smb: move client and server files to common directory fs/smb

Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:

   fs/cifs --> fs/smb/client
   fs/ksmbd --> fs/smb/server
   fs/smbfs_common --> fs/smb/common

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 934 insertions, 0 deletions

diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c
new file mode 100644
index 000000000000..790acf65a092
--- /dev/null
+++ b/fs/smb/client/smb2transport.c
@@ -0,0 +1,934 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ *
+ *   Copyright (C) International Business Machines  Corp., 2002, 2011
+ *                 Etersoft, 2012
+ *   Author(s): Steve French (sfrench@us.ibm.com)
+ *              Jeremy Allison (jra@samba.org) 2006
+ *              Pavel Shilovsky (pshilovsky@samba.org) 2012
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/net.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <asm/processor.h>
+#include <linux/mempool.h>
+#include <linux/highmem.h>
+#include <crypto/aead.h>
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "smb2proto.h"
+#include "cifs_debug.h"
+#include "smb2status.h"
+#include "smb2glob.h"
+
+static int
+smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
+{
+	struct cifs_secmech *p = &server->secmech;
+	int rc;
+
+	rc = cifs_alloc_hash("hmac(sha256)", &p->hmacsha256);
+	if (rc)
+		goto err;
+
+	rc = cifs_alloc_hash("cmac(aes)", &p->aes_cmac);
+	if (rc)
+		goto err;
+
+	return 0;
+err:
+	cifs_free_hash(&p->hmacsha256);
+	return rc;
+}
+
+int
+smb311_crypto_shash_allocate(struct TCP_Server_Info *server)
+{
+	struct cifs_secmech *p = &server->secmech;
+	int rc = 0;
+
+	rc = cifs_alloc_hash("hmac(sha256)", &p->hmacsha256);
+	if (rc)
+		return rc;
+
+	rc = cifs_alloc_hash("cmac(aes)", &p->aes_cmac);
+	if (rc)
+		goto err;
+
+	rc = cifs_alloc_hash("sha512", &p->sha512);
+	if (rc)
+		goto err;
+
+	return 0;
+
+err:
+	cifs_free_hash(&p->aes_cmac);
+	cifs_free_hash(&p->hmacsha256);
+	return rc;
+}
+
+
+static
+int smb2_get_sign_key(__u64 ses_id, struct TCP_Server_Info *server, u8 *key)
+{
+	struct cifs_chan *chan;
+	struct TCP_Server_Info *pserver;
+	struct cifs_ses *ses = NULL;
+	int i;
+	int rc = 0;
+	bool is_binding = false;
+
+	spin_lock(&cifs_tcp_ses_lock);
+
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+		if (ses->Suid == ses_id)
+			goto found;
+	}
+	cifs_server_dbg(VFS, "%s: Could not find session 0x%llx\n",
+			__func__, ses_id);
+	rc = -ENOENT;
+	goto out;
+
+found:
+	spin_lock(&ses->ses_lock);
+	spin_lock(&ses->chan_lock);
+
+	is_binding = (cifs_chan_needs_reconnect(ses, server) &&
+		      ses->ses_status == SES_GOOD);
+	if (is_binding) {
+		/*
+		 * If we are in the process of binding a new channel
+		 * to an existing session, use the master connection
+		 * session key
+		 */
+		memcpy(key, ses->smb3signingkey, SMB3_SIGN_KEY_SIZE);
+		spin_unlock(&ses->chan_lock);
+		spin_unlock(&ses->ses_lock);
+		goto out;
+	}
+
+	/*
+	 * Otherwise, use the channel key.
+	 */
+
+	for (i = 0; i < ses->chan_count; i++) {
+		chan = ses->chans + i;
+		if (chan->server == server) {
+			memcpy(key, chan->signkey, SMB3_SIGN_KEY_SIZE);
+			spin_unlock(&ses->chan_lock);
+			spin_unlock(&ses->ses_lock);
+			goto out;
+		}
+	}
+	spin_unlock(&ses->chan_lock);
+	spin_unlock(&ses->ses_lock);
+
+	cifs_dbg(VFS,
+		 "%s: Could not find channel signing key for session 0x%llx\n",
+		 __func__, ses_id);
+	rc = -ENOENT;
+
+out:
+	spin_unlock(&cifs_tcp_ses_lock);
+	return rc;
+}
+
+static struct cifs_ses *
+smb2_find_smb_ses_unlocked(struct TCP_Server_Info *server, __u64 ses_id)
+{
+	struct TCP_Server_Info *pserver;
+	struct cifs_ses *ses;
+
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+		if (ses->Suid != ses_id)
+			continue;
+		++ses->ses_count;
+		return ses;
+	}
+
+	return NULL;
+}
+
+struct cifs_ses *
+smb2_find_smb_ses(struct TCP_Server_Info *server, __u64 ses_id)
+{
+	struct cifs_ses *ses;
+
+	spin_lock(&cifs_tcp_ses_lock);
+	ses = smb2_find_smb_ses_unlocked(server, ses_id);
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	return ses;
+}
+
+static struct cifs_tcon *
+smb2_find_smb_sess_tcon_unlocked(struct cifs_ses *ses, __u32  tid)
+{
+	struct cifs_tcon *tcon;
+
+	list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
+		if (tcon->tid != tid)
+			continue;
+		++tcon->tc_count;
+		return tcon;
+	}
+
+	return NULL;
+}
+
+/*
+ * Obtain tcon corresponding to the tid in the given
+ * cifs_ses
+ */
+
+struct cifs_tcon *
+smb2_find_smb_tcon(struct TCP_Server_Info *server, __u64 ses_id, __u32  tid)
+{
+	struct cifs_ses *ses;
+	struct cifs_tcon *tcon;
+
+	spin_lock(&cifs_tcp_ses_lock);
+	ses = smb2_find_smb_ses_unlocked(server, ses_id);
+	if (!ses) {
+		spin_unlock(&cifs_tcp_ses_lock);
+		return NULL;
+	}
+	tcon = smb2_find_smb_sess_tcon_unlocked(ses, tid);
+	if (!tcon) {
+		cifs_put_smb_ses(ses);
+		spin_unlock(&cifs_tcp_ses_lock);
+		return NULL;
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+	/* tcon already has a ref to ses, so we don't need ses anymore */
+	cifs_put_smb_ses(ses);
+
+	return tcon;
+}
+
+int
+smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server,
+			bool allocate_crypto)
+{
+	int rc;
+	unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
+	unsigned char *sigptr = smb2_signature;
+	struct kvec *iov = rqst->rq_iov;
+	struct smb2_hdr *shdr = (struct smb2_hdr *)iov[0].iov_base;
+	struct cifs_ses *ses;
+	struct shash_desc *shash = NULL;
+	struct smb_rqst drqst;
+
+	ses = smb2_find_smb_ses(server, le64_to_cpu(shdr->SessionId));
+	if (unlikely(!ses)) {
+		cifs_server_dbg(VFS, "%s: Could not find session\n", __func__);
+		return -ENOENT;
+	}
+
+	memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
+	memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);
+
+	if (allocate_crypto) {
+		rc = cifs_alloc_hash("hmac(sha256)", &shash);
+		if (rc) {
+			cifs_server_dbg(VFS,
+					"%s: sha256 alloc failed\n", __func__);
+			goto out;
+		}
+	} else {
+		shash = server->secmech.hmacsha256;
+	}
+
+	rc = crypto_shash_setkey(shash->tfm, ses->auth_key.response,
+			SMB2_NTLMV2_SESSKEY_SIZE);
+	if (rc) {
+		cifs_server_dbg(VFS,
+				"%s: Could not update with response\n",
+				__func__);
+		goto out;
+	}
+
+	rc = crypto_shash_init(shash);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not init sha256", __func__);
+		goto out;
+	}
+
+	/*
+	 * For SMB2+, __cifs_calc_signature() expects to sign only the actual
+	 * data, that is, iov[0] should not contain a rfc1002 length.
+	 *
+	 * Sign the rfc1002 length prior to passing the data (iov[1-N]) down to
+	 * __cifs_calc_signature().
