On Tue, 06 Feb 2018 17:43:39 -0500 Steven Rostedt rostedt@goodmis.org wrote:

From: "Steven Rostedt (VMware)" rostedt@goodmis.org

__unregister_ftrace_function_probe() will incorrectly parse the glob filter because it resets the search variable that was setup by filter_parse_regex().

Al Viro reported this:

After that call of filter_parse_regex() we could have func_g.search not
equal to glob only if glob started with '!' or '*'.  In the former case
we would've buggered off with -EINVAL (not = 1).  In the latter we
would've set func_g.search equal to glob + 1, calculated the length of
that thing in func_g.len and proceeded to reset func_g.search back to
glob.

Suppose the glob is e.g. *foo*.  We end up with
   func_g.type = MATCH_MIDDLE_ONLY;
   func_g.len = 3;
   func_g.search = "*foo";
Feeding that to ftrace_match_record() will not do anything sane - we
will be looking for names containing "*foo" (->len is ignored for that
one).

Link: http://lkml.kernel.org/r/20180127031706.GE13338@ZenIV.linux.org.uk

Cc: stable@vger.kernel.org Cc: Dmitry Safonov 0x7f454c46@gmail.com Fixes: 3ba009297149f ("ftrace: Introduce ftrace_glob structure") Reported-by: Al Viro viro@ZenIV.linux.org.uk Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org

Reviewed-by: Masami Hiramatsu mhiramat@kernel.org

Thank you!

---

kernel/trace/ftrace.c | 1 - 1 file changed, 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index dabd9d167d42..eac9ce2c57a2 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4456,7 +4456,6 @@ unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr, func_g.type = filter_parse_regex(glob, strlen(glob), &func_g.search, &not); func_g.len = strlen(func_g.search);

• func_g.search = glob;
  

/* we do not support '!' for function probes */ if (WARN_ON(not)) -- 2.15.1