s3:libsmb: use new simplified smb_signing code for the client side

We store the seqnum/mid mapping in the cli_request structure
for async requests and in the cli_state structure for sync calls.

We skip the signing check for oplock requests while waiting
for async requests coming in.

metze

1 files changed, 32 insertions, 618 deletions

diff --git a/source3/libsmb/clisigning.c b/source3/libsmb/clisigning.c
index 6644bc0d60..0d0e926e6c 100644
--- a/source3/libsmb/clisigning.c
+++ b/source3/libsmb/clisigning.c
@@ -1,8 +1,9 @@
-/* 
+/*
    Unix SMB/CIFS implementation.
    SMB Signing Code
    Copyright (C) Jeremy Allison 2003.
    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
+   Copyright (C) Stefan Metzmacher 2009
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -20,654 +21,67 @@
 
 #include "includes.h"
 
-/* Lookup a packet's MID (multiplex id) and figure out it's sequence number */
-struct outstanding_packet_lookup {
-	struct outstanding_packet_lookup *prev, *next;
-	uint16 mid;
-	uint32 reply_seq_num;
-	bool can_delete; /* Set to False in trans state. */
-};
-
-struct smb_basic_signing_context {
-	DATA_BLOB mac_key;
-	uint32 send_seq_num;
-	struct outstanding_packet_lookup *outstanding_packet_list;
-};
-
-static bool store_sequence_for_reply(struct outstanding_packet_lookup **list, 
-				     uint16 mid, uint32 reply_seq_num)
-{
-	struct outstanding_packet_lookup *t;
-
-	/* Ensure we only add a mid once. */
-	for (t = *list; t; t = t->next) {
-		if (t->mid == mid) {
-			return False;
-		}
-	}
-
-	t = SMB_XMALLOC_P(struct outstanding_packet_lookup);
-	ZERO_STRUCTP(t);
-
-	t->mid = mid;
-	t->reply_seq_num = reply_seq_num;
-	t->can_delete = True;
-
-	/*
-	 * Add to the *start* of the list not the end of the list.
-	 * This ensures that the *last* send sequence with this mid
-	 * is returned by preference.
-	 * This can happen if the mid wraps and one of the early
-	 * mid numbers didn't get a reply and is still lurking on
-	 * the list. JRA. Found by Fran Fabrizio <fran@cis.uab.edu>.
-	 */
-
-	DLIST_ADD(*list, t);
-	DEBUG(10,("store_sequence_for_reply: stored seq = %u mid = %u\n",
-			(unsigned int)reply_seq_num, (unsigned int)mid ));
-	return True;
-}
-
-static bool get_sequence_for_reply(struct outstanding_packet_lookup **list,
-				   uint16 mid, uint32 *reply_seq_num)
-{
-	struct outstanding_packet_lookup *t;
-
-	for (t = *list; t; t = t->next) {
-		if (t->mid == mid) {
-			*reply_seq_num = t->reply_seq_num;
-			DEBUG(10,("get_sequence_for_reply: found seq = %u mid = %u\n",
-				(unsigned int)t->reply_seq_num, (unsigned int)t->mid ));
-			if (t->can_delete) {
-				DLIST_REMOVE(*list, t);
-				SAFE_FREE(t);
-			}
-			return True;
-		}
-	}
-	return False;
-}
-
-static bool set_sequence_can_delete_flag(struct outstanding_packet_lookup **list, uint16 mid, bool can_delete_entry)
-{
-	struct outstanding_packet_lookup *t;
-
-	for (t = *list; t; t = t->next) {
-		if (t->mid == mid) {
-			t->can_delete = can_delete_entry;
-			return True;
-		}
-	}
-	return False;
-}
-
-/***********************************************************
- SMB signing - Common code before we set a new signing implementation
-************************************************************/
-
-static bool cli_set_smb_signing_common(struct cli_state *cli) 
-{
-	if (!cli->sign_info.allow_smb_signing) {
-		return False;
-	}
-
-	if (!cli->sign_info.negotiated_smb_signing 
-	    && !cli->sign_info.mandatory_signing) {
-		return False;
-	}
-
-	if (cli->sign_info.doing_signing) {
-		return False;
-	}
-
-	if (cli->sign_info.free_signing_context)
-		cli->sign_info.free_signing_context(&cli->sign_info);
-
-	/* These calls are INCOMPATIBLE with SMB signing */
-	cli->readbraw_supported = False;
-	cli->writebraw_supported = False;
-
-	return True;
-}
-
-/***********************************************************
- SMB signing - Common code for 'real' implementations
-************************************************************/
-
-static bool set_smb_signing_real_common(struct smb_sign_info *si)
-{
-	if (si->mandatory_signing) {
-		DEBUG(5, ("Mandatory SMB signing enabled!\n"));
-	}
-
-	si->doing_signing = True;
-	DEBUG(5, ("SMB signing enabled!\n"));
-
-	return True;
-}
-
-static void mark_packet_signed(char *outbuf)
-{
-	uint16 flags2;
-	flags2 = SVAL(outbuf,smb_flg2);
-	flags2 |= FLAGS2_SMB_SECURITY_SIGNATURES;
-	SSVAL(outbuf,smb_flg2, flags2);
-}
-
-/***********************************************************
- SMB signing - NULL implementation - calculate a MAC to send.
-************************************************************/
-
-static void null_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
-{
-	/* we can't zero out the sig, as we might be trying to send a
-	   session request - which is NBT-level, not SMB level and doesn't
-	   have the field */
-	return;
-}
-
-/***********************************************************
- SMB signing - NULL implementation - check a MAC sent by server.
-************************************************************/
-
-static bool null_check_incoming_message(const char *inbuf,
-					struct smb_sign_info *si,
-					bool must_be_ok)
-{
-	return True;
-}
-
-/***********************************************************
- SMB signing - NULL implementation - free signing context
-************************************************************/
-
-static void null_free_signing_context(struct smb_sign_info *si)
-{
-	return;
-}
-
-/**
- SMB signing - NULL implementation - setup the MAC key.
-
- @note Used as an initialisation only - it will not correctly
-       shut down a real signing mechanism
-*/
-
-static bool null_set_signing(struct smb_sign_info *si)
-{
-	si->signing_context = NULL;
-
-	si->sign_outgoing_message = null_sign_outgoing_message;
-	si->check_incoming_message = null_check_incoming_message;
-	si->free_signing_context = null_free_signing_context;
-
-	return True;
-}
-
-/**
- * Free the signing context
- */
-
-static void free_signing_context(struct smb_sign_info *si)
-{
-	if (si->free_signing_context) {
-		si->free_signing_context(si);
-		si->signing_context = NULL;
-	}
-
-	null_set_signing(si);
-}
-
-
-static bool signing_good(const char *inbuf, struct smb_sign_info *si,
-			 bool good, uint32 seq, bool must_be_ok)
-{
-	if (good) {
-
-		if (!si->doing_signing) {
-			si->doing_signing = True;
-		}
-
-		if (!si->seen_valid) {
-			si->seen_valid = True;
-		}
-
-	} else {
-		if (!si->mandatory_signing && !si->seen_valid) {
-
-			if (!must_be_ok) {
-				return True;
-			}
-			/* Non-mandatory signing - just turn off if this is the first bad packet.. */
-			DEBUG(5, ("srv_check_incoming_message: signing negotiated but not required and peer\n"
-				  "isn't sending correct signatures. Turning off.\n"));
-			si->negotiated_smb_signing = False;
-			si->allow_smb_signing = False;
-			si->doing_signing = False;
-			free_signing_context(si);
-			return True;
-		} else if (!must_be_ok) {
-			/* This packet is known to be unsigned */
-			return True;
-		} else {
-			/* Mandatory signing or bad packet after signing started - fail and disconnect. */
-			if (seq)
-				DEBUG(0, ("signing_good: BAD SIG: seq %u\n", (unsigned int)seq));
-			return False;
-		}
-	}
-	return True;
-}	
-
-/***********************************************************
- SMB signing - Simple implementation - calculate a MAC on the packet
-************************************************************/
-
-static void simple_packet_signature(struct smb_basic_signing_context *data, 
-				    const uchar *buf, uint32 seq_number, 
-				    unsigned char calc_md5_mac[16])
-{
-	const size_t offset_end_of_sig = (smb_ss_field + 8);
-	unsigned char sequence_buf[8];
-	struct MD5Context md5_ctx;
-#if 0
-        /* JRA - apparently this is incorrect. */
-	unsigned char key_buf[16];
-#endif
-
-	/*
-	 * Firstly put the sequence number into the first 4 bytes.
-	 * and zero out the next 4 bytes.
-	 *
-	 * We do this here, to avoid modifying the packet.
-	 */
-
-	DEBUG(10,("simple_packet_signature: sequence number %u\n", seq_number ));
-
-	SIVAL(sequence_buf, 0, seq_number);
-	SIVAL(sequence_buf, 4, 0);
-
-	/* Calculate the 16 byte MAC - but don't alter the data in the
-	   incoming packet.
-
-	   This makes for a bit of fussing about, but it's not too bad.
-	*/
-	MD5Init(&md5_ctx);
-
-	/* intialise with the key */
-	MD5Update(&md5_ctx, data->mac_key.data, data->mac_key.length); 
-#if 0
-	/* JRA - apparently this is incorrect. */
-	/* NB. When making and verifying SMB signatures, Windows apparently
-		zero-pads the key to 128 bits if it isn't long enough.
-		From Nalin Dahyabhai <nalin@redhat.com> */
-	if (data->mac_key.length < sizeof(key_buf)) {
-		memset(key_buf, 0, sizeof(key_buf));
-		MD5Update(&md5_ctx, key_buf, sizeof(key_buf) - data->mac_key.length);
-	}
-#endif
-
-	/* copy in the first bit of the SMB header */
-	MD5Update(&md5_ctx, buf + 4, smb_ss_field - 4);
-
-	/* copy in the sequence number, instead of the signature */
-	MD5Update(&md5_ctx, sequence_buf, sizeof(sequence_buf));
-
-	/* copy in the rest of the packet in, skipping the signature */
-	MD5Update(&md5_ctx, buf + offset_end_of_sig, 
-		  smb_len(buf) - (offset_end_of_sig - 4));
-
-	/* calculate the MD5 sig */ 
-	MD5Final(calc_md5_mac, &md5_ctx);
-}
-
-
-/***********************************************************
- SMB signing - Client implementation - send the MAC.
-************************************************************/
-
-static void client_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
-{
-	unsigned char calc_md5_mac[16];
-	struct smb_basic_signing_context *data =
-		(struct smb_basic_signing_context *)si->signing_context;
-
-	if (!si->doing_signing)
-		return;
-
-	/* JRA Paranioa test - we should be able to get rid of this... */
-	if (smb_len(outbuf) < (smb_ss_field + 8 - 4)) {
-		DEBUG(1, ("client_sign_outgoing_message: Logic error. Can't check signature on short packet! smb_len = %u\n",
-					smb_len(outbuf) ));
-		abort();
-	}
-
-	/* mark the packet as signed - BEFORE we sign it...*/
-	mark_packet_signed(outbuf);
-
-	simple_packet_signature(data, (const unsigned char *)outbuf,
