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    SubjectRe: [PATCH v5 12/12] user_events: Validate user payloads for size and null termination
    On Mon, Nov 15, 2021 at 04:50:47PM -0800, Beau Belgrave wrote:
    > +static int user_event_validate(struct user_event *user, void *data, int len)
    > +{
    > + struct list_head *head = &user->validators;
    > + struct user_event_validator *validator;
    > + void *pos, *end = data + len;
    > + u16 *val, offset, size;
    > +
    > + list_for_each_entry(validator, head, link) {
    > + pos = data + validator->offset;
    > + val = pos;
    > +
    > + /* Already done min_size check, no bounds check here */
    > + offset = *val++;
    > + size = *val++;

    I believe I have these backwards, size should come first for both dyn
    and rel data. Is this correct?

    > diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c
    > index 9d53717139e6..bea694e9df8c 100644
    > --- a/tools/testing/selftests/user_events/ftrace_test.c
    > +++ b/tools/testing/selftests/user_events/ftrace_test.c
    > @@ -21,6 +21,11 @@ const char *status_file = "/sys/kernel/debug/tracing/user_events_status";
    > const char *enable_file = "/sys/kernel/debug/tracing/events/user_events/__test_event/enable";
    > const char *trace_file = "/sys/kernel/debug/tracing/trace";
    >
    > +struct rel_loc {
    > + __u16 offset;
    > + __u16 size;
    > +} __packed;
    > +

    Same here.

    Thanks,
    -Beau

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