Commit 3fdacf40 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-v5.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 

Pull tracing fix from Steven Rostedt:
 "Fix the histogram logic from possibly crashing the kernel

  Working on the histogram code, I found that if you dereference a char
  pointer in a trace event that happens to point to user space, it can
  crash the kernel, as it does no checks of that pointer. I have code
  coming that will do this better, so just remove this ability to treat
  character pointers in trace events as stings in the histogram"

* tag 'trace-v5.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Do not reference char * as a string in histograms
parents d980cc06 704adfb5

kernel/trace/trace_events_hist.c

+3 −3
Original line number Diff line number Diff line
@@ -1689,7 +1689,9 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, 
	if (WARN_ON_ONCE(!field))

		goto out;



	if (is_string_field(field)) {

	/* Pointers to strings are just pointers and dangerous to dereference */

	if (is_string_field(field) &&

	    (field->filter_type != FILTER_PTR_STRING)) {

		flags |= HIST_FIELD_FL_STRING;



		hist_field->size = MAX_FILTER_STR_VAL;
@@ -4495,8 +4497,6 @@ static inline void add_to_key(char *compound_key, void *key, 
		field = key_field->field;

		if (field->filter_type == FILTER_DYN_STRING)

			size = *(u32 *)(rec + field->offset) >> 16;

		else if (field->filter_type == FILTER_PTR_STRING)

			size = strlen(key);

		else if (field->filter_type == FILTER_STATIC_STRING)

			size = field->size;