[PATCH 4.2 137/258] [SMB3] Fix sec=krb5 on smb3 mounts
From: Greg Kroah-Hartman
Date: Sun Oct 18 2015 - 00:26:28 EST
4.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Steve French <smfrench@xxxxxxxxx>
commit ceb1b0b9b4d1089e9f2731a314689ae17784c861 upstream.
Kerberos, which is very important for security, was only enabled for
CIFS not SMB2/SMB3 mounts (e.g. vers=3.0)
Patch based on the information detailed in
http://thread.gmane.org/gmane.linux.kernel.cifs/10081/focus=10307
to enable Kerberized SMB2/SMB3
a) SMB2_negotiate: enable/use decode_negTokenInit in SMB2_negotiate
b) SMB2_sess_setup: handle Kerberos sectype and replicate Kerberos
SMB1 processing done in sess_auth_kerberos
Signed-off-by: Noel Power <noel.power@xxxxxxxx>
Signed-off-by: Jim McDonough <jmcd@xxxxxxxxx>
Signed-off-by: Steve French <steve.french@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/cifs/smb2pdu.c | 76 +++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 61 insertions(+), 15 deletions(-)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -46,6 +46,7 @@
#include "smb2status.h"
#include "smb2glob.h"
#include "cifspdu.h"
+#include "cifs_spnego.h"
/*
* The following table defines the expected "StructureSize" of SMB2 requests
@@ -486,19 +487,15 @@ SMB2_negotiate(const unsigned int xid, s
cifs_dbg(FYI, "missing security blob on negprot\n");
rc = cifs_enable_signing(server, ses->sign);
-#ifdef CONFIG_SMB2_ASN1 /* BB REMOVEME when updated asn1.c ready */
if (rc)
goto neg_exit;
- if (blob_length)
+ if (blob_length) {
rc = decode_negTokenInit(security_blob, blob_length, server);
- if (rc == 1)
- rc = 0;
- else if (rc == 0) {
- rc = -EIO;
- goto neg_exit;
+ if (rc == 1)
+ rc = 0;
+ else if (rc == 0)
+ rc = -EIO;
}
-#endif
-
neg_exit:
free_rsp_buf(resp_buftype, rsp);
return rc;
@@ -592,7 +589,8 @@ SMB2_sess_setup(const unsigned int xid,
__le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
struct TCP_Server_Info *server = ses->server;
u16 blob_length = 0;
- char *security_blob;
+ struct key *spnego_key = NULL;
+ char *security_blob = NULL;
char *ntlmssp_blob = NULL;
bool use_spnego = false; /* else use raw ntlmssp */
@@ -620,7 +618,8 @@ SMB2_sess_setup(const unsigned int xid,
ses->ntlmssp->sesskey_per_smbsess = true;
/* FIXME: allow for other auth types besides NTLMSSP (e.g. krb5) */
- ses->sectype = RawNTLMSSP;
+ if (ses->sectype != Kerberos && ses->sectype != RawNTLMSSP)
+ ses->sectype = RawNTLMSSP;
ssetup_ntlmssp_authenticate:
if (phase == NtLmChallenge)
@@ -649,7 +648,48 @@ ssetup_ntlmssp_authenticate:
iov[0].iov_base = (char *)req;
/* 4 for rfc1002 length field and 1 for pad */
iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;
- if (phase == NtLmNegotiate) {
+
+ if (ses->sectype == Kerberos) {
+#ifdef CONFIG_CIFS_UPCALL
+ struct cifs_spnego_msg *msg;
+
+ spnego_key = cifs_get_spnego_key(ses);
+ if (IS_ERR(spnego_key)) {
+ rc = PTR_ERR(spnego_key);
+ spnego_key = NULL;
+ goto ssetup_exit;
+ }
+
+ msg = spnego_key->payload.data;
+ /*
+ * check version field to make sure that cifs.upcall is
+ * sending us a response in an expected form
+ */
+ if (msg->version != CIFS_SPNEGO_UPCALL_VERSION) {
+ cifs_dbg(VFS,
+ "bad cifs.upcall version. Expected %d got %d",
+ CIFS_SPNEGO_UPCALL_VERSION, msg->version);
+ rc = -EKEYREJECTED;
+ goto ssetup_exit;
+ }
+ ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
+ GFP_KERNEL);
+ if (!ses->auth_key.response) {
+ cifs_dbg(VFS,
+ "Kerberos can't allocate (%u bytes) memory",
+ msg->sesskey_len);
+ rc = -ENOMEM;
+ goto ssetup_exit;
+ }
+ ses->auth_key.len = msg->sesskey_len;
+ blob_length = msg->secblob_len;
+ iov[1].iov_base = msg->data + msg->sesskey_len;
+ iov[1].iov_len = blob_length;
+#else
+ rc = -EOPNOTSUPP;
+ goto ssetup_exit;
+#endif /* CONFIG_CIFS_UPCALL */
+ } else if (phase == NtLmNegotiate) { /* if not krb5 must be ntlmssp */
ntlmssp_blob = kmalloc(sizeof(struct _NEGOTIATE_MESSAGE),
GFP_KERNEL);
if (ntlmssp_blob == NULL) {
@@ -672,6 +712,8 @@ ssetup_ntlmssp_authenticate:
/* with raw NTLMSSP we don't encapsulate in SPNEGO */
security_blob = ntlmssp_blob;
}
+ iov[1].iov_base = security_blob;
+ iov[1].iov_len = blob_length;
} else if (phase == NtLmAuthenticate) {
req->hdr.SessionId = ses->Suid;
ntlmssp_blob = kzalloc(sizeof(struct _NEGOTIATE_MESSAGE) + 500,
@@ -699,6 +741,8 @@ ssetup_ntlmssp_authenticate:
} else {
security_blob = ntlmssp_blob;
}
+ iov[1].iov_base = security_blob;
+ iov[1].iov_len = blob_length;
} else {
cifs_dbg(VFS, "illegal ntlmssp phase\n");
rc = -EIO;
@@ -710,8 +754,6 @@ ssetup_ntlmssp_authenticate:
cpu_to_le16(sizeof(struct smb2_sess_setup_req) -
1 /* pad */ - 4 /* rfc1001 len */);
req->SecurityBufferLength = cpu_to_le16(blob_length);
- iov[1].iov_base = security_blob;
- iov[1].iov_len = blob_length;
inc_rfc1001_len(req, blob_length - 1 /* pad */);
@@ -722,6 +764,7 @@ ssetup_ntlmssp_authenticate:
kfree(security_blob);
rsp = (struct smb2_sess_setup_rsp *)iov[0].iov_base;
+ ses->Suid = rsp->hdr.SessionId;
if (resp_buftype != CIFS_NO_BUFFER &&
rsp->hdr.Status == STATUS_MORE_PROCESSING_REQUIRED) {
if (phase != NtLmNegotiate) {
@@ -739,7 +782,6 @@ ssetup_ntlmssp_authenticate:
/* NTLMSSP Negotiate sent now processing challenge (response) */
phase = NtLmChallenge; /* process ntlmssp challenge */
rc = 0; /* MORE_PROCESSING is not an error here but expected */
- ses->Suid = rsp->hdr.SessionId;
rc = decode_ntlmssp_challenge(rsp->Buffer,
le16_to_cpu(rsp->SecurityBufferLength), ses);
}
@@ -796,6 +838,10 @@ keygen_exit:
kfree(ses->auth_key.response);
ses->auth_key.response = NULL;
}
+ if (spnego_key) {
+ key_invalidate(spnego_key);
+ key_put(spnego_key);
+ }
kfree(ses->ntlmssp);
return rc;
--
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