// SPDX-License-Identifier: GPL-2.0-only/* * Minimal file system backend for holding eBPF maps and programs, * used by bpf(2) object pinning. * * Authors: * * Daniel Borkmann <daniel@iogearbox.net> */ #include <linux/init.h>#include <linux/magic.h>#include <linux/major.h>#include <linux/mount.h>#include <linux/namei.h>#include <linux/fs.h>#include <linux/kdev_t.h>#include <linux/parser.h>#include <linux/filter.h>#include <linux/bpf.h>#include <linux/bpf_trace.h> enum bpf_type { BPF_TYPE_UNSPEC = 0, BPF_TYPE_PROG, BPF_TYPE_MAP,}; static void *bpf_any_get(void *raw, enum bpf_type type){ switch (type) { case BPF_TYPE_PROG: raw = bpf_prog_inc(raw); break; case BPF_TYPE_MAP: raw = bpf_map_inc(raw, true); break; default: WARN_ON_ONCE(1); break; } return raw;} static void bpf_any_put(void *raw, enum bpf_type type){ switch (type) { case BPF_TYPE_PROG: bpf_prog_put(raw); break; case BPF_TYPE_MAP: bpf_map_put_with_uref(raw); break; default: WARN_ON_ONCE(1); break; }} static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type){ void *raw; *type = BPF_TYPE_MAP; raw = bpf_map_get_with_uref(ufd); if (IS_ERR(raw)) { *type = BPF_TYPE_PROG; raw = bpf_prog_get(ufd); } return raw;} static const struct inode_operations bpf_dir_iops; static const struct inode_operations bpf_prog_iops = { };static const struct inode_operations bpf_map_iops = { }; static struct inode *bpf_get_inode(struct super_block *sb, const struct inode *dir, umode_t mode){ struct inode *inode; switch (mode & S_IFMT) { case S_IFDIR: case S_IFREG: case S_IFLNK: break; default: return ERR_PTR(-EINVAL); } inode = new_inode(sb); if (!inode) return ERR_PTR(-ENOSPC); inode->i_ino = get_next_ino(); inode->i_atime = current_time(inode); inode->i_mtime = inode->i_atime; inode->i_ctime = inode->i_atime; inode_init_owner(inode, dir, mode); return inode;} static int bpf_inode_type(const struct inode *inode, enum bpf_type *type){ *type = BPF_TYPE_UNSPEC; if (inode->i_op == &bpf_prog_iops) *type = BPF_TYPE_PROG; else if (inode->i_op == &bpf_map_iops) *type = BPF_TYPE_MAP; else return -EACCES; return 0;} static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode, struct inode *dir){ d_instantiate(dentry, inode); dget(dentry); dir->i_mtime = current_time(dir); dir->i_ctime = dir->i_mtime;} static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode){ struct inode *inode; inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR); if (IS_ERR(inode)) return PTR_ERR(inode); inode->i_op = &bpf_dir_iops; inode->i_fop = &simple_dir_operations; inc_nlink(inode); inc_nlink(dir); bpf_dentry_finalize(dentry, inode, dir); return 0;} struct map_iter { void *key; bool done;}; static struct map_iter *map_iter(struct seq_file *m){ return m->private;} static struct bpf_map *seq_file_to_map(struct seq_file *m){ return file_inode(m->file)->i_private;} static void map_iter_free(struct map_iter *iter){ if (iter) { kfree(iter->key); kfree(iter); }} static struct map_iter *map_iter_alloc(struct bpf_map *map){ struct map_iter *iter; iter = kzalloc(sizeof(*iter), GFP_KERNEL | __GFP_NOWARN); if (!iter) goto error; iter->key = kzalloc(map->key_size, GFP_KERNEL | __GFP_NOWARN); if (!iter->key) goto error; return iter; error: map_iter_free(iter); return NULL;} static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos){ struct bpf_map *map = seq_file_to_map(m); void *key = map_iter(m)->key; void *prev_key; if (map_iter(m)->done) return NULL; if (unlikely(v == SEQ_START_TOKEN)) prev_key = NULL; else prev_key = key; if (map->ops->map_get_next_key(map, prev_key, key)) { map_iter(m)->done = true; return NULL; } ++(*pos); return key;} static void *map_seq_start(struct seq_file *m, loff_t *pos){ if (map_iter(m)->done) return NULL; return *pos ? map_iter(m)->key : SEQ_START_TOKEN;} static void map_seq_stop(struct seq_file *m, void *v){} static int map_seq_show(struct seq_file *m, void *v){ struct bpf_map *map = seq_file_to_map(m); void *key = map_iter(m)->key; if (unlikely(v == SEQ_START_TOKEN)) { seq_puts(m, "# WARNING!! The output is for debug purpose only\n"); seq_puts(m, "# WARNING!! The output format will change\n"); } else { map->ops->map_seq_show_elem(map, key, m); } return 0;} static const struct seq_operations bpffs_map_seq_ops = { .start = map_seq_start, .next = map_seq_next, .show = map_seq_show, .stop = map_seq_stop,}; static int bpffs_map_open(struct inode *inode, struct file *file){ struct bpf_map *map = inode->i_private; struct map_iter *iter; struct seq_file *m; int err; iter = map_iter_alloc(map); if (!iter) return -ENOMEM; err = seq_open(file, &bpffs_map_seq_ops); if (err) { map_iter_free(iter); return err; } m = file->private_data; m->private = iter; return 0;} static int bpffs_map_release(struct inode *inode, struct file *file){ struct seq_file *m = file->private_data; map_iter_free(map_iter(m)); return seq_release(inode, file);} /* bpffs_map_fops should only implement the basic * read operation for a BPF map. The purpose is to * provide a simple user intuitive way to do * "cat bpffs/pathto/a-pinned-map". * * Other operations (e.g. write, lookup...) should be realized by * the userspace tools (e.g. bpftool) through the * BPF_OBJ_GET_INFO_BY_FD and the map's lookup/update * interface. */static const struct file_operations bpffs_map_fops = { .open = bpffs_map_open, .read = seq_read, .release = bpffs_map_release,}; static int bpffs_obj_open(struct inode *inode, struct file *file){ return -EIO;} static const struct file_operations bpffs_obj_fops = { .open = bpffs_obj_open,}; static int bpf_mkobj_ops(struct dentry *dentry, umode_t mode, void *raw, const struct inode_operations *iops, const struct file_operations *fops){ struct inode *dir = dentry->d_parent->d_inode; struct inode *inode = bpf_get_inode(dir->i_sb, dir, mode); if (IS_ERR(inode)) return PTR_ERR(inode); inode->i_op = iops; inode->i_fop = fops; inode->i_private = raw; bpf_dentry_finalize(dentry, inode, dir); return 0;} static int bpf_mkprog(struct dentry *dentry, umode_t mode, void *arg){ return bpf_mkobj_ops(dentry, mode, arg, &bpf_prog_iops, &bpffs_obj_fops);} static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg){ struct bpf_map *map = arg; return bpf_mkobj_ops(dentry, mode, arg, &bpf_map_iops, bpf_map_support_seq_show(map) ? &bpffs_map_fops : &bpffs_obj_fops);} static struct dentry *bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags){ /* Dots in names (e.g. "/sys/fs/bpf/foo.bar") are reserved for future * extensions. */ if (strchr(dentry->d_name.name, '.')) return ERR_PTR(-EPERM); return simple_lookup(dir, dentry, flags);} static int bpf_symlink(struct inode *dir, struct dentry *dentry, const char *target){ char *link = kstrdup(target, GFP_USER | __GFP_NOWARN); struct inode *inode; if (!link) return -ENOMEM; inode = bpf_get_inode(dir->i_sb, dir, S_IRWXUGO | S_IFLNK); if (IS_ERR(inode)) { kfree(link); return PTR_ERR(inode); } inode->i_op = &simple_symlink_inode_operations; inode->i_link = link; bpf_dentry_finalize(dentry, inode, dir); return 0;} static const struct inode_operations bpf_dir_iops = { .lookup = bpf_lookup, .mkdir = bpf_mkdir, .symlink = bpf_symlink, .rmdir = simple_rmdir, .rename = simple_rename, .link = simple_link, .unlink = simple_unlink,}; static int bpf_obj_do_pin(const struct filename *pathname, void *raw, enum bpf_type type){ struct dentry *dentry; struct inode *dir; struct path path; umode_t mode; int ret; dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0); if (IS_ERR(dentry)) return