On Mon, Jun 12, 2023 at 03:16:06PM +0000, Yafang Shao wrote:
SNIP
>
> /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 80c9ec0..fe354d5 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3303,9 +3303,133 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
> kfree(perf_link);
> }
>
> +static int bpf_perf_link_fill_name(const struct perf_event *event,
> + char __user *uname, u32 ulen,
> + u64 *probe_offset, u64 *probe_addr,
> + u32 *fd_type)
> +{
this function name sounds misleading, it does query all the link data
plus copying the name.. seems like this should be renamed and separated
> + const char *buf;
> + u32 prog_id;
> + size_t len;
> + int err;
> +
> + if (!ulen ^ !uname)
> + return -EINVAL;
> + if (!uname)
> + return 0;
> +
> + err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
> + probe_offset, probe_addr);
> + if (err)
> + return err;
> +
> + len = strlen(buf);
> + if (buf) {
> + err = bpf_copy_to_user(uname, buf, ulen, len);
> + if (err)
> + return err;
> + } else {
> + char zero = '\0';
> +
> + if (put_user(zero, uname))
> + return -EFAULT;
> + }
> + return 0;
> +}
> +
> +static int bpf_perf_link_fill_probe(const struct perf_event *event,
> + struct bpf_link_info *info)
> +{
> + char __user *uname;
> + u64 addr, offset;
> + u32 ulen, type;
> + int err;
> +
> +#ifdef CONFIG_KPROBE_EVENTS
this will break compilation when CONFIG_KPROBE_EVENTS or CONFIG_UPROBE_EVENTS
options are not defined
jirka
> + if (event->tp_event->flags & TRACE_EVENT_FL_KPROBE) {
> + uname = u64_to_user_ptr(info->kprobe.func_name);
> + ulen = info->kprobe.name_len;
> + info->perf_link_type = BPF_PERF_LINK_KPROBE;
> + err = bpf_perf_link_fill_name(event, uname, ulen, &offset,
> + &addr, &type);
> + if (err)
> + return err;
> +
> + info->kprobe.offset = offset;
> + if (type == BPF_FD_TYPE_KRETPROBE)
> + info->kprobe.flags = 1;
> + if (!kallsyms_show_value(current_cred()))
> + return 0;
> + info->kprobe.addr = addr;
> + return 0;
> + }
> +#endif
> +
> +#ifdef CONFIG_UPROBE_EVENTS
> + if (event->tp_event->flags & TRACE_EVENT_FL_UPROBE) {
> + uname = u64_to_user_ptr(info->uprobe.file_name);
> + ulen = info->uprobe.name_len;
> + info->perf_link_type = BPF_PERF_LINK_UPROBE;
> + err = bpf_perf_link_fill_name(event, uname, ulen, &offset,
> + &addr, &type);
> + if (err)
> + return err;
> +
> + info->uprobe.offset = offset;
> + if (type == BPF_FD_TYPE_URETPROBE)
> + info->uprobe.flags = 1;
> + return 0;
> + }
> +#endif
> +
> + return -EOPNOTSUPP;
> +}
> +
SNIP
