diff options
Diffstat (limited to 'kernel/bpf/bpf_iter.c')
| -rw-r--r-- | kernel/bpf/bpf_iter.c | 77 |
1 files changed, 74 insertions, 3 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index b6715964b685..8f10e30ea0b0 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -67,6 +67,9 @@ static void bpf_iter_done_stop(struct seq_file *seq) iter_priv->done_stop = true; } +/* maximum visited objects before bailing out */ +#define MAX_ITER_OBJECTS 1000000 + /* bpf_seq_read, a customized and simpler version for bpf iterator. * no_llseek is assumed for this file. * The following are differences from seq_read(): @@ -79,14 +82,14 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, { struct seq_file *seq = file->private_data; size_t n, offs, copied = 0; - int err = 0; + int err = 0, num_objs = 0; void *p; mutex_lock(&seq->lock); if (!seq->buf) { - seq->size = PAGE_SIZE; - seq->buf = kmalloc(seq->size, GFP_KERNEL); + seq->size = PAGE_SIZE << 3; + seq->buf = kvmalloc(seq->size, GFP_KERNEL); if (!seq->buf) { err = -ENOMEM; goto done; @@ -135,6 +138,7 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, while (1) { loff_t pos = seq->index; + num_objs++; offs = seq->count; p = seq->op->next(seq, p, &seq->index); if (pos == seq->index) { @@ -153,6 +157,15 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, 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); @@ -377,10 +390,68 @@ out_unlock: 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) |