libcli/smb: move smb_seal.c to the toplevel

metze

Autobuild-User: Stefan Metzmacher <metze@samba.org>
Autobuild-Date: Fri Oct 21 10:22:39 CEST 2011 on sn-devel-104

4 files changed, 503 insertions, 2 deletions

diff --git a/libcli/smb/smb_common.h b/libcli/smb/smb_common.h
index 1f21e553ba..228e451b8d 100644
--- a/libcli/smb/smb_common.h
+++ b/libcli/smb/smb_common.h
@@ -28,5 +28,6 @@
 #include "libcli/smb/smb_constants.h"
 #include "libcli/smb/smb_util.h"
 #include "libcli/smb/smb_unix_ext.h"
+#include "libcli/smb/smb_seal.h"
 
 #endif
diff --git a/libcli/smb/smb_seal.c b/libcli/smb/smb_seal.c
new file mode 100644
index 0000000000..bf9576f288
--- /dev/null
+++ b/libcli/smb/smb_seal.c
@@ -0,0 +1,428 @@
+/*
+   Unix SMB/CIFS implementation.
+   SMB Transport encryption (sealing) code.
+   Copyright (C) Jeremy Allison 2007.
+
+   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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "smb_common.h"
+#include "libcli/auth/krb5_wrap.h"
+#include "auth/gensec/gensec.h"
+
+#undef malloc
+
+/******************************************************************************
+ Pull out the encryption context for this packet. 0 means global context.
+******************************************************************************/
+
+NTSTATUS get_enc_ctx_num(const uint8_t *buf, uint16_t *p_enc_ctx_num)
+{
+	if (smb_len_nbt(buf) < 8) {
+		return NT_STATUS_INVALID_BUFFER_SIZE;
+	}
+
+	if (buf[4] == 0xFF) {
+		if (buf[5] == 'S' && buf [6] == 'M' && buf[7] == 'B') {
+			/* Not an encrypted buffer. */
+			return NT_STATUS_NOT_FOUND;
+		}
+		if (buf[5] == 'E') {
+			*p_enc_ctx_num = SVAL(buf,6);
+			return NT_STATUS_OK;
+		}
+	}
+	return NT_STATUS_INVALID_NETWORK_RESPONSE;
+}
+
+/*******************************************************************
+ Set the length and marker of an encrypted smb packet.
+********************************************************************/
+
+static void smb_set_enclen(char *buf,int len,uint16_t enc_ctx_num)
+{
+	_smb_setlen_nbt(buf,len);
+
+	SCVAL(buf,4,0xFF);
+	SCVAL(buf,5,'E');
+	SSVAL(buf,6,enc_ctx_num);
+}
+
+/******************************************************************************
+ Generic code for client and server.
+ Is encryption turned on ?
+******************************************************************************/
+
+bool common_encryption_on(struct smb_trans_enc_state *es)
+{
+	return ((es != NULL) && es->enc_on);
+}
+
+/******************************************************************************
+ Generic code for client and server.
+ GENSEC decrypt an incoming buffer.
+******************************************************************************/
+
+static NTSTATUS common_gensec_decrypt_buffer(struct gensec_security *gensec,
+					     char *buf)
+{
+	NTSTATUS status;
+	size_t buf_len = smb_len_nbt(buf) + 4; /* Don't forget the 4 length bytes. */
+	DATA_BLOB in_buf, out_buf;
+	TALLOC_CTX *frame;
+
+	if (buf_len < 8) {
+		return NT_STATUS_BUFFER_TOO_SMALL;
+	}
+
+	frame = talloc_stackframe();
+
+	in_buf = data_blob_const(buf + 8, buf_len - 8);
+
+	status = gensec_unwrap(gensec, frame, &in_buf, &out_buf);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0,("common_gensec_decrypt_buffer: gensec_unwrap failed. Error %s\n",
+			 nt_errstr(status)));
+		TALLOC_FREE(frame);
+		return status;
+	}
+
+	if (out_buf.length > in_buf.length) {
+		DEBUG(0,("common_gensec_decrypt_buffer: gensec_unwrap size (%u) too large (%u) !\n",
+			(unsigned int)out_buf.length,
+			(unsigned int)in_buf.length ));
+		TALLOC_FREE(frame);
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	memcpy(buf + 8, out_buf.data, out_buf.length);
+
+	/* Reset the length and overwrite the header. */
+	smb_setlen_nbt(buf, out_buf.length + 4);
+
+	TALLOC_FREE(frame);
+
+	return NT_STATUS_OK;
+}
+
+/******************************************************************************
+ Generic code for client and server.
+ NTLM encrypt an outgoing buffer. Return the encrypted pointer in ppbuf_out.
+******************************************************************************/
+
+static NTSTATUS common_gensec_encrypt_buffer(struct gensec_security *gensec,
+				      uint16_t enc_ctx_num,
+				      char *buf,
+				      char **ppbuf_out)
+{
+	NTSTATUS status;
+	DATA_BLOB in_buf, out_buf;
+	size_t buf_len = smb_len_nbt(buf) + 4; /* Don't forget the 4 length bytes. */
+	TALLOC_CTX *frame;
+
+	*ppbuf_out = NULL;
+
+	if (buf_len < 8) {
+		return NT_STATUS_BUFFER_TOO_SMALL;
+	}
+	in_buf = data_blob_const(buf + 8, buf_len - 8);
+
+	frame = talloc_stackframe();
+
+	status = gensec_wrap(gensec, frame, &in_buf, &out_buf);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0,("common_gensec_encrypt_buffer: gensec_wrap failed. Error %s\n",
+			 nt_errstr(status)));
+		TALLOC_FREE(frame);
+		return status;
+	}
+
+	*ppbuf_out = (char *)malloc(out_buf.length + 8); /* We know this can't wrap. */
+	if (!*ppbuf_out) {
+		TALLOC_FREE(frame);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	memcpy(*ppbuf_out+8, out_buf.data, out_buf.length);
+	smb_set_enclen(*ppbuf_out, out_buf.length + 4, enc_ctx_num);
+
+	TALLOC_FREE(frame);
+
+	return NT_STATUS_OK;
+}
+
+/******************************************************************************
+ Generic code for client and server.
+ gss-api decrypt an incoming buffer. We insist that the size of the
+ unwrapped buffer must be smaller or identical to the incoming buffer.
+******************************************************************************/
+
+#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
+static NTSTATUS common_gss_decrypt_buffer(struct smb_tran_enc_state_gss *gss_state, char *buf)
+{
+	gss_ctx_id_t gss_ctx = gss_state->gss_ctx;
+	OM_uint32 ret = 0;
+	OM_uint32 minor = 0;
+	int flags_got = 0;
+	gss_buffer_desc in_buf, out_buf;
+	size_t buf_len = smb_len_nbt(buf) + 4; /* Don't forget the 4 length bytes. */
+
+	if (buf_len < 8) {
+		return NT_STATUS_BUFFER_TOO_SMALL;
+	}
+
+	in_buf.value = buf + 8;
+	in_buf.length = buf_len - 8;
+
+	ret = gss_unwrap(&minor,
+			gss_ctx,
+			&in_buf,
+			&out_buf,
+			&flags_got,		/* did we get sign+seal ? */
+			(gss_qop_t *) NULL);
+
+	if (ret != GSS_S_COMPLETE) {
+		NTSTATUS status = NT_STATUS_ACCESS_DENIED;
+		char *gss_err;
+
+		gss_err = gssapi_error_string(talloc_tos(),
+					      ret, minor,
+					      GSS_C_NULL_OID);
+		DEBUG(0,("common_gss_decrypt_buffer: gss_unwrap failed. "
+			 "Error [%d/%d] - %s - %s\n",
+			 ret, minor, nt_errstr(status),
+			 gss_err ? gss_err : "<unknown>"));
+		talloc_free(gss_err);
+
+		return status;
+	}
+
+	if (out_buf.length > in_buf.length) {
+		DEBUG(0,("common_gss_decrypt_buffer: gss_unwrap size (%u) too large (%u) !\n",
+			(unsigned int)out_buf.length,
+			(unsigned int)in_buf.length ));
+		gss_release_buffer(&minor, &out_buf);
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	memcpy(buf + 8, out_buf.value, out_buf.length);
+	/* Reset the length and overwrite the header. */
+	smb_setlen_nbt(buf, out_buf.length + 4);
+
+	gss_release_buffer(&minor, &out_buf);
+	return NT_STATUS_OK;
+}
+
+/******************************************************************************
+ Generic code for client and server.
