[-v2,1/6] functions to either extract or create av_ pair/ti_info blob
diff mbox

Message ID 1295560604-4941-1-git-send-email-shirishpargaonkar@gmail.com
State New, archived
Headers show

Commit Message

Shirish Pargaonkar Jan. 20, 2011, 9:56 p.m. UTC
None

Patch
diff mbox

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 35042d8..a547d24 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>
 
@@ -262,6 +263,79 @@  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 session.
+ * We parse that blob here to find netbios domain name to be used
+ * as part of ntlmv2 authentication (in Target String), 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;
+	unsigned char *blobend;
+	struct ntlmssp2_name *attrptr;
+
+	if (ses->tiblob) {
+		blobend = ses->tiblob + ses->tilen;
+		blobptr = ses->tiblob;
+		attrptr = (struct ntlmssp2_name *) blobptr;
+
+		while (blobptr <= blobend &&
+				(type = attrptr->type) != NTLMSSP_AV_EOL) {
+			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)
 {
@@ -333,10 +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/cifsglob.h b/fs/cifs/cifsglob.h
index 0cdfb8c..2bfe682 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -222,6 +222,8 @@  struct cifsSesInfo {
 	char userName[MAX_USERNAME_SIZE + 1];
 	char *domainName;
 	char *password;
+	unsigned int tilen; /* length of the target info blob */
+	unsigned char *tiblob; /* target info blob in challenge response */
 	bool need_reconnect:1; /* connection reset, uid now invalid */
 };
 /* no more than one of the following three session flags may be set */
diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
index 14d036d..b0f4b56 100644
--- a/fs/cifs/cifspdu.h
+++ b/fs/cifs/cifspdu.h
@@ -663,7 +663,6 @@  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 67dad54..f8891a2 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1740,6 +1740,8 @@  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/ntlmssp.h b/fs/cifs/ntlmssp.h
index 49c9a4e..5d52e4a 100644
--- a/fs/cifs/ntlmssp.h
+++ b/fs/cifs/ntlmssp.h
@@ -61,6 +61,21 @@ 
 #define NTLMSSP_NEGOTIATE_KEY_XCH   0x40000000
 #define NTLMSSP_NEGOTIATE_56        0x80000000
 
+/* Define AV Pair Field IDs */
+enum av_field_type {
+	NTLMSSP_AV_EOL = 0,
+	NTLMSSP_AV_NB_COMPUTER_NAME,
+	NTLMSSP_AV_NB_DOMAIN_NAME,
+	NTLMSSP_AV_DNS_COMPUTER_NAME,
+	NTLMSSP_AV_DNS_DOMAIN_NAME,
+	NTLMSSP_AV_DNS_TREE_NAME,
+	NTLMSSP_AV_FLAGS,
+	NTLMSSP_AV_TIMESTAMP,
+	NTLMSSP_AV_RESTRICTION,
+	NTLMSSP_AV_TARGET_NAME,
+	NTLMSSP_AV_CHANNEL_BINDINGS
+};
+
 /* Although typedefs are not commonly used for structure definitions */
 /* in the Linux kernel, in this particular case they are useful      */
 /* to more closely match the standards document for NTLMSSP from     */
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 0a57cb7..2de5f08 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 +408,18 @@  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 */
 
+	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;
 }