Hi Jann, On Wed, 20 Feb 2019 16:19:10 +0100 Jann Horn <ja...@google.com> wrote:
> On Tue, Feb 19, 2019 at 3:51 PM Masami Hiramatsu <mhira...@kernel.org> wrote: > > On Tue, 19 Feb 2019 20:45:02 +0900 > > Masami Hiramatsu <mhira...@kernel.org> wrote: > > > > > On Mon, 18 Feb 2019 23:07:23 +0100 > > > Jann Horn <ja...@google.com> wrote: > > > > > > > The first version of this method was missing the check for > > > > `ret == PATH_MAX`; then such a check was added, but it didn't call > > > > kfree() > > > > on error, so there was still a small memory leak in the error case. > > > > Fix it by using strndup_user() instead of open-coding it. > > > > > > > > > > This looks good to me. > > > > > > Reviewed-by: Masami Hiramatsu <mhira...@kernel.org> > > > > BTW, I think it should note that if the string is longer than PATH_MAX. > > caller will receive -EINVAL instead of -E2BIG with this fix. > > Oh, whoops, I hadn't noticed that. > > Do you want me to just add a note to the changelog, or do I have to > work around this in the code? I think work around will be good if this goes to stable, since I guess this return code may go to user space. Thank you, > > > > > Fixes: 0eadcc7a7bc0 ("perf/core: Fix perf_uprobe_init()") > > > > Signed-off-by: Jann Horn <ja...@google.com> > > > > --- > > > > compile-tested only > > > > > > > > kernel/trace/trace_event_perf.c | 14 +++++--------- > > > > 1 file changed, 5 insertions(+), 9 deletions(-) > > > > > > > > diff --git a/kernel/trace/trace_event_perf.c > > > > b/kernel/trace/trace_event_perf.c > > > > index 76217bbef815..c744b02081c3 100644 > > > > --- a/kernel/trace/trace_event_perf.c > > > > +++ b/kernel/trace/trace_event_perf.c > > > > @@ -299,15 +299,11 @@ int perf_uprobe_init(struct perf_event *p_event, > > > > > > > > if (!p_event->attr.uprobe_path) > > > > return -EINVAL; > > > > - path = kzalloc(PATH_MAX, GFP_KERNEL); > > > > - if (!path) > > > > - return -ENOMEM; > > > > - ret = strncpy_from_user( > > > > - path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX); > > > > - if (ret == PATH_MAX) > > > > - return -E2BIG; > > > > - if (ret < 0) > > > > - goto out; > > > > + > > > > + path = strndup_user(u64_to_user_ptr(p_event->attr.uprobe_path), > > > > + PATH_MAX); > > > > + if (IS_ERR(path)) > > > > + return PTR_ERR(path); > > > > if (path[0] == '\0') { > > > > ret = -EINVAL; > > > > goto out; -- Masami Hiramatsu <mhira...@kernel.org>