// SPDX-License-Identifier: GPL-2.0-only/* Copyright (c) 2020 Facebook */ #include <linux/fs.h>#include <linux/anon_inodes.h>#include <linux/filter.h>#include <linux/bpf.h>#include <linux/rcupdate_trace.h> struct bpf_iter_target_info { struct list_head list; const struct bpf_iter_reg *reg_info; u32 btf_id; /* cached value */}; struct bpf_iter_link { struct bpf_link link; struct bpf_iter_aux_info aux; struct bpf_iter_target_info *tinfo;}; struct bpf_iter_priv_data { struct bpf_iter_target_info *tinfo; const struct bpf_iter_seq_info *seq_info; struct bpf_prog *prog; u64 session_id; u64 seq_num; bool done_stop; u8 target_private[] __aligned(8);}; static struct list_head targets = LIST_HEAD_INIT(targets);static DEFINE_MUTEX(targets_mutex); /* protect bpf_iter_link changes */static DEFINE_MUTEX(link_mutex); /* incremented on every opened seq_file */static atomic64_t session_id; static int prepare_seq_file(struct file *file, struct bpf_iter_link *link); static void bpf_iter_inc_seq_num(struct seq_file *seq){ struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); iter_priv->seq_num++;} static void bpf_iter_dec_seq_num(struct seq_file *seq){ struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); iter_priv->seq_num--;} static void bpf_iter_done_stop(struct seq_file *seq){ struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); iter_priv->done_stop = true;} static inline bool bpf_iter_target_support_resched(const struct bpf_iter_target_info *tinfo){ return tinfo->reg_info->feature & BPF_ITER_RESCHED;} static bool bpf_iter_support_resched(struct seq_file *seq){ struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); return bpf_iter_target_support_resched(iter_priv->tinfo);} /* maximum visited objects before bailing out */#define MAX_ITER_OBJECTS 1000000 /* bpf_seq_read, a customized and simpler version for bpf iterator. * The following are differences from seq_read(): * . fixed buffer size (PAGE_SIZE << 3) * . assuming NULL ->llseek() * . stop() may call bpf program, handling potential overflow there */static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos){ struct seq_file *seq = file->private_data; size_t n, offs, copied = 0; int err = 0, num_objs = 0; bool can_resched; void *p; mutex_lock(&seq->lock); if (!seq->buf) { seq->size = PAGE_SIZE << 3; seq->buf = kvmalloc(seq->size, GFP_KERNEL); if (!seq->buf) { err = -ENOMEM; goto done; } } if (seq->count) { n = min(seq->count, size); err = copy_to_user(buf, seq->buf + seq->from, n); if (err) { err = -EFAULT; goto done; } seq->count -= n; seq->from += n; copied = n; goto done; } seq->from = 0; p = seq->op->start(seq, &seq->index); if (!p) goto stop; if (IS_ERR(p)) { err = PTR_ERR(p); seq->op->stop(seq, p); seq->count = 0; goto done; } err = seq->op->show(seq, p); if (err > 0) { /* object is skipped, decrease seq_num, so next * valid object can reuse the same seq_num. */ bpf_iter_dec_seq_num(seq); seq->count = 0; } else if (err < 0 || seq_has_overflowed(seq)) { if (!err) err = -E2BIG; seq->op->stop(seq, p); seq->count = 0; goto done; } can_resched = bpf_iter_support_resched(seq); while (1) { loff_t pos = seq->index; num_objs++; offs = seq->count; p = seq->op->next(seq, p, &seq->index); if (pos == seq->index) { pr_info_ratelimited("buggy seq_file .next function %ps " "did not updated position index\n", seq->op->next); seq->index++; } if (IS_ERR_OR_NULL(p)) break; /* got a valid next object, increase seq_num */ bpf_iter_inc_seq_num(seq); if (seq->count >= size) break; if (num_objs >= MAX_ITER_OBJECTS) { if (offs == 0) { err = -EAGAIN; seq->op->stop(seq, p); goto done; } break; } err = seq->op->show(seq, p); if (err > 0) { bpf_iter_dec_seq_num(seq); seq->count = offs; } else if (err < 0 || seq_has_overflowed(seq)) { seq->count = offs; if (offs == 0) { if (!err) err = -E2BIG; seq->op->stop(seq, p); goto done; } break; } if (can_resched) cond_resched(); }stop: offs = seq->count; if (IS_ERR(p)) { seq->op->stop(seq, NULL); err = PTR_ERR(p); goto done; } /* bpf program called if !p */ seq->op->stop(seq, p); if (!p) { if (!seq_has_overflowed(seq)) { bpf_iter_done_stop(seq); } else { seq->count = offs; if (offs == 0) { err = -E2BIG; goto done; } } } n = min(seq->count, size); err = copy_to_user(buf, seq->buf, n); if (err) { err = -EFAULT; goto done; } copied = n; seq->count -= n; seq->from = n;done: if (!copied) copied = err; else *ppos += copied; mutex_unlock(&seq->lock); return copied;} static const struct bpf_iter_seq_info *__get_seq_info(struct bpf_iter_link *link){ const struct bpf_iter_seq_info *seq_info; if (link->aux.map) { seq_info = link->aux.map->ops->iter_seq_info; if (seq_info) return seq_info; } return link->tinfo->reg_info->seq_info;} static int iter_open(struct inode *inode, struct file *file){ struct bpf_iter_link *link = inode->i_private; return prepare_seq_file(file, link);} static int iter_release(struct inode *inode, struct file *file){ struct bpf_iter_priv_data *iter_priv; struct seq_file *seq; seq = file->private_data; if (!seq) return 0; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); if (iter_priv->seq_info->fini_seq_private) iter_priv->seq_info->fini_seq_private(seq->private); bpf_prog_put(iter_priv->prog); seq->private = iter_priv; return seq_release_private(inode, file);} const struct file_operations bpf_iter_fops = { .open = iter_open, .read = bpf_seq_read, .release = iter_release,}; /* The argument reg_info will be cached in bpf_iter_target_info. * The common practice is to declare target reg_info as * a const static variable and passed as an argument to * bpf_iter_reg_target(). */int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info){ struct bpf_iter_target_info *tinfo; tinfo = kzalloc_obj(*tinfo); if (!tinfo) return -ENOMEM; tinfo->reg_info = reg_info; INIT_LIST_HEAD(&tinfo->list); mutex_lock(&targets_mutex); list_add(&tinfo->list, &targets); mutex_unlock(&targets_mutex); return 0;} void bpf_iter_unreg_target(const struct bpf_iter_reg *reg_info){ struct bpf_iter_target_info *tinfo; bool found = false; mutex_lock(&targets_mutex); list_for_each_entry(tinfo, &targets, list) { if (reg_info == tinfo->reg_info) { list_del(&tinfo->list); kfree(tinfo); found = true; break; } } mutex_unlock(&targets_mutex); WARN_ON(found == false);} static void cache_btf_id(struct bpf_iter_target_info *tinfo, struct bpf_prog *prog){ tinfo->btf_id = prog->aux->attach_btf_id;} int bpf_iter_prog_supported(struct bpf_prog *prog){ const char *attach_fname = prog->aux->attach_func_name; struct bpf_iter_target_info *tinfo = NULL, *iter; u32 prog_btf_id = prog->aux->attach_btf_id; const char *prefix = BPF_ITER_FUNC_PREFIX; int prefix_len = strlen(prefix); if (strncmp(attach_fname, prefix, prefix_len)) return -EINVAL; mutex_lock(&targets_mutex); list_for_each_entry(iter, &targets, list) { if (iter->btf_id && iter->btf_id == prog_btf_id) { tinfo = iter; break; } if (!strcmp(attach_fname + prefix_len, iter->reg_info->target)) { cache_btf_id(iter, prog); tinfo = iter; break; } } mutex_unlock(&targets_mutex); if (!tinfo) return -EINVAL; return bpf_prog_ctx_arg_info_init(prog, tinfo->reg_info->ctx_arg_info, tinfo->reg_info->ctx_arg_info_size);} const struct bpf_func_proto *bpf_iter_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog){ const struct bpf_iter_target_info *tinfo; const struct bpf_func_proto *fn = NULL; mutex_lock(&targets_mutex); list_for_each_entry(tinfo, &targets, list) { if (tinfo->btf_id == prog->aux->attach_btf_id) { const struct bpf_iter_reg *reg_info; reg_info = tinfo->reg_info; if (reg_info->get_func_proto) fn = reg_info->get_func_proto(func_id, prog); break; } } mutex_unlock(&targets_mutex); return fn;} static void bpf_iter_link_release(struct bpf_link *link){ struct bpf_iter_link *iter_link = container_of(link, struct bpf_iter_link, link); if (iter_link->tinfo->reg_info->detach_target) iter_link->tinfo->reg_info->detach_target(&iter_link->aux);} static void bpf_iter_link_dealloc(struct bpf_link *link){ struct bpf_iter_link *iter_link = container_of(link, struct bpf_iter_link, link); kfree(iter_link);} static int bpf_iter_link_replace(struct bpf_link *link, struct bpf_prog *new_prog, struct bpf_prog *old_prog){ int ret = 0; mutex_lock(&link_mutex); if (old_prog && link->prog != old_prog) { ret = -EPERM; goto out_unlock; } if (link->prog->type != new_prog->type || link->prog->expected_attach_type != new_prog->expected_attach_type || link->prog->aux->attach_btf_id != new_prog->aux->attach_btf_id) { ret = -EINVAL; goto out_unlock; } old_prog = xchg(&link->prog, new_prog); bpf_prog_put(old_prog); out_unlock: mutex_unlock(&link_mutex); return ret;} static void bpf_iter_link_show_fdinfo(const struct bpf_link *link, struct seq_file *seq){ struct bpf_iter_link *iter_link = container_of(link, struct bpf_iter_link, link); bpf_iter_show_fdinfo_t show_fdinfo; seq_printf(seq, "target_name:\t%s\n", iter_link->tinfo->reg_info->target); show_fdinfo = iter_link->tinfo->reg_info->show_fdinfo; if (show_fdinfo) show_fdinfo(&iter_link->aux, seq);} static int bpf_iter_link_fill_link_info(const struct bpf_link *link, struct bpf_link_info *info){ struct bpf_iter_link *iter_link = container_of(link, struct bpf_iter_link, link); char __user *ubuf = u64_to_user_ptr(info->iter.target_name); bpf_iter_fill_link_info_t fill_link_info; u32 ulen = info->iter.target_name_len; const char *target_name; u32 target_len; if (!ulen ^ !ubuf) return -EINVAL; target_name = iter_link->tinfo->reg_info->target; target_len = strlen(target_name); info->iter.target_name_len = target_len + 1; if (ubuf) { if (ulen >= target_len + 1) { if (copy_to_user(ubuf, target_name, target_len + 1)) return -EFAULT; } else { char zero = '\0'; if (copy_to_user(ubuf, target_name, ulen - 1)) return -EFAULT; if (put_user(zero, ubuf + ulen - 1)) return -EFAULT; return -ENOSPC; } } fill_link_info = iter_link->tinfo->reg_info->fill_link_info; if (fill_link_info) return fill_link_info(&iter_link->aux, info); return 0;} static const struct bpf_link_ops bpf_iter_link_lops = { .release = bpf_iter_link_release, .dealloc = bpf_iter_link_dealloc, .update_prog = bpf_iter_link_replace, .show_fdinfo = bpf_iter_link_show_fdinfo, .fill_link_info = bpf_iter_link_fill_link_info,}; bool bpf_link_is_iter(struct bpf_link *link){Lines 1–500 of 824. 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// SPDX-License-Identifier: GPL-2.0-only /* Copyright (c) 2020 Facebook */ #include <linux/fs.h> #include <linux/anon_inodes.h> #include <linux/filter.h> #include <linux/bpf.h> #include <linux/rcupdate_trace.h> struct bpf_iter_target_info { struct list_head list; const struct bpf_iter_reg *reg_info; u32 btf_id; /* cached value */ }; struct bpf_iter_link { struct bpf_link link; struct bpf_iter_aux_info aux; struct bpf_iter_target_info *tinfo; }; struct bpf_iter_priv_data { struct bpf_iter_target_info *tinfo; const struct bpf_iter_seq_info *seq_info; struct bpf_prog *prog; u64 session_id; u64 seq_num; bool done_stop; u8 target_private[] __aligned(8); }; static struct list_head targets = LIST_HEAD_INIT(targets); static DEFINE_MUTEX(targets_mutex); /* protect bpf_iter_link changes */ static DEFINE_MUTEX(link_mutex); /* incremented on every opened seq_file */ static atomic64_t session_id; static int prepare_seq_file(struct file *file, struct bpf_iter_link *link); static void bpf_iter_inc_seq_num(struct seq_file *seq) { struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); iter_priv->seq_num++; } static void bpf_iter_dec_seq_num(struct seq_file *seq) { struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); iter_priv->seq_num--; } static void bpf_iter_done_stop(struct seq_file *seq) { struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); iter_priv->done_stop = true; } static inline bool bpf_iter_target_support_resched(const struct bpf_iter_target_info *tinfo) { return tinfo->reg_info->feature & BPF_ITER_RESCHED; } static bool bpf_iter_support_resched(struct seq_file *seq) { struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); return bpf_iter_target_support_resched(iter_priv->tinfo); } /* maximum visited objects before bailing out */ #define MAX_ITER_OBJECTS 1000000 /* bpf_seq_read, a customized and simpler version for bpf iterator. * The following are differences from seq_read(): * . fixed buffer size (PAGE_SIZE << 3) * . assuming NULL ->llseek() * . stop() may call bpf program, handling potential overflow there */ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) { struct seq_file *seq = file->private_data; size_t n, offs, copied = 0; int err = 0, num_objs = 0; bool can_resched; void *p; mutex_lock(&seq->lock); if (!seq->buf) { seq->size = PAGE_SIZE << 3; seq->buf = kvmalloc(seq->size, GFP_KERNEL); if (!seq->buf) { err = -ENOMEM; goto done; } } if (seq->count) { n = min(seq->count, size); err = copy_to_user(buf, seq->buf + seq->from, n); if (err) { err = -EFAULT; goto done; } seq->count -= n; seq->from += n; copied = n; goto done; } seq->from = 0; p = seq->op->start(seq, &seq->index); if (!p) goto stop; if (IS_ERR(p)) { err = PTR_ERR(p); seq->op->stop(seq, p); seq->count = 0; goto done; } err = seq->op->show(seq, p); if (err > 0) { /* object is skipped, decrease seq_num, so next * valid object can reuse the same seq_num. */ bpf_iter_dec_seq_num(seq); seq->count = 0; } else if (err < 0 || seq_has_overflowed(seq)) { if (!err) err = -E2BIG; seq->op->stop(seq, p); seq->count = 0; goto done; } can_resched = bpf_iter_support_resched(seq); while (1) { loff_t pos = seq->index; num_objs++; offs = seq->count; p = seq->op->next(seq, p, &seq->index); if (pos == seq->index) { pr_info_ratelimited("buggy seq_file .next function %ps " "did not updated position index\n", seq->op->next); seq->index++; } if (IS_ERR_OR_NULL(p)) break; /* got a valid