security, overlayfs: provide copy up security hook for unioned files

[deliverable/linux.git] / fs / overlayfs / copy_up.c

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 54e5d6681786780812c9a5adddc27dd782b40bbb..c297b1f5a05ef8fae0de4320fdbe20a11ee189fc 100644 (file)
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -246,6 +246,8 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
        struct dentry *upper = NULL;
        umode_t mode = stat->mode;
        int err;
+       const struct cred *old_creds = NULL;
+       struct cred *new_creds = NULL;
 
        newdentry = ovl_lookup_temp(workdir, dentry);
        err = PTR_ERR(newdentry);
@@ -258,10 +260,23 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
        if (IS_ERR(upper))
                goto out1;
 
+       err = security_inode_copy_up(dentry, &new_creds);
+       if (err < 0)
+               goto out2;
+
+       if (new_creds)
+               old_creds = override_creds(new_creds);
+
        /* Can't properly set mode on creation because of the umask */
        stat->mode &= S_IFMT;
        err = ovl_create_real(wdir, newdentry, stat, link, NULL, true);
        stat->mode = mode;
+
+       if (new_creds) {
+               revert_creds(old_creds);
+               put_cred(new_creds);
+       }
+
        if (err)
                goto out2;