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Subject[PATCH 4.16 056/196] CIFS: implement v3.11 preauth integrity
Date
4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Aurelien Aptel <aaptel@suse.com>

commit 8bd68c6e47abff34e412a0c68cecb4a36bf0198b upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/cifs/cifsglob.h | 5 ++--
fs/cifs/smb2misc.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/cifs/smb2pdu.c | 25 ++++++++++++++++++++
fs/cifs/smb2pdu.h | 1
fs/cifs/smb2proto.h | 2 +
fs/cifs/transport.c | 17 +++++++++++++
6 files changed, 112 insertions(+), 2 deletions(-)

--- 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 */
};

--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -706,3 +706,67 @@ smb2_handle_cancelled_mid(char *buffer,

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
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -453,6 +453,10 @@ SMB2_negotiate(const unsigned int xid, s
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, s

/* 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 unsign
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,
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);

--- 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 */
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -204,5 +204,7 @@ extern enum securityEnum smb2_select_sec
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 */
--- 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, s
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, s
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,

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