* [PATCH 1/2] tracing: Use strncpy instead of memcpy when copying comm for hist triggers
2019-03-05 16:11 [PATCH 0/2] tracing: memcpy->strncpy changes for comm strings Tom Zanussi
@ 2019-03-05 16:11 ` Tom Zanussi
2019-03-05 16:12 ` [PATCH 2/2] tracing: Use strncpy instead of memcpy when copying comm in trace.c Tom Zanussi
1 sibling, 0 replies; 3+ messages in thread
From: Tom Zanussi @ 2019-03-05 16:11 UTC (permalink / raw)
To: rostedt; +Cc: linux-kernel
From: Tom Zanussi <tom.zanussi@linux.intel.com>
Because there may be random garbage beyond a string's null terminator,
code that might use the entire comm array e.g. histogram keys, can
give unexpected results if that garbage is copied in too, so avoid
that possibility by using strncpy instead of memcpy.
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
kernel/trace/trace_events_hist.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index c7774fa119a7..ca46339f3009 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2141,7 +2141,7 @@ static inline void save_comm(char *comm, struct task_struct *task)
return;
}
- memcpy(comm, task->comm, TASK_COMM_LEN);
+ strncpy(comm, task->comm, TASK_COMM_LEN);
}
static void hist_elt_data_free(struct hist_elt_data *elt_data)
@@ -3557,7 +3557,7 @@ static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
elt_data = context->elt->private_data;
track_elt_data = track_data->elt.private_data;
if (elt_data->comm)
- memcpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
+ strncpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
track_data->updated = true;
--
2.14.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 2/2] tracing: Use strncpy instead of memcpy when copying comm in trace.c
2019-03-05 16:11 [PATCH 0/2] tracing: memcpy->strncpy changes for comm strings Tom Zanussi
2019-03-05 16:11 ` [PATCH 1/2] tracing: Use strncpy instead of memcpy when copying comm for hist triggers Tom Zanussi
@ 2019-03-05 16:12 ` Tom Zanussi
1 sibling, 0 replies; 3+ messages in thread
From: Tom Zanussi @ 2019-03-05 16:12 UTC (permalink / raw)
To: rostedt; +Cc: linux-kernel
From: Tom Zanussi <tom.zanussi@linux.intel.com>
Because there may be random garbage beyond a string's null terminator,
code that might use the entire comm array e.g. histogram keys, can
give unexpected results if that garbage is copied in too, so avoid
that possibility by using strncpy instead of memcpy.
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3835f7ed3293..e9cc47e59d25 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1497,7 +1497,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
max_data->critical_start = data->critical_start;
max_data->critical_end = data->critical_end;
- memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
+ strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
max_data->pid = tsk->pid;
/*
* If tsk == current, then use current_uid(), as that does not use
@@ -1923,7 +1923,7 @@ static inline char *get_saved_cmdlines(int idx)
static inline void set_cmdline(int idx, const char *cmdline)
{
- memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
+ strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
}
static int allocate_cmdlines_buffer(unsigned int val,
--
2.14.1
^ permalink raw reply related [flat|nested] 3+ messages in thread