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

[ Upstream commit 63f84ae6b82bb4dff672f76f30c6fd7b9d3766bc ]

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: 02205a6752 (tracing: Add support for 'field variables')
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Masami Hiramatsu 2021-11-13 01:02:08 +09:00 committed by Greg Kroah-Hartman
parent 1d61255327
commit 5b2f2cbbc9

View File

@ -1684,9 +1684,10 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
if (!hist_field->type) if (!hist_field->type)
goto free; goto free;
if (field->filter_type == FILTER_STATIC_STRING) if (field->filter_type == FILTER_STATIC_STRING) {
hist_field->fn = hist_field_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; hist_field->fn = hist_field_dynstring;
else else
hist_field->fn = hist_field_pstring; hist_field->fn = hist_field_pstring;
@ -2624,7 +2625,7 @@ static inline void __update_field_vars(struct tracing_map_elt *elt,
char *str = elt_data->field_var_str[j++]; char *str = elt_data->field_var_str[j++];
char *val_str = (char *)(uintptr_t)var_val; 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; var_val = (u64)(uintptr_t)str;
} }
tracing_map_set_var(elt, var_idx, var_val); tracing_map_set_var(elt, var_idx, var_val);
@ -4472,7 +4473,7 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
str = elt_data->field_var_str[idx]; str = elt_data->field_var_str[idx];
val_str = (char *)(uintptr_t)hist_val; 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; hist_val = (u64)(uintptr_t)str;
} }