PTR_ERR(dentry); mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask()); ret = security_path_mknod(&path, dentry, mode, 0); if (ret) goto out; dir = d_inode(path.dentry); if (dir->i_op != &bpf_dir_iops) { ret = -EPERM; goto out; } switch (type) { case BPF_TYPE_PROG: ret = vfs_mkobj(dentry, mode, bpf_mkprog, raw); break; case BPF_TYPE_MAP: ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw); break; default: ret = -EPERM; }out: done_path_create(&path, dentry); return ret;} int bpf_obj_pin_user(u32 ufd, const char __user *pathname){ struct filename *pname; enum bpf_type type; void *raw; int ret; pname = getname(pathname); if (IS_ERR(pname)) return PTR_ERR(pname); raw = bpf_fd_probe_obj(ufd, &type); if (IS_ERR(raw)) { ret = PTR_ERR(raw); goto out; } ret = bpf_obj_do_pin(pname, raw, type); if (ret != 0) bpf_any_put(raw, type);out: putname(pname); return ret;} static void *bpf_obj_do_get(const struct filename *pathname, enum bpf_type *type, int flags){ struct inode *inode; struct path path; void *raw; int ret; ret = kern_path(pathname->name, LOOKUP_FOLLOW, &path); if (ret) return ERR_PTR(ret); inode = d_backing_inode(path.dentry); ret = inode_permission(inode, ACC_MODE(flags)); if (ret) goto out; ret = bpf_inode_type(inode, type); if (ret) goto out; raw = bpf_any_get(inode->i_private, *type); if (!IS_ERR(raw)) touch_atime(&path); path_put(&path); return raw;out: path_put(&path); return ERR_PTR(ret);} int bpf_obj_get_user(const char __user *pathname, int flags){ enum bpf_type type = BPF_TYPE_UNSPEC; struct filename *pname; int ret = -ENOENT; int f_flags; void *raw; f_flags = bpf_get_file_flag(flags); if (f_flags < 0) return f_flags; pname = getname(pathname); if (IS_ERR(pname)) return PTR_ERR(pname); raw = bpf_obj_do_get(pname, &type, f_flags); if (IS_ERR(raw)) { ret = PTR_ERR(raw); goto out; } Lines 1–500 of 679. 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// SPDX-License-Identifier: GPL-2.0-only /* * Minimal file system backend for holding eBPF maps and programs, * used by bpf(2) object pinning. * * Authors: * * Daniel Borkmann <daniel@iogearbox.net> */ #include <linux/init.h> #include <linux/magic.h> #include <linux/major.h> #include <linux/mount.h> #include <linux/namei.h> #include <linux/fs.h> #include <linux/kdev_t.h> #include <linux/parser.h> #include <linux/filter.h> #include <linux/bpf.h> #include <linux/bpf_trace.h> enum bpf_type { BPF_TYPE_UNSPEC = 0, BPF_TYPE_PROG, BPF_TYPE_MAP, }; static void *bpf_any_get(void *raw, enum bpf_type type) { switch (type) { case BPF_TYPE_PROG: raw = bpf_prog_inc(raw); break; case BPF_TYPE_MAP: raw = bpf_map_inc(raw, true); break; default: WARN_ON_ONCE(1); break; } return raw; } static void bpf_any_put(void *raw, enum bpf_type type) { switch (type) { case BPF_TYPE_PROG: bpf_prog_put(raw); break; case BPF_TYPE_MAP: bpf_map_put_with_uref(raw); break; default: WARN_ON_ONCE(1); break; } } static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type) { void *raw; *type = BPF_TYPE_MAP; raw = bpf_map_get_with_uref(ufd); if (IS_ERR(raw)) { *type = BPF_TYPE_PROG; raw = bpf_prog_get(ufd); } return raw; } static const struct inode_operations bpf_dir_iops; static const struct inode_operations bpf_prog_iops = { }; static const struct inode_operations bpf_map_iops = { }; static struct inode *bpf_get_inode(struct super_block *sb, const struct inode *dir, umode_t mode) { struct inode *inode; switch (mode & S_IFMT) { case S_IFDIR: case S_IFREG: case S_IFLNK: break; default: return ERR_PTR(-EINVAL); } inode = new_inode(sb); if (!inode) return ERR_PTR(-ENOSPC); inode->i_ino = get_next_ino(); inode->i_atime = current_time(inode); inode->i_mtime = inode->i_atime; inode->i_ctime = inode->i_atime; inode_init_owner(inode, dir, mode); return inode; } static