directory with a symlink pointing to non-existing file

[Jeremy Allison]

On Mon, Oct 25, 2021 at 06:21:00PM +0200, Pavel Filipensky via samba-technical wrote:
>Hi Jeremy,
>
>thanks for looking into this and providing the fix. I was trying to test
>the fix attached to https://bugzilla.samba.org/show_bug.cgi?id=14879 but
>still doesn't work.
>I am using this env:
>
>make -j8 testenv SELFTEST_TESTENV=ad_member_idmap_rid:local SCREEN=1
> SMBD_OPTIONS=-d100
>mkdir st/ad_member_idmap_rid/share/test1
>ln -s st/ad_member_idmap_rid/share/test1/l1
>st/ad_member_idmap_rid/share/test1/l2
>
>smb.conf has "delete veto files = yes"
>
>then I run "rmdir test1" in
>
>bin/smbclient //$SERVER/tmp -U$DC_USERNAME%$DC_PASSWORD
>
>
>The point where it all  fails is here:
>
>(gdb) bt 6
>#0  xattr_tdb_unlinkat (handle=0x557646d5cd30, dirfsp=0x557646d69fc0,
>smb_fname=0x557646d70a50, flags=0) at
>../../source3/modules/vfs_xattr_tdb.c:524
>#1  0x00007f84d2fd73ce in smb_vfs_call_unlinkat (handle=0x557646d5cd30,
>dirfsp=0x557646d69fc0, smb_fname=0x557646d70a50, flags=0) at
>../../source3/smbd/vfs.c:2218
>#2  0x00007f84d31141ca in unlink_acl_common (handle=0x557646d54170,
>dirfsp=0x557646d69fc0, smb_fname=0x557646d70a50, flags=0) at
>../../source3/modules/vfs_acl_common.c:1146
>#3  0x00007f84bdb0ed06 in acl_xattr_unlinkat (handle=0x557646d54170,
>dirfsp=0x557646d69fc0, smb_fname=0x557646d70a50, flags=0) at
>../../source3/modules/vfs_acl_xattr.c:265
>#4  0x00007f84d2fd73ce in smb_vfs_call_unlinkat (handle=0x557646d54170,
>dirfsp=0x557646d69fc0, smb_fname=0x557646d70a50, flags=0) at
>../../source3/smbd/vfs.c:2218
>#5  0x00007f84d2fcdb5a in rmdir_internals (ctx=0x557646c91760,
>fsp=0x557646d628f0) at ../../source3/smbd/close.c:1285
>
>On line 522 SMB_VFS_NEXT_STAT() returns -1 with errno 2:
>
>
>  519 »·······if (full_fname->flags & SMB_FILENAME_POSIX_PATH) {
>
>  520 »·······»·······ret = SMB_VFS_NEXT_LSTAT(handle, full_fname);
>
>  521 »·······} else {
>
>  522 »·······»·······ret = SMB_VFS_NEXT_STAT(handle, full_fname);
>
>                                            523 »·······}
>
>  524 »·······if (ret == -1) {
>
>  525 »·······»·······goto out;
>
>  526 »·······}
>
>==============
>
>If it helps I can prepare some regression test.

That's probably expected when you have xattr_tdb loaded.
That's an unusual configuration to be running with dangling
symlinks and I don't expect any normal fileserver to be
doing that.

Don't do that (ie. don't run the regression test against
ad_member_idmap_rid :-).

I have a regression test that works against the "fileserver"
environment. I'm planning on fixing this up and submitting
to Ralph for review this week.

Once it's in, if you really want to make it work against
an AD-DC config with xattr_tdb loaded then we'll log a
separate bug and deal with it there, but to be honest
it's unlikely anyone would care.

Jeremy.