[SCM] Samba Shared Repository - branch v4-4-stable updated
Karolin Seeger
kseeger at samba.org
Thu Jul 7 08:52:46 UTC 2016
The branch, v4-4-stable has been updated
via fb3e629 VERSION: Disable git snapshots for the 4.4.5 release.
via a1a715f WHATSNEW: Add release notes for Samba 4.4.5.
via f7e1a59 CVE-2016-2019: s3:selftest: add regression tests for guest logins and mandatory signing
via 94295b7 CVE-2016-2019: s3:libsmb: add comment regarding smbXcli_session_is_guest() with mandatory signing
via 46b5e4a CVE-2016-2019: libcli/smb: don't allow guest sessions if we require signing
via a9a1ec7 dcerpc.idl: remove unused DCERPC_NCACN_PAYLOAD_MAX_SIZE
via eb09411 s4:rpc_server: use a variable for the max total reassembled request payload
via cba64f2 s4:librpc/rpc: allow a total reassembled response payload of 240 MBytes
via 203c0a5 dcerpc.idl: add DCERPC_NCACN_{REQUEST,RESPONSE}_DEFAULT_MAX_SIZE
via 3eb3214 VERSION: Bump version up to 4.4.5...
from ad4db24 VERSION: Disable git snapshots for the 4.4.4 release.
https://git.samba.org/?p=samba.git;a=shortlog;h=v4-4-stable
- Log -----------------------------------------------------------------
commit fb3e6296bb09534f882ea35e7f7ca4e5871d3222
Author: Karolin Seeger <kseeger at samba.org>
Date: Mon Jul 4 09:50:23 2016 +0200
VERSION: Disable git snapshots for the 4.4.5 release.
CVE-2016-2119: Client side SMB2 signing downgrade.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11860
Signed-off-by: Karolin Seeger <kseeger at samba.org>
commit a1a715fb94905b832d41b4cda166cf9b71deb748
Author: Karolin Seeger <kseeger at samba.org>
Date: Mon Jul 4 09:48:29 2016 +0200
WHATSNEW: Add release notes for Samba 4.4.5.
CVE-2016-2119: Client side SMB2 signing downgrade.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11860
Signed-off-by: Karolin Seeger <kseeger at samba.org>
commit f7e1a590cc8246514445cb287541e6d5dca6c699
Author: Stefan Metzmacher <metze at samba.org>
Date: Thu Apr 28 02:24:52 2016 +0200
CVE-2016-2019: s3:selftest: add regression tests for guest logins and mandatory signing
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11860
Signed-off-by: Stefan Metzmacher <metze at samba.org>
commit 94295b7aa22d2544af5323bca70d3dcb97fd7c64
Author: Stefan Metzmacher <metze at samba.org>
Date: Thu Apr 28 02:36:35 2016 +0200
CVE-2016-2019: s3:libsmb: add comment regarding smbXcli_session_is_guest() with mandatory signing
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11860
Signed-off-by: Stefan Metzmacher <metze at samba.org>
commit 46b5e4aca6adb12a27efaad3bfe66c2d8a82ec95
Author: Stefan Metzmacher <metze at samba.org>
Date: Wed Apr 20 11:26:57 2016 +0200
CVE-2016-2019: libcli/smb: don't allow guest sessions if we require signing
Note real anonymous sessions (with "" as username) don't hit this
as we don't even call smb2cli_session_set_session_key() in that case.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11860
Signed-off-by: Stefan Metzmacher <metze at samba.org>
commit a9a1ec7ad4312f3dea93ca9dbb6d9d67ad5c18ea
Author: Stefan Metzmacher <metze at samba.org>
Date: Wed Jun 22 20:38:01 2016 +0200
dcerpc.idl: remove unused DCERPC_NCACN_PAYLOAD_MAX_SIZE
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11948
Signed-off-by: Stefan Metzmacher <metze at samba.org>
Reviewed-by: Ralph Boehme <slow at samba.org>
(cherry picked from commit d9e242e9035c15e49b041afc61e5a4a08877f289)
commit eb09411ca491b6e877ec63fbaeb4d21b292808ee
Author: Stefan Metzmacher <metze at samba.org>
Date: Wed Jun 22 17:18:28 2016 +0200
s4:rpc_server: use a variable for the max total reassembled request payload