+	 */
+	drqst = *rqst;
+	if (drqst.rq_nvec >= 2 && iov[0].iov_len == 4) {
+		rc = crypto_shash_update(shash, iov[0].iov_base,
+					 iov[0].iov_len);
+		if (rc) {
+			cifs_server_dbg(VFS,
+					"%s: Could not update with payload\n",
+					__func__);
+			goto out;
+		}
+		drqst.rq_iov++;
+		drqst.rq_nvec--;
+	}
+
+	rc = __cifs_calc_signature(&drqst, server, sigptr, shash);
+	if (!rc)
+		memcpy(shdr->Signature, sigptr, SMB2_SIGNATURE_SIZE);
+
+out:
+	if (allocate_crypto)
+		cifs_free_hash(&shash);
+	if (ses)
+		cifs_put_smb_ses(ses);
+	return rc;
+}
+
+static int generate_key(struct cifs_ses *ses, struct kvec label,
+			struct kvec context, __u8 *key, unsigned int key_size)
+{
+	unsigned char zero = 0x0;
+	__u8 i[4] = {0, 0, 0, 1};
+	__u8 L128[4] = {0, 0, 0, 128};
+	__u8 L256[4] = {0, 0, 1, 0};
+	int rc = 0;
+	unsigned char prfhash[SMB2_HMACSHA256_SIZE];
+	unsigned char *hashptr = prfhash;
+	struct TCP_Server_Info *server = ses->server;
+
+	memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
+	memset(key, 0x0, key_size);
+
+	rc = smb3_crypto_shash_allocate(server);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: crypto alloc failed\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	rc = crypto_shash_setkey(server->secmech.hmacsha256->tfm,
+		ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not set with session key\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	rc = crypto_shash_init(server->secmech.hmacsha256);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not init sign hmac\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	rc = crypto_shash_update(server->secmech.hmacsha256, i, 4);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not update with n\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	rc = crypto_shash_update(server->secmech.hmacsha256, label.iov_base, label.iov_len);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not update with label\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	rc = crypto_shash_update(server->secmech.hmacsha256, &zero, 1);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not update with zero\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	rc = crypto_shash_update(server->secmech.hmacsha256, context.iov_base, context.iov_len);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not update with context\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	if ((server->cipher_type == SMB2_ENCRYPTION_AES256_CCM) ||
+		(server->cipher_type == SMB2_ENCRYPTION_AES256_GCM)) {
+		rc = crypto_shash_update(server->secmech.hmacsha256, L256, 4);
+	} else {
+		rc = crypto_shash_update(server->secmech.hmacsha256, L128, 4);
+	}
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not update with L\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	rc = crypto_shash_final(server->secmech.hmacsha256, hashptr);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
+		goto smb3signkey_ret;
+	}
+
+	memcpy(key, hashptr, key_size);
+
+smb3signkey_ret:
+	return rc;
+}
+
+struct derivation {
+	struct kvec label;
+	struct kvec context;
+};
+
+struct derivation_triplet {
+	struct derivation signing;
+	struct derivation encryption;
+	struct derivation decryption;
+};
+
+static int
+generate_smb3signingkey(struct cifs_ses *ses,
+			struct TCP_Server_Info *server,
+			const struct derivation_triplet *ptriplet)
+{
+	int rc;
+	bool is_binding = false;
+	int chan_index = 0;
+
+	spin_lock(&ses->ses_lock);
+	spin_lock(&ses->chan_lock);
+	is_binding = (cifs_chan_needs_reconnect(ses, server) &&
+		      ses->ses_status == SES_GOOD);
+
+	chan_index = cifs_ses_get_chan_index(ses, server);
+	/* TODO: introduce ref counting for channels when the can be freed */
+	spin_unlock(&ses->chan_lock);
+	spin_unlock(&ses->ses_lock);
+
+	/*
+	 * All channels use the same encryption/decryption keys but
+	 * they have their own signing key.