int bpf_inode_type(const struct inode *inode, enum bpf_type *type) { *type = BPF_TYPE_UNSPEC; if (inode->i_op == &bpf_prog_iops) *type = BPF_TYPE_PROG; else if (inode->i_op == &bpf_map_iops) *type = BPF_TYPE_MAP; else return -EACCES; return 0; } static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode, struct inode *dir) { d_instantiate(dentry, inode); dget(dentry); dir->i_mtime = current_time(dir); dir->i_ctime = dir->i_mtime; } static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { struct inode *inode; inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR); if (IS_ERR(inode)) return PTR_ERR(inode); inode->i_op = &bpf_dir_iops; inode->i_fop = &simple_dir_operations; inc_nlink(inode); inc_nlink(dir); bpf_dentry_finalize(dentry, inode, dir); return 0; } struct map_iter { void *key; bool done; }; static struct map_iter *map_iter(struct seq_file *m) { return m->private; } static struct bpf_map *seq_file_to_map(struct seq_file *m) { return file_inode(m->file)->i_private; } static void map_iter_free(struct map_iter *iter) { if (iter) { kfree(iter->key); kfree(iter); } } static struct map_iter *map_iter_alloc(struct bpf_map *map) { struct map_iter *iter; iter = kzalloc(sizeof(*iter), GFP_KERNEL | __GFP_NOWARN); if (!iter) goto error; iter->key = kzalloc(map->key_size, GFP_KERNEL | __GFP_NOWARN); if (!iter->key) goto error; return iter; error: map_iter_free(iter); return NULL; } static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos) { struct bpf_map *map = seq_file_to_map(m); void *key = map_iter(m)->key; void *prev_key; if (map_iter(m)->done) return NULL; if (unlikely(v == SEQ_START_TOKEN)) prev_key = NULL; else prev_key = key; if (map->ops->map_get_next_key(map, prev_key, key)) { map_iter(m)->done = true; return NULL; } ++(*pos); return key; } static void *map_seq_start(struct seq_file *m, loff_t *pos) { if (map_iter(m)->done) return NULL; return *pos ? map_iter(m)->key : SEQ_START_TOKEN; } static void map_seq_stop(struct seq_file *m, void *v) { } static int map_seq_show(struct seq_file *m, void *v) { struct bpf_map *map = seq_file_to_map(m); void *key = map_iter(m)->key; if (unlikely(v == SEQ_START_TOKEN)) { seq_puts(m, "# WARNING!! The output is for debug purpose only\n"); seq_puts(m, "# WARNING!! The output format will change\n"); } else { map->ops->map_seq_show_elem(map, key, m); } return 0; } static const struct seq_operations bpffs_map_seq_ops = { .start = map_seq_start, .next = map_seq_next, .show = map_seq_show, .stop = map_seq_stop, }; static int bpffs_map_open(struct inode *inode, struct file *file) { struct bpf_map *map = inode->i_private; struct map_iter *iter; struct seq_file *m; int err; iter = map_iter_alloc(map); if (!iter) return -ENOMEM; err = seq_open(file, &bpffs_map_seq_ops); if (err) { map_iter_free(iter); return err; } m = file->private_data; m->private = iter; return 0; } static int bpffs_map_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; map_iter_free(map_iter(m)); return seq_release(inode, file); } /* bpffs_map_fops should only implement the basic * read operation for a BPF map. The purpose is to * provide a simple user intuitive way to do * "cat bpffs/pathto/a-pinned-map". * * Other operations (e.g. write, lookup...) should be realized by * the userspace tools (e.g. bpftool) through the * BPF_OBJ_GET_INFO_BY_FD and the map's lookup/update * interface. */ static const struct file_operations bpffs_map_fops = { .open = bpffs_map_open, .read = seq_read, .release = bpffs_map_release, }; static int bpffs_obj_open(struct inode *inode, struct file *file) { return -EIO; } static const struct file_operations bpffs_obj_fops = { .open = bpffs_obj_open, }; static int bpf_mkobj_ops(struct dentry *dentry, umode_t mode, void *raw, const struct inode_operations *iops, const struct file_operations *fops) { struct inode *dir = dentry->d_parent->d_inode; struct inode *inode = bpf_get_inode(dir->i_sb, dir, mode); if (IS_ERR(inode)) return PTR_ERR(inode); inode->i_op = iops; inode->i_fop = fops; inode->i_private = raw; bpf_dentry_finalize(dentry, inode, dir); return 0; } static int bpf_mkprog(struct dentry *dentry, umode_t mode, void *arg) { return bpf_mkobj_ops(dentry, mode, arg, &bpf_prog_iops, &bpffs_obj_fops); } static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg) { struct bpf_map *map = arg; return bpf_mkobj_ops(dentry, mode, arg, &bpf_map_iops, bpf_map_support_seq_show(map) ? &bpffs_map_fops : &bpffs_obj_fops); } static struct dentry * bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags) { /* Dots in names (e.g. "/sys/fs/bpf/foo.bar") are reserved for future * extensions. */ if (strchr(dentry->d_name.name, '.')) return ERR_PTR(-EPERM); return simple_lookup(dir, dentry, flags); } static int bpf_symlink(struct inode *dir, struct dentry *dentry, const char *target) { char *link = kstrdup(target, GFP_USER | __GFP_NOWARN); struct inode *inode; if (!link) return -ENOMEM; inode = bpf_get_inode(dir->i_sb, dir, S_IRWXUGO | S_IFLNK); if (IS_ERR(inode)) { kfree(link); return PTR_ERR(inode); } inode->i_op = &simple_symlink_inode_operations; inode->i_link = link; bpf_dentry_finalize(dentry, inode, dir); return 0; } static const struct inode_operations bpf_dir_iops = { .lookup = bpf_lookup, .mkdir = bpf_mkdir, .symlink = bpf_symlink, .rmdir = simple_rmdir, .rename = simple_rename, .link = simple_link, .unlink = simple_unlink, }; static int bpf_obj_do_pin(const struct filename *pathname, void *raw, enum bpf_type type) { struct dentry *dentry; struct inode *dir; struct path path; umode_t mode; int ret; dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0); if (IS_ERR(dentry)) return PTR_ERR(dentry); mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask()); ret = security_path_mknod(&path, dentry, mode, 0); if (ret) goto out; dir = d_inode(path.dentry); if (dir->i_op != &bpf_dir_iops) { ret = -EPERM; goto out; } switch (type) { case BPF_TYPE_PROG: ret = vfs_mkobj(dentry, mode, bpf_mkprog, raw); break; case BPF_TYPE_MAP: ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw); break; default: ret = -EPERM; } out: done_path_create(&path, dentry); return ret; } int bpf_obj_pin_user(u32 ufd, const char __user *pathname) { struct filename *pname; enum bpf_type type; void *raw; int ret; pname = getname(pathname); if (IS_ERR(pname)) return PTR_ERR(pname); raw = bpf_fd_probe_obj(ufd, &type); if (IS_ERR(raw)) { ret = PTR_ERR(raw); goto out; } ret = bpf_obj_do_pin(pname, raw, type); if (ret != 0) bpf_any_put(raw, type); out: putname(pname); return ret; } static void *bpf_obj_do_get(const struct filename *pathname, enum bpf_type *type, int flags) { struct inode *inode; struct path path; void *raw; int ret; ret = kern_path(pathname->name, LOOKUP_FOLLOW, &path); if (ret) return ERR_PTR(ret); inode = d_backing_inode(path.dentry); ret = inode_permission(inode, ACC_MODE(flags)); if (ret) goto out; ret = bpf_inode_type(inode, type); if (ret) goto out; raw = bpf_any_get(inode->i_private, *type); if (!IS_ERR(raw)) touch_atime(&path); path_put(&path); return raw; out: path_put(&path); return ERR_PTR(ret); } int bpf_obj_get_user(const char __user *pathname, int flags) { enum bpf_type type = BPF_TYPE_UNSPEC; struct filename *pname; int ret = -ENOENT; int f_flags; void *raw; f_flags = bpf_get_file_flag(flags); if (f_flags < 0) return f_flags; pname = getname(pathname); if (IS_ERR(pname)) return PTR_ERR(pname); raw = bpf_obj_do_get(pname, &type, f_flags); if (IS_ERR(raw)) { ret = PTR_ERR(raw); goto out; }