diff options
| -rw-r--r-- | fs/overlayfs/inode.c | 17 |
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); |