[PATCH] tracepoint: don't make assumptions about length of string on task rename

From: Sasha Levin
Date: Fri Aug 28 2015 - 07:07:19 EST


While the dest comm string size is assured to be at least TASK_COMM_LEN long,
doing a memcpy() also adds the assumption that the source is at least that
long as well, which isn't assured, and isn't true in cases such as:

set_task_comm(worker->task, "kworker/dying");

This leads to accessing invalid memory.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
include/trace/events/task.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/trace/events/task.h b/include/trace/events/task.h
index dee3bb1..2cca6cd 100644
--- a/include/trace/events/task.h
+++ b/include/trace/events/task.h
@@ -46,7 +46,7 @@ TRACE_EVENT(task_rename,
TP_fast_assign(
__entry->pid = task->pid;
memcpy(entry->oldcomm, task->comm, TASK_COMM_LEN);
- memcpy(entry->newcomm, comm, TASK_COMM_LEN);
+ strlcpy(entry->newcomm, comm, TASK_COMM_LEN);
__entry->oom_score_adj = task->signal->oom_score_adj;
),

--
1.7.10.4

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