s3:smbd: mask security_information input values with SMB_SUPPORTED_SECINFO_FLAGS

Sometimes Windows clients doesn't filter SECINFO_[UN]PROTECTED_[D|S]ACL flags
before sending the security_information to the server.

security_information = SECINFO_PROTECTED_DACL| SECINFO_DACL
results in a NULL dacl being returned from an GetSecurityDecriptor
request. This happens because posix_get_nt_acl_common()
has the following logic:

if ((security_info & SECINFO_DACL) && !(security_info & SECINFO_PROTECTED_DACL)) {
    ... create DACL ...
}

I'm not sure if the logic is correct or wrong in this place (I guess it's
wrong...).

But what I know is that the SMB server should filter the given
security_information flags before passing to the filesystem.

[MS-SMB2] 3.3.5.20.3 Handling SMB2_0_INFO_SECURITY
...
The server MUST ignore any flag value in the AdditionalInformation field that
is not specified in section 2.2.37.

Section 2.2.37 lists:
OWNER_SECURITY_INFORMATION
GROUP_SECURITY_INFORMATION
DACL_SECURITY_INFORMATION
SACL_SECURITY_INFORMATION
LABEL_SECURITY_INFORMATION
ATTRIBUTE_SECURITY_INFORMATION
SCOPE_SECURITY_INFORMATION
BACKUP_SECURITY_INFORMATION

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10773

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>

4 files changed, 12 insertions, 5 deletions

diff --git a/source3/smbd/nttrans.c b/source3/smbd/nttrans.c
index 5a0ac39e91..131009b14c 100644
--- a/source3/smbd/nttrans.c
+++ b/source3/smbd/nttrans.c
@@ -2046,7 +2046,8 @@ static void call_nt_transact_query_security_desc(connection_struct *conn,
 	status = smbd_do_query_security_desc(conn,
 					talloc_tos(),
 					fsp,
-					security_info_wanted,
+					security_info_wanted &
+					SMB_SUPPORTED_SECINFO_FLAGS,
 					max_data_count,
 					&marshalled_sd,
 					&sd_size);
@@ -2139,8 +2140,8 @@ static void call_nt_transact_set_security_desc(connection_struct *conn,
 		return;
 	}
 
-	status = set_sd_blob(fsp, (uint8 *)data, data_count, security_info_sent);
-
+	status = set_sd_blob(fsp, (uint8 *)data, data_count,
+			     security_info_sent & SMB_SUPPORTED_SECINFO_FLAGS);
 	if (!NT_STATUS_IS_OK(status)) {
 		reply_nterror(req, status);
 		return;
diff --git a/source3/smbd/posix_acls.c b/source3/smbd/posix_acls.c
index 621457e051..635494d223 100644
--- a/source3/smbd/posix_acls.c
+++ b/source3/smbd/posix_acls.c
@@ -3288,6 +3288,10 @@ static NTSTATUS posix_get_nt_acl_common(struct connection_struct *conn,
 		num_profile_acls = 3;
 	}
 
+	/*
+	 * TODO: is this logic with SECINFO_PROTECTED_DACL, correct?
+	 * See bug #10773.
+	 */
 	if ((security_info & SECINFO_DACL) && !(security_info & SECINFO_PROTECTED_DACL)) {
 
 		/*
diff --git a/source3/smbd/smb2_getinfo.c b/source3/smbd/smb2_getinfo.c
index 449aeb3f5f..bbc838dcc2 100644
--- a/source3/smbd/smb2_getinfo.c
+++ b/source3/smbd/smb2_getinfo.c
@@ -478,7 +478,8 @@ static struct tevent_req *smbd_smb2_getinfo_send(TALLOC_CTX *mem_ctx,
 				state,
 				fsp,
 				/* Security info wanted. */
-				in_additional_information,
+				in_additional_information &
+				SMB_SUPPORTED_SECINFO_FLAGS,
 				in_output_buffer_length,
 				&p_marshalled_sd,
 				&sd_size);
diff --git a/source3/smbd/smb2_setinfo.c b/source3/smbd/smb2_setinfo.c
index d88f7ac8a2..cda8abc2bd 100644
--- a/source3/smbd/smb2_setinfo.c
+++ b/source3/smbd/smb2_setinfo.c
@@ -311,7 +311,8 @@ static struct tevent_req *smbd_smb2_setinfo_send(TALLOC_CTX *mem_ctx,
 		status = set_sd_blob(fsp,
 				in_input_buffer.data,
 				in_input_buffer.length,
-				in_additional_information);
+				in_additional_information &
+				SMB_SUPPORTED_SECINFO_FLAGS);
 		if (!NT_STATUS_IS_OK(status)) {
 			tevent_req_nterror(req, status);
 			return tevent_req_post(req, ev);