In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields.
Add struct_group() to mark region of struct trace_iterator that should be initialized to zero.
Signed-off-by: Kees Cook keescook@chromium.org --- include/linux/trace_events.h | 26 ++++++++++++++------------ kernel/trace/trace.c | 4 +--- 2 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index ad413b382a3c..cadad77fe524 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -101,18 +101,20 @@ struct trace_iterator { bool snapshot;
/* The below is zeroed out in pipe_read */ - struct trace_seq seq; - struct trace_entry *ent; - unsigned long lost_events; - int leftover; - int ent_size; - int cpu; - u64 ts; - - loff_t pos; - long idx; - - /* All new field here will be zeroed out in pipe_read */ + struct_group(init, + struct trace_seq seq; + struct trace_entry *ent; + unsigned long lost_events; + int leftover; + int ent_size; + int cpu; + u64 ts; + + loff_t pos; + long idx; + + /* All new field here will be zeroed out in pipe_read */ + ); };
enum trace_iter_flags { diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c59dd35a6da5..9f83864b0be6 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6691,9 +6691,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, cnt = PAGE_SIZE - 1;
/* reset all but tr, trace, and overruns */ - memset(&iter->seq, 0, - sizeof(struct trace_iterator) - - offsetof(struct trace_iterator, seq)); + memset(&iter->init, 0, sizeof(iter->init)); cpumask_clear(iter->started); trace_seq_init(&iter->seq); iter->pos = -1;