From e97cf207fac5e4101376d2a10dd95a93a9a1e0fb Mon Sep 17 00:00:00 2001 From: Andrew Tridgell Date: Fri, 6 Jun 2008 22:10:30 -0700 Subject: added server side SMB2 signing (This used to be commit 8e919dcb0826a5b25d037ee6144af5f7cb21f3ae) --- source4/libcli/smb2/session.c | 8 ++-- source4/libcli/smb2/signing.c | 74 +++++++++---------------------------- source4/libcli/smb2/transport.c | 32 ++++++++++------ source4/smb_server/smb2/negprot.c | 13 ++++++- source4/smb_server/smb2/receive.c | 36 ++++++++++++++++++ source4/smb_server/smb2/sesssetup.c | 9 +++++ source4/smb_server/smb_server.h | 2 + 7 files changed, 103 insertions(+), 71 deletions(-) diff --git a/source4/libcli/smb2/session.c b/source4/libcli/smb2/session.c index 54915d8535..42fd4840a1 100644 --- a/source4/libcli/smb2/session.c +++ b/source4/libcli/smb2/session.c @@ -188,11 +188,13 @@ static void session_request_handler(struct smb2_request *req) } if (session->transport->signing.doing_signing) { - c->status = smb2_start_signing(session->transport); - if (!NT_STATUS_IS_OK(c->status)) { - composite_error(c, c->status); + if (session->transport->signing.session_key.length != 16) { + DEBUG(2,("Wrong session key length %u for SMB2 signing\n", + (unsigned)session->transport->signing.session_key.length)); + composite_error(c, NT_STATUS_ACCESS_DENIED); return; } + session->transport->signing.signing_started = true; } composite_done(c); diff --git a/source4/libcli/smb2/signing.c b/source4/libcli/smb2/signing.c index 16c0ff99c1..fb2c22db4e 100644 --- a/source4/libcli/smb2/signing.c +++ b/source4/libcli/smb2/signing.c @@ -25,42 +25,14 @@ #include "libcli/smb2/smb2_calls.h" #include "lib/crypto/crypto.h" -/* - NOTE: this code does not yet interoperate with the windows SMB2 - implementation. We are waiting on feedback on the docs to find out - why - */ - - -/* - setup signing on a transport - */ -NTSTATUS smb2_start_signing(struct smb2_transport *transport) -{ - if (transport->signing.session_key.length != 16) { - DEBUG(2,("Wrong session key length %u for SMB2 signing\n", - (unsigned)transport->signing.session_key.length)); - return NT_STATUS_ACCESS_DENIED; - } - - transport->signing.signing_started = true; - return NT_STATUS_OK; -} - /* sign an outgoing message */ -NTSTATUS smb2_sign_message(struct smb2_request *req) +NTSTATUS smb2_sign_message(struct smb2_request_buffer *buf, DATA_BLOB session_key) { - struct smb2_request_buffer *buf = &req->out; - uint64_t session_id; struct HMACSHA256Context m; uint8_t res[32]; - - if (!req->transport->signing.doing_signing || - !req->transport->signing.signing_started) { - return NT_STATUS_OK; - } + uint64_t session_id; if (buf->size < NBT_HDR_SIZE + SMB2_HDR_SIGNATURE + 16) { /* can't sign non-SMB2 messages */ @@ -74,9 +46,9 @@ NTSTATUS smb2_sign_message(struct smb2_request *req) return NT_STATUS_OK; } - if (req->transport->signing.session_key.length != 16) { + if (session_key.length != 16) { DEBUG(2,("Wrong session key length %u for SMB2 signing\n", - (unsigned)req->transport->signing.session_key.length)); + (unsigned)session_key.length)); return NT_STATUS_ACCESS_DENIED; } @@ -85,7 +57,7 @@ NTSTATUS smb2_sign_message(struct smb2_request *req) SIVAL(buf->hdr, SMB2_HDR_FLAGS, IVAL(buf->hdr, SMB2_HDR_FLAGS) | SMB2_HDR_FLAG_SIGNED); ZERO_STRUCT(m); - hmac_sha256_init(req->transport->signing.session_key.data, 16, &m); + hmac_sha256_init(session_key.data, 16, &m); hmac_sha256_update(buf->buffer+NBT_HDR_SIZE, buf->size-NBT_HDR_SIZE, &m); hmac_sha256_final(res, &m); @@ -93,66 +65,56 @@ NTSTATUS smb2_sign_message(struct smb2_request *req) memcpy(buf->hdr + SMB2_HDR_SIGNATURE, res, 16); - if (DEBUGLVL(5)) { - /* check our own signature */ - smb2_check_signature(req->transport, buf->buffer, buf->size); - } - return NT_STATUS_OK; } /* check an incoming signature */ -NTSTATUS smb2_check_signature(struct smb2_transport *transport, - uint8_t *buffer, uint_t length) +NTSTATUS smb2_check_signature(struct smb2_request_buffer *buf, DATA_BLOB session_key) { uint64_t session_id; struct HMACSHA256Context m; uint8_t res[SHA256_DIGEST_LENGTH]; uint8_t sig[16]; - if (!transport->signing.signing_started || - !transport->signing.doing_signing) { - return NT_STATUS_OK; - } - - if (length < NBT_HDR_SIZE + SMB2_HDR_SIGNATURE + 16) { + if (buf->size < NBT_HDR_SIZE + SMB2_HDR_SIGNATURE + 16) { /* can't check non-SMB2 messages */ return NT_STATUS_OK; } - session_id = BVAL(buffer+NBT_HDR_SIZE, SMB2_HDR_SESSION_ID); + session_id = BVAL(buf->hdr, SMB2_HDR_SESSION_ID); if (session_id == 0) { /* don't sign messages with a zero session_id. See MS-SMB2 3.2.4.1.1 */ return NT_STATUS_OK; } - if (transport->signing.session_key.length == 0) { + if (session_key.length == 0) { /* we don't have the session key yet */ return NT_STATUS_OK; } - if (transport->signing.session_key.length != 16) { + if (session_key.length != 16) { DEBUG(2,("Wrong session key length %u for SMB2 signing\n", - (unsigned)transport->signing.session_key.length)); + (unsigned)session_key.length)); return NT_STATUS_ACCESS_DENIED; } - memcpy(sig, buffer+NBT_HDR_SIZE+SMB2_HDR_SIGNATURE, 16); + memcpy(sig, buf->hdr+SMB2_HDR_SIGNATURE, 16); - memset(buffer + NBT_HDR_SIZE + SMB2_HDR_SIGNATURE, 0, 16); + memset(buf->hdr + SMB2_HDR_SIGNATURE, 0, 16); ZERO_STRUCT(m); - hmac_sha256_init(transport->signing.session_key.data, 16, &m); - hmac_sha256_update(buffer+NBT_HDR_SIZE, length-NBT_HDR_SIZE, &m); + hmac_sha256_init(session_key.data, 16, &m); + hmac_sha256_update(buf->hdr, buf->size-NBT_HDR_SIZE, &m); hmac_sha256_final(res, &m); - memcpy(buffer+NBT_HDR_SIZE+SMB2_HDR_SIGNATURE, sig, 16); + memcpy(buf->hdr+SMB2_HDR_SIGNATURE, sig, 16); if (memcmp(res, sig, 16) != 0) { - DEBUG(0,("Bad SMB2 signature for message of size %u\n", length)); + DEBUG(0,("Bad SMB2 signature for message of size %u\n", + (unsigned)buf->size-NBT_HDR_SIZE)); dump_data(0, sig, 16); dump_data(0, res, 16); return NT_STATUS_ACCESS_DENIED; diff --git a/source4/libcli/smb2/transport.c b/source4/libcli/smb2/transport.c index 561b6e528e..a9a9efb3aa 100644 --- a/source4/libcli/smb2/transport.c +++ b/source4/libcli/smb2/transport.c @@ -205,12 +205,6 @@ static NTSTATUS smb2_transport_finish_recv(void *private, DATA_BLOB blob) goto error; } - status = smb2_check_signature(transport, buffer, len); - if (!NT_STATUS_IS_OK(status)) { - talloc_free(buffer); - return status; - } - flags = IVAL(hdr, SMB2_HDR_FLAGS); seqnum = BVAL(hdr, SMB2_HDR_MESSAGE_ID); @@ -241,6 +235,18 @@ static NTSTATUS smb2_transport_finish_recv(void *private, DATA_BLOB blob) req->in.body_size = req->in.size - (SMB2_HDR_BODY+NBT_HDR_SIZE); req->status = NT_STATUS(IVAL(hdr, SMB2_HDR_STATUS)); + if (transport->signing.signing_started && + transport->signing.doing_signing) { + status = smb2_check_signature(&req->in, + transport->signing.session_key); + if (!NT_STATUS_IS_OK(status)) { + /* the spec says to ignore packets with a bad signature */ + talloc_free(buffer); + return status; + } + } + + if (NT_STATUS_EQUAL(req->status, STATUS_PENDING)) { if (flags & 0x00000002) { req->cancel.can_cancel = true; @@ -346,11 +352,15 @@ void smb2_transport_send(struct smb2_request *req) return; } - status = smb2_sign_message(req); - if (!NT_STATUS_IS_OK(status)) { - req->state = SMB2_REQUEST_ERROR; - req->status = status; - return; + /* possibly sign the message */ + if (req->transport->signing.doing_signing && + req->transport->signing.signing_started) { + status = smb2_sign_message(&req->out, req->transport->signing.session_key); + if (!NT_STATUS_IS_OK(status)) { + req->state = SMB2_REQUEST_ERROR; + req->status = status; + return; + } } blob = data_blob_const(req->out.buffer, req->out.size); diff --git a/source4/smb_server/smb2/negprot.c b/source4/smb_server/smb2/negprot.c index 4479ae2da1..2da39001ab 100644 --- a/source4/smb_server/smb2/negprot.c +++ b/source4/smb_server/smb2/negprot.c @@ -111,7 +111,18 @@ static NTSTATUS smb2srv_negprot_backend(struct smb2srv_request *req, struct smb2 boot_time = timeval_current(); /* TODO: fix me */ ZERO_STRUCT(io->out); - io->out.security_mode = 0; /* no signing yet */ + switch (lp_server_signing(req->smb_conn->lp_ctx)) { + case SMB_SIGNING_OFF: + io->out.security_mode = 0; + break; + case SMB_SIGNING_SUPPORTED: + case SMB_SIGNING_AUTO: + io->out.security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED; + break; + case SMB_SIGNING_REQUIRED: + io->out.security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED | SMB2_NEGOTIATE_SIGNING_REQUIRED; + break; + } io->out.dialect_revision = SMB2_DIALECT_REVISION; io->out.capabilities = 0; io->out.max_transact_size = lp_parm_ulong(req->smb_conn->lp_ctx, NULL, diff --git a/source4/smb_server/smb2/receive.c b/source4/smb_server/smb2/receive.c index dea7c9e79e..3def8fe563 100644 --- a/source4/smb_server/smb2/receive.c +++ b/source4/smb_server/smb2/receive.c @@ -29,6 +29,8 @@ #include "lib/stream/packet.h" #include "ntvfs/ntvfs.h" #include "param/param.h" +#include "auth/gensec/gensec.h" +#include "auth/auth.h" /* fill in the bufinfo */ @@ -233,6 +235,20 @@ void smb2srv_send_reply(struct smb2srv_request *req) _smb2_setlen(req->out.buffer, req->out.size - NBT_HDR_SIZE); } + /* if the request was signed or doing_signing is true, then we + must sign the reply */ + if (req->session && + (req->smb_conn->doing_signing || + (IVAL(req->in.hdr, SMB2_HDR_FLAGS) & SMB2_HDR_FLAG_SIGNED))) { + status = smb2_sign_message(&req->out, + req->session->session_info->session_key); + if (!NT_STATUS_IS_OK(status)) { + smbsrv_terminate_connection(req->smb_conn, nt_errstr(status)); + return; + } + } + + blob = data_blob_const(req->out.buffer, req->out.size); status = packet_send(req->smb_conn->packet, blob); if (!NT_STATUS_IS_OK(status)) { @@ -275,18 +291,38 @@ static NTSTATUS smb2srv_reply(struct smb2srv_request *req) uint16_t opcode; uint32_t tid; uint64_t uid; + uint32_t flags; opcode = SVAL(req->in.hdr, SMB2_HDR_OPCODE); req->chain_offset = IVAL(req->in.hdr, SMB2_HDR_NEXT_COMMAND); req->seqnum = BVAL(req->in.hdr, SMB2_HDR_MESSAGE_ID); tid = IVAL(req->in.hdr, SMB2_HDR_TID); uid = BVAL(req->in.hdr, SMB2_HDR_SESSION_ID); + flags = IVAL(req->in.hdr, SMB2_HDR_FLAGS); req->session = smbsrv_session_find(req->smb_conn, uid, req->request_time); req->tcon = smbsrv_smb2_tcon_find(req->session, tid, req->request_time); errno = 0; + /* supporting signing is mandatory in SMB2, and is per-packet. So we + should check the signature on any incoming packet that is signed, and + should give a signed reply to any signed request */ + if (flags & SMB2_HDR_FLAG_SIGNED) { + NTSTATUS status; + if (req->session == NULL) { + /* we can't check signing with no session */ + smb2srv_send_error(req, NT_STATUS_ACCESS_DENIED); + return NT_STATUS_OK; + } + status = smb2_check_signature(&req->in, + req->session->session_info->session_key); + if (!NT_STATUS_IS_OK(status)) { + smb2srv_send_error(req, status); + return NT_STATUS_OK; + } + } + /* TODO: check the seqnum */ switch (opcode) { diff --git a/source4/smb_server/smb2/sesssetup.c b/source4/smb_server/smb2/sesssetup.c index d386bfc72d..482dd181c2 100644 --- a/source4/smb_server/smb2/sesssetup.c +++ b/source4/smb_server/smb2/sesssetup.c @@ -177,6 +177,15 @@ static void smb2srv_sesssetup_backend(struct smb2srv_request *req, union smb_ses gensec_update_send(smb_sess->gensec_ctx, io->smb2.in.secblob, smb2srv_sesssetup_callback, callback_ctx); + + /* note that we ignore SMB2_NEGOTIATE_SIGNING_ENABLED from the client. + This is deliberate as windows does not set it even when it does + set SMB2_NEGOTIATE_SIGNING_REQUIRED */ + if ((io->smb2.in.security_mode & SMB2_NEGOTIATE_SIGNING_REQUIRED) || + lp_server_signing(req->smb_conn->lp_ctx) == SMB_SIGNING_REQUIRED) { + req->smb_conn->doing_signing = true; + } + return; nomem: status = NT_STATUS_NO_MEMORY; diff --git a/source4/smb_server/smb_server.h b/source4/smb_server/smb_server.h index 776fe1b71b..ac3e0f3bd3 100644 --- a/source4/smb_server/smb_server.h +++ b/source4/smb_server/smb_server.h @@ -376,6 +376,8 @@ struct smbsrv_connection { struct share_context *share_context; struct loadparm_context *lp_ctx; + + bool doing_signing; }; struct model_ops; -- cgit