next object, increase seq_num */ bpf_iter_inc_seq_num(seq); if (seq->count >= size) break; if (num_objs >= MAX_ITER_OBJECTS) { if (offs == 0) { err = -EAGAIN; seq->op->stop(seq, p); goto done; } break; } err = seq->op->show(seq, p); if (err > 0) { bpf_iter_dec_seq_num(seq); seq->count = offs; } else if (err < 0 || seq_has_overflowed(seq)) { seq->count = offs; if (offs == 0) { if (!err) err = -E2BIG; seq->op->stop(seq, p); goto done; } break; } if (can_resched) cond_resched(); } stop: offs = seq->count; if (IS_ERR(p)) { seq->op->stop(seq, NULL); err = PTR_ERR(p); goto done; } /* bpf program called if !p */ seq->op->stop(seq, p); if (!p) { if (!seq_has_overflowed(seq)) { bpf_iter_done_stop(seq); } else { seq->count = offs; if (offs == 0) { err = -E2BIG; goto done; } } } n = min(seq->count, size); err = copy_to_user(buf, seq->buf, n); if (err) { err = -EFAULT; goto done; } copied = n; seq->count -= n; seq->from = n; done: if (!copied) copied = err; else *ppos += copied; mutex_unlock(&seq->lock); return copied; } static const struct bpf_iter_seq_info * __get_seq_info(struct bpf_iter_link *link) { const struct bpf_iter_seq_info *seq_info; if (link->aux.map) { seq_info = link->aux.map->ops->iter_seq_info; if (seq_info) return seq_info; } return link->tinfo->reg_info->seq_info; } static int iter_open(struct inode *inode, struct file *file) { struct bpf_iter_link *link = inode->i_private; return prepare_seq_file(file, link); } static int iter_release(struct inode *inode, struct file *file) { struct bpf_iter_priv_data *iter_priv; struct seq_file *seq; seq = file->private_data; if (!seq) return 0; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); if (iter_priv->seq_info->fini_seq_private) iter_priv->seq_info->fini_seq_private(seq->private); bpf_prog_put(iter_priv->prog); seq->private = iter_priv; return seq_release_private(inode, file); } const struct file_operations bpf_iter_fops = { .open = iter_open, .read = bpf_seq_read, .release = iter_release, }; /* The argument reg_info will be cached in bpf_iter_target_info. * The common practice is to declare target reg_info as * a const static variable and passed as an argument to * bpf_iter_reg_target(). */ int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info) { struct bpf_iter_target_info *tinfo; tinfo = kzalloc_obj(*tinfo); if (!tinfo) return -ENOMEM; tinfo->reg_info = reg_info; INIT_LIST_HEAD(&tinfo->list); mutex_lock(&targets_mutex); list_add(&tinfo->list, &targets); mutex_unlock(&targets_mutex); return 0; } void bpf_iter_unreg_target(const struct bpf_iter_reg *reg_info) { struct bpf_iter_target_info *tinfo; bool found = false; mutex_lock(&targets_mutex); list_for_each_entry(tinfo, &targets, list) { if (reg_info == tinfo->reg_info) { list_del(&tinfo->list); kfree(tinfo); found = true; break; } } mutex_unlock(&targets_mutex); WARN_ON(found == false); } static void cache_btf_id(struct bpf_iter_target_info *tinfo, struct bpf_prog *prog) { tinfo->btf_id = prog->aux->attach_btf_id; } int bpf_iter_prog_supported(struct bpf_prog *prog) { const char *attach_fname = prog->aux->attach_func_name; struct bpf_iter_target_info *tinfo = NULL, *iter; u32 prog_btf_id = prog->aux->attach_btf_id; const char *prefix = BPF_ITER_FUNC_PREFIX; int prefix_len = strlen(prefix); if (strncmp(attach_fname, prefix, prefix_len)) return -EINVAL; mutex_lock(&targets_mutex); list_for_each_entry(iter, &targets, list) { if (iter->btf_id && iter->btf_id == prog_btf_id) { tinfo = iter; break; } if (!strcmp(attach_fname + prefix_len, iter->reg_info->target)) { cache_btf_id(iter, prog); tinfo = iter; break; } } mutex_unlock(&targets_mutex); if (!tinfo) return -EINVAL; return bpf_prog_ctx_arg_info_init(prog, tinfo->reg_info->ctx_arg_info, tinfo->reg_info->ctx_arg_info_size); } const struct bpf_func_proto * bpf_iter_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { const struct bpf_iter_target_info *tinfo; const struct bpf_func_proto *fn = NULL; mutex_lock(&targets_mutex); list_for_each_entry(tinfo, &targets, list) { if (tinfo->btf_id == prog->aux->attach_btf_id) { const struct bpf_iter_reg *reg_info; reg_info = tinfo->reg_info; if (reg_info->get_func_proto) fn = reg_info->get_func_proto(func_id, prog); break; } } mutex_unlock(&targets_mutex); return fn; } static void bpf_iter_link_release(struct bpf_link *link) { struct bpf_iter_link *iter_link = container_of(link, struct bpf_iter_link, link); if (iter_link->tinfo->reg_info->detach_target) iter_link->tinfo->reg_info->detach_target(&iter_link->aux); } static void bpf_iter_link_dealloc(struct bpf_link *link) { struct bpf_iter_link *iter_link = container_of(link, struct bpf_iter_link, link); kfree(iter_link); } static int bpf_iter_link_replace(struct bpf_link *link, struct bpf_prog *new_prog, struct bpf_prog *old_prog) { int ret = 0; mutex_lock(&link_mutex); if (old_prog && link->prog != old_prog) { ret = -EPERM; goto out_unlock; } if (link->prog->type != new_prog->type || link->prog->expected_attach_type != new_prog->expected_attach_type || link->prog->aux->attach_btf_id != new_prog->aux->attach_btf_id) { ret = -EINVAL; goto out_unlock; } old_prog = xchg(&link->prog, new_prog); bpf_prog_put(old_prog); out_unlock: mutex_unlock(&link_mutex); return ret; } static void bpf_iter_link_show_fdinfo(const struct bpf_link *link, struct seq_file *seq) { struct bpf_iter_link *iter_link = container_of(link, struct bpf_iter_link, link); bpf_iter_show_fdinfo_t show_fdinfo; seq_printf(seq, "target_name:\t%s\n", iter_link->tinfo->reg_info->target); show_fdinfo = iter_link->tinfo->reg_info->show_fdinfo; if (show_fdinfo) show_fdinfo(&iter_link->aux, seq); } static int bpf_iter_link_fill_link_info(const struct bpf_link *link, struct bpf_link_info *info) { struct bpf_iter_link *iter_link = container_of(link, struct bpf_iter_link, link); char __user *ubuf = u64_to_user_ptr(info->iter.target_name); bpf_iter_fill_link_info_t fill_link_info; u32 ulen = info->iter.target_name_len; const char *target_name; u32 target_len; if (!ulen ^ !ubuf) return -EINVAL; target_name = iter_link->tinfo->reg_info->target; target_len = strlen(target_name); info->iter.target_name_len = target_len + 1; if (ubuf) { if (ulen >= target_len + 1) { if (copy_to_user(ubuf, target_name, target_len + 1)) return -EFAULT; } else { char zero = '\0'; if (copy_to_user(ubuf, target_name, ulen - 1)) return -EFAULT; if (put_user(zero, ubuf + ulen - 1)) return -EFAULT; return -ENOSPC; } } fill_link_info = iter_link->tinfo->reg_info->fill_link_info; if (fill_link_info) return fill_link_info(&iter_link->aux, info); return 0; } static const struct bpf_link_ops bpf_iter_link_lops = { .release = bpf_iter_link_release, .dealloc = bpf_iter_link_dealloc, .update_prog = bpf_iter_link_replace, .show_fdinfo = bpf_iter_link_show_fdinfo, .fill_link_info = bpf_iter_link_fill_link_info, }; bool bpf_link_is_iter(struct bpf_link *link) {