From c0ca3d70e8d3cf81e2255a217f7ca402f5ed0862 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Fri, 1 Jul 2016 16:34:27 -0400 Subject: ovl: modify ovl_permission() to do checks on two inodes Right now ovl_permission() calls __inode_permission(realinode), to do permission checks on real inode and no checks are done on overlay inode. Modify it to do checks both on overlay inode as well as underlying inode. Checks on overlay inode will be done with the creds of calling task while checks on underlying inode will be done with the creds of mounter. Signed-off-by: Vivek Goyal Signed-off-by: Miklos Szeredi --- fs/overlayfs/inode.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'fs/overlayfs') diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index a574108f52a8..f84492ff505d 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -113,6 +113,7 @@ int ovl_permission(struct inode *inode, int mask) bool is_upper; struct dentry *realdentry = ovl_entry_real(oe, &is_upper); struct inode *realinode; + const struct cred *old_cred; int err; if (ovl_is_default_permissions(inode)) { @@ -166,7 +167,19 @@ int ovl_permission(struct inode *inode, int mask) return -EROFS; } - return __inode_permission(realinode, mask); + /* + * Check overlay inode with the creds of task and underlying inode + * with creds of mounter + */ + err = generic_permission(inode, mask); + if (err) + return err; + + old_cred = ovl_override_creds(inode->i_sb); + err = __inode_permission(realinode, mask); + revert_creds(old_cred); + + return err; } static const char *ovl_get_link(struct dentry *dentry, @@ -314,9 +327,6 @@ struct posix_acl *ovl_get_acl(struct inode *inode, int type) { struct inode *realinode = ovl_inode_real(inode); - if (!realinode) - return ERR_PTR(-ENOENT); - if (!IS_POSIXACL(realinode)) return NULL; -- cgit v1.2.1