+ gss-api encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
+******************************************************************************/
+
+static NTSTATUS common_gss_encrypt_buffer(struct smb_tran_enc_state_gss *gss_state,
+					uint16_t enc_ctx_num,
+					char *buf,
+					char **ppbuf_out)
+{
+	gss_ctx_id_t gss_ctx = gss_state->gss_ctx;
+	OM_uint32 ret = 0;
+	OM_uint32 minor = 0;
+	int flags_got = 0;
+	gss_buffer_desc in_buf, out_buf;
+	size_t buf_len = smb_len_nbt(buf) + 4; /* Don't forget the 4 length bytes. */
+
+	*ppbuf_out = NULL;
+
+	if (buf_len < 8) {
+		return NT_STATUS_BUFFER_TOO_SMALL;
+	}
+
+	in_buf.value = buf + 8;
+	in_buf.length = buf_len - 8;
+
+	ret = gss_wrap(&minor,
+			gss_ctx,
+			true,			/* we want sign+seal. */
+			GSS_C_QOP_DEFAULT,
+			&in_buf,
+			&flags_got,		/* did we get sign+seal ? */
+			&out_buf);
+
+	if (ret != GSS_S_COMPLETE) {
+		NTSTATUS status = NT_STATUS_ACCESS_DENIED;
+		char *gss_err;
+
+		gss_err = gssapi_error_string(talloc_tos(),
+					      ret, minor,
+					      GSS_C_NULL_OID);
+		DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap failed. "
+			 "Error [%d/%d] - %s - %s\n",
+			 ret, minor, nt_errstr(status),
+			 gss_err ? gss_err : "<unknown>"));
+		talloc_free(gss_err);
+
+		return status;
+	}
+
+	if (!flags_got) {
+		/* Sign+seal not supported. */
+		gss_release_buffer(&minor, &out_buf);
+		return NT_STATUS_NOT_SUPPORTED;
+	}
+
+	/* Ya see - this is why I *hate* gss-api. I don't
+	 * want to have to malloc another buffer of the
+	 * same size + 8 bytes just to get a continuous
+	 * header + buffer, but gss won't let me pass in
+	 * a pre-allocated buffer. Bastards (and you know
+	 * who you are....). I might fix this by
+	 * going to "encrypt_and_send" passing in a file
+	 * descriptor and doing scatter-gather write with
+	 * TCP cork on Linux. But I shouldn't have to
+	 * bother :-*(. JRA.
+	 */
+
+	*ppbuf_out = (char *)malloc(out_buf.length + 8); /* We know this can't wrap. */
+	if (!*ppbuf_out) {
+		gss_release_buffer(&minor, &out_buf);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	memcpy(*ppbuf_out+8, out_buf.value, out_buf.length);
+	smb_set_enclen(*ppbuf_out, out_buf.length + 4, enc_ctx_num);
+
+	gss_release_buffer(&minor, &out_buf);
+	return NT_STATUS_OK;
+}
+#endif
+
+/******************************************************************************
+ Generic code for client and server.
+ Encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
+******************************************************************************/
+
+NTSTATUS common_encrypt_buffer(struct smb_trans_enc_state *es, char *buffer, char **buf_out)
+{
+	if (!common_encryption_on(es)) {
+		/* Not encrypting. */
+		*buf_out = buffer;
+		return NT_STATUS_OK;
+	}
+
+	switch (es->smb_enc_type) {
+		case SMB_TRANS_ENC_NTLM:
+			return common_gensec_encrypt_buffer(es->s.gensec_security, es->enc_ctx_num, buffer, buf_out);
+#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
+		case SMB_TRANS_ENC_GSS:
+			return common_gss_encrypt_buffer(es->s.gss_state, es->enc_ctx_num, buffer, buf_out);
+#endif
+		default:
+			return NT_STATUS_NOT_SUPPORTED;
+	}
+}
+
+/******************************************************************************
+ Generic code for client and server.
+ Decrypt an incoming SMB buffer. Replaces the data within it.
+ New data must be less than or equal to the current length.
+******************************************************************************/
+
+NTSTATUS common_decrypt_buffer(struct smb_trans_enc_state *es, char *buf)
+{
+	if (!common_encryption_on(es)) {
+		/* Not decrypting. */
+		return NT_STATUS_OK;
+	}
+
+	switch (es->smb_enc_type) {
+		case SMB_TRANS_ENC_NTLM:
+			return common_gensec_decrypt_buffer(es->s.gensec_security, buf);
+#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
+		case SMB_TRANS_ENC_GSS:
+			return common_gss_decrypt_buffer(es->s.gss_state, buf);
+#endif
+		default:
+			return NT_STATUS_NOT_SUPPORTED;
+	}
+}
+
+#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
+/******************************************************************************
+ Shutdown a gss encryption state.
+******************************************************************************/
+
+static void common_free_gss_state(struct smb_tran_enc_state_gss **pp_gss_state)
+{
+	OM_uint32 minor = 0;
+	struct smb_tran_enc_state_gss *gss_state = *pp_gss_state;
+
+	if (gss_state->creds != GSS_C_NO_CREDENTIAL) {
+		gss_release_cred(&minor, &gss_state->creds);
+	}
+	if (gss_state->gss_ctx != GSS_C_NO_CONTEXT) {
+		gss_delete_sec_context(&minor, &gss_state->gss_ctx, NULL);
+	}
+	SAFE_FREE(*pp_gss_state);
+}
+#endif
+
+/******************************************************************************
+ Shutdown an encryption state.