-				data->send_seq_num, calc_md5_mac);
-
-	DEBUG(10, ("client_sign_outgoing_message: sent SMB signature of\n"));
-	dump_data(10, calc_md5_mac, 8);
-
-	memcpy(&outbuf[smb_ss_field], calc_md5_mac, 8);
-
-/*	cli->outbuf[smb_ss_field+2]=0; 
-	Uncomment this to test if the remote server actually verifies signatures...*/
-
-	/* Instead of re-introducing the trans_info_conect we
-	   used to have here, we use the fact that during a
-	   SMBtrans/SMBtrans2/SMBnttrans send that the mid stays
-	   constant. This means that calling store_sequence_for_reply()
-	   will return False for all trans secondaries, as the mid is already
-	   on the stored sequence list. As the send_seqence_number must
-	   remain constant for all primary+secondary trans sends, we
-	   only increment the send sequence number when we successfully
-	   add a new entry to the outstanding sequence list. This means
-	   I can isolate the fix here rather than re-adding the trans
-	   signing on/off calls in libsmb/clitrans2.c JRA.
-	 */
-
-	if (store_sequence_for_reply(&data->outstanding_packet_list, SVAL(outbuf,smb_mid), data->send_seq_num + 1)) {
-		data->send_seq_num += 2;
-	}
-}
-
-/***********************************************************
- SMB signing - Client implementation - check a MAC sent by server.
-************************************************************/
-
-static bool client_check_incoming_message(const char *inbuf,
-					  struct smb_sign_info *si,
-					  bool must_be_ok)
-{
-	bool good;
-	uint32 reply_seq_number;
-	unsigned char calc_md5_mac[16];
-	unsigned char *server_sent_mac;
-
-	struct smb_basic_signing_context *data =
-		(struct smb_basic_signing_context *)si->signing_context;
-
-	if (!si->doing_signing)
-		return True;
-
-	if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) {
-		DEBUG(1, ("client_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf)));
-		return False;
-	}
-
-	if (!get_sequence_for_reply(&data->outstanding_packet_list, SVAL(inbuf, smb_mid), &reply_seq_number)) {
-		DEBUG(1, ("client_check_incoming_message: received message "
-			"with mid %u with no matching send record.\n", (unsigned int)SVAL(inbuf, smb_mid) ));
-		return False;
-	}
-
-	simple_packet_signature(data, (const unsigned char *)inbuf,
-				reply_seq_number, calc_md5_mac);
-
-	server_sent_mac = (unsigned char *)&inbuf[smb_ss_field];
-	good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
-
-	if (!good) {
-		DEBUG(5, ("client_check_incoming_message: BAD SIG: wanted SMB signature of\n"));
-		dump_data(5, calc_md5_mac, 8);
-
-		DEBUG(5, ("client_check_incoming_message: BAD SIG: got SMB signature of\n"));
-		dump_data(5, server_sent_mac, 8);
-#if 1 /* JRATEST */
-		{
-			int i;
-			for (i = -5; i < 5; i++) {
-				simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number+i, calc_md5_mac);
-				if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) {
-					DEBUG(0,("client_check_incoming_message: out of seq. seq num %u matches. \
-We were expecting seq %u\n", reply_seq_number+i, reply_seq_number ));
-					break;
-				}
-			}
-		}
-#endif /* JRATEST */
-
-	} else {
-		DEBUG(10, ("client_check_incoming_message: seq %u: got good SMB signature of\n", (unsigned int)reply_seq_number));
-		dump_data(10, server_sent_mac, 8);
-	}
-	return signing_good(inbuf, si, good, reply_seq_number, must_be_ok);
-}
-
-/***********************************************************
- SMB signing - Simple implementation - free signing context
-************************************************************/
-
-static void simple_free_signing_context(struct smb_sign_info *si)
-{
-	struct smb_basic_signing_context *data =
-		(struct smb_basic_signing_context *)si->signing_context;
-	struct outstanding_packet_lookup *list;
-	struct outstanding_packet_lookup *next;
-
-	for (list = data->outstanding_packet_list; list; list = next) {
-		next = list->next;
-		DLIST_REMOVE(data->outstanding_packet_list, list);
-		SAFE_FREE(list);
-	}
-
-	data_blob_free(&data->mac_key);
-
-	SAFE_FREE(si->signing_context);
-
-	return;
-}
-
-/***********************************************************
- SMB signing - Simple implementation - setup the MAC key.
-************************************************************/
-
 bool cli_simple_set_signing(struct cli_state *cli,
 			    const DATA_BLOB user_session_key,
 			    const DATA_BLOB response)
 {
-	struct smb_basic_signing_context *data;
-
-	if (!user_session_key.length)
-		return False;
-
-	if (!cli_set_smb_signing_common(cli)) {
-		return False;
-	}
-
-	if (!set_smb_signing_real_common(&cli->sign_info)) {
-		return False;
-	}
-
-	data = SMB_XMALLOC_P(struct smb_basic_signing_context);
-	memset(data, '\0', sizeof(*data));
-
-	cli->sign_info.signing_context = data;
-
-	data->mac_key = data_blob(NULL, response.length + user_session_key.length);
-
-	memcpy(&data->mac_key.data[0], user_session_key.data, user_session_key.length);
-
-	DEBUG(10, ("cli_simple_set_signing: user_session_key\n"));
-	dump_data(10, user_session_key.data, user_session_key.length);
+	bool ok;
 
-	if (response.length) {
-		memcpy(&data->mac_key.data[user_session_key.length],response.data, response.length);
-		DEBUG(10, ("cli_simple_set_signing: response_data\n"));
-		dump_data(10, response.data, response.length);
-	} else {
-		DEBUG(10, ("cli_simple_set_signing: NULL response_data\n"));
+	ok = smb_signing_activate(cli->signing_state,
+				  user_session_key,
+				  response);
+	if (!ok) {
+		return false;
 	}
 
-	dump_data_pw("MAC ssession key is:\n", data->mac_key.data, data->mac_key.length);
+	cli->readbraw_supported = false;
+	cli->writebraw_supported = false;
 
-	/* Initialise the sequence number */
-	data->send_seq_num = 0;
-
-	/* Initialise the list of outstanding packets */
-	data->outstanding_packet_list = NULL;
-
-	cli->sign_info.sign_outgoing_message = client_sign_outgoing_message;
-	cli->sign_info.check_incoming_message = client_check_incoming_message;
-	cli->sign_info.free_signing_context = simple_free_signing_context;
-
-	return True;
-}
-
-/***********************************************************
- SMB signing - TEMP implementation - calculate a MAC to send.
-************************************************************/
-
-static void temp_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
-{
-	/* mark the packet as signed - BEFORE we sign it...*/
-	mark_packet_signed(outbuf);
-
-	/* I wonder what BSRSPYL stands for - but this is what MS 
-	   actually sends! */
-	memcpy(&outbuf[smb_ss_field], "BSRSPYL ", 8);
-	return;
+	return true;
 }
 
