[patch] SMB1 NTLM backport for kernel 5.15.12

cifs_smb1_ntlm_backport.patch (text/plain), 31.46 KB, created by Robert Schultz on 2022-01-04 15:44:39 UTC

# This patch is the reversal of: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=76a3c92ec9e0668e4cd0e9ff1782eb68f61a179c
# This is probably the better way to backport, but it's not ready yet: https://sourceforge.net/p/linux-cifsd/mailman/message/37391155/
diff -Naur a/fs/cifs/Kconfig b/fs/cifs/Kconfig
--- a/fs/cifs/Kconfig	2022-01-04 10:08:06.565157021 -0500
+++ b/fs/cifs/Kconfig	2022-01-04 10:09:16.715075368 -0500
@@ -14,6 +14,7 @@
 	select CRYPTO_GCM
 	select CRYPTO_ECB
 	select CRYPTO_AES
+	select CRYPTO_LIB_DES
 	select KEYS
 	select DNS_RESOLVER
 	select ASN1
@@ -82,6 +83,33 @@
 
 	  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
diff -Naur a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
--- a/fs/cifs/cifs_debug.c	2022-01-04 10:08:06.566157020 -0500
+++ b/fs/cifs/cifs_debug.c	2022-01-04 10:10:04.274019962 -0500
@@ -249,6 +249,9 @@
 #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
@@ -927,6 +930,14 @@
 		*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;
 }
diff -Naur a/fs/cifs/cifs_swn.c b/fs/cifs/cifs_swn.c
--- a/fs/cifs/cifs_swn.c	2022-01-04 10:08:06.565157021 -0500
+++ b/fs/cifs/cifs_swn.c	2022-01-04 10:10:33.337985265 -0500
@@ -147,6 +147,8 @@
 			goto nlmsg_fail;
 		}
 		break;
+	case LANMAN:
+	case NTLM:
 	case NTLMv2:
 	case RawNTLMSSP:
 		ret = cifs_swn_auth_info_ntlm(swnreg->tcon, skb);
diff -Naur a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
--- a/fs/cifs/cifsencrypt.c	2022-01-04 10:08:06.565157021 -0500
+++ b/fs/cifs/cifsencrypt.c	2022-01-04 10:11:09.538941598 -0500
@@ -249,6 +249,87 @@
 
 }
 
+/* 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.
diff -Naur a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
--- a/fs/cifs/cifsfs.c	2022-01-04 10:08:06.565157021 -0500
+++ b/fs/cifs/cifsfs.c	2022-01-04 10:12:59.922808378 -0500
@@ -436,9 +436,15 @@
 	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;
diff -Naur a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
--- a/fs/cifs/cifsglob.h	2022-01-04 10:08:06.566157020 -0500
+++ b/fs/cifs/cifsglob.h	2022-01-04 10:16:24.194561579 -0500
@@ -114,6 +114,8 @@
 
 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 */
@@ -633,6 +635,7 @@
 	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 */
@@ -1733,8 +1736,16 @@
 
 /* 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 */
 
@@ -1742,19 +1753,32 @@
 /* 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_NTLMV2)
-#define   CIFSSEC_AUTH_MASK (CIFSSEC_MAY_NTLMV2 | CIFSSEC_MAY_KRB5 | 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)
 /*
  *****************************************************************
  * All constants go here
@@ -1918,6 +1942,10 @@
 		return "Kerberos";
 	case NTLMv2:
 		return "NTLMv2";
+	case NTLM:
+		return "NTLM";
+	case LANMAN:
+		return "LANMAN";
 	default:
 		return "Unknown";
 	}
diff -Naur a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
--- a/fs/cifs/cifspdu.h	2022-01-04 10:08:06.565157021 -0500
+++ b/fs/cifs/cifspdu.h	2022-01-04 10:17:47.914460331 -0500
@@ -13,7 +13,13 @@
 #include <asm/unaligned.h>
 #include "../smbfs_common/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
 
