Fix readlink of dfs junctions

fs/cifs/cifspdu.h

@@ -1263,6 +1263,7 @@ typedef struct dfs_referral_level_3 {
 	__u16 ServerType;	/* 0x0001 = CIFS server */
 	__u16 ReferralFlags;	/* or proximity - not clear which since always set to zero - SNIA spec says 0x01 means strip off PathConsumed chars before submitting RequestFileName to remote node */
 	__u16 TimeToLive;
+	__u16 Proximity;
 	__u16 DfsPathOffset;
 	__u16 DfsAlternatePathOffset;
 	__u16 NetworkAddressOffset;

fs/cifs/cifsproto.h

@@ -127,13 +127,15 @@ extern int CIFSSMBUnixQPathInfo(const int xid,
 extern int CIFSGetDFSRefer(const int xid, struct cifsSesInfo *ses,
 			const unsigned char *searchName,
 			unsigned char **targetUNCs,
-			int *number_of_UNC_in_array,
+			unsigned int *number_of_UNC_in_array,
 			const struct nls_table *nls_codepage);
 
 extern int connect_to_dfs_path(int xid, struct cifsSesInfo *pSesInfo,
 			const char *old_path,
 			const struct nls_table *nls_codepage);
-
+extern int get_dfs_path(int xid, struct cifsSesInfo *pSesInfo,
+			const char *old_path, const struct nls_table *nls_codepage, 
+			unsigned int *pnum_referrals, unsigned char ** preferrals);
 extern int CIFSSMBQFSInfo(const int xid, struct cifsTconInfo *tcon,
 			struct statfs *FSData,
 			const struct nls_table *nls_codepage);

fs/cifs/cifssmb.c

@@ -1625,15 +1625,18 @@ int
 CIFSGetDFSRefer(const int xid, struct cifsSesInfo *ses,
 		const unsigned char *searchName,
 		unsigned char **targetUNCs,
-		int *number_of_UNC_in_array,
+		unsigned int *number_of_UNC_in_array,
 		const struct nls_table *nls_codepage)
 {
 /* TRANS2_GET_DFS_REFERRAL */
 	TRANSACTION2_GET_DFS_REFER_REQ *pSMB = NULL;
 	TRANSACTION2_GET_DFS_REFER_RSP *pSMBr = NULL;
+	struct dfs_referral_level_3 * referrals = NULL;
 	int rc = 0;
 	int bytes_returned;
 	int name_len;
+	unsigned int i;
+	char * temp;
 	*number_of_UNC_in_array = 0;
 	*targetUNCs = NULL;
 
@@ -1701,6 +1704,76 @@ CIFSGetDFSRefer(const int xid, struct cifsSesInfo *ses,
 		cFYI(1, ("Send error in GetDFSRefer = %d", rc));
 	} else {		/* decode response */
 /* BB Add logic to parse referrals here */
+		pSMBr->DataOffset = le16_to_cpu(pSMBr->DataOffset);
+		pSMBr->DataCount = le16_to_cpu(pSMBr->DataCount);
+		cFYI(1,
+		     ("Decoding GetDFSRefer response.  BCC: %d  Offset %d",
+		      pSMBr->ByteCount, pSMBr->DataOffset));
+		if ((pSMBr->ByteCount < 17) || (pSMBr->DataOffset > 512))	/* BB also check enough total bytes returned */
+			rc = -EIO;	/* bad smb */
+		else {
+			referrals = 
+			    (struct dfs_referral_level_3 *) 
+					(8 /* sizeof start of data block */ +
+					pSMBr->DataOffset +
+					(char *) &pