cifs: remove support for NTLM and weaker authentication algorithms

for SMB1.
This removes the dependency to DES.

Signed-off-by: Ronnie Sahlberg <[email protected]>
Signed-off-by: Steve French <[email protected]>

Author: Ronnie Sahlberg

fs/cifs/Kconfig

@@ -16,7 +16,6 @@ config CIFS
 	select CRYPTO_GCM
 	select CRYPTO_ECB
 	select CRYPTO_AES
-	select CRYPTO_LIB_DES
 	select KEYS
 	select DNS_RESOLVER
 	select ASN1
@@ -85,33 +84,6 @@ config CIFS_ALLOW_INSECURE_LEGACY
 
 	  If unsure, say Y.
 
-config CIFS_WEAK_PW_HASH
-	bool "Support legacy servers which use weaker LANMAN security"
-	depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY
-	help
-	  Modern CIFS servers including Samba and most Windows versions
-	  (since 1997) support stronger NTLM (and even NTLMv2 and Kerberos)
-	  security mechanisms. These hash the password more securely
-	  than the mechanisms used in the older LANMAN version of the
-	  SMB protocol but LANMAN based authentication is needed to
-	  establish sessions with some old SMB servers.
-
-	  Enabling this option allows the cifs module to mount to older
-	  LANMAN based servers such as OS/2 and Windows 95, but such
-	  mounts may be less secure than mounts using NTLM or more recent
-	  security mechanisms if you are on a public network.  Unless you
-	  have a need to access old SMB servers (and are on a private
-	  network) you probably want to say N.  Even if this support
-	  is enabled in the kernel build, LANMAN authentication will not be
-	  used automatically. At runtime LANMAN mounts are disabled but
-	  can be set to required (or optional) either in
-	  /proc/fs/cifs (see Documentation/admin-guide/cifs/usage.rst for
-	  more detail) or via an option on the mount command. This support
-	  is disabled by default in order to reduce the possibility of a
-	  downgrade attack.
-
-	  If unsure, say N.
-
 config CIFS_UPCALL
 	bool "Kerberos/SPNEGO advanced session setup"
 	depends on CIFS

fs/cifs/cifs_debug.c

@@ -250,9 +250,6 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 	seq_printf(m, ",ALLOW_INSECURE_LEGACY");
 #endif
-#ifdef CONFIG_CIFS_WEAK_PW_HASH
-	seq_printf(m, ",WEAK_PW_HASH");
-#endif
 #ifdef CONFIG_CIFS_POSIX
 	seq_printf(m, ",CIFS_POSIX");
 #endif
@@ -929,14 +926,6 @@ cifs_security_flags_handle_must_flags(unsigned int *flags)
 		*flags = CIFSSEC_MUST_NTLMSSP;
 	else if ((*flags & CIFSSEC_MUST_NTLMV2) == CIFSSEC_MUST_NTLMV2)
 		*flags = CIFSSEC_MUST_NTLMV2;
-	else if ((*flags & CIFSSEC_MUST_NTLM) == CIFSSEC_MUST_NTLM)
-		*flags = CIFSSEC_MUST_NTLM;
-	else if (CIFSSEC_MUST_LANMAN &&
-		 (*flags & CIFSSEC_MUST_LANMAN) == CIFSSEC_MUST_LANMAN)
-		*flags = CIFSSEC_MUST_LANMAN;
-	else if (CIFSSEC_MUST_PLNTXT &&
-		 (*flags & CIFSSEC_MUST_PLNTXT) == CIFSSEC_MUST_PLNTXT)
-		*flags = CIFSSEC_MUST_PLNTXT;
 
