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Commit 429b46f4 authored by Steve French's avatar Steve French
Browse files

[CIFS] SMB3 Signing enablement 



SMB3 uses a much faster method of signing (which is also better in other ways),
AES-CMAC.  With the kernel now supporting AES-CMAC since last release, we
are overdue to allow SMB3 signing (today only CIFS and SMB2 and SMB2.1,
but not SMB3 and SMB3.1 can sign) - and we need this also for checking
secure negotation and also per-share encryption (two other new SMB3 features
which we need to implement).

This patch needs some work in a few areas - for example we need to
move signing for SMB2/SMB3 from per-socket to per-user (we may be able to
use the "nosharesock" mount option in the interim for the multiuser case),
and Shirish found a bug in the earlier authentication overhaul
(setting signing flags properly) - but those can be done in followon
patches.

Signed-off-by: default avatarShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent f87ab88b

fs/cifs/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ config CIFS 
	select CRYPTO_ECB

	select CRYPTO_DES

	select CRYPTO_SHA256

	select CRYPTO_CMAC

	help

	  This is the client VFS module for the Common Internet File System

	  (CIFS) protocol which is the successor to the Server Message Block

fs/cifs/cifsencrypt.c

+29 −0
Original line number Diff line number Diff line
@@ -705,6 +705,9 @@ calc_seckey(struct cifs_ses *ses) 
void

cifs_crypto_shash_release(struct TCP_Server_Info *server)

{

	if (server->secmech.cmacaes)

		crypto_free_shash(server->secmech.cmacaes);



	if (server->secmech.hmacsha256)

		crypto_free_shash(server->secmech.hmacsha256);
@@ -714,6 +717,8 @@ cifs_crypto_shash_release(struct TCP_Server_Info *server) 
	if (server->secmech.hmacmd5)

		crypto_free_shash(server->secmech.hmacmd5);



	kfree(server->secmech.sdesccmacaes);



	kfree(server->secmech.sdeschmacsha256);



	kfree(server->secmech.sdeschmacmd5);
@@ -747,6 +752,13 @@ cifs_crypto_shash_allocate(struct TCP_Server_Info *server) 
		goto crypto_allocate_hmacsha256_fail;

	}



	server->secmech.cmacaes = crypto_alloc_shash("cmac(aes)", 0, 0);

	if (IS_ERR(server->secmech.cmacaes)) {

		cifs_dbg(VFS, "could not allocate crypto cmac-aes");

		rc = PTR_ERR(server->secmech.cmacaes);

		goto crypto_allocate_cmacaes_fail;

	}



	size = sizeof(struct shash_desc) +

			crypto_shash_descsize(server->secmech.hmacmd5);

	server->secmech.sdeschmacmd5 = kmalloc(size, GFP_KERNEL);
@@ -777,8 +789,22 @@ cifs_crypto_shash_allocate(struct TCP_Server_Info *server) 
	server->secmech.sdeschmacsha256->shash.tfm = server->secmech.hmacsha256;

	server->secmech.sdeschmacsha256->shash.flags = 0x0;



	size = sizeof(struct shash_desc) +

			crypto_shash_descsize(server->secmech.cmacaes);

	server->secmech.sdesccmacaes = kmalloc(size, GFP_KERNEL);

	if (!server->secmech.sdesccmacaes) {

		cifs_dbg(VFS, "%s: Can't alloc cmacaes\n", __func__);

		rc = -ENOMEM;

		goto crypto_allocate_cmacaes_sdesc_fail;

	}

	server->secmech.sdesccmacaes->shash.tfm = server->secmech.cmacaes;

	server->secmech.sdesccmacaes->shash.flags = 0x0;



	return 0;



crypto_allocate_cmacaes_sdesc_fail:

	kfree(server->secmech.sdeschmacsha256);



crypto_allocate_hmacsha256_sdesc_fail:

	kfree(server->secmech.sdescmd5);
@@ -786,6 +812,9 @@ crypto_allocate_md5_sdesc_fail: 
	kfree(server->secmech.sdeschmacmd5);



crypto_allocate_hmacmd5_sdesc_fail:

	crypto_free_shash(server->secmech.cmacaes);



crypto_allocate_cmacaes_fail:

	crypto_free_shash(server->secmech.hmacsha256);



crypto_allocate_hmacsha256_fail:

fs/cifs/cifsglob.h

+3 −0
Original line number Diff line number Diff line
@@ -125,9 +125,11 @@ struct cifs_secmech { 
	struct crypto_shash *hmacmd5; /* hmac-md5 hash function */

	struct crypto_shash *md5; /* md5 hash function */

	struct crypto_shash *hmacsha256; /* hmac-sha256 hash function */

	struct crypto_shash *cmacaes; /* block-cipher based MAC function */

	struct sdesc *sdeschmacmd5;  /* ctxt to generate ntlmv2 hash, CR1 */

	struct sdesc *sdescmd5; /* ctxt to generate cifs/smb signature */

	struct sdesc *sdeschmacsha256;  /* ctxt to generate smb2 signature */

	struct sdesc *sdesccmacaes;  /* ctxt to generate smb3 signature */

};



/* per smb session structure/fields */
@@ -538,6 +540,7 @@ struct TCP_Server_Info { 
	int timeAdj;  /* Adjust for difference in server time zone in sec */

	__u64 CurrentMid;         /* multiplex id - rotating counter */

	char cryptkey[CIFS_CRYPTO_KEY_SIZE]; /* used by ntlm, ntlmv2 etc */

	char smb3signingkey[SMB3_SIGN_KEY_SIZE]; /* for signing smb3 packets */

	/* 16th byte of RFC1001 workstation name is always null */

	char workstation_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL];

	__u32 sequence_number; /* for signing, protected by srv_mutex */

fs/cifs/cifspdu.h

+5 −0
Original line number Diff line number Diff line
@@ -142,6 +142,11 @@ 
 */

#define CIFS_SESS_KEY_SIZE (16)



/*

 * Size of the smb3 signing key

 */

#define SMB3_SIGN_KEY_SIZE (16)



#define CIFS_CLIENT_CHALLENGE_SIZE (8)

#define CIFS_SERVER_CHALLENGE_SIZE (8)

#define CIFS_HMAC_MD5_HASH_SIZE (16)

fs/cifs/cifsproto.h

+1 −0
Original line number Diff line number Diff line
@@ -436,6 +436,7 @@ extern int setup_ntlmv2_rsp(struct cifs_ses *, const struct nls_table *); 
extern int cifs_crypto_shash_allocate(struct TCP_Server_Info *);

extern void cifs_crypto_shash_release(struct TCP_Server_Info *);

extern int calc_seckey(struct cifs_ses *);

extern int generate_smb3signingkey(struct TCP_Server_Info *);



#ifdef CONFIG_CIFS_WEAK_PW_HASH

extern int calc_lanman_hash(const char *password, const char *cryptkey,