@@ -498,8 +504,30 @@
 	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)
diff -Naur a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
--- a/fs/cifs/cifsproto.h	2022-01-04 10:08:06.565157021 -0500
+++ b/fs/cifs/cifsproto.h	2022-01-04 10:19:01.425371381 -0500
@@ -500,12 +500,19 @@
 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,
@@ -542,8 +549,11 @@
 			      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);
diff -Naur a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
--- a/fs/cifs/cifssmb.c	2022-01-04 10:08:06.565157021 -0500
+++ b/fs/cifs/cifssmb.c	2022-01-04 10:23:09.332071089 -0500
@@ -41,6 +41,10 @@
 	int index;
 	char *name;
 } protocols[] = {
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+	{LANMAN_PROT, "\2LM1.2X002"},
+	{LANMAN2_PROT, "\2LANMAN2.1"},
+#endif /* weak password hashing for legacy clients */
 	{CIFS_PROT, "\2NT LM 0.12"},
 	{POSIX_PROT, "\2POSIX 2"},
 	{BAD_PROT, "\2"}
@@ -50,6 +54,10 @@
 	int index;
 	char *name;
 } protocols[] = {
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+	{LANMAN_PROT, "\2LM1.2X002"},
+	{LANMAN2_PROT, "\2LANMAN2.1"},
+#endif /* weak password hashing for legacy clients */
 	{CIFS_PROT, "\2NT LM 0.12"},
 	{BAD_PROT, "\2"}
 };
@@ -57,9 +65,17 @@
 
 /* define the number of elements in the cifs dialect array */
 #ifdef CONFIG_CIFS_POSIX
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+#define CIFS_NUM_PROT 4
+#else
 #define CIFS_NUM_PROT 2
+#endif /* CIFS_WEAK_PW_HASH */
 #else /* not posix */
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+#define CIFS_NUM_PROT 3
+#else
 #define CIFS_NUM_PROT 1
+#endif /* CONFIG_CIFS_WEAK_PW_HASH */
 #endif /* CIFS_POSIX */
 
 /*
@@ -458,6 +474,89 @@
 	return 0;
 }
 
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+static int
+decode_lanman_negprot_rsp(struct TCP_Server_Info *server, NEGOTIATE_RSP *pSMBr)
+{
+	__s16 tmp;
+	struct lanman_neg_rsp *rsp = (struct lanman_neg_rsp *)pSMBr;
+
+	if (server->dialect != LANMAN_PROT && server->dialect != LANMAN2_PROT)
+		return -EOPNOTSUPP;
+
+	server->sec_mode = le16_to_cpu(rsp->SecurityMode);
+	server->maxReq = min_t(unsigned int,
+			       le16_to_cpu(rsp->MaxMpxCount),
+			       cifs_max_pending);
+	set_credits(server, server->maxReq);
+	server->maxBuf = le16_to_cpu(rsp->MaxBufSize);
+	/* set up max_read for readpages check */
+	server->max_read = server->maxBuf;
+	/* even though we do not use raw we might as well set this
+	accurately, in case we ever find a need for it */
+	if ((le16_to_cpu(rsp->RawMode) & RAW_ENABLE) == RAW_ENABLE) {
+		server->max_rw = 0xFF00;
+		server->capabilities = CAP_MPX_MODE | CAP_RAW_MODE;
+	} else {
+		server->max_rw = 0;/* do not need to use raw anyway */
+		server->capabilities = CAP_MPX_MODE;
+	}
+	tmp = (__s16)le16_to_cpu(rsp->ServerTimeZone);
+	if (tmp == -1) {
+		/* OS/2 often does not set timezone therefore
+		 * we must use server time to calc time zone.
+		 * Could deviate slightly from the right zone.
+		 * Smallest defined timezone difference is 15 minutes
+		 * (i.e. Nepal).  Rounding up/down is done to match
+		 * this requirement.
+		 */
+		int val, seconds, remain, result;
+		struct timespec64 ts;
+		time64_t utc = ktime_get_real_seconds();
+		ts = cnvrtDosUnixTm(rsp->SrvTime.Date,
+				    rsp->SrvTime.Time, 0);
+		cifs_dbg(FYI, "SrvTime %lld sec since 1970 (utc: %lld) diff: %lld\n",
+			 ts.tv_sec, utc,
+			 utc - ts.tv_sec);
+		val = (int)(utc - ts.tv_sec);
+		seconds = abs(val);
+		result = (seconds / MIN_TZ_ADJ) * MIN_TZ_ADJ;
+		remain = seconds % MIN_TZ_ADJ;
+		if (remain >= (MIN_TZ_ADJ / 2))
+			result += MIN_TZ_ADJ;
+		if (val < 0)
+			result = -result;
+		server->timeAdj = result;
+	} else {
+		server->timeAdj = (int)tmp;
+		server->timeAdj *= 60; /* also in seconds */
+	}
+	cifs_dbg(FYI, "server->timeAdj: %d seconds\n", server->timeAdj);
+
+
+	/* BB get server time for time conversions and add
+	code to use it and timezone since this is not UTC */
+
+	if (rsp->EncryptionKeyLength ==
+			cpu_to_le16(CIFS_CRYPTO_KEY_SIZE)) {
+		memcpy(server->cryptkey, rsp->EncryptionKey,
+			CIFS_CRYPTO_KEY_SIZE);
+	} else if (server->sec_mode & SECMODE_PW_ENCRYPT) {
+		return -EIO; /* need cryptkey unless plain text */
+	}
+
+	cifs_dbg(FYI, "LANMAN negotiated\n");
+	return 0;
+}
+#else
+static inline int
+decode_lanman_negprot_rsp(struct TCP_Server_Info *server, NEGOTIATE_RSP *pSMBr)
+{
+	cifs_dbg(VFS, "mount failed, cifs module not built with CIFS_WEAK_PW_HASH support\n");
+	return -EOPNOTSUPP;
+}
+#endif
+
 static bool
 should_set_ext_sec_flag(enum securityEnum sectype)
 {
@@ -526,12 +625,16 @@
 	server->dialect = le16_to_cpu(pSMBr->DialectIndex);
 	cifs_dbg(FYI, "Dialect: %d\n", server->dialect);
 	/* Check wct = 1 error case */
-	if ((pSMBr->hdr.WordCount <= 13) || (server->dialect == BAD_PROT)) {
+	if ((pSMBr->hdr.WordCount < 13) || (server->dialect == BAD_PROT)) {
 		/* core returns wct = 1, but we do not ask for core - otherwise
 		small wct just comes when dialect index is -1 indicating we
 		could not negotiate a common dialect */
 		rc = -EOPNOTSUPP;
 		goto neg_err_exit;
+	} else if (pSMBr->hdr.WordCount == 13) {
+		server->negflavor = CIFS_NEGFLAVOR_LANMAN;
+		rc = decode_lanman_negprot_rsp(server, pSMBr);
+		goto signing_check;
 	} else if (pSMBr->hdr.WordCount != 17) {
 		/* unknown wct */
 		rc = -EOPNOTSUPP;
@@ -573,6 +676,7 @@
 		server->capabilities &= ~CAP_EXTENDED_SECURITY;
 	}
 
+signing_check:
 	if (!rc)
 		rc = cifs_enable_signing(server, ses->sign);
 neg_err_exit:
diff -Naur a/fs/cifs/connect.c b/fs/cifs/connect.c
--- a/fs/cifs/connect.c	2022-01-04 10:08:06.566157020 -0500
+++ b/fs/cifs/connect.c	2022-01-04 10:24:01.234986739 -0500
@@ -3702,6 +3702,38 @@
 		*bcc_ptr = 0; /* password is null byte */
 		bcc_ptr++;              /* skip password */
 		/* already aligned so no need to do it below */
+	} else {
+		pSMB->PasswordLength = cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+		/* BB FIXME add code to fail this if NTLMv2 or Kerberos
+		   specified as required (when that support is added to
+		   the vfs in the future) as only NTLM or the much
+		   weaker LANMAN (which we do not send by default) is accepted
+		   by Samba (not sure whether other servers allow
+		   NTLMv2 password here) */
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+		if ((global_secflags & CIFSSEC_MAY_LANMAN) &&
+		    (ses->sectype == LANMAN))
+			calc_lanman_hash(tcon->password, ses->server->cryptkey,
+					 ses->server->sec_mode &
+					    SECMODE_PW_ENCRYPT ? true : false,
+					 bcc_ptr);
+		else
+#endif /* CIFS_WEAK_PW_HASH */
+		rc = SMBNTencrypt(tcon->password, ses->server->cryptkey,
+					bcc_ptr, nls_codepage);
+		if (rc) {
+			cifs_dbg(FYI, "%s Can't generate NTLM rsp. Error: %d\n",
+				 __func__, rc);
+			cifs_buf_release(smb_buffer);
+			return rc;
+		}
+
+		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+		if (ses->capabilities & CAP_UNICODE) {
+			/* must align unicode strings */
+			*bcc_ptr = 0; /* null byte password */
+			bcc_ptr++;
+		}
 	}
 
