sdcardfs: fix wrong ENOENT when creating a file

There is subtle race condtion where lower_dentry is null. If we retry lookup again, we should get the correct dentry. Bug: 110585947 Bug: 110464178 Bug: 80587794 Bug: 37231161 Bug: 110199687 Change-Id: I39b95de4649b034287776f5c8a5d197b6ebd9ada Signed-off-by: Jaegeuk Kim <[email protected]> Signed-off-by: Dhruv <[email protected]> Signed-off-by: negrroo <[email protected]>
reocat · Jan 24, 2024 · 63b6c05 · 63b6c05
1 parent aa08197
commit 63b6c05
Showing 1 changed file with 10 additions and 2 deletions.
diff --git a/fs/sdcardfs/lookup.c b/fs/sdcardfs/lookup.c
@@ -18,6 +18,7 @@
  * General Public License.
  */
 
+#include <linux/fscrypt.h>
 #include "sdcardfs.h"
 #include "linux/delay.h"
 
@@ -274,6 +275,7 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
 	lower_dir_dentry = lower_parent_path->dentry;
 	lower_dir_mnt = lower_parent_path->mnt;
 
+retry_lookup:
 	/* Use vfs_path_lookup to check if the dentry exists or not */
 	err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name->name, 0,
 				&lower_path);
@@ -377,8 +379,14 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
 		 * dentry then. Don't confuse the lower filesystem by forcing
 		 * one on it now...
 		 */
-		err = -ENOENT;
-		goto out;
+		struct inode *lower_dir = d_inode(lower_dir_dentry);
+
+		if (IS_ENCRYPTED(lower_dir) &&
+				!fscrypt_has_encryption_key(lower_dir)) {
+			err = -ENOENT;
+			goto out;
+		}
+		goto retry_lookup;
 	}
 
 	lower_path.dentry = lower_dentry;