Commit 83540fbc authored Feb 20, 2019 by Jann Horn Committed by Steven Rostedt (VMware) Feb 21, 2019

tracing/perf: Use strndup_user() instead of buggy open-coded version

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.

Link: http://lkml.kernel.org/r/20190220165443.152385-1-jannh@google.com



Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 0eadcc7a ("perf/core: Fix perf_uprobe_init()")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent b689269b

kernel/trace/trace_event_perf.c

+7 −9

Original line number	Diff line number	Diff line
		@@ -299,15 +299,13 @@ 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)) {
		ret = PTR_ERR(path);
		return (ret == -EINVAL) ? -E2BIG : ret;
		}
		if (path[0] == '\0') {
		ret = -EINVAL;
		goto out;