 	if (ses->server->sign)
diff -Naur a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
--- a/fs/cifs/fs_context.c	2022-01-04 10:08:06.566157020 -0500
+++ b/fs/cifs/fs_context.c	2022-01-04 10:25:05.128873894 -0500
@@ -57,9 +57,12 @@
 	{ Opt_sec_krb5p, "krb5p" },
 	{ Opt_sec_ntlmsspi, "ntlmsspi" },
 	{ Opt_sec_ntlmssp, "ntlmssp" },
+	{ Opt_ntlm, "ntlm" },
+	{ Opt_sec_ntlmi, "ntlmi" },
 	{ Opt_sec_ntlmv2, "nontlm" },
 	{ Opt_sec_ntlmv2, "ntlmv2" },
 	{ Opt_sec_ntlmv2i, "ntlmv2i" },
+	{ Opt_sec_lanman, "lanman" },
 	{ Opt_sec_none, "none" },
 
 	{ Opt_sec_err, NULL }
@@ -218,12 +221,23 @@
 	case Opt_sec_ntlmssp:
 		ctx->sectype = RawNTLMSSP;
 		break;
+	case Opt_sec_ntlmi:
+		ctx->sign = true;
+		fallthrough;
+	case Opt_ntlm:
+		ctx->sectype = NTLM;
+		break;
 	case Opt_sec_ntlmv2i:
 		ctx->sign = true;
 		fallthrough;
 	case Opt_sec_ntlmv2:
 		ctx->sectype = NTLMv2;
 		break;
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+	case Opt_sec_lanman:
+		ctx->sectype = LANMAN;
+		break;
+#endif
 	case Opt_sec_none:
 		ctx->nullauth = 1;
 		break;
diff -Naur a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
--- a/fs/cifs/fs_context.h	2022-01-04 10:08:06.566157020 -0500
+++ b/fs/cifs/fs_context.h	2022-01-04 10:25:28.895832049 -0500
@@ -47,8 +47,11 @@
 	Opt_sec_krb5p,
 	Opt_sec_ntlmsspi,
 	Opt_sec_ntlmssp,
+	Opt_ntlm,
+	Opt_sec_ntlmi,
 	Opt_sec_ntlmv2,
 	Opt_sec_ntlmv2i,
+	Opt_sec_lanman,
 	Opt_sec_none,
 
 	Opt_sec_err
diff -Naur a/fs/cifs/sess.c b/fs/cifs/sess.c
--- a/fs/cifs/sess.c	2022-01-04 10:08:06.565157021 -0500
+++ b/fs/cifs/sess.c	2022-01-04 10:27:24.809628964 -0500
@@ -798,16 +798,30 @@
 		}
 	case CIFS_NEGFLAVOR_UNENCAP:
 		switch (requested) {
+		case NTLM:
 		case NTLMv2:
 			return requested;
 		case Unspecified:
 			if (global_secflags & CIFSSEC_MAY_NTLMV2)
 				return NTLMv2;
+			if (global_secflags & CIFSSEC_MAY_NTLM)
+				return NTLM;
 			break;
 		default:
 			break;
 		}
-		fallthrough;
+		fallthrough;	/* to attempt LANMAN authentication next */
+	case CIFS_NEGFLAVOR_LANMAN:
+		switch (requested) {
+		case LANMAN:
+			return requested;
+		case Unspecified:
+			if (global_secflags & CIFSSEC_MAY_LANMAN)
+				return LANMAN;
+			fallthrough;
+		default:
+			return Unspecified;
+		}
 	default:
 		return Unspecified;
 	}
@@ -932,6 +946,230 @@
 	return rc;
 }
 
