updated ksmbd (cifsd)
namjae.jeon at samsung.com
Wed Dec 16 08:50:32 UTC 2020
> >> 2. Why does smb2_set_info_sec() have fp->saccess |= FILE_SHARE_DELETE_LE; ?
> > Because of smb2.acls.GENERIC failure.
> > TESTING FILE GENERIC BITS
> > get the original sd
> > Testing generic bits 0x00000000
> > time: 2020-12-15 00:00:37.940992
> > failure: GENERIC [
> > (../../source4/torture/smb2/acls.c:439) Incorrect status
> > NT_STATUS_SHARING_VIOLATION - should be NT_STATUS_OK
> > I really don't understand this test. This testcase expect that
> > FILE_DELETE is set in response if desired access of smb2 open is FILE_MAXIMAL_ACCESS.
> > I don't know why smb2 open should be allowed although FILE_SHARE_DELETE is not set in previous open
> in this test.
> > Can you give me a hint ?
> As far as I can see the test assumes the user has SeRestorePrivilege, with that
> SEC_FLAG_MAXIMUM_ALLOWED will add FILE_DELETE, see https://protect2.fireeye.com/v1/url?k=3a9ae45d-
The question I'm asking is how it can be opened with FILE DELETE that adding
by SEC_FLAG_MAXIMUM_ALLOWED without FILE_SHARE_DELETE in 1st open.
NT_STATUS_SHARING_VIOLATION error should be returned? but this test should be allowed to open.
It test in the following sequences.
- 1st smb2 open with NTCREATEX_SHARE_ACCESS_READ | NTCREATEX_SHARE_ACCESS_WRITE
- SMB2 set info security().
- 2nd open with SEC_FLAG_MAXIMUM_ALLOWED(adding FILE DELETE) => NT_STATUS_SHARING_VIOLATION or NT_STATUS_OK ?
> >> 3. Why does ksmbd_override_fsids() only reset cred->fs[g|u]id, but group_info
> >> is kept unchanged, I guess at least the groups array should be set to be empty.
> > Yes, We need to handle the groups list. Will fix it.
> >> 4. What is work->saved_cred_level used for in ksmbd_override_fsids()?
> >> It seems to be unused and adds a lot of complexity.
> > ksmbd_override_fsids could be called recursively.
> > work->saved_cred_level prevents ksmbd from overriding fs[g|u]id again.
> But that will always be on the same session/share combination?
Ah, ksmbd_override_fsids() has been recursively called to handle SMB1 requests.
At present, SMB1 codes was removed in smb3_kernel tree, So we can remove work->saved_cred_level.
Thanks for your review!
> >> 5. Documentation/filesystems/cifsd.rst and fs/cifsd/Kconfig still references
> >> instead of
> >> https://protect2.fireeye.com/v1/url?k=cf0932a6-90920bbc-cf08b9e9-000b
> >> abff24ad-ea69fcf05590fae2&q=1&e=bdf5897b-3ecc-49dc-9105-2d6782854fcc&
> >> u=https%3A%2F%2Fgithub.com%2Fcifsd-team%2Fksmbd-tools
> > Okay. Will update it.
> >> 6. Why is SMB_SERVER_CHECK_CAP_NET_ADMIN an compile time option and why is it off by default?
> >> I think the behavior should be enforced without a switch.
> > I can make it default yes. Can you explain more why it should be enforced ?
> Why should an unprivileged user ever be able to start the server?
> Wouldn't that be a massive security problem as that user would provide the share definitions and users
> and controls what ksmbd_override_fsids() will use?
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