+	 *
+	 * When we generate the keys, check if it is for a new channel
+	 * (binding) in which case we only need to generate a signing
+	 * key and store it in the channel as to not overwrite the
+	 * master connection signing key stored in the session
+	 */
+
+	if (is_binding) {
+		rc = generate_key(ses, ptriplet->signing.label,
+				  ptriplet->signing.context,
+				  ses->chans[chan_index].signkey,
+				  SMB3_SIGN_KEY_SIZE);
+		if (rc)
+			return rc;
+	} else {
+		rc = generate_key(ses, ptriplet->signing.label,
+				  ptriplet->signing.context,
+				  ses->smb3signingkey,
+				  SMB3_SIGN_KEY_SIZE);
+		if (rc)
+			return rc;
+
+		/* safe to access primary channel, since it will never go away */
+		spin_lock(&ses->chan_lock);
+		memcpy(ses->chans[chan_index].signkey, ses->smb3signingkey,
+		       SMB3_SIGN_KEY_SIZE);
+		spin_unlock(&ses->chan_lock);
+
+		rc = generate_key(ses, ptriplet->encryption.label,
+				  ptriplet->encryption.context,
+				  ses->smb3encryptionkey,
+				  SMB3_ENC_DEC_KEY_SIZE);
+		rc = generate_key(ses, ptriplet->decryption.label,
+				  ptriplet->decryption.context,
+				  ses->smb3decryptionkey,
+				  SMB3_ENC_DEC_KEY_SIZE);
+		if (rc)
+			return rc;
+	}
+
+	if (rc)
+		return rc;
+
+#ifdef CONFIG_CIFS_DEBUG_DUMP_KEYS
+	cifs_dbg(VFS, "%s: dumping generated AES session keys\n", __func__);
+	/*
+	 * The session id is opaque in terms of endianness, so we can't
+	 * print it as a long long. we dump it as we got it on the wire
+	 */
+	cifs_dbg(VFS, "Session Id    %*ph\n", (int)sizeof(ses->Suid),
+			&ses->Suid);
+	cifs_dbg(VFS, "Cipher type   %d\n", server->cipher_type);
+	cifs_dbg(VFS, "Session Key   %*ph\n",
+		 SMB2_NTLMV2_SESSKEY_SIZE, ses->auth_key.response);
+	cifs_dbg(VFS, "Signing Key   %*ph\n",
+		 SMB3_SIGN_KEY_SIZE, ses->smb3signingkey);
+	if ((server->cipher_type == SMB2_ENCRYPTION_AES256_CCM) ||
+		(server->cipher_type == SMB2_ENCRYPTION_AES256_GCM)) {
+		cifs_dbg(VFS, "ServerIn Key  %*ph\n",
+				SMB3_GCM256_CRYPTKEY_SIZE, ses->smb3encryptionkey);
+		cifs_dbg(VFS, "ServerOut Key %*ph\n",
+				SMB3_GCM256_CRYPTKEY_SIZE, ses->smb3decryptionkey);
+	} else {
+		cifs_dbg(VFS, "ServerIn Key  %*ph\n",
+				SMB3_GCM128_CRYPTKEY_SIZE, ses->smb3encryptionkey);
+		cifs_dbg(VFS, "ServerOut Key %*ph\n",
+				SMB3_GCM128_CRYPTKEY_SIZE, ses->smb3decryptionkey);
+	}
+#endif
+	return rc;
+}
+
+int
+generate_smb30signingkey(struct cifs_ses *ses,
+			 struct TCP_Server_Info *server)
+
+{
+	struct derivation_triplet triplet;
+	struct derivation *d;
+
+	d = &triplet.signing;
+	d->label.iov_base = "SMB2AESCMAC";
+	d->label.iov_len = 12;
+	d->context.iov_base = "SmbSign";
+	d->context.iov_len = 8;
+
+	d = &triplet.encryption;
+	d->label.iov_base = "SMB2AESCCM";
+	d->label.iov_len = 11;
+	d->context.iov_base = "ServerIn ";
+	d->context.iov_len = 10;
+
+	d = &triplet.decryption;
+	d->label.iov_base = "SMB2AESCCM";
+	d->label.iov_len = 11;
+	d->context.iov_base = "ServerOut";
+	d->context.iov_len = 10;
+
+	return generate_smb3signingkey(ses, server, &triplet);
+}
+
+int
+generate_smb311signingkey(struct cifs_ses *ses,
+			  struct TCP_Server_Info *server)
+
+{
+	struct derivation_triplet triplet;
+	struct derivation *d;
+
+	d = &triplet.signing;
+	d->label.iov_base = "SMBSigningKey";
+	d->label.iov_len = 14;
+	d->context.iov_base = ses->preauth_sha_hash;
+	d->context.iov_len = 64;
+
+	d = &triplet.encryption;
+	d->label.iov_base = "SMBC2SCipherKey";
+	d->label.iov_len = 16;
+	d->context.iov_base = ses->preauth_sha_hash;
+	d->context.iov_len = 64;
+
+	d = &triplet.decryption;
+	d->label.iov_base = "SMBS2CCipherKey";
+	d->label.iov_len = 16;
+	d->context.iov_base = ses->preauth_sha_hash;
+	d->context.iov_len = 64;
+
+	return generate_smb3signingkey(ses, server, &triplet);
+}
+
+int
+smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server,