 	*flags |= signflags;
 }

fs/cifs/cifs_swn.c

@@ -147,8 +147,6 @@ static int cifs_swn_send_register_message(struct cifs_swn_reg *swnreg)
 			goto nlmsg_fail;
 		}
 		break;
-	case LANMAN:
-	case NTLM:
 	case NTLMv2:
 	case RawNTLMSSP:
 		ret = cifs_swn_auth_info_ntlm(swnreg->tcon, skb);

fs/cifs/cifsencrypt.c

@@ -250,87 +250,6 @@ int cifs_verify_signature(struct smb_rqst *rqst,
 
 }
 
-/* first calculate 24 bytes ntlm response and then 16 byte session key */
-int setup_ntlm_response(struct cifs_ses *ses, const struct nls_table *nls_cp)
-{
-	int rc = 0;
-	unsigned int temp_len = CIFS_SESS_KEY_SIZE + CIFS_AUTH_RESP_SIZE;
-	char temp_key[CIFS_SESS_KEY_SIZE];
-
-	if (!ses)
-		return -EINVAL;
-
-	ses->auth_key.response = kmalloc(temp_len, GFP_KERNEL);
-	if (!ses->auth_key.response)
-		return -ENOMEM;
-
-	ses->auth_key.len = temp_len;
-
-	rc = SMBNTencrypt(ses->password, ses->server->cryptkey,
-			ses->auth_key.response + CIFS_SESS_KEY_SIZE, nls_cp);
-	if (rc) {
-		cifs_dbg(FYI, "%s Can't generate NTLM response, error: %d\n",
-			 __func__, rc);
-		return rc;
-	}
-
-	rc = E_md4hash(ses->password, temp_key, nls_cp);
-	if (rc) {
-		cifs_dbg(FYI, "%s Can't generate NT hash, error: %d\n",
-			 __func__, rc);
-		return rc;
-	}
-
-	rc = mdfour(ses->auth_key.response, temp_key, CIFS_SESS_KEY_SIZE);
-	if (rc)
-		cifs_dbg(FYI, "%s Can't generate NTLM session key, error: %d\n",
-			 __func__, rc);
-
-	return rc;
-}
-
-#ifdef CONFIG_CIFS_WEAK_PW_HASH
-int calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
-			char *lnm_session_key)
-{
-	int i, len;
-	int rc;
-	char password_with_pad[CIFS_ENCPWD_SIZE] = {0};
-
-	if (password) {
-		for (len = 0; len < CIFS_ENCPWD_SIZE; len++)
-			if (!password[len])
-				break;
-
-		memcpy(password_with_pad, password, len);
-	}
-
-	if (!encrypt && global_secflags & CIFSSEC_MAY_PLNTXT) {
-		memcpy(lnm_session_key, password_with_pad,
-			CIFS_ENCPWD_SIZE);
-		return 0;
-	}
-
-	/* calculate old style session key */
-	/* calling toupper is less broken than repeatedly
-	calling nls_toupper would be since that will never
-	work for UTF8, but neither handles multibyte code pages
-	but the only alternative would be converting to UCS-16 (Unicode)
-	(using a routine something like UniStrupr) then
-	uppercasing and then converting back from Unicode - which
-	would only worth doing it if we knew it were utf8. Basically
-	utf8 and other multibyte codepages each need their own strupper
-	function since a byte at a time will ont work. */
-
-	for (i = 0; i < CIFS_ENCPWD_SIZE; i++)
-		password_with_pad[i] = toupper(password_with_pad[i]);
-
-	rc = SMBencrypt(password_with_pad, cryptkey, lnm_session_key);
-
-	return rc;
-}
-#endif /* CIFS_WEAK_PW_HASH */
-
 /* Build a proper attribute value/target info pairs blob.
  * Fill in netbios and dns domain name and workstation name
  * and client time (total five av pairs and + one end of fields indicator.

fs/cifs/cifsfs.c

@@ -437,15 +437,9 @@ cifs_show_security(struct seq_file *s, struct cifs_ses *ses)
 	seq_puts(s, ",sec=");
 
 	switch (ses->sectype) {
-	case LANMAN:
-		seq_puts(s, "lanman");
-		break;
 	case NTLMv2:
 		seq_puts(s, "ntlmv2");
 		break;
-	case NTLM:
-		seq_puts(s, "ntlm");
-		break;
 	case Kerberos:
 		seq_puts(s, "krb5");
 		break;