+/*
+ * LANMAN and plaintext are less secure and off by default.
+ * So we make this explicitly be turned on in kconfig (in the
+ * build) and turned on at runtime (changed from the default)
+ * in proc/fs/cifs or via mount parm.  Unfortunately this is
+ * needed for old Win (e.g. Win95), some obscure NAS and OS/2
+ */
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+static void
+sess_auth_lanman(struct sess_data *sess_data)
+{
+	int rc = 0;
+	struct smb_hdr *smb_buf;
+	SESSION_SETUP_ANDX *pSMB;
+	char *bcc_ptr;
+	struct cifs_ses *ses = sess_data->ses;
+	char lnm_session_key[CIFS_AUTH_RESP_SIZE];
+	__u16 bytes_remaining;
+
+	/* lanman 2 style sessionsetup */
+	/* wct = 10 */
+	rc = sess_alloc_buffer(sess_data, 10);
+	if (rc)
+		goto out;
+
+	pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
+	bcc_ptr = sess_data->iov[2].iov_base;
+	(void)cifs_ssetup_hdr(ses, pSMB);
+
+	pSMB->req.hdr.Flags2 &= ~SMBFLG2_UNICODE;
+
+	if (ses->user_name != NULL) {
+		/* no capabilities flags in old lanman negotiation */
+		pSMB->old_req.PasswordLength = cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+
+		/* Calculate hash with password and copy into bcc_ptr.
+		 * Encryption Key (stored as in cryptkey) gets used if the
+		 * security mode bit in Negotiate Protocol response states
+		 * to use challenge/response method (i.e. Password bit is 1).
+		 */
+		rc = calc_lanman_hash(ses->password, ses->server->cryptkey,
+				      ses->server->sec_mode & SECMODE_PW_ENCRYPT ?
+				      true : false, lnm_session_key);
+		if (rc)
+			goto out;
+
+		memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_AUTH_RESP_SIZE);
+		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+	} else {
+		pSMB->old_req.PasswordLength = 0;
+	}
+
+	/*
+	 * can not sign if LANMAN negotiated so no need
+	 * to calculate signing key? but what if server
+	 * changed to do higher than lanman dialect and
+	 * we reconnected would we ever calc signing_key?
+	 */
+
+	cifs_dbg(FYI, "Negotiating LANMAN setting up strings\n");
+	/* Unicode not allowed for LANMAN dialects */
+	ascii_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
+
+	sess_data->iov[2].iov_len = (long) bcc_ptr -
+			(long) sess_data->iov[2].iov_base;
+
+	rc = sess_sendreceive(sess_data);
+	if (rc)
+		goto out;
+
+	pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
+	smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;
+
+	/* lanman response has a word count of 3 */
+	if (smb_buf->WordCount != 3) {
+		rc = -EIO;
+		cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
+		goto out;
+	}
+
+	if (le16_to_cpu(pSMB->resp.Action) & GUEST_LOGIN)
+		cifs_dbg(FYI, "Guest login\n"); /* BB mark SesInfo struct? */
+
+	ses->Suid = smb_buf->Uid;   /* UID left in wire format (le) */
+	cifs_dbg(FYI, "UID = %llu\n", ses->Suid);
+
+	bytes_remaining = get_bcc(smb_buf);
+	bcc_ptr = pByteArea(smb_buf);
+
+	/* BB check if Unicode and decode strings */
+	if (bytes_remaining == 0) {
+		/* no string area to decode, do nothing */
+	} else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
+		/* unicode string area must be word-aligned */
+		if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
+			++bcc_ptr;
+			--bytes_remaining;
+		}
+		decode_unicode_ssetup(&bcc_ptr, bytes_remaining, ses,
+				      sess_data->nls_cp);
+	} else {
+		decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses,
+				    sess_data->nls_cp);
+	}
+
+	rc = sess_establish_session(sess_data);
+out:
+	sess_data->result = rc;
+	sess_data->func = NULL;
+	sess_free_buffer(sess_data);
+}
+
+#endif
+
+static void
+sess_auth_ntlm(struct sess_data *sess_data)
+{
+	int rc = 0;
+	struct smb_hdr *smb_buf;
+	SESSION_SETUP_ANDX *pSMB;
+	char *bcc_ptr;
+	struct cifs_ses *ses = sess_data->ses;
+	__u32 capabilities;
+	__u16 bytes_remaining;
+
+	/* old style NTLM sessionsetup */
+	/* wct = 13 */
+	rc = sess_alloc_buffer(sess_data, 13);
+	if (rc)
+		goto out;
+
+	pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
+	bcc_ptr = sess_data->iov[2].iov_base;
+	capabilities = cifs_ssetup_hdr(ses, pSMB);
+
+	pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
+	if (ses->user_name != NULL) {
+		pSMB->req_no_secext.CaseInsensitivePasswordLength =
+				cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+		pSMB->req_no_secext.CaseSensitivePasswordLength =
+				cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+
+		/* calculate ntlm response and session key */
+		rc = setup_ntlm_response(ses, sess_data->nls_cp);
+		if (rc) {
+			cifs_dbg(VFS, "Error %d during NTLM authentication\n",
+					 rc);
+			goto out;
+		}
+
+		/* copy ntlm response */
+		memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+				CIFS_AUTH_RESP_SIZE);
+		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+		memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+				CIFS_AUTH_RESP_SIZE);
+		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+	} else {
+		pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;
+		pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
+	}
+
+	if (ses->capabilities & CAP_UNICODE) {
+		/* unicode strings must be word aligned */
+		if (sess_data->iov[0].iov_len % 2) {
+			*bcc_ptr = 0;
+			bcc_ptr++;
+		}
+		unicode_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
+	} else {
+		ascii_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
+	}
+
+
+	sess_data->iov[2].iov_len = (long) bcc_ptr -
+			(long) sess_data->iov[2].iov_base;
+
+	rc = sess_sendreceive(sess_data);
+	if (rc)
+		goto out;
+
+	pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
+	smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;
+
+	if (smb_buf->WordCount != 3) {
+		rc = -EIO;
+		cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
+		goto out;
+	}
+
+	if (le16_to_cpu(pSMB->resp.Action) & GUEST_LOGIN)
+		cifs_dbg(FYI, "Guest login\n"); /* BB mark SesInfo struct? */
+
+	ses->Suid = smb_buf->Uid;   /* UID left in wire format (le) */
+	cifs_dbg(FYI, "UID = %llu\n", ses->Suid);
+
+	bytes_remaining = get_bcc(smb_buf);
+	bcc_ptr = pByteArea(smb_buf);
+
+	/* BB check if Unicode and decode strings */
+	if (bytes_remaining == 0) {
+		/* no string area to decode, do nothing */
+	} else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
+		/* unicode string area must be word-aligned */
+		if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
+			++bcc_ptr;
+			--bytes_remaining;
+		}
+		decode_unicode_ssetup(&bcc_ptr, bytes_remaining, ses,
+				      sess_data->nls_cp);
+	} else {
+		decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses,
+				    sess_data->nls_cp);
+	}
+
+	rc = sess_establish_session(sess_data);
+out:
+	sess_data->result = rc;
+	sess_data->func = NULL;
+	sess_free_buffer(sess_data);
+	kfree(ses->auth_key.response);
+	ses->auth_key.response = NULL;
+}
+
 static void
 sess_auth_ntlmv2(struct sess_data *sess_data)
 {
@@ -1436,6 +1674,21 @@
 	}
 