+			bool allocate_crypto)
+{
+	int rc;
+	unsigned char smb3_signature[SMB2_CMACAES_SIZE];
+	unsigned char *sigptr = smb3_signature;
+	struct kvec *iov = rqst->rq_iov;
+	struct smb2_hdr *shdr = (struct smb2_hdr *)iov[0].iov_base;
+	struct shash_desc *shash = NULL;
+	struct smb_rqst drqst;
+	u8 key[SMB3_SIGN_KEY_SIZE];
+
+	rc = smb2_get_sign_key(le64_to_cpu(shdr->SessionId), server, key);
+	if (unlikely(rc)) {
+		cifs_server_dbg(VFS, "%s: Could not get signing key\n", __func__);
+		return rc;
+	}
+
+	if (allocate_crypto) {
+		rc = cifs_alloc_hash("cmac(aes)", &shash);
+		if (rc)
+			return rc;
+	} else {
+		shash = server->secmech.aes_cmac;
+	}
+
+	memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
+	memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);
+
+	rc = crypto_shash_setkey(shash->tfm, key, SMB2_CMACAES_SIZE);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__);
+		goto out;
+	}
+
+	/*
+	 * we already allocate aes_cmac when we init smb3 signing key,
+	 * so unlike smb2 case we do not have to check here if secmech are
+	 * initialized
+	 */
+	rc = crypto_shash_init(shash);
+	if (rc) {
+		cifs_server_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
+		goto out;
+	}
+
+	/*
+	 * For SMB2+, __cifs_calc_signature() expects to sign only the actual
+	 * data, that is, iov[0] should not contain a rfc1002 length.
+	 *
+	 * Sign the rfc1002 length prior to passing the data (iov[1-N]) down to
+	 * __cifs_calc_signature().
+	 */
+	drqst = *rqst;
+	if (drqst.rq_nvec >= 2 && iov[0].iov_len == 4) {
+		rc = crypto_shash_update(shash, iov[0].iov_base,
+					 iov[0].iov_len);
+		if (rc) {
+			cifs_server_dbg(VFS, "%s: Could not update with payload\n",
+				 __func__);
+			goto out;
+		}
+		drqst.rq_iov++;
+		drqst.rq_nvec--;
+	}
+
+	rc = __cifs_calc_signature(&drqst, server, sigptr, shash);
+	if (!rc)
+		memcpy(shdr->Signature, sigptr, SMB2_SIGNATURE_SIZE);
+
+out:
+	if (allocate_crypto)
+		cifs_free_hash(&shash);
+	return rc;
+}
+
+/* must be called with server->srv_mutex held */
+static int
+smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
+{
+	int rc = 0;
+	struct smb2_hdr *shdr;
+	struct smb2_sess_setup_req *ssr;
+	bool is_binding;
+	bool is_signed;
+
+	shdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+	ssr = (struct smb2_sess_setup_req *)shdr;
+
+	is_binding = shdr->Command == SMB2_SESSION_SETUP &&
+		(ssr->Flags & SMB2_SESSION_REQ_FLAG_BINDING);
+	is_signed = shdr->Flags & SMB2_FLAGS_SIGNED;
+
+	if (!is_signed)
+		return 0;
+	spin_lock(&server->srv_lock);
+	if (server->ops->need_neg &&
+	    server->ops->need_neg(server)) {
+		spin_unlock(&server->srv_lock);
+		return 0;
+	}
+	spin_unlock(&server->srv_lock);
+	if (!is_binding && !server->session_estab) {
+		strncpy(shdr->Signature, "BSRSPYL", 8);
+		return 0;
+	}
+
+	rc = server->ops->calc_signature(rqst, server, false);
+
+	return rc;
+}
+
+int
+smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
+{
+	unsigned int rc;
+	char server_response_sig[SMB2_SIGNATURE_SIZE];
+	struct smb2_hdr *shdr =
+			(struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+
+	if ((shdr->Command == SMB2_NEGOTIATE) ||
+	    (shdr->Command == SMB2_SESSION_SETUP) ||
+	    (shdr->Command == SMB2_OPLOCK_BREAK) ||
+	    server->ignore_signature ||
+	    (!server->session_estab))
+		return 0;
+
+	/*
+	 * BB what if signatures are supposed to be on for session but
+	 * server does not send one? BB
+	 */
+
+	/* Do not need to verify session setups with signature "BSRSPYL " */
+	if (memcmp(shdr->Signature, "BSRSPYL ", 8) == 0)
+		cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
+			 shdr->Command);
+
+	/*
+	 * Save off the origiginal signature so we can modify the smb and check
+	 * our calculated signature against what the server sent.
