On Wed, Dec 02, 2015 at 09:40:09AM -0600, Seth Forshee wrote: > Add checks to inode_change_ok to verify that uid and gid changes > will map into the superblock's user namespace. If they do not > fail with -EOVERFLOW. This cannot be overriden with ATTR_FORCE. > > Signed-off-by: Seth Forshee <seth.fors...@canonical.com>
Acked-by: Serge Hallyn <serge.hal...@canonical.com> ... although i could see root on the host being upset that it can't assign a uid not valid in the mounter's ns. But it does seem safer. > --- > fs/attr.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/fs/attr.c b/fs/attr.c > index 6530ced19697..55b46e3aa888 100644 > --- a/fs/attr.c > +++ b/fs/attr.c > @@ -42,6 +42,17 @@ int inode_change_ok(const struct inode *inode, struct > iattr *attr) > return error; > } > > + /* > + * Verify that uid/gid changes are valid in the target namespace > + * of the superblock. This cannot be overriden using ATTR_FORCE. > + */ > + if (ia_valid & ATTR_UID && > + from_kuid(inode->i_sb->s_user_ns, attr->ia_uid) == (uid_t)-1) > + return -EOVERFLOW; > + if (ia_valid & ATTR_GID && > + from_kgid(inode->i_sb->s_user_ns, attr->ia_gid) == (gid_t)-1) > + return -EOVERFLOW; > + > /* If force is set do it anyway. */ > if (ia_valid & ATTR_FORCE) > return 0; > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