+******************************************************************************/
+
+void common_free_encryption_state(struct smb_trans_enc_state **pp_es)
+{
+	struct smb_trans_enc_state *es = *pp_es;
+
+	if (es == NULL) {
+		return;
+	}
+
+	if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
+		if (es->s.gensec_security) {
+			TALLOC_FREE(es->s.gensec_security);
+		}
+	}
+#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
+	if (es->smb_enc_type == SMB_TRANS_ENC_GSS) {
+		/* Free the gss context handle. */
+		if (es->s.gss_state) {
+			common_free_gss_state(&es->s.gss_state);
+		}
+	}
+#endif
+	SAFE_FREE(es);
+	*pp_es = NULL;
+}
+
+/******************************************************************************
+ Free an encryption-allocated buffer.
+******************************************************************************/
+
+void common_free_enc_buffer(struct smb_trans_enc_state *es, char *buf)
+{
+	uint16_t enc_ctx_num;
+
+	if (!common_encryption_on(es)) {
+		return;
+	}
+
+	if (!NT_STATUS_IS_OK(get_enc_ctx_num((const uint8_t *)buf,
+			&enc_ctx_num))) {
+		return;
+	}
+
+	SAFE_FREE(buf);
+}
diff --git a/libcli/smb/smb_seal.h b/libcli/smb/smb_seal.h
new file mode 100644
index 0000000000..fcee2057d8
--- /dev/null
+++ b/libcli/smb/smb_seal.h
@@ -0,0 +1,71 @@
+/*
+   Unix SMB/CIFS implementation.
+   SMB Transport encryption code.
+   Copyright (C) Jeremy Allison 2007.
+
+   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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _HEADER_SMB_CRYPT_H
+#define _HEADER_SMB_CRYPT_H
+
+#if HAVE_GSSAPI_GSSAPI_H
+#include <gssapi/gssapi.h>
+#elif HAVE_GSSAPI_GSSAPI_GENERIC_H
+#include <gssapi/gssapi_generic.h>
+#elif HAVE_GSSAPI_H
+#include <gssapi.h>
+#endif
+
+#if HAVE_COM_ERR_H
+#include <com_err.h>
+#endif
+
+/* Transport encryption state. */
+enum smb_trans_enc_type {
+		SMB_TRANS_ENC_NTLM
+#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
+		, SMB_TRANS_ENC_GSS
+#endif
+};
+
+#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
+struct smb_tran_enc_state_gss {
+        gss_ctx_id_t gss_ctx;
+        gss_cred_id_t creds;
+};
+#endif
+
+struct smb_trans_enc_state {
+        enum smb_trans_enc_type smb_enc_type;
+        uint16_t enc_ctx_num;
+        bool enc_on;
+        union {
+                struct gensec_security *gensec_security;
+#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
+                struct smb_tran_enc_state_gss *gss_state;
+#endif
+        } s;
+};
+
+/* The following definitions come from smb_seal.c  */
+
+NTSTATUS get_enc_ctx_num(const uint8_t *buf, uint16_t *p_enc_ctx_num);
+bool common_encryption_on(struct smb_trans_enc_state *es);
+NTSTATUS common_encrypt_buffer(struct smb_trans_enc_state *es, char *buffer, char **buf_out);
+NTSTATUS common_decrypt_buffer(struct smb_trans_enc_state *es, char *buf);
+void common_free_encryption_state(struct smb_trans_enc_state **pp_es);
+void common_free_enc_buffer(struct smb_trans_enc_state *es, char *buf);
+
+#endif /* _HEADER_SMB_CRYPT_H */
diff --git a/libcli/smb/wscript_build b/libcli/smb/wscript_build
index 8043c8049b..63349586f4 100644
--- a/libcli/smb/wscript_build
+++ b/libcli/smb/wscript_build
@@ -2,12 +2,13 @@
 
 
 bld.SAMBA_LIBRARY('cli_smb_common',
-	source='smb2_create_blob.c smb2_signing.c util.c',
+	source='smb_seal.c smb2_create_blob.c smb2_signing.c util.c',
 	autoproto='smb_common_proto.h',
-	deps='LIBCRYPTO',
+	deps='LIBCRYPTO errors gssapi gensec KRB5_WRAP',
 	public_deps='talloc samba-util',
 	private_library=True,
 	public_headers='''smb_common.h smb2_constants.h smb_constants.h
+			smb_seal.h
 			smb2_create_blob.h smb2_signing.h smb_util.h smb_unix_ext.h
 	''',
 	)