[PATCH 2/7] tracing/filters: fix NULL pointer dereference

From: Li Zefan
Date: Sat Apr 11 2009 - 03:52:49 EST


Try this, and you'll see NULL pointer dereference bug:
# echo -n 'parent_comm ==' > sched/sched_process_fork/filter

Because we passed NULL ptr to simple_strtoull().

Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
---
kernel/trace/trace_events_filter.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 026be41..9d2162f 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -410,6 +410,11 @@ int filter_parse(char **pbuf, struct filter_pred *pred)
}
}

+ if (!val_str) {
+ pred->field_name = NULL;
+ return -EINVAL;
+ }
+
pred->field_name = kstrdup(pred->field_name, GFP_KERNEL);
if (!pred->field_name)
return -ENOMEM;
--
1.5.4.rc3

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