[PATCH V2 2/2] debugfs: Fix crash problem caused by accessing uninitialized nodes
From: Yibin Ding
Date: Sat Sep 14 2024 - 06:25:30 EST
From: Yibin Ding <Yibin.ding@xxxxxxxxxx>
For uninitialized nodes such as
/sys/kernel/debug/interconnect/test_client/dst_node, if the cat operation
is performed directly without writing content to the node, it will cause
a crash due to accessing a null pointer. So it is necessary to add a null
pointer check in the debugfs_read_file_str() function.
Signed-off-by: Yibin Ding <Yibin.ding@xxxxxxxxxx>
---
fs/debugfs/file.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index c6f4a9a98b85..8bbe7df6dfd1 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -970,6 +970,10 @@ ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
return ret;
str = *(char **)file->private_data;
+ if (!str) {
+ debugfs_file_put(dentry);
+ return -EINVAL;
+ }
len = strlen(str) + 1;
copy = kmalloc(len, GFP_KERNEL);
if (!copy) {
--
2.25.1