We still use the same limit of 4 MByte (DCERPC_NCACN_REQUEST_DEFAULT_MAX_SIZE)
by default.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11948
Signed-off-by: Stefan Metzmacher <metze at samba.org>
Reviewed-by: Andrew Bartlett <abartlet at samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet at samba.org>
Autobuild-Date(master): Thu Jun 23 04:51:16 CEST 2016 on sn-devel-144
(cherry picked from commit 3f36d31c848496bf509db573e4c12821905b448d)
commit cba64f242dbae6c8ddb0e3c522aea2152faea5ca
Author: Stefan Metzmacher <metze at samba.org>
Date: Wed Jun 22 17:18:28 2016 +0200
s4:librpc/rpc: allow a total reassembled response payload of 240 MBytes
This will replace DCERPC_NCACN_PAYLOAD_MAX_SIZE (4 MByte),
The limit of DCERPC_NCACN_PAYLOAD_MAX_SIZE (4 MByte) was too
strict for some workloads, e.g. DRSUAPI replication with large objects.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11948
Signed-off-by: Stefan Metzmacher <metze at samba.org>
Reviewed-by: Andrew Bartlett <abartlet at samba.org>
(cherry picked from commit 7413e73c5331b760dc84b3843059230ec5fcfc7b)
commit 203c0a5e4f6c84532dfec03b5666c30f004a13cf
Author: Stefan Metzmacher <metze at samba.org>
Date: Wed Jun 22 16:58:03 2016 +0200
dcerpc.idl: add DCERPC_NCACN_{REQUEST,RESPONSE}_DEFAULT_MAX_SIZE
This will replace DCERPC_NCACN_PAYLOAD_MAX_SIZE (4 MByte),
this limit is too strict for some workloads, e.g. DRSUAPI replication
with large objects.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11948
Signed-off-by: Stefan Metzmacher <metze at samba.org>
Reviewed-by: Andrew Bartlett <abartlet at samba.org>
(cherry picked from commit 281e11b53f676647997fb9ce21227782529a62ad)
commit 3eb32148bd49e7898231406bf512f773adc3fbee
Author: Karolin Seeger <kseeger at samba.org>
Date: Fri Jun 3 12:08:37 2016 +0200
VERSION: Bump version up to 4.4.5...
and re-enable git snapshots.
Signed-off-by: Karolin Seeger <kseeger at samba.org>
(cherry picked from commit e9ea633d3c673432dc6ce21e1fddde59f88f3720)
-----------------------------------------------------------------------
Summary of changes:
VERSION | 2 +-
WHATSNEW.txt | 77 ++++++++++++++++++++++++++++-
libcli/smb/smbXcli_base.c | 19 ++++++-
librpc/idl/dcerpc.idl | 18 ++++++-
source3/libsmb/cliconnect.c | 3 ++
source3/script/tests/test_smbclient_ntlm.sh | 4 ++
source4/librpc/rpc/dcerpc.c | 5 +-
source4/librpc/rpc/dcerpc.h | 3 ++
source4/rpc_server/dcerpc_server.c | 5 +-
source4/rpc_server/dcerpc_server.h | 3 ++
10 files changed, 129 insertions(+), 10 deletions(-)
Changeset truncated at 500 lines:
diff --git a/VERSION b/VERSION
index 667e0e5..bc1234c 100644
--- a/VERSION
+++ b/VERSION
@@ -25,7 +25,7 @@
########################################################
SAMBA_VERSION_MAJOR=4
SAMBA_VERSION_MINOR=4
-SAMBA_VERSION_RELEASE=4
+SAMBA_VERSION_RELEASE=5
########################################################
# If a official release has a serious bug #
diff --git a/WHATSNEW.txt b/WHATSNEW.txt
index ca3c325..0e2de46 100644
--- a/WHATSNEW.txt
+++ b/WHATSNEW.txt
@@ -1,4 +1,77 @@
=============================
+ Release Notes for Samba 4.4.5
+ July 7, 2016
+ =============================
+
+
+This is a security release in order to address the following defect:
+
+o CVE-2016-2119 (Client side SMB2/3 required signing can be downgraded)
+
+=======
+Details
+=======
+
+o CVE-2016-2119:
+ It's possible for an attacker to downgrade the required signing for
+ an SMB2/3 client connection, by injecting the SMB2_SESSION_FLAG_IS_GUEST
+ or SMB2_SESSION_FLAG_IS_NULL flags.
+
+ This means that the attacker can impersonate a server being connected to by
+ Samba, and return malicious results.
+
+ The primary concern is with winbindd, as it uses DCERPC over SMB2 when talking
+ to domain controllers as a member server, and trusted domains as a domain
+ controller. These DCE/RPC connections were intended to protected by the
+ combination of "client ipc signing" and
+ "client ipc max protocol" in their effective default settings
+ ("mandatory" and "SMB3_11").
+
+ Additionally, management tools like net, samba-tool and rpcclient use DCERPC
+ over SMB2/3 connections.
+
+ By default, other tools in Samba are unprotected, but rarely they are
+ configured to use smb signing, via the "client signing" parameter (the default
+ is "if_required"). Even more rarely the "client max protocol" is set to SMB2,
+ rather than the NT1 default.
+
+ If both these conditions are met, then this issue would also apply to these
+ other tools, including command line tools like smbcacls, smbcquota, smbclient,
+ smbget and applications using libsmbclient.
+
+
+Changes since 4.4.4:
+--------------------
+
+o Stefan Metzmacher <metze at samba.org>
+ * BUG 11860: CVE-2016-2119: Fix client side SMB2 signing downgrade.
+ * BUG 11948: Total dcerpc response payload more than 0x400000.
+
+
+#######################################
+Reporting bugs & Development Discussion
+#######################################
+
+Please discuss this release on the samba-technical mailing list or by
+joining the #samba-technical IRC channel on irc.freenode.net.
+
+If you do report problems then please try to send high quality
+feedback. If you don't provide vital information to help us track down
+the problem then you will probably be ignored. All bug reports should
+be filed under the "Samba 4.1 and newer" product in the project's Bugzilla
+database (https://bugzilla.samba.org/).
+
+
+======================================================================
+== Our Code, Our Bugs, Our Responsibility.
+== The Samba Team
+======================================================================
+
+
+Release notes for older releases follow:
+----------------------------------------
+
+ =============================
Release Notes for Samba 4.4.4
June 7, 2016
=============================
@@ -108,8 +181,8 @@ database (https://bugzilla.samba.org/).
======================================================================
-Release notes for older releases follow:
-----------------------------------------
+----------------------------------------------------------------------
+
=============================
Release Notes for Samba 4.4.3
diff --git a/libcli/smb/smbXcli_base.c b/libcli/smb/smbXcli_base.c
index 4332374..691b8ff 100644
--- a/libcli/smb/smbXcli_base.c
+++ b/libcli/smb/smbXcli_base.c
@@ -5312,6 +5312,10 @@ bool smbXcli_session_is_guest(struct smbXcli_session *session)
return false;
}
+ if (session->conn->mandatory_signing) {
+ return false;
+ }
+
if (session->conn->protocol >= PROTOCOL_SMB2_02) {
if (session->smb2->session_flags & SMB2_SESSION_FLAG_IS_GUEST) {
return true;
@@ -5571,7 +5575,7 @@ NTSTATUS smb2cli_session_set_session_key(struct smbXcli_session *session,
const struct iovec *recv_iov)
{
struct smbXcli_conn *conn = session->conn;
- uint16_t no_sign_flags;
+ uint16_t no_sign_flags = 0;
uint8_t session_key[16];
bool check_signature = true;
uint32_t hdr_flags;
@@ -5596,7 +5600,18 @@ NTSTATUS smb2cli_session_set_session_key(struct smbXcli_session *session,
return NT_STATUS_INVALID_PARAMETER_MIX;
}
- no_sign_flags = SMB2_SESSION_FLAG_IS_GUEST | SMB2_SESSION_FLAG_IS_NULL;
+ if (!conn->mandatory_signing) {
+ /*
+ * only allow guest sessions without
+ * mandatory signing.
