smb3: simplify code by removing CONFIG_CIFS_SMB311

We really, really want to be encouraging use of secure dialects,
and SMB3.1.1 offers useful security features, and will soon
be the recommended dialect for many use cases. Simplify the code
by removing the CONFIG_CIFS_SMB311 ifdef so users don't disable
it in the build, and create compatibility and/or security issues
with modern servers - many of which have been supporting this
dialect for multiple years.

Also clarify some of the Kconfig text for cifs.ko about
SMB3.1.1 and current supported features in the module.

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

fs/cifs/smb2pdu.c

@@ -370,7 +370,7 @@ smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
 	return rc;
 }
 
-#ifdef CONFIG_CIFS_SMB311
+
 /* offset is sizeof smb2_negotiate_req but rounded up to 8 bytes */
 #define OFFSET_OF_NEG_CONTEXT 0x68  /* sizeof(struct smb2_negotiate_req) */
 
@@ -585,13 +585,6 @@ add_posix_context(struct kvec *iov, unsigned int *num_iovec, umode_t mode)
 	return 0;
 }
 
-#else
-static void assemble_neg_contexts(struct smb2_negotiate_req *req,
-				  unsigned int *total_len)
-{
-	return;
-}
-#endif /* SMB311 */
 
 /*
  *
@@ -636,10 +629,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 		return rc;
 
 	req->sync_hdr.SessionId = 0;
-#ifdef CONFIG_CIFS_SMB311
+
 	memset(server->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);
 	memset(ses->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);
-#endif
 
 	if (strcmp(ses->server->vals->version_string,
 		   SMB3ANY_VERSION_STRING) == 0) {
@@ -741,10 +733,8 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 		cifs_dbg(FYI, "negotiated smb3.0 dialect\n");
 	else if (rsp->DialectRevision == cpu_to_le16(SMB302_PROT_ID))
 		cifs_dbg(FYI, "negotiated smb3.02 dialect\n");
-#ifdef CONFIG_CIFS_SMB311
 	else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID))
 		cifs_dbg(FYI, "negotiated smb3.1.1 dialect\n");
-#endif /* SMB311 */
 	else {
 		cifs_dbg(VFS, "Illegal dialect returned by server 0x%x\n",
 			 le16_to_cpu(rsp->DialectRevision));
@@ -753,9 +743,6 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 	}
 	server->dialect = le16_to_cpu(rsp->DialectRevision);
 
-	/* BB: add check that dialect was valid given dialect(s) we asked for */
-
-#ifdef CONFIG_CIFS_SMB311
 	/*
 	 * Keep a copy of the hash after negprot. This hash will be
 	 * the starting hash value for all sessions made from this
@@ -763,7 +750,7 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 	 */
 	memcpy(server->preauth_sha_hash, ses->preauth_sha_hash,
 	       SMB2_PREAUTH_HASH_SIZE);
-#endif
+
 	/* SMB2 only has an extended negflavor */
 	server->negflavor = CIFS_NEGFLAVOR_EXTENDED;
 	/* set it to the maximum buffer size value we can send with 1 credit */
@@ -804,7 +791,6 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 			rc = -EIO;
 	}
 
-#ifdef CONFIG_CIFS_SMB311
 	if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
 		if (rsp->NegotiateContextCount)
 			rc = smb311_decode_neg_context(rsp, server,
@@ -812,7 +798,6 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 		else
 			cifs_dbg(VFS, "Missing expected negotiate contexts\n");
 	}
-#endif /* CONFIG_CIFS_SMB311 */
 neg_exit:
 	free_rsp_buf(resp_buftype, rsp);
 	return rc;
@@ -1373,13 +1358,11 @@ SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
 	sess_data->nls_cp = (struct nls_table *) nls_cp;
 	sess_data->previous_session = ses->Suid;
 
-#ifdef CONFIG_CIFS_SMB311
 	/*
 	 * Initialize the session hash with the server one.
 	 */
 	memcpy(ses->preauth_sha_hash, ses->server->preauth_sha_hash,
 	       SMB2_PREAUTH_HASH_SIZE);
-#endif
 
 	while (sess_data->func)
 		sess_data->func(sess_data);
@@ -1920,7 +1903,6 @@ alloc_path_with_tree_prefix(__le16 **out_path, int *out_size, int *out_len,
 	return 0;
 }
 
-#ifdef CONFIG_CIFS_SMB311
 int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
 			       umode_t mode, struct cifs_tcon *tcon,
 			       const char *full_path,
@@ -2070,7 +2052,6 @@ err_free_path:
 	kfree(utf16_path);
 	return rc;
 }
-#endif /* SMB311 */
 
 int
 SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
@@ -2210,7 +2191,6 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 		dhc_buf = iov[n_iov-1].iov_base;
 	}
 
-#ifdef CONFIG_CIFS_SMB311
 	if (tcon->posix_extensions) {
 		if (n_iov > 2) {
 			struct create_context *ccontext =
@@ -2229,7 +2209,6 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 		}
 		pc_buf = iov[n_iov-1].iov_base;
 	}
-#endif /* SMB311 */
 
 	memset(&rqst, 0, sizeof(struct smb_rqst));
 	rqst.rq_iov = iov;
@@ -3938,7 +3917,6 @@ copy_fs_info_to_kstatfs(struct smb2_fs_full_size_info *pfs_inf,
 	return;
 }
 
-#ifdef CONFIG_CIFS_SMB311
 static void
 copy_posix_fs_info_to_kstatfs(FILE_SYSTEM_POSIX_INFO *response_data,
 			struct kstatfs *kst)
@@ -3957,7 +3935,6 @@ copy_posix_fs_info_to_kstatfs(FILE_SYSTEM_POSIX_INFO *response_data,
 
 	return;
 }
-#endif /* SMB311 */
 
 static int
 build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
@@ -3995,7 +3972,6 @@ build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
 	return 0;
 }
 
-#ifdef CONFIG_CIFS_SMB311
 int
 SMB311_posix_qfs_info(const unsigned int xid, struct cifs_tcon *tcon,
 	      u64 persistent_fid, u64 volatile_fid, struct kstatfs *fsdata)
@@ -4043,7 +4019,6 @@ posix_qfsinf_exit:
 	free_rsp_buf(resp_buftype, rsp_iov.iov_base);
 	return rc;
 }
-#endif /* SMB311 */
 
 int
 SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon,