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Subject[PATCH] namei: free new_dentry late
Date
After calling dput(new_dentry), new_dentry is passed to fsnotify_move.
This may result in a use-after-free bug. This patch moves the put
operation late.

Fixes: 49d31c2f389a("dentry name snapshots")
Signed-off-by: Pan Bian <bianpan2016@163.com>
---
fs/namei.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index 0cab649..8b104d9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4498,7 +4498,6 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
unlock_two_nondirectories(source, target);
else if (target)
inode_unlock(target);
- dput(new_dentry);
if (!error) {
fsnotify_move(old_dir, new_dir, old_name.name, is_dir,
!(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry);
@@ -4507,6 +4506,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
new_is_dir, NULL, new_dentry);
}
}
+ dput(new_dentry);
release_dentry_name_snapshot(&old_name);

return error;
--
2.7.4

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