diff options
Diffstat (limited to 'kernel/bpf/inode.c')
-rw-r--r-- | kernel/bpf/inode.c | 171 |
1 files changed, 155 insertions, 16 deletions
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index 5e40e7fccc21..4f841e16779e 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -20,11 +20,13 @@ #include <linux/filter.h> #include <linux/bpf.h> #include <linux/bpf_trace.h> +#include "preload/bpf_preload.h" enum bpf_type { BPF_TYPE_UNSPEC = 0, BPF_TYPE_PROG, BPF_TYPE_MAP, + BPF_TYPE_LINK, }; static void *bpf_any_get(void *raw, enum bpf_type type) @@ -36,6 +38,9 @@ static void *bpf_any_get(void *raw, enum bpf_type type) case BPF_TYPE_MAP: bpf_map_inc_with_uref(raw); break; + case BPF_TYPE_LINK: + bpf_link_inc(raw); + break; default: WARN_ON_ONCE(1); break; @@ -53,6 +58,9 @@ static void bpf_any_put(void *raw, enum bpf_type type) case BPF_TYPE_MAP: bpf_map_put_with_uref(raw); break; + case BPF_TYPE_LINK: + bpf_link_put(raw); + break; default: WARN_ON_ONCE(1); break; @@ -63,20 +71,32 @@ 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)) { + if (!IS_ERR(raw)) { + *type = BPF_TYPE_MAP; + return raw; + } + + raw = bpf_prog_get(ufd); + if (!IS_ERR(raw)) { *type = BPF_TYPE_PROG; - raw = bpf_prog_get(ufd); + return raw; } - return raw; + raw = bpf_link_get_from_fd(ufd); + if (!IS_ERR(raw)) { + *type = BPF_TYPE_LINK; + return raw; + } + + return ERR_PTR(-EINVAL); } 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 const struct inode_operations bpf_link_iops = { }; static struct inode *bpf_get_inode(struct super_block *sb, const struct inode *dir, @@ -102,7 +122,7 @@ static struct inode *bpf_get_inode(struct super_block *sb, inode->i_mtime = inode->i_atime; inode->i_ctime = inode->i_atime; - inode_init_owner(inode, dir, mode); + inode_init_owner(&init_user_ns, inode, dir, mode); return inode; } @@ -114,6 +134,8 @@ static int bpf_inode_type(const struct inode *inode, enum bpf_type *type) *type = BPF_TYPE_PROG; else if (inode->i_op == &bpf_map_iops) *type = BPF_TYPE_MAP; + else if (inode->i_op == &bpf_link_iops) + *type = BPF_TYPE_LINK; else return -EACCES; @@ -130,7 +152,8 @@ static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode, dir->i_ctime = dir->i_mtime; } -static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) +static int bpf_mkdir(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode) { struct inode *inode; @@ -205,10 +228,12 @@ static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos) else prev_key = key; + rcu_read_lock(); if (map->ops->map_get_next_key(map, prev_key, key)) { map_iter(m)->done = true; - return NULL; + key = NULL; } + rcu_read_unlock(); return key; } @@ -335,20 +360,30 @@ static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg) &bpffs_map_fops : &bpffs_obj_fops); } +static int bpf_mklink(struct dentry *dentry, umode_t mode, void *arg) +{ + struct bpf_link *link = arg; + + return bpf_mkobj_ops(dentry, mode, arg, &bpf_link_iops, + bpf_link_is_iter(link) ? + &bpf_iter_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. + * extensions. That allows popoulate_bpffs() create special files. */ - if (strchr(dentry->d_name.name, '.')) + if ((dir->i_mode & S_IALLUGO) && + 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) +static int bpf_symlink(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, const char *target) { char *link = kstrdup(target, GFP_USER | __GFP_NOWARN); struct inode *inode; @@ -379,6 +414,27 @@ static const struct inode_operations bpf_dir_iops = { .unlink = simple_unlink, }; +/* pin iterator link into bpffs */ +static int bpf_iter_link_pin_kernel(struct dentry *parent, + const char *name, struct bpf_link *link) +{ + umode_t mode = S_IFREG | S_IRUSR; + struct dentry *dentry; + int ret; + + inode_lock(parent->d_inode); + dentry = lookup_one_len(name, parent, strlen(name)); + if (IS_ERR(dentry)) { + inode_unlock(parent->d_inode); + return PTR_ERR(dentry); + } + ret = bpf_mkobj_ops(dentry, mode, link, &bpf_link_iops, + &bpf_iter_fops); + dput(dentry); + inode_unlock(parent->d_inode); + return ret; +} + static int bpf_obj_do_pin(const char __user *pathname, void *raw, enum bpf_type type) { @@ -411,6 +467,9 @@ static int bpf_obj_do_pin(const char __user *pathname, void *raw, case BPF_TYPE_MAP: ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw); break; + case BPF_TYPE_LINK: + ret = vfs_mkobj(dentry, mode, bpf_mklink, raw); + break; default: ret = -EPERM; } @@ -449,7 +508,7 @@ static void *bpf_obj_do_get(const char __user *pathname, return ERR_PTR(ret); inode = d_backing_inode(path.dentry); - ret = inode_permission(inode, ACC_MODE(flags)); + ret = path_permission(&path, ACC_MODE(flags)); if (ret) goto out; @@ -487,6 +546,8 @@ int bpf_obj_get_user(const char __user *pathname, int flags) ret = bpf_prog_new_fd(raw); else if (type == BPF_TYPE_MAP) ret = bpf_map_new_fd(raw, f_flags); + else if (type == BPF_TYPE_LINK) + ret = (f_flags != O_RDWR) ? -EINVAL : bpf_link_new_fd(raw); else return -ENOENT; @@ -498,12 +559,14 @@ int bpf_obj_get_user(const char __user *pathname, int flags) static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type type) { struct bpf_prog *prog; - int ret = inode_permission(inode, MAY_READ); + int ret = inode_permission(&init_user_ns, inode, MAY_READ); if (ret) return ERR_PTR(ret); if (inode->i_op == &bpf_map_iops) return ERR_PTR(-EINVAL); + if (inode->i_op == &bpf_link_iops) + return ERR_PTR(-EINVAL); if (inode->i_op != &bpf_prog_iops) return ERR_PTR(-EACCES); @@ -585,12 +648,22 @@ static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param) int opt; opt = fs_parse(fc, bpf_fs_parameters, param, &result); - if (opt < 0) + if (opt < 0) { /* We might like to report bad mount options here, but * traditionally we've ignored all mount options, so we'd * better continue to ignore non-existing options for bpf. */ - return opt == -ENOPARAM ? 0 : opt; + if (opt == -ENOPARAM) { + opt = vfs_parse_fs_param_source(fc, param); + if (opt != -ENOPARAM) + return opt; + + return 0; + } + + if (opt < 0) + return opt; + } switch (opt) { case OPT_MODE: @@ -601,6 +674,72 @@ static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param) return 0; } +struct bpf_preload_ops *bpf_preload_ops; +EXPORT_SYMBOL_GPL(bpf_preload_ops); + +static bool bpf_preload_mod_get(void) +{ + /* If bpf_preload.ko wasn't loaded earlier then load it now. + * When bpf_preload is built into vmlinux the module's __init + * function will populate it. + */ + if (!bpf_preload_ops) { + request_module("bpf_preload"); + if (!bpf_preload_ops) + return false; + } + /* And grab the reference, so the module doesn't disappear while the + * kernel is interacting with the kernel module and its UMD. + */ + if (!try_module_get(bpf_preload_ops->owner)) { + pr_err("bpf_preload module get failed.\n"); + return false; + } + return true; +} + +static void bpf_preload_mod_put(void) +{ + if (bpf_preload_ops) + /* now user can "rmmod bpf_preload" if necessary */ + module_put(bpf_preload_ops->owner); +} + +static DEFINE_MUTEX(bpf_preload_lock); + +static int populate_bpffs(struct dentry *parent) +{ + struct bpf_preload_info objs[BPF_PRELOAD_LINKS] = {}; + int err = 0, i; + + /* grab the mutex to make sure the kernel interactions with bpf_preload + * are serialized + */ + mutex_lock(&bpf_preload_lock); + + /* if bpf_preload.ko wasn't built into vmlinux then load it */ + if (!bpf_preload_mod_get()) + goto out; + + err = bpf_preload_ops->preload(objs); + if (err) + goto out_put; + for (i = 0; i < BPF_PRELOAD_LINKS; i++) { + bpf_link_inc(objs[i].link); + err = bpf_iter_link_pin_kernel(parent, + objs[i].link_name, objs[i].link); + if (err) { + bpf_link_put(objs[i].link); + goto out_put; + } + } +out_put: + bpf_preload_mod_put(); +out: + mutex_unlock(&bpf_preload_lock); + return err; +} + static int bpf_fill_super(struct super_block *sb, struct fs_context *fc) { static const struct tree_descr bpf_rfiles[] = { { "" } }; @@ -617,8 +756,8 @@ static int bpf_fill_super(struct super_block *sb, struct fs_context *fc) inode = sb->s_root->d_inode; inode->i_op = &bpf_dir_iops; inode->i_mode &= ~S_IALLUGO; + populate_bpffs(sb->s_root); inode->i_mode |= S_ISVTX | opts->mode; - return 0; } |