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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2021-11-13 01:02:08 +0900 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-11-12 15:48:46 -0500 |
| commit | 63f84ae6b82bb4dff672f76f30c6fd7b9d3766bc (patch) | |
| tree | fb646bd1bb322d521f83f081f635e9b4fac7747c /kernel | |
| parent | d7458bc0d8b409460713228d2ed279addb38947a (diff) | |
| download | lwn-63f84ae6b82bb4dff672f76f30c6fd7b9d3766bc.tar.gz lwn-63f84ae6b82bb4dff672f76f30c6fd7b9d3766bc.zip | |
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: 02205a6752f2 (tracing: Add support for 'field variables')
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_events_hist.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 8ff572a31fd3..6a9fa34e2785 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -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; } |