cifs: track the enablement of signing in the TCP_Server_Info

Currently, we determine this according to flags in the sec_mode, flags
in the global_secflags and via other methods. That makes the semantics
very hard to follow and there are corner cases where we don't handle
this correctly.

Add a new bool to the TCP_Server_Info that acts as a simple flag to tell
us whether signing is enabled on this connection or not, and fix up the
places that need to determine this to use that flag.

This is a bit weird for the SMB2 case, where signing is per-session.
SMB2 needs work in this area already though. The existing SMB2 code has
similar logic to what we're using here, so there should be no real
change in behavior. These changes should make it easier to implement
per-session signing in the future though.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 2f3a89a2c497767ac47e549f2fbaebe47ab15f0c..49020ae460cff5e0e1dd5c9e34bfc5d1d1b5c4ff 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -511,6 +511,7 @@ struct TCP_Server_Info {
        struct task_struct *tsk;
        char server_GUID[16];
        __u16 sec_mode;
+       bool sign; /* is signing enabled on this connection? */
        bool session_estab; /* mark when very first sess is established */
 #ifdef CONFIG_CIFS_SMB2
        int echo_credits;  /* echo reserved slots */

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index f0e93ffe654cc8cdb556468f34e8d9b81199aa99..ede010fd046af07dcc0138a6a280c7019894e876 100644 (file)
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -212,7 +212,7 @@ extern int cifs_negotiate_protocol(const unsigned int xid,
                                   struct cifs_ses *ses);
 extern int cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
                              struct nls_table *nls_info);
-extern int cifs_enable_signing(struct TCP_Server_Info *server, unsigned int secFlags);
+extern int cifs_enable_signing(struct TCP_Server_Info *server, bool mnt_sign_required);
 extern int CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses);
 
 extern int CIFSTCon(const unsigned int xid, struct cifs_ses *ses,

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 80ca6886a8166310635a1855da9b4e4204a14504..dd7e2f61f6078620776d8c942e4929061ae82d27 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -418,32 +418,43 @@ decode_ext_sec_blob(struct TCP_Server_Info *server, NEGOTIATE_RSP *pSMBr)
 }
 
 int
-cifs_enable_signing(struct TCP_Server_Info *server, unsigned int secFlags)
+cifs_enable_signing(struct TCP_Server_Info *server, bool mnt_sign_required)
 {
-       if ((secFlags & CIFSSEC_MAY_SIGN) == 0) {
-               /* MUST_SIGN already includes the MAY_SIGN FLAG
-                  so if this is zero it means that signing is disabled */
-               cifs_dbg(FYI, "Signing disabled\n");
-               if (server->sec_mode & SECMODE_SIGN_REQUIRED) {
-                       cifs_dbg(VFS, "Server requires packet signing to be enabled in /proc/fs/cifs/SecurityFlags\n");
-                       return -EOPNOTSUPP;
+       bool srv_sign_required = server->sec_mode & SECMODE_SIGN_REQUIRED;
+       bool srv_sign_enabled = server->sec_mode & SECMODE_SIGN_ENABLED;
+       bool mnt_sign_enabled = global_secflags & CIFSSEC_MAY_SIGN;
+
+       /*
+        * Is signing required by mnt options? If not then check
+        * global_secflags to see if it is there.
+        */
+       if (!mnt_sign_required)
+               mnt_sign_required = ((global_secflags & CIFSSEC_MUST_SIGN) ==
+                                               CIFSSEC_MUST_SIGN);
+
+       /*
+        * If signing is required then it's automatically enabled too,
+        * otherwise, check to see if the secflags allow it.
+        */
+       mnt_sign_enabled = mnt_sign_required ? mnt_sign_required :
+                               (global_secflags & CIFSSEC_MAY_SIGN);
+
+       /* If server requires signing, does client allow it? */
+       if (srv_sign_required) {
+               if (!mnt_sign_enabled) {
+                       cifs_dbg(VFS, "Server requires signing, but it's disabled in SecurityFlags!");
+                       return -ENOTSUPP;
                }
-               server->sec_mode &=
-                       ~(SECMODE_SIGN_ENABLED | SECMODE_SIGN_REQUIRED);
-       } else if ((secFlags & CIFSSEC_MUST_SIGN) == CIFSSEC_MUST_SIGN) {
-               /* signing required */
-               cifs_dbg(FYI, "Must sign - secFlags 0x%x\n", secFlags);
-               if ((server->sec_mode &
-                       (SECMODE_SIGN_ENABLED | SECMODE_SIGN_REQUIRED)) == 0) {
-                       cifs_dbg(VFS, "signing required but server lacks support\n");
-                       return -EOPNOTSUPP;
-               } else
-                       server->sec_mode |= SECMODE_SIGN_REQUIRED;
-       } else {
-               /* signing optional ie CIFSSEC_MAY_SIGN */
-               if ((server->sec_mode & SECMODE_SIGN_REQUIRED) == 0)
-                       server->sec_mode &=
-                               ~(SECMODE_SIGN_ENABLED | SECMODE_SIGN_REQUIRED);
+               server->sign = true;
+       }
+
+       /* If client requires signing, does server allow it? */
+       if (mnt_sign_required) {
+               if (!srv_sign_enabled) {
+                       cifs_dbg(VFS, "Server does not support signing!");
+                       return -ENOTSUPP;
+               }
+               server->sign = true;
        }
 