+ *
+ * If we try an authentication with username != ""
+ * and the server let us in without verifying the
+ * password we don't have a negotiated session key
+ * for signing.
+ */
+ no_sign_flags = SMB2_SESSION_FLAG_IS_GUEST;
+ }
if (session->smb2->session_flags & no_sign_flags) {
session->smb2->should_sign = false;
diff --git a/librpc/idl/dcerpc.idl b/librpc/idl/dcerpc.idl
index 015eb3d..527804d 100644
--- a/librpc/idl/dcerpc.idl
+++ b/librpc/idl/dcerpc.idl
@@ -535,7 +535,23 @@ interface dcerpc
const uint32 DCERPC_FRAG_MAX_SIZE = 5840;
const uint8 DCERPC_AUTH_LEN_OFFSET = 10;
const uint8 DCERPC_NCACN_PAYLOAD_OFFSET = 16;
- const uint32 DCERPC_NCACN_PAYLOAD_MAX_SIZE = 0x400000; /* 4 MByte */
+
+ /*
+ * See [MS-RPCE] 3.3.3.5.4 Maximum Server Input Data Size
+ * 4 MByte is the default limit of reassembled request payload
+ */
+ const uint32 DCERPC_NCACN_REQUEST_DEFAULT_MAX_SIZE = 0x400000;
+
+ /*
+ * See [MS-RPCE] 3.3.2.5.2 Handling Responses
+ *
+ * Indicates that Windows accepts up to 0x7FFFFFFF ~2 GByte
+ *
+ * talloc has a limit of 256 MByte, so we need to use something smaller.
+ *
+ * For now we try our luck with 240 MByte.
+ */
+ const uint32 DCERPC_NCACN_RESPONSE_DEFAULT_MAX_SIZE = 0xf000000; /* 240 MByte */
/* little-endian flag */
const uint8 DCERPC_DREP_LE = 0x10;
diff --git a/source3/libsmb/cliconnect.c b/source3/libsmb/cliconnect.c
index ea92c8f..ebba8f2 100644
--- a/source3/libsmb/cliconnect.c
+++ b/source3/libsmb/cliconnect.c
@@ -1588,6 +1588,9 @@ static void cli_session_setup_gensec_remote_done(struct tevent_req *subreq)
* have a negotiated session key.
*
* So just pretend we are completely done.
+ *
+ * Note that smbXcli_session_is_guest()
+ * always returns false if we require signing.
*/
state->blob_in = data_blob_null;
state->local_ready = true;
diff --git a/source3/script/tests/test_smbclient_ntlm.sh b/source3/script/tests/test_smbclient_ntlm.sh
index b8fc564..33a927f 100755
--- a/source3/script/tests/test_smbclient_ntlm.sh
+++ b/source3/script/tests/test_smbclient_ntlm.sh
@@ -37,4 +37,8 @@ else
testit "smbclient baduser.badpassword.NT1NEW.guest" $SMBCLIENT //$SERVER/IPC\$ $CONFIGURATION -Ubaduser%badpassword -mNT1 -c quit $ADDARGS
testit "smbclient baduser.badpassword.SMB3.guest" $SMBCLIENT //$SERVER/IPC\$ $CONFIGURATION -Ubaduser%badpassword -mSMB3 -c quit $ADDARGS
+
+ testit_expect_failure "smbclient baduser.badpassword.NT1OLD.signfail" $SMBCLIENT //$SERVER/IPC\$ $CONFIGURATION -Ubaduser%badpassword -mNT1 --option=clientusespnego=no --option=clientntlmv2auth=no --signing=required -c quit $ADDARGS
+ testit_expect_failure "smbclient baduser.badpassword.NT1NEW.signfail" $SMBCLIENT //$SERVER/IPC\$ $CONFIGURATION -Ubaduser%badpassword -mNT1 --signing=required -c quit $ADDARGS
+ testit_expect_failure "smbclient baduser.badpassword.SMB3.signfail" $SMBCLIENT //$SERVER/IPC\$ $CONFIGURATION -Ubaduser%badpassword -mSMB3 --signing=required -c quit $ADDARGS
fi
diff --git a/source4/librpc/rpc/dcerpc.c b/source4/librpc/rpc/dcerpc.c
index 464ae95..55b4385 100644
--- a/source4/librpc/rpc/dcerpc.c