+	 */
+	memcpy(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE);
+
+	memset(shdr->Signature, 0, SMB2_SIGNATURE_SIZE);
+
+	rc = server->ops->calc_signature(rqst, server, true);
+
+	if (rc)
+		return rc;
+
+	if (memcmp(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE)) {
+		cifs_dbg(VFS, "sign fail cmd 0x%x message id 0x%llx\n",
+			shdr->Command, shdr->MessageId);
+		return -EACCES;
+	} else
+		return 0;
+}
+
+/*
+ * Set message id for the request. Should be called after wait_for_free_request
+ * and when srv_mutex is held.
+ */
+static inline void
+smb2_seq_num_into_buf(struct TCP_Server_Info *server,
+		      struct smb2_hdr *shdr)
+{
+	unsigned int i, num = le16_to_cpu(shdr->CreditCharge);
+
+	shdr->MessageId = get_next_mid64(server);
+	/* skip message numbers according to CreditCharge field */
+	for (i = 1; i < num; i++)
+		get_next_mid(server);
+}
+
+static struct mid_q_entry *
+smb2_mid_entry_alloc(const struct smb2_hdr *shdr,
+		     struct TCP_Server_Info *server)
+{
+	struct mid_q_entry *temp;
+	unsigned int credits = le16_to_cpu(shdr->CreditCharge);
+
+	if (server == NULL) {
+		cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
+		return NULL;
+	}
+
+	temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
+	memset(temp, 0, sizeof(struct mid_q_entry));
+	kref_init(&temp->refcount);
+	temp->mid = le64_to_cpu(shdr->MessageId);
+	temp->credits = credits > 0 ? credits : 1;
+	temp->pid = current->pid;
+	temp->command = shdr->Command; /* Always LE */
+	temp->when_alloc = jiffies;
+	temp->server = server;
+
+	/*
+	 * The default is for the mid to be synchronous, so the
+	 * default callback just wakes up the current task.
+	 */
+	get_task_struct(current);
+	temp->creator = current;
+	temp->callback = cifs_wake_up_task;
+	temp->callback_data = current;
+
+	atomic_inc(&mid_count);
+	temp->mid_state = MID_REQUEST_ALLOCATED;
+	trace_smb3_cmd_enter(le32_to_cpu(shdr->Id.SyncId.TreeId),
+			     le64_to_cpu(shdr->SessionId),
+			     le16_to_cpu(shdr->Command), temp->mid);
+	return temp;
+}
+
+static int
+smb2_get_mid_entry(struct cifs_ses *ses, struct TCP_Server_Info *server,
+		   struct smb2_hdr *shdr, struct mid_q_entry **mid)
+{
+	spin_lock(&server->srv_lock);
+	if (server->tcpStatus == CifsExiting) {
+		spin_unlock(&server->srv_lock);
+		return -ENOENT;
+	}
+
+	if (server->tcpStatus == CifsNeedReconnect) {
+		spin_unlock(&server->srv_lock);
+		cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
+		return -EAGAIN;
+	}
+
+	if (server->tcpStatus == CifsNeedNegotiate &&
+	   shdr->Command != SMB2_NEGOTIATE) {
+		spin_unlock(&server->srv_lock);
+		return -EAGAIN;
+	}
+	spin_unlock(&server->srv_lock);
+
+	spin_lock(&ses->ses_lock);
+	if (ses->ses_status == SES_NEW) {
+		if ((shdr->Command != SMB2_SESSION_SETUP) &&
+		    (shdr->Command != SMB2_NEGOTIATE)) {
+			spin_unlock(&ses->ses_lock);
+			return -EAGAIN;
+		}
+		/* else ok - we are setting up session */
+	}
+
+	if (ses->ses_status == SES_EXITING) {
+		if (shdr->Command != SMB2_LOGOFF) {
+			spin_unlock(&ses->ses_lock);
+			return -EAGAIN;
+		}
+		/* else ok - we are shutting down the session */
+	}
+	spin_unlock(&ses->ses_lock);
+
+	*mid = smb2_mid_entry_alloc(shdr, server);
+	if (*mid == NULL)
+		return -ENOMEM;
+	spin_lock(&server->mid_lock);