 	switch (type) {
+	case LANMAN:
+		/* LANMAN and plaintext are less secure and off by default.
+		 * So we make this explicitly be turned on in kconfig (in the
+		 * build) and turned on at runtime (changed from the default)
+		 * in proc/fs/cifs or via mount parm.  Unfortunately this is
+		 * needed for old Win (e.g. Win95), some obscure NAS and OS/2 */
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+		sess_data->func = sess_auth_lanman;
+		break;
+#else
+		return -EOPNOTSUPP;
+#endif
+	case NTLM:
+		sess_data->func = sess_auth_ntlm;
+		break;
 	case NTLMv2:
 		sess_data->func = sess_auth_ntlmv2;
 		break;
diff -Naur a/fs/cifs/smbencrypt.c b/fs/cifs/smbencrypt.c
--- a/fs/cifs/smbencrypt.c	2022-01-04 10:08:06.566157020 -0500
+++ b/fs/cifs/smbencrypt.c	2022-01-04 10:30:19.497325942 -0500
@@ -18,6 +18,7 @@
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/random.h>
+#include <crypto/des.h>
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
 #include "cifspdu.h"
@@ -38,8 +39,74 @@
 #define SSVALX(buf,pos,val) (CVAL(buf,pos)=(val)&0xFF,CVAL(buf,pos+1)=(val)>>8)
 #define SSVAL(buf,pos,val) SSVALX((buf),(pos),((__u16)(val)))
 
