diff mbox series

[V2,2/2] debugfs: Fix crash problem caused by accessing uninitialized nodes

Message ID 20240914102453.3879527-1-Yibin.Ding@unisoc.com
State New
Headers show
Series [V2,1/2] interconnect: Add character pointer initialization | expand

Commit Message

Yibin Ding Sept. 14, 2024, 10:24 a.m. UTC 
From: Yibin Ding <Yibin.ding@unisoc.com>

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@unisoc.com>
---
 fs/debugfs/file.c | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

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) {