        return 0;
@@ -685,7 +696,7 @@ CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses)
 
 signing_check:
        if (!rc)
-               rc = cifs_enable_signing(server, secFlags);
+               rc = cifs_enable_signing(server, ses->sign);
 neg_err_exit:
        cifs_buf_release(pSMB);
 
@@ -810,9 +821,8 @@ CIFSSMBLogoff(const unsigned int xid, struct cifs_ses *ses)
 
        pSMB->hdr.Mid = get_next_mid(ses->server);
 
-       if (ses->server->sec_mode &
-                  (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
-                       pSMB->hdr.Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
+       if (ses->server->sign)
+               pSMB->hdr.Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 
        pSMB->hdr.Uid = ses->Suid;
 
@@ -1573,8 +1583,7 @@ cifs_readv_callback(struct mid_q_entry *mid)
        switch (mid->mid_state) {
        case MID_RESPONSE_RECEIVED:
                /* result already set, check signature */
-               if (server->sec_mode &
-                   (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
+               if (server->sign) {
                        int rc = 0;
 
                        rc = cifs_verify_signature(&rqst, server,
@@ -4827,11 +4836,8 @@ getDFSRetry:
                strncpy(pSMB->RequestFileName, search_name, name_len);
        }
 
-       if (ses->server) {
-               if (ses->server->sec_mode &
-                  (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
-                       pSMB->hdr.Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
-       }
+       if (ses->server && ses->server->sign)
+               pSMB->hdr.Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 
        pSMB->hdr.Uid = ses->Suid;
 

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index f638b5e1a2d27eeac1e75610eea772ef5b0f0ab9..acbb255352af78e46ea974e6355b398a779a7500 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2037,13 +2037,8 @@ match_security(struct TCP_Server_Info *server, struct smb_vol *vol)
        }
 
        /* now check if signing mode is acceptable */
-       if ((secFlags & CIFSSEC_MAY_SIGN) == 0 &&
-           (server->sec_mode & SECMODE_SIGN_REQUIRED))
-                       return false;
-       else if (((secFlags & CIFSSEC_MUST_SIGN) == CIFSSEC_MUST_SIGN) &&
-                (server->sec_mode &
-                 (SECMODE_SIGN_ENABLED|SECMODE_SIGN_REQUIRED)) == 0)
-                       return false;
+       if (vol->sign && !server->sign)
+               return false;
 
        return true;
 }
@@ -3704,8 +3699,7 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
                }
        }
 
-       if (ses->server->sec_mode &
-                       (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
+       if (ses->server->sign)
                smb_buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 
        if (ses->capabilities & CAP_STATUS32) {

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 1bec014779fd8e92a679643fd1a554de68fbd96a..f7d4b2285efea06fee58d52b94e72a332412cb1a 100644 (file)
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -267,8 +267,7 @@ header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
                if (treeCon->nocase)
                        buffer->Flags  |= SMBFLG_CASELESS;
                if ((treeCon->ses) && (treeCon->ses->server))
-                       if (treeCon->ses->server->sec_mode &
-                         (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
+                       if (treeCon->ses->server->sign)
                                buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
        }
 

