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Diffstat (limited to '')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/local_storage.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c new file mode 100644 index 000000000000..19423ed862e3 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/local_storage.c @@ -0,0 +1,188 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright 2020 Google LLC. + */ + +#include "vmlinux.h" +#include <errno.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +#define DUMMY_STORAGE_VALUE 0xdeadbeef + +int monitored_pid = 0; +int inode_storage_result = -1; +int sk_storage_result = -1; + +struct local_storage { + struct inode *exec_inode; + __u32 value; +}; + +struct { + __uint(type, BPF_MAP_TYPE_INODE_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, struct local_storage); +} inode_storage_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_SK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE); + __type(key, int); + __type(value, struct local_storage); +} sk_storage_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_SK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE); + __type(key, int); + __type(value, struct local_storage); +} sk_storage_map2 SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, struct local_storage); +} task_storage_map SEC(".maps"); + +SEC("lsm/inode_unlink") +int BPF_PROG(unlink_hook, struct inode *dir, struct dentry *victim) +{ + __u32 pid = bpf_get_current_pid_tgid() >> 32; + struct local_storage *storage; + bool is_self_unlink; + + if (pid != monitored_pid) + return 0; + + storage = bpf_task_storage_get(&task_storage_map, + bpf_get_current_task_btf(), 0, 0); + if (storage) { + /* Don't let an executable delete itself */ + is_self_unlink = storage->exec_inode == victim->d_inode; + if (is_self_unlink) + return -EPERM; + } + + return 0; +} + +SEC("lsm.s/inode_rename") +int BPF_PROG(inode_rename, struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry, + unsigned int flags) +{ + __u32 pid = bpf_get_current_pid_tgid() >> 32; + struct local_storage *storage; + int err; + + /* new_dentry->d_inode can be NULL when the inode is renamed to a file + * that did not exist before. The helper should be able to handle this + * NULL pointer. + */ + bpf_inode_storage_get(&inode_storage_map, new_dentry->d_inode, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + + storage = bpf_inode_storage_get(&inode_storage_map, old_dentry->d_inode, + 0, 0); + if (!storage) + return 0; + + if (storage->value != DUMMY_STORAGE_VALUE) + inode_storage_result = -1; + + err = bpf_inode_storage_delete(&inode_storage_map, old_dentry->d_inode); + if (!err) + inode_storage_result = err; + + return 0; +} + +SEC("lsm.s/socket_bind") +int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address, + int addrlen) +{ + __u32 pid = bpf_get_current_pid_tgid() >> 32; + struct local_storage *storage; + int err; + + if (pid != monitored_pid) + return 0; + + storage = bpf_sk_storage_get(&sk_storage_map, sock->sk, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!storage) + return 0; + + if (storage->value != DUMMY_STORAGE_VALUE) + sk_storage_result = -1; + + /* This tests that we can associate multiple elements + * with the local storage. + */ + storage = bpf_sk_storage_get(&sk_storage_map2, sock->sk, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!storage) + return 0; + + err = bpf_sk_storage_delete(&sk_storage_map, sock->sk); + if (err) + return 0; + + err = bpf_sk_storage_delete(&sk_storage_map2, sock->sk); + if (!err) + sk_storage_result = err; + + return 0; +} + +SEC("lsm.s/socket_post_create") +int BPF_PROG(socket_post_create, struct socket *sock, int family, int type, + int protocol, int kern) +{ + __u32 pid = bpf_get_current_pid_tgid() >> 32; + struct local_storage *storage; + + if (pid != monitored_pid) + return 0; + + storage = bpf_sk_storage_get(&sk_storage_map, sock->sk, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!storage) + return 0; + + storage->value = DUMMY_STORAGE_VALUE; + + return 0; +} + +/* This uses the local storage to remember the inode of the binary that a + * process was originally executing. + */ +SEC("lsm.s/bprm_committed_creds") +void BPF_PROG(exec, struct linux_binprm *bprm) +{ + __u32 pid = bpf_get_current_pid_tgid() >> 32; + struct local_storage *storage; + + if (pid != monitored_pid) + return; + + storage = bpf_task_storage_get(&task_storage_map, + bpf_get_current_task_btf(), 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (storage) + storage->exec_inode = bprm->file->f_inode; + + storage = bpf_inode_storage_get(&inode_storage_map, bprm->file->f_inode, + 0, BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!storage) + return; + + storage->value = DUMMY_STORAGE_VALUE; +} |