+++ b/source4/librpc/rpc/dcerpc.c
@@ -155,6 +155,7 @@ static struct dcecli_connection *dcerpc_connection_init(TALLOC_CTX *mem_ctx,
*/
c->srv_max_xmit_frag = 5840;
c->srv_max_recv_frag = 5840;
+ c->max_total_response_size = DCERPC_NCACN_RESPONSE_DEFAULT_MAX_SIZE;
c->pending = NULL;
c->io_trigger = tevent_create_immediate(c);
@@ -1577,10 +1578,10 @@ static void dcerpc_request_recv_data(struct dcecli_connection *c,
length = pkt->u.response.stub_and_verifier.length;
- if (req->payload.length + length > DCERPC_NCACN_PAYLOAD_MAX_SIZE) {
+ if (req->payload.length + length > c->max_total_response_size) {
DEBUG(2,("Unexpected total payload 0x%X > 0x%X dcerpc response\n",
(unsigned)req->payload.length + length,
- DCERPC_NCACN_PAYLOAD_MAX_SIZE));
+ (unsigned)c->max_total_response_size));
dcerpc_connection_dead(c, NT_STATUS_RPC_PROTOCOL_ERROR);
return;
}
diff --git a/source4/librpc/rpc/dcerpc.h b/source4/librpc/rpc/dcerpc.h
index 39d28a6..24c7948 100644
--- a/source4/librpc/rpc/dcerpc.h
+++ b/source4/librpc/rpc/dcerpc.h
@@ -107,6 +107,9 @@ struct dcecli_connection {
/* the next context_id to be assigned */
uint32_t next_context_id;
+
+ /* The maximum total payload of reassembled response pdus */
+ size_t max_total_response_size;
};
/*
diff --git a/source4/rpc_server/dcerpc_server.c b/source4/rpc_server/dcerpc_server.c
index 8c69351..ea29d9d 100644
--- a/source4/rpc_server/dcerpc_server.c
+++ b/source4/rpc_server/dcerpc_server.c
@@ -408,6 +408,7 @@ _PUBLIC_ NTSTATUS dcesrv_endpoint_connect(struct dcesrv_context *dce_ctx,
p->allow_bind = true;
p->max_recv_frag = 5840;
p->max_xmit_frag = 5840;
+ p->max_total_request_size = DCERPC_NCACN_REQUEST_DEFAULT_MAX_SIZE;
*_p = p;
return NT_STATUS_OK;
@@ -1532,7 +1533,7 @@ static NTSTATUS dcesrv_process_ncacn_packet(struct dcesrv_connection *dce_conn,
/*
* Up to 4 MByte are allowed by all fragments
*/
- available = DCERPC_NCACN_PAYLOAD_MAX_SIZE;
+ available = dce_conn->max_total_request_size;
if (er->stub_and_verifier.length > available) {
dcesrv_call_disconnect_after(existing,
"dcesrv_auth_request - existing payload too large");
@@ -1585,7 +1586,7 @@ static NTSTATUS dcesrv_process_ncacn_packet(struct dcesrv_connection *dce_conn,
/*
* Up to 4 MByte are allowed by all fragments
*/
- if (call->pkt.u.request.alloc_hint > DCERPC_NCACN_PAYLOAD_MAX_SIZE) {
+ if (call->pkt.u.request.alloc_hint > dce_conn->max_total_request_size) {
dcesrv_call_disconnect_after(call,
"dcesrv_auth_request - initial alloc hint too large");
return dcesrv_fault(call, DCERPC_FAULT_ACCESS_DENIED);
diff --git a/source4/rpc_server/dcerpc_server.h b/source4/rpc_server/dcerpc_server.h
index 7e8b18a..b6fac6c 100644
--- a/source4/rpc_server/dcerpc_server.h
+++ b/source4/rpc_server/dcerpc_server.h
@@ -273,6 +273,9 @@ struct dcesrv_connection {
/* the association group the connection belongs to */
struct dcesrv_assoc_group *assoc_group;
+
+ /* The maximum total payload of reassembled request pdus */
+ size_t max_total_request_size;
};
--
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