-/* produce a md4 message digest from data of length n bytes */
+static void
+str_to_key(unsigned char *str, unsigned char *key)
+{
+	int i;
+
+	key[0] = str[0] >> 1;
+	key[1] = ((str[0] & 0x01) << 6) | (str[1] >> 2);
+	key[2] = ((str[1] & 0x03) << 5) | (str[2] >> 3);
+	key[3] = ((str[2] & 0x07) << 4) | (str[3] >> 4);
+	key[4] = ((str[3] & 0x0F) << 3) | (str[4] >> 5);
+	key[5] = ((str[4] & 0x1F) << 2) | (str[5] >> 6);
+	key[6] = ((str[5] & 0x3F) << 1) | (str[6] >> 7);
+	key[7] = str[6] & 0x7F;
+	for (i = 0; i < 8; i++)
+		key[i] = (key[i] << 1);
+}
+
+static int
+smbhash(unsigned char *out, const unsigned char *in, unsigned char *key)
+{
+	unsigned char key2[8];
+	struct des_ctx ctx;
+
+	str_to_key(key, key2);
+
+	if (fips_enabled) {
+		cifs_dbg(VFS, "FIPS compliance enabled: DES not permitted\n");
+		return -ENOENT;
+	}
+
+	des_expand_key(&ctx, key2, DES_KEY_SIZE);
+	des_encrypt(&ctx, out, in);
+	memzero_explicit(&ctx, sizeof(ctx));
+
+	return 0;
+}
+
 static int
+E_P16(unsigned char *p14, unsigned char *p16)
+{
+	int rc;
+	unsigned char sp8[8] =
+	    { 0x4b, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25 };
+
+	rc = smbhash(p16, sp8, p14);
+	if (rc)
+		return rc;
+	rc = smbhash(p16 + 8, sp8, p14 + 7);
+	return rc;
+}
+
+static int
+E_P24(unsigned char *p21, const unsigned char *c8, unsigned char *p24)
+{
+	int rc;
+
+	rc = smbhash(p24, c8, p21);
+	if (rc)
+		return rc;
+	rc = smbhash(p24 + 8, c8, p21 + 7);
+	if (rc)
+		return rc;
+	rc = smbhash(p24 + 16, c8, p21 + 14);
+	return rc;
+}
+
+/* produce a md4 message digest from data of length n bytes */
+int
 mdfour(unsigned char *md4_hash, unsigned char *link_str, int link_len)
 {
 	int rc;
@@ -65,6 +132,32 @@
 }
 
 /*
+   This implements the X/Open SMB password encryption
+   It takes a password, a 8 byte "crypt key" and puts 24 bytes of
+   encrypted password into p24 */
+/* Note that password must be uppercased and null terminated */
+int
+SMBencrypt(unsigned char *passwd, const unsigned char *c8, unsigned char *p24)
+{
+	int rc;
+	unsigned char p14[14], p16[16], p21[21];
+
+	memset(p14, '\0', 14);
+	memset(p16, '\0', 16);
+	memset(p21, '\0', 21);
+
+	memcpy(p14, passwd, 14);
+	rc = E_P16(p14, p16);
+	if (rc)
+		return rc;
+
+	memcpy(p21, p16, 16);
+	rc = E_P24(p21, c8, p24);
+
+	return rc;
+}
+
+/*
  * Creates the MD4 Hash of the users password in NT UNICODE.
  */
 
@@ -89,3 +182,25 @@
 
 	return rc;
 }
+
+/* Does the NT MD4 hash then des encryption. */
+int
+SMBNTencrypt(unsigned char *passwd, unsigned char *c8, unsigned char *p24,
+		const struct nls_table *codepage)
+{
+	int rc;
+	unsigned char p16[16], p21[21];
+
+	memset(p16, '\0', 16);
+	memset(p21, '\0', 21);
+
+	rc = E_md4hash(passwd, p16, codepage);
+	if (rc) {
+		cifs_dbg(FYI, "%s Can't generate NT hash, error: %d\n",
+			 __func__, rc);
+		return rc;
+	}
+	memcpy(p21, p16, 16);
+	rc = E_P24(p21, c8, p24);
+	return rc;
+}