fs/cifs/cifsglob.h

@@ -114,8 +114,6 @@ enum statusEnum {
 
 enum securityEnum {
 	Unspecified = 0,	/* not specified */
-	LANMAN,			/* Legacy LANMAN auth */
-	NTLM,			/* Legacy NTLM012 auth with NTLM hash */
 	NTLMv2,			/* Legacy NTLM auth with NTLMv2 hash */
 	RawNTLMSSP,		/* NTLMSSP without SPNEGO, NTLMv2 hash */
 	Kerberos,		/* Kerberos via SPNEGO */
@@ -634,7 +632,6 @@ struct TCP_Server_Info {
 	struct session_key session_key;
 	unsigned long lstrp; /* when we got last response from this server */
 	struct cifs_secmech secmech; /* crypto sec mech functs, descriptors */
-#define	CIFS_NEGFLAVOR_LANMAN	0	/* wct == 13, LANMAN */
 #define	CIFS_NEGFLAVOR_UNENCAP	1	/* wct == 17, but no ext_sec */
 #define	CIFS_NEGFLAVOR_EXTENDED	2	/* wct == 17, ext_sec bit set */
 	char	negflavor;	/* NEGOTIATE response flavor */
@@ -1734,49 +1731,28 @@ static inline bool is_retryable_error(int error)
 
 /* Security Flags: indicate type of session setup needed */
 #define   CIFSSEC_MAY_SIGN	0x00001
-#define   CIFSSEC_MAY_NTLM	0x00002
 #define   CIFSSEC_MAY_NTLMV2	0x00004
 #define   CIFSSEC_MAY_KRB5	0x00008
-#ifdef CONFIG_CIFS_WEAK_PW_HASH
-#define   CIFSSEC_MAY_LANMAN	0x00010
-#define   CIFSSEC_MAY_PLNTXT	0x00020
-#else
-#define   CIFSSEC_MAY_LANMAN    0
-#define   CIFSSEC_MAY_PLNTXT    0
-#endif /* weak passwords */
 #define   CIFSSEC_MAY_SEAL	0x00040 /* not supported yet */
 #define   CIFSSEC_MAY_NTLMSSP	0x00080 /* raw ntlmssp with ntlmv2 */
 
 #define   CIFSSEC_MUST_SIGN	0x01001
 /* note that only one of the following can be set so the
 result of setting MUST flags more than once will be to
 require use of the stronger protocol */
-#define   CIFSSEC_MUST_NTLM	0x02002
 #define   CIFSSEC_MUST_NTLMV2	0x04004
 #define   CIFSSEC_MUST_KRB5	0x08008
-#ifdef CONFIG_CIFS_WEAK_PW_HASH
-#define   CIFSSEC_MUST_LANMAN	0x10010
-#define   CIFSSEC_MUST_PLNTXT	0x20020
-#ifdef CONFIG_CIFS_UPCALL
-#define   CIFSSEC_MASK          0xBF0BF /* allows weak security but also krb5 */
-#else
-#define   CIFSSEC_MASK          0xB70B7 /* current flags supported if weak */
-#endif /* UPCALL */
-#else /* do not allow weak pw hash */
-#define   CIFSSEC_MUST_LANMAN	0
-#define   CIFSSEC_MUST_PLNTXT	0
 #ifdef CONFIG_CIFS_UPCALL
 #define   CIFSSEC_MASK          0x8F08F /* flags supported if no weak allowed */
 #else
 #define	  CIFSSEC_MASK          0x87087 /* flags supported if no weak allowed */
 #endif /* UPCALL */
-#endif /* WEAK_PW_HASH */
 #define   CIFSSEC_MUST_SEAL	0x40040 /* not supported yet */
 #define   CIFSSEC_MUST_NTLMSSP	0x80080 /* raw ntlmssp with ntlmv2 */
 
 #define   CIFSSEC_DEF (CIFSSEC_MAY_SIGN | CIFSSEC_MAY_NTLMV2 | CIFSSEC_MAY_NTLMSSP)
-#define   CIFSSEC_MAX (CIFSSEC_MUST_SIGN | CIFSSEC_MUST_NTLMV2)
-#define   CIFSSEC_AUTH_MASK (CIFSSEC_MAY_NTLM | CIFSSEC_MAY_NTLMV2 | CIFSSEC_MAY_LANMAN | CIFSSEC_MAY_PLNTXT | CIFSSEC_MAY_KRB5 | CIFSSEC_MAY_NTLMSSP)
+#define   CIFSSEC_MAX (CIFSSEC_MUST_NTLMV2)
+#define   CIFSSEC_AUTH_MASK (CIFSSEC_MAY_NTLMV2 | CIFSSEC_MAY_KRB5 | CIFSSEC_MAY_NTLMSSP)
 /*
  *****************************************************************
  * All constants go here
@@ -1940,10 +1916,6 @@ static inline char *get_security_type_str(enum securityEnum sectype)
 		return "Kerberos";
 	case NTLMv2:
 		return "NTLMv2";
-	case NTLM:
-		return "NTLM";
-	case LANMAN:
-		return "LANMAN";
 	default:
 		return "Unknown";
 	}

