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-rw-r--r--fs/overlayfs/inode.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 3b7ed5d2279c..6bcc9dedc342 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -286,13 +286,22 @@ int ovl_permission(struct inode *inode, int mask)
if (err)
return err;
- old_cred = ovl_override_creds(inode->i_sb);
- if (!upperinode &&
- !special_file(realinode->i_mode) && mask & MAY_WRITE) {
+ /* No need to do any access on underlying for special files */
+ if (special_file(realinode->i_mode))
+ return 0;
+
+ /* No need to access underlying for execute */
+ mask &= ~MAY_EXEC;
+ if ((mask & (MAY_READ | MAY_WRITE)) == 0)
+ return 0;
+
+ /* Lower files get copied up, so turn write access into read */
+ if (!upperinode && mask & MAY_WRITE) {
mask &= ~(MAY_WRITE | MAY_APPEND);
- /* Make sure mounter can read file for copy up later */
mask |= MAY_READ;
}
+
+ old_cred = ovl_override_creds(inode->i_sb);
err = inode_permission(realinode, mask);
revert_creds(old_cred);