Commit 63f84ae6 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
Browse files

tracing/histogram: Do not copy the fixed-size char array field over the field size 

Do not copy the fixed-size char array field of the events over
the field size. The histogram treats char array as a string and
there are 2 types of char array in the event, fixed-size and
dynamic string. The dynamic string (__data_loc) field must be
null terminated, but the fixed-size char array field may not
be null terminated (not a string, but just a data).
In that case, histogram can copy the data after the field.
This uses the original field size for fixed-size char array
field to restrict the histogram not to access over the original
field size.

Link: https://lkml.kernel.org/r/163673292822.195747.3696966210526410250.stgit@devnote2



Fixes: 02205a67 (tracing: Add support for 'field variables')
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent d7458bc0

kernel/trace/trace_events_hist.c

+5 −4
Original line number Diff line number Diff line
@@ -1953,9 +1953,10 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, 
		if (!hist_field->type)

			goto free;



		if (field->filter_type == FILTER_STATIC_STRING)

		if (field->filter_type == FILTER_STATIC_STRING) {

			hist_field->fn = hist_field_string;

		else if (field->filter_type == FILTER_DYN_STRING)

			hist_field->size = field->size;

		} else if (field->filter_type == FILTER_DYN_STRING)

			hist_field->fn = hist_field_dynstring;

		else

			hist_field->fn = hist_field_pstring;
@@ -3025,7 +3026,7 @@ static inline void __update_field_vars(struct tracing_map_elt *elt, 
			char *str = elt_data->field_var_str[j++];

			char *val_str = (char *)(uintptr_t)var_val;



			strscpy(str, val_str, STR_VAR_LEN_MAX);

			strscpy(str, val_str, val->size);

			var_val = (u64)(uintptr_t)str;

		}

		tracing_map_set_var(elt, var_idx, var_val);
@@ -4920,7 +4921,7 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data, 


				str = elt_data->field_var_str[idx];

				val_str = (char *)(uintptr_t)hist_val;

				strscpy(str, val_str, STR_VAR_LEN_MAX);

				strscpy(str, val_str, hist_field->size);



				hist_val = (u64)(uintptr_t)str;

			}