fs/cifs/cifspdu.h

@@ -14,13 +14,7 @@
 #include <asm/unaligned.h>
 #include "smbfsctl.h"
 
-#ifdef CONFIG_CIFS_WEAK_PW_HASH
-#define LANMAN_PROT 0
-#define LANMAN2_PROT 1
-#define CIFS_PROT   2
-#else
 #define CIFS_PROT   0
-#endif
 #define POSIX_PROT  (CIFS_PROT+1)
 #define BAD_PROT 0xFFFF
 
@@ -505,30 +499,8 @@ typedef struct negotiate_req {
 	unsigned char DialectsArray[1];
 } __attribute__((packed)) NEGOTIATE_REQ;
 
-/* Dialect index is 13 for LANMAN */
-
 #define MIN_TZ_ADJ (15 * 60) /* minimum grid for timezones in seconds */
 
-typedef struct lanman_neg_rsp {
-	struct smb_hdr hdr;	/* wct = 13 */
-	__le16 DialectIndex;
-	__le16 SecurityMode;
-	__le16 MaxBufSize;
-	__le16 MaxMpxCount;
-	__le16 MaxNumberVcs;
-	__le16 RawMode;
-	__le32 SessionKey;
-	struct {
-		__le16 Time;
-		__le16 Date;
-	} __attribute__((packed)) SrvTime;
-	__le16 ServerTimeZone;
-	__le16 EncryptionKeyLength;
-	__le16 Reserved;
-	__u16  ByteCount;
-	unsigned char EncryptionKey[1];
-} __attribute__((packed)) LANMAN_NEG_RSP;
-
 #define READ_RAW_ENABLE 1
 #define WRITE_RAW_ENABLE 2
 #define RAW_ENABLE (READ_RAW_ENABLE | WRITE_RAW_ENABLE)

fs/cifs/cifsproto.h

@@ -498,19 +498,12 @@ extern int cifs_sign_smb(struct smb_hdr *, struct TCP_Server_Info *, __u32 *);
 extern int cifs_verify_signature(struct smb_rqst *rqst,
 				 struct TCP_Server_Info *server,
 				__u32 expected_sequence_number);
-extern int SMBNTencrypt(unsigned char *, unsigned char *, unsigned char *,
-			const struct nls_table *);
-extern int setup_ntlm_response(struct cifs_ses *, const struct nls_table *);
 extern int setup_ntlmv2_rsp(struct cifs_ses *, const struct nls_table *);
 extern void cifs_crypto_secmech_release(struct TCP_Server_Info *server);
 extern int calc_seckey(struct cifs_ses *);
 extern int generate_smb30signingkey(struct cifs_ses *);
 extern int generate_smb311signingkey(struct cifs_ses *);
 
-#ifdef CONFIG_CIFS_WEAK_PW_HASH
-extern int calc_lanman_hash(const char *password, const char *cryptkey,
-				bool encrypt, char *lnm_session_key);
-#endif /* CIFS_WEAK_PW_HASH */
 extern int CIFSSMBCopy(unsigned int xid,
 			struct cifs_tcon *source_tcon,
 			const char *fromName,
@@ -547,11 +540,8 @@ extern int check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 			      struct cifs_sb_info *cifs_sb,
 			      struct cifs_fattr *fattr,
 			      const unsigned char *path);
-extern int mdfour(unsigned char *, unsigned char *, int);
 extern int E_md4hash(const unsigned char *passwd, unsigned char *p16,
 			const struct nls_table *codepage);
-extern int SMBencrypt(unsigned char *passwd, const unsigned char *c8,
-			unsigned char *p24);
 
 extern int
 cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname);