NTLM auth and sign - Define crypto hash functions and create and send keys needed for key exchange

Mark dependency on crypto modules in Kconfig.

Defining per structures sdesc and cifs_secmech which are used to store
crypto hash functions and contexts.  They are stored per smb connection
and used for all auth mechs to genereate hash values and signatures.

Allocate crypto hashing functions, security descriptiors, and respective
contexts when a smb/tcp connection is established.
Release them when a tcp/smb connection is taken down.

md5 and hmac-md5 are two crypto hashing functions that are used
throught the life of an smb/tcp connection by various functions that
calcualte signagure and ntlmv2 hash, HMAC etc.

structure ntlmssp_auth is defined as per smb connection.

ntlmssp_auth holds ciphertext which is genereated by rc4/arc4 encryption of
secondary key, a nonce using ntlmv2 session key and sent in the session key
field of the type 3 message sent by the client during ntlmssp
negotiation/exchange

A key is exchanged with the server if client indicates so in flags in
type 1 messsage and server agrees in flag in type 2 message of ntlmssp
negotiation.  If both client and agree, a key sent by client in
type 3 message of ntlmssp negotiation in the session key field.
The key is a ciphertext generated off of secondary key, a nonce, using
ntlmv2 hash via rc4/arc4.

Signing works for ntlmssp in this patch. The sequence number within
the server structure needs to be zero until session is established
i.e. till type 3 packet of ntlmssp exchange of a to be very first
smb session on that smb connection is sent.

Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 66f76b2..7ca5f6d 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -25,6 +25,9 @@
 #include <linux/workqueue.h>
 #include "cifs_fs_sb.h"
 #include "cifsacl.h"
+#include <crypto/internal/hash.h>
+#include <linux/scatterlist.h>
+
 /*
  * The sizes of various internal tables and strings
  */
@@ -102,6 +105,27 @@ struct session_key {
 	char *response;
 };
 
+/* crypto security descriptor definition */
+struct sdesc {
+	struct shash_desc shash;
+	char ctx[];
+};
+
+/* crypto hashing related structure/fields, not speicific to a sec mech */
+struct cifs_secmech {
+	struct crypto_shash *hmacmd5; /* hmac-md5 hash function */
+	struct crypto_shash *md5; /* md5 hash function */
+	struct sdesc *sdeschmacmd5;  /* ctxt to generate ntlmv2 hash, CR1 */
+	struct sdesc *sdescmd5; /* ctxt to generate cifs/smb signature */
+};
+
+/* per smb connection structure/fields */
+struct ntlmssp_auth {
+	__u32 client_flags; /* sent by client in type 1 ntlmsssp exchange */
+	__u32 server_flags; /* sent by server in type 2 ntlmssp exchange */
+	unsigned char ciphertext[CIFS_CPHTXT_SIZE]; /* sent to server */
+};
+
 struct cifs_cred {
 	int uid;
 	int gid;
@@ -178,6 +202,7 @@ struct TCP_Server_Info {
 	struct session_key session_key;
 	unsigned long lstrp; /* when we got last response from this server */
 	u16 dialect; /* dialect index that server chose */
+	struct cifs_secmech secmech; /* crypto sec mech functs, descriptors */
 	/* extended security flavors that server supports */
 	bool	sec_kerberos;		/* supports plain Kerberos */
 	bool	sec_mskerberos;		/* supports legacy MS Kerberos */
@@ -220,6 +245,7 @@ struct cifsSesInfo {
 	char ntlmv2_hash[16];
 	unsigned int tilen; /* length of the target info blob */
 	unsigned char *tiblob; /* target info blob in challenge response */
+	struct ntlmssp_auth ntlmssp; /* ciphertext, flags */
 	bool need_reconnect:1; /* connection reset, uid now invalid */
 };
 /* no more than one of the following three session flags may be set */