On 07/09/2023 21:06, Jiri Olsa wrote:
Currently the multi_kprobe link attach does not check error injection list for programs with bpf_override_return helper and allows them to attach anywhere. Adding the missing check.
Cc: stable@vger.kernel.org Fixes: 0dcac2725406 ("bpf: Add multi kprobe link") Signed-off-by: Jiri Olsa jolsa@kernel.org
For the series,
Reviewed-by: Alan Maguire alan.maguire@oracle.com
...with one small question below...
kernel/trace/bpf_trace.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index a7264b2c17ad..c1c1af63ced2 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2853,6 +2853,17 @@ static int get_modules_for_addrs(struct module ***mods, unsigned long *addrs, u3 return arr.mods_cnt; } +static int addrs_check_error_injection_list(unsigned long *addrs, u32 cnt) +{
- u32 i;
- for (i = 0; i < cnt; i++) {
if (!within_error_injection_list(addrs[i]))return -EINVAL;
do we need a check like trace_kprobe_on_func_entry() to verify that it's a combination of function entry+kprobe override, or is that handled elsewhere/not needed? perf_event_attach_bpf_prog() does
/* * Kprobe override only works if they are on the function entry, * and only if they are on the opt-in list. */ if (prog->kprobe_override && (!trace_kprobe_on_func_entry(event->tp_event) || !trace_kprobe_error_injectable(event->tp_event))) return -EINVAL;
if this is needed, it might be good to augment the selftest to cover the case of specifying non-entry+kprobe override. thanks!
Alan
- return 0;
+}
int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { struct bpf_kprobe_multi_link *link = NULL; @@ -2930,6 +2941,11 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr goto error; }
- if (prog->kprobe_override && addrs_check_error_injection_list(addrs, cnt)) {
err = -EINVAL;goto error;- }
- link = kzalloc(sizeof(*link), GFP_KERNEL); if (!link) { err = -ENOMEM;