+	list_add_tail(&(*mid)->qhead, &server->pending_mid_q);
+	spin_unlock(&server->mid_lock);
+
+	return 0;
+}
+
+int
+smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
+		   bool log_error)
+{
+	unsigned int len = mid->resp_buf_size;
+	struct kvec iov[1];
+	struct smb_rqst rqst = { .rq_iov = iov,
+				 .rq_nvec = 1 };
+
+	iov[0].iov_base = (char *)mid->resp_buf;
+	iov[0].iov_len = len;
+
+	dump_smb(mid->resp_buf, min_t(u32, 80, len));
+	/* convert the length into a more usable form */
+	if (len > 24 && server->sign && !mid->decrypted) {
+		int rc;
+
+		rc = smb2_verify_signature(&rqst, server);
+		if (rc)
+			cifs_server_dbg(VFS, "SMB signature verification returned error = %d\n",
+				 rc);
+	}
+
+	return map_smb2_to_linux_error(mid->resp_buf, log_error);
+}
+
+struct mid_q_entry *
+smb2_setup_request(struct cifs_ses *ses, struct TCP_Server_Info *server,
+		   struct smb_rqst *rqst)
+{
+	int rc;
+	struct smb2_hdr *shdr =
+			(struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+	struct mid_q_entry *mid;
+
+	smb2_seq_num_into_buf(server, shdr);
+
+	rc = smb2_get_mid_entry(ses, server, shdr, &mid);
+	if (rc) {
+		revert_current_mid_from_hdr(server, shdr);
+		return ERR_PTR(rc);
+	}
+
+	rc = smb2_sign_rqst(rqst, server);
+	if (rc) {
+		revert_current_mid_from_hdr(server, shdr);
+		delete_mid(mid);
+		return ERR_PTR(rc);
+	}
+
+	return mid;
+}
+
+struct mid_q_entry *
+smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
+{
+	int rc;
+	struct smb2_hdr *shdr =
+			(struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+	struct mid_q_entry *mid;
+
+	spin_lock(&server->srv_lock);
+	if (server->tcpStatus == CifsNeedNegotiate &&
+	   shdr->Command != SMB2_NEGOTIATE) {
+		spin_unlock(&server->srv_lock);
+		return ERR_PTR(-EAGAIN);
+	}
+	spin_unlock(&server->srv_lock);
+
+	smb2_seq_num_into_buf(server, shdr);
+
+	mid = smb2_mid_entry_alloc(shdr, server);
+	if (mid == NULL) {
+		revert_current_mid_from_hdr(server, shdr);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	rc = smb2_sign_rqst(rqst, server);
+	if (rc) {
+		revert_current_mid_from_hdr(server, shdr);
+		release_mid(mid);
+		return ERR_PTR(rc);
+	}
+
+	return mid;
+}
+
+int
+smb3_crypto_aead_allocate(struct TCP_Server_Info *server)
+{
+	struct crypto_aead *tfm;
+
+	if (!server->secmech.enc) {
+		if ((server->cipher_type == SMB2_ENCRYPTION_AES128_GCM) ||
+		    (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM))
+			tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
+		else
+			tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
+		if (IS_ERR(tfm)) {
+			cifs_server_dbg(VFS, "%s: Failed alloc encrypt aead\n",
+				 __func__);
+			return PTR_ERR(tfm);
+		}
+		server->secmech.enc = tfm;
+	}
+
+	if (!server->secmech.dec) {
+		if ((server->cipher_type == SMB2_ENCRYPTION_AES128_GCM) ||
+		    (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM))
+			tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
+		else
+			tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
+		if (IS_ERR(tfm)) {
+			crypto_free_aead(server->secmech.enc);
+			server->secmech.enc = NULL;
+			cifs_server_dbg(VFS, "%s: Failed to alloc decrypt aead\n",
+				 __func__);
+			return PTR_ERR(tfm);
+		}
+		server->secmech.dec = tfm;
+	}
+
+	return 0;
+}