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 0d0fe38f66a2293a6964f9a53a337c2ecc0a0ad3..82b784a62c16424cddecf2374fc4560e0507e739 100644 (file)
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -138,8 +138,7 @@ static __u32 cifs_ssetup_hdr(struct cifs_ses *ses, SESSION_SETUP_ANDX *pSMB)
        capabilities = CAP_LARGE_FILES | CAP_NT_SMBS | CAP_LEVEL_II_OPLOCKS |
                        CAP_LARGE_WRITE_X | CAP_LARGE_READ_X;
 
-       if (ses->server->sec_mode &
-           (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
+       if (ses->server->sign)
                pSMB->req.hdr.Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 
        if (ses->capabilities & CAP_UNICODE) {
@@ -427,8 +426,7 @@ void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
        flags = NTLMSSP_NEGOTIATE_56 |  NTLMSSP_REQUEST_TARGET |
                NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
                NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC;
-       if (ses->server->sec_mode &
-                       (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
+       if (ses->server->sign) {
                flags |= NTLMSSP_NEGOTIATE_SIGN;
                if (!ses->server->session_estab)
                        flags |= NTLMSSP_NEGOTIATE_KEY_XCH;
@@ -466,8 +464,7 @@ int build_ntlmssp_auth_blob(unsigned char *pbuffer,
                NTLMSSP_REQUEST_TARGET | NTLMSSP_NEGOTIATE_TARGET_INFO |
                NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
                NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC;
-       if (ses->server->sec_mode &
-          (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
+       if (ses->server->sign) {
                flags |= NTLMSSP_NEGOTIATE_SIGN;
                if (!ses->server->session_estab)
                        flags |= NTLMSSP_NEGOTIATE_KEY_XCH;

diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index 7d1c78bce4ae4d708268852f6488a24fd0e236ab..b28aabd33edd18a54192c909802c680cd6b3445e 100644 (file)
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -449,8 +449,7 @@ cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
         * WRITEX header, not including the 4 byte RFC1001 length.
         */
        if (!(server->capabilities & CAP_LARGE_WRITE_X) ||
-           (!(server->capabilities & CAP_UNIX) &&
-            (server->sec_mode & (SECMODE_SIGN_ENABLED|SECMODE_SIGN_REQUIRED))))
+           (!(server->capabilities & CAP_UNIX) && server->sign))
                wsize = min_t(unsigned int, wsize,
                                server->maxBuf - sizeof(WRITE_REQ) + 4);
 

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 1609699e7bec3a6ae4b1912df4af9dbe77de3059..ad8ef10de0bdda16fb2b544007521e831e5e577e 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -119,8 +119,7 @@ smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
        /* BB how does SMB2 do case sensitive? */
        /* if (tcon->nocase)
                hdr->Flags |= SMBFLG_CASELESS; */
-       if (tcon->ses && tcon->ses->server &&
-           (tcon->ses->server->sec_mode & SECMODE_SIGN_REQUIRED))
+       if (tcon->ses && tcon->ses->server && tcon->ses->server->sign)
                hdr->Flags |= SMB2_FLAGS_SIGNED;
 out:
        pdu->StructureSize2 = cpu_to_le16(parmsize);
@@ -330,7 +329,6 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
        int resp_buftype;
        struct TCP_Server_Info *server = ses->server;
        unsigned int sec_flags;
-       u16 temp = 0;
        int blob_offset, blob_length;
        char *security_blob;
        int flags = CIFS_NEG_OP;
@@ -362,12 +360,12 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
        inc_rfc1001_len(req, 2);
 
        /* only one of SMB2 signing flags may be set in SMB2 request */
-       if ((sec_flags & CIFSSEC_MUST_SIGN) == CIFSSEC_MUST_SIGN)
-               temp = SMB2_NEGOTIATE_SIGNING_REQUIRED;
-       else if (sec_flags & CIFSSEC_MAY_SIGN) /* MAY_SIGN is a single flag */
-               temp = SMB2_NEGOTIATE_SIGNING_ENABLED;
-
-       req->SecurityMode = cpu_to_le16(temp);
+       if (ses->sign)
+               req->SecurityMode = SMB2_NEGOTIATE_SIGNING_REQUIRED;
+       else if (global_secflags & CIFSSEC_MAY_SIGN)
+               req->SecurityMode = SMB2_NEGOTIATE_SIGNING_ENABLED;
+       else
+               req->SecurityMode = 0;
 
        req->Capabilities = cpu_to_le32(ses->server->vals->req_capabilities);
 
