From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
Attribue Value (AV) pairs or Target Info (TI) pairs are part of
ntlmv2 authentication.
Structure ntlmv2_resp had only definition for two av pairs.
So removed it, and now allocation of av pairs is dynamic.
For servers like Windows 7/2008, av pairs sent by server in
challege packet (type 2 in the ntlmssp exchange/negotiation) can
vary.
Server sends them during ntlmssp negotiation. So when ntlmssp is used
as an authentication mechanism, type 2 challenge packet from server
has this information. Pluck it and use the entire blob for
authenticaiton purpose. If user has not specified, extract
(netbios) domain name from the av pairs which is used to calculate
ntlmv2 hash. Servers like Windows 7 are particular about the AV pair
blob.
Servers like Windows 2003, are not very strict about the contents
of av pair blob used during ntlmv2 authentication.
So when security mechanism such as ntlmv2 is used (not ntlmv2 in ntlmssp),
there is no negotiation and so genereate a minimal blob that gets
used in ntlmv2 authentication as well as gets sent.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
---
fs/cifs/cifsencrypt.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++--
fs/cifs/cifspdu.h | 1 -
fs/cifs/connect.c | 2 +
fs/cifs/sess.c | 18 +++++++++++
4 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 4772c4d..e53fbeb 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -27,6 +27,7 @@
#include "md5.h"
#include "cifs_unicode.h"
#include "cifsproto.h"
+#include "ntlmssp.h"
#include <linux/ctype.h>
#include <linux/random.h>
@@ -263,6 +264,78 @@ void calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
}
#endif /* CIFS_WEAK_PW_HASH */
+/* This is just a filler for ntlmv2 type of security mechanisms.
+ * Older servers are not very particular about the contents of av pairs
+ * in the blob and for sec mechs like ntlmv2, there is no negotiation
+ * as in ntlmssp, so unless domain and server netbios and dns names
+ * are specified, there is no way to obtain name. In case of ntlmssp,
+ * server provides that info in type 2 challenge packet
+ */
+
+static int
+build_avpair_blob(struct cifsSesInfo *ses)
+{
+ struct ntlmssp2_name *attrptr;
+
+ ses->tilen = 2 * sizeof(struct ntlmssp2_name);
+ ses->tiblob = kzalloc(ses->tilen, GFP_KERNEL);
+ if (!ses->tiblob) {
+ ses->tilen = 0;
+ cERROR(1, "Challenge target info allocation failure");
+ return -ENOMEM;
+ }
+ attrptr = (struct ntlmssp2_name *) ses->tiblob;
+ attrptr->type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
+
+ return 0;
+}
+
+/* Server has provided av pairs/target info in the type 2 challenge
+ * packet and we have plucked it and stored within smb connection.
+ * We parse that blob here to find netbios domain name to be used
+ * as part of ntlmv2 authentication, if not already specified on
+ * the command line
+ */
+
+static int
+find_domain_name(struct cifsSesInfo *ses)
+{
+ int rc = 0;
+ unsigned int attrsize;
+ unsigned int type;
+ unsigned char *blobptr;
+ struct ntlmssp2_name *attrptr;
+
+ if (ses->tiblob) {
+ blobptr = ses->tiblob;
+ attrptr = (struct ntlmssp2_name *) blobptr;
+
+ while ((type = attrptr->type) != 0) {
+ blobptr += 2; /* advance attr type */
+ attrsize = attrptr->length;
+ blobptr += 2; /* advance attr size */
+ if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
+ if (!ses->domainName) {
+ ses->domainName =
+ kmalloc(attrptr->length + 1,
+ GFP_KERNEL);
+ if (!ses->domainName)
+ return -ENOMEM;
+ cifs_from_ucs2(ses->domainName,
+ (__le16 *)blobptr,
+ attrptr->length,
+ attrptr->length,
+ load_nls_default(), false);
+ }
+ }
+ blobptr += attrsize; /* advance attr value */
+ attrptr = (struct ntlmssp2_name *) blobptr;
+ }
+ }
+
+ return rc;
+}
+
static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
const struct nls_table *nls_cp)
{
@@ -334,10 +407,6 @@ void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
buf->reserved2 = 0;
- buf->names[0].type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
- buf->names[0].length = 0;
- buf->names[1].type = 0;
- buf->names[1].length = 0;
/* calculate buf->ntlmv2_hash */
rc = calc_ntlmv2_hash(ses, nls_cp);
diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
index f5c78fb..dc90a36 100644
--- a/fs/cifs/cifspdu.h
+++ b/fs/cifs/cifspdu.h
@@ -670,7 +670,6 @@ struct ntlmv2_resp {
__le64 time;
__u64 client_chal; /* random */
__u32 reserved2;
- struct ntlmssp2_name names[2];
/* array of name entries could follow ending in minimum 4 byte struct */
} __attribute__((packed));
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index f5369e7..0621a72 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1768,6 +1768,8 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info)
if (ses == NULL)
goto get_ses_fail;
+ ses->tilen = 0;
+ ses->tiblob = NULL;
/* new SMB session uses our server ref */
ses->server = server;
if (server->addr.sockAddr6.sin6_family == AF_INET6)
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 0a57cb7..756f410 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -383,6 +383,9 @@ static int decode_ascii_ssetup(char **pbcc_area, int bleft,
static int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
struct cifsSesInfo *ses)
{
+ unsigned int tioffset; /* challenge message target info area */
+ unsigned int tilen; /* challenge message target info area length */
+
CHALLENGE_MESSAGE *pblob = (CHALLENGE_MESSAGE *)bcc_ptr;
if (blob_len < sizeof(CHALLENGE_MESSAGE)) {
@@ -405,6 +408,20 @@ static int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
/* BB spec says that if AvId field of MsvAvTimestamp is populated then
we must set the MIC field of the AUTHENTICATE_MESSAGE */
+ ses->server->ntlmssp.server_flags = le32_to_cpu(pblob->NegotiateFlags);
+
+ tioffset = cpu_to_le16(pblob->TargetInfoArray.BufferOffset);
+ tilen = cpu_to_le16(pblob->TargetInfoArray.Length);
+ ses->tilen = tilen;
+ if (ses->tilen) {
+ ses->tiblob = kmalloc(tilen, GFP_KERNEL);
+ if (!ses->tiblob) {
+ cERROR(1, "Challenge target info allocation failure");
+ return -ENOMEM;
+ }
+ memcpy(ses->tiblob, bcc_ptr + tioffset, ses->tilen);
+ }
+
return 0;
}
@@ -533,6 +550,7 @@ static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
sec_blob->SessionKey.BufferOffset = cpu_to_le32(tmp - pbuffer);
sec_blob->SessionKey.Length = 0;
sec_blob->SessionKey.MaximumLength = 0;
+
return tmp - pbuffer;
}
--
1.6.0.2
--
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