_lsm_sb_kern_mount)
+BTF_ID(func, bpf_lsm_sb_mount)
+BTF_ID(func, bpf_lsm_sb_remount)
+BTF_ID(func, bpf_lsm_sb_set_mnt_opts)
+BTF_ID(func, bpf_lsm_sb_show_options)
+BTF_ID(func, bpf_lsm_sb_statfs)
+BTF_ID(func, bpf_lsm_sb_umount)
+BTF_ID(func, bpf_lsm_settime)
+
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_socket_accept)
+BTF_ID(func, bpf_lsm_socket_bind)
+BTF_ID(func, bpf_lsm_socket_connect)
+BTF_ID(func, bpf_lsm_socket_create)
+BTF_ID(func, bpf_lsm_socket_getpeername)
+BTF_ID(func, bpf_lsm_socket_getpeersec_dgram)
+BTF_ID(func, bpf_lsm_socket_getsockname)
+BTF_ID(func, bpf_lsm_socket_getsockopt)
+BTF_ID(func, bpf_lsm_socket_listen)
+BTF_ID(func, bpf_lsm_socket_post_create)
+BTF_ID(func, bpf_lsm_socket_recvmsg)
+BTF_ID(func, bpf_lsm_socket_sendmsg)
+BTF_ID(func, bpf_lsm_socket_shutdown)
+BTF_ID(func, bpf_lsm_socket_socketpair)
+#endif /* CONFIG_SECURITY_NETWORK */
+
+BTF_ID(func, bpf_lsm_syslog)
+BTF_ID(func, bpf_lsm_task_alloc)
+BTF_ID(func, bpf_lsm_current_getsecid_subj)
+BTF_ID(func, bpf_lsm_task_getsecid_obj)
+BTF_ID(func, bpf_lsm_task_prctl)
+BTF_ID(func, bpf_lsm_task_setscheduler)
+BTF_ID(func, bpf_lsm_task_to_inode)
+BTF_ID(func, bpf_lsm_userns_create)
+BTF_SET_END(sleepable_lsm_hooks)
+
+bool bpf_lsm_is_sleepable_hook(u32 btf_id)
+{
+ return btf_id_set_contains(&sleepable_lsm_hooks, btf_id);
+}
+
+const struct bpf_prog_ops lsm_prog_ops = {
+};
+
+const struct bpf_verifier_ops lsm_verifier_ops = {
+ .get_func_proto = bpf_lsm_func_proto,
+ .is_valid_access = btf_ctx_access,
+};