-/***********************************************************
- SMB signing - TEMP implementation - check a MAC sent by server.
-************************************************************/
-
-static bool temp_check_incoming_message(const char *inbuf,
-					struct smb_sign_info *si, bool foo)
+bool cli_temp_set_signing(struct cli_state *cli)
 {
-	return True;
+	return smb_signing_set_bsrspyl(cli->signing_state);
 }
 
-/***********************************************************
- SMB signing - TEMP implementation - free signing context
-************************************************************/
-
-static void temp_free_signing_context(struct smb_sign_info *si)
+void cli_calculate_sign_mac(struct cli_state *cli, char *buf, uint32_t *seqnum)
 {
-	return;
+	*seqnum = smb_signing_next_seqnum(cli->signing_state, false);
+	smb_signing_sign_pdu(cli->signing_state, (uint8_t *)buf, *seqnum);
 }
 
-/***********************************************************
- SMB signing - NULL implementation - setup the MAC key.
-************************************************************/
-
-bool cli_null_set_signing(struct cli_state *cli)
+bool cli_check_sign_mac(struct cli_state *cli, const char *buf, uint32_t seqnum)
 {
-	return null_set_signing(&cli->sign_info);
-}
+	bool ok;
 
-/***********************************************************
- SMB signing - temp implementation - setup the MAC key.
-************************************************************/
+	ok = smb_signing_check_pdu(cli->signing_state,
+				   (const uint8_t *)buf,
+				   seqnum);
 
-bool cli_temp_set_signing(struct cli_state *cli)
-{
-	if (!cli_set_smb_signing_common(cli)) {
-		return False;
+	if (!ok) {
+		return false;
 	}
 
-	cli->sign_info.signing_context = NULL;
-
-	cli->sign_info.sign_outgoing_message = temp_sign_outgoing_message;
-	cli->sign_info.check_incoming_message = temp_check_incoming_message;
-	cli->sign_info.free_signing_context = temp_free_signing_context;
-
-	return True;
-}
-
-void cli_free_signing_context(struct cli_state *cli)
-{
-	free_signing_context(&cli->sign_info);
+	return true;
 }
 
-/**
- * Sign a packet with the current mechanism
- */
-
-void cli_calculate_sign_mac(struct cli_state *cli, char *buf)
+void cli_set_signing_negotiated(struct cli_state *cli)
 {
-	cli->sign_info.sign_outgoing_message(buf, &cli->sign_info);
+	smb_signing_set_negotiated(cli->signing_state);
 }
 
-/**
- * Check a packet with the current mechanism
- * @return False if we had an established signing connection
- *         which had a bad checksum, True otherwise.
- */
-
-bool cli_check_sign_mac(struct cli_state *cli, char *buf)
-{
-	if (!cli->sign_info.check_incoming_message(buf, &cli->sign_info, True)) {
-		free_signing_context(&cli->sign_info);	
-		return False;
-	}
-	return True;
-}
-
-/***********************************************************
- Enter trans/trans2/nttrans state.
-************************************************************/
-
-bool client_set_trans_sign_state_on(struct cli_state *cli, uint16 mid)
+bool client_is_signing_on(struct cli_state *cli)
 {
-	struct smb_sign_info *si = &cli->sign_info;
-	struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context;
-
-	if (!si->doing_signing) {
-		return True;
-	}
-
-	if (!data) {
-		return False;
-	}
-
-	if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, False)) {
-		return False;
-	}
-
-	return True;
+	return smb_signing_is_active(cli->signing_state);
 }
 
-/***********************************************************
- Leave trans/trans2/nttrans state.
-************************************************************/
-
-bool client_set_trans_sign_state_off(struct cli_state *cli, uint16 mid)
+bool client_is_signing_allowed(struct cli_state *cli)
 {
-	uint32 reply_seq_num;
-	struct smb_sign_info *si = &cli->sign_info;
-	struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context;
-
-	if (!si->doing_signing) {
-		return True;
-	}
-
-	if (!data) {
-		return False;
-	}
-
-	if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, True)) {
-		return False;
-	}
-
-	/* Now delete the stored mid entry. */
-	if (!get_sequence_for_reply(&data->outstanding_packet_list, mid, &reply_seq_num)) {
-		return False;
-	}
-
-	return True;
+	return smb_signing_is_allowed(cli->signing_state);
 }
 
-/***********************************************************
- Is client signing on ?
-************************************************************/
-
-bool client_is_signing_on(struct cli_state *cli)
+bool client_is_signing_mandatory(struct cli_state *cli)
 {
-	struct smb_sign_info *si = &cli->sign_info;
-	return si->doing_signing;
+	return smb_signing_is_mandatory(cli->signing_state);
 }