CIFS: implement v3.11 preauth integrity

SMB3.11 clients must implement pre-authentification integrity.

* new mechanism to certify requests/responses happening before Tree
  Connect.
* supersedes VALIDATE_NEGOTIATE
* fixes signing for SMB3.11

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 765fc2c..c294093 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -675,7 +675,8 @@ struct TCP_Server_Info {
        unsigned int    max_read;
        unsigned int    max_write;
 #ifdef CONFIG_CIFS_SMB311
-       __u8    preauth_sha_hash[64]; /* save initital negprot hash */
+        /* save initital negprot hash */
+       __u8    preauth_sha_hash[SMB2_PREAUTH_HASH_SIZE];
 #endif /* 3.1.1 */
        struct delayed_work reconnect; /* reconnect workqueue job */
        struct mutex reconnect_mutex; /* prevent simultaneous reconnects */
@@ -864,7 +865,7 @@ struct cifs_ses {
        __u8 smb3encryptionkey[SMB3_SIGN_KEY_SIZE];
        __u8 smb3decryptionkey[SMB3_SIGN_KEY_SIZE];
 #ifdef CONFIG_CIFS_SMB311
-       __u8 preauth_sha_hash[64];
+       __u8 preauth_sha_hash[SMB2_PREAUTH_HASH_SIZE];
 #endif /* 3.1.1 */
 };
 

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 76d03ab..da012c3 100644 (file)
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -706,3 +706,67 @@ smb2_handle_cancelled_mid(char *buffer, struct TCP_Server_Info *server)
 
        return 0;
 }
+
+#ifdef CONFIG_CIFS_SMB311
+/**
+ * smb311_update_preauth_hash - update @ses hash with the packet data in @iov
+ *
+ * Assumes @iov does not contain the rfc1002 length and iov[0] has the
+ * SMB2 header.
+ */
+int
+smb311_update_preauth_hash(struct cifs_ses *ses, struct kvec *iov, int nvec)
+{
+       int i, rc;
+       struct sdesc *d;
+       struct smb2_sync_hdr *hdr;
+
+       if (ses->server->tcpStatus == CifsGood) {
+               /* skip non smb311 connections */
+               if (ses->server->dialect != SMB311_PROT_ID)
+                       return 0;
+
+               /* skip last sess setup response */
+               hdr = (struct smb2_sync_hdr *)iov[0].iov_base;
+               if (hdr->Flags & SMB2_FLAGS_SIGNED)
+                       return 0;
+       }
+
+       rc = smb311_crypto_shash_allocate(ses->server);
+       if (rc)
+               return rc;
+
+       d = ses->server->secmech.sdescsha512;
+       rc = crypto_shash_init(&d->shash);
+       if (rc) {
+               cifs_dbg(VFS, "%s: could not init sha512 shash\n", __func__);
+               return rc;
+       }
+
+       rc = crypto_shash_update(&d->shash, ses->preauth_sha_hash,
+                                SMB2_PREAUTH_HASH_SIZE);
+       if (rc) {
+               cifs_dbg(VFS, "%s: could not update sha512 shash\n", __func__);
+               return rc;
+       }
+
+       for (i = 0; i < nvec; i++) {
+               rc = crypto_shash_update(&d->shash,
+                                        iov[i].iov_base, iov[i].iov_len);
+               if (rc) {
+                       cifs_dbg(VFS, "%s: could not update sha512 shash\n",
+                                __func__);
+                       return rc;
+               }
+       }
+
+       rc = crypto_shash_final(&d->shash, ses->preauth_sha_hash);
+       if (rc) {
+               cifs_dbg(VFS, "%s: could not finalize sha512 shash\n",
+                        __func__);
+               return rc;
+       }
+
+       return 0;
+}
+#endif

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index ab4c206..4b6920d 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -453,6 +453,10 @@ 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) {
@@ -564,6 +568,15 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 
        /* 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
+        * server.
+        */
+       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 */
@@ -621,6 +634,10 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
                return 0;
 #endif
 
+       /* In SMB3.11 preauth integrity supersedes validate negotiate */
+       if (tcon->ses->server->dialect == SMB311_PROT_ID)
+               return 0;
+
        /*
         * validation ioctl must be signed, so no point sending this if we
         * can not sign it (ie are not known user).  Even if signing is not
@@ -1148,6 +1165,14 @@ SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
        sess_data->buf0_type = CIFS_NO_BUFFER;
        sess_data->nls_cp = (struct nls_table *) nls_cp;
 
+#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);
 

diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 2a2b34c..8b901c6 100644 (file)
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -264,6 +264,7 @@ struct smb2_negotiate_req {
 #define SMB311_SALT_SIZE                       32
 /* Hash Algorithm Types */
 #define SMB2_PREAUTH_INTEGRITY_SHA512  cpu_to_le16(0x0001)
+#define SMB2_PREAUTH_HASH_SIZE 64
 
 struct smb2_preauth_neg_context {
        __le16  ContextType; /* 1 */

diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 3b8e9c2..cbcce3f 100644 (file)
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -204,5 +204,7 @@ extern enum securityEnum smb2_select_sectype(struct TCP_Server_Info *,
                                        enum securityEnum);
 #ifdef CONFIG_CIFS_SMB311
 extern int smb311_crypto_shash_allocate(struct TCP_Server_Info *server);
+extern int smb311_update_preauth_hash(struct cifs_ses *ses,
+                                     struct kvec *iov, int nvec);
 #endif
 #endif                 /* _SMB2PROTO_H */

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 9779b32..6656614 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -37,6 +37,7 @@
 #include "cifsglob.h"
 #include "cifsproto.h"
 #include "cifs_debug.h"
+#include "smb2proto.h"
 #include "smbdirect.h"
 
 /* Max number of iovectors we can use off the stack when sending requests. */
@@ -751,6 +752,12 @@ cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
        if (rc < 0)
                goto out;
 
+#ifdef CONFIG_CIFS_SMB311
+       if (ses->status == CifsNew)
+               smb311_update_preauth_hash(ses, rqst->rq_iov+1,
+                                          rqst->rq_nvec-1);
+#endif
+
        if (timeout == CIFS_ASYNC_OP)
                goto out;
 
@@ -789,6 +796,16 @@ cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
        else
                *resp_buf_type = CIFS_SMALL_BUFFER;
 
+#ifdef CONFIG_CIFS_SMB311
+       if (ses->status == CifsNew) {
+               struct kvec iov = {
+                       .iov_base = buf + 4,
+                       .iov_len = get_rfc1002_length(buf)
+               };
+               smb311_update_preauth_hash(ses, &iov, 1);
+       }
+#endif
+
        credits = ses->server->ops->get_credits(midQ);
 
        rc = ses->server->ops->check_receive(midQ, ses->server,