@@ -424,8 +422,7 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
                goto neg_exit;
        }
 
-       cifs_dbg(FYI, "sec_flags 0x%x\n", sec_flags);
-       rc = cifs_enable_signing(server, sec_flags);
+       rc = cifs_enable_signing(server, ses->sign);
 #ifdef CONFIG_SMB2_ASN1  /* BB REMOVEME when updated asn1.c ready */
        if (rc)
                goto neg_exit;
@@ -457,7 +454,6 @@ SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
        __le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
        struct TCP_Server_Info *server = ses->server;
        unsigned int sec_flags;
-       u8 temp = 0;
        u16 blob_length = 0;
        char *security_blob;
        char *ntlmssp_blob = NULL;
@@ -502,14 +498,13 @@ ssetup_ntlmssp_authenticate:
        req->hdr.CreditRequest = cpu_to_le16(3);
 
        /* only one of SMB2 signing flags may be set in SMB2 request */
-       if ((sec_flags & CIFSSEC_MUST_SIGN) == CIFSSEC_MUST_SIGN)
-               temp = SMB2_NEGOTIATE_SIGNING_REQUIRED;
-       else if (ses->server->sec_mode & SMB2_NEGOTIATE_SIGNING_REQUIRED)
-               temp = SMB2_NEGOTIATE_SIGNING_REQUIRED;
-       else if (sec_flags & CIFSSEC_MAY_SIGN) /* MAY_SIGN is a single flag */
-               temp = SMB2_NEGOTIATE_SIGNING_ENABLED;
-
-       req->SecurityMode = temp;
+       if (server->sign)
+               req->SecurityMode = SMB2_NEGOTIATE_SIGNING_REQUIRED;
+       else if (global_secflags & CIFSSEC_MAY_SIGN) /* one flag unlike MUST_ */
+               req->SecurityMode = SMB2_NEGOTIATE_SIGNING_ENABLED;
+       else
+               req->SecurityMode = 0;
+
        req->Capabilities = 0;
        req->Channel = 0; /* MBZ */
 
@@ -652,7 +647,7 @@ SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
 
         /* since no tcon, smb2_init can not do this, so do here */
        req->hdr.SessionId = ses->Suid;
-       if (server->sec_mode & SECMODE_SIGN_REQUIRED)
+       if (server->sign)
                req->hdr.Flags |= SMB2_FLAGS_SIGNED;
 
        rc = SendReceiveNoRsp(xid, ses, (char *) &req->hdr, 0);
@@ -1357,8 +1352,7 @@ smb2_readv_callback(struct mid_q_entry *mid)
        case MID_RESPONSE_RECEIVED:
                credits_received = le16_to_cpu(buf->CreditRequest);
                /* result already set, check signature */
-               if (server->sec_mode &
-                   (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
+               if (server->sign) {
                        int rc;
 
                        rc = smb2_verify_signature(&rqst, server);

diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index 01f0ac8007809a9514ac72ae34f066914168afb0..c802ecfa770e0812edd995fac7ff98c4bc2e43f6 100644 (file)
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -275,8 +275,7 @@ smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 
        dump_smb(mid->resp_buf, min_t(u32, 80, len));
        /* convert the length into a more usable form */
-       if ((len > 24) &&
-           (server->sec_mode & (SECMODE_SIGN_REQUIRED|SECMODE_SIGN_ENABLED))) {
+       if (len > 24 && server->sign) {
                int rc;
 
                rc = smb2_verify_signature(&rqst, server);

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index bfbf4700d160f8a4d54f7cc0446a35c4de8c747d..1996d6ceb8338651dd1fce8df90af787ae2ad680 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -463,7 +463,7 @@ cifs_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
        struct mid_q_entry *mid;
 
        /* enable signing if server requires it */
-       if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
+       if (server->sign)
                hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 
        mid = AllocMidQEntry(hdr, server);
@@ -612,7 +612,7 @@ cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
        dump_smb(mid->resp_buf, min_t(u32, 92, len));
 
        /* convert the length into a more usable form */
-       if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
+       if (server->sign) {
                struct kvec iov;
                int rc = 0;
                struct smb_rqst rqst = { .rq_iov = &iov,