Date: Tue, 19 May 2020 02:41:05 +0000 (UTC) From: Kyle Evans <kevans@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r361238 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <202005190241.04J2f54E001347@repo.freebsd.org>
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Author: kevans Date: Tue May 19 02:41:05 2020 New Revision: 361238 URL: https://svnweb.freebsd.org/changeset/base/361238 Log: zfs: reject read(2) of a dirfd with EISDIR This is independent of the recently-discussed global change, which is still in review/discussion stage. This is effectively a measure for consistency in the ZFS world, where FreeBSD was the only platform (as far as I could find) that allowed this. What ZFS exposes is decidedly not useful for any real purposes, to paraphrase (hopefully faithfully) jhb's findings when exploring this: The size of a directory in ZFS is the number of directory entries within. When reading a directory, you would instead get the leading part of its raw contents; the amount you get being dictated by the "size," i.e. number of directory entries. There's decidedly (luckily) no stack disclosure happening here, though the behavior is bizarre and almost certainly a historical accident. This change has already been upstreamed to OpenZFS. MFC after: 1 week Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Tue May 19 02:07:08 2020 (r361237) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Tue May 19 02:41:05 2020 (r361238) @@ -646,6 +646,12 @@ zfs_read(vnode_t *vp, uio_t *uio, int ioflag, cred_t * ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zp); + /* We don't copy out anything useful for directories. */ + if (vp->v_type == VDIR) { + ZFS_EXIT(zfsvfs); + return (SET_ERROR(EISDIR)); + } + if (zp->z_pflags & ZFS_AV_QUARANTINED) { ZFS_EXIT(zfsvfs); return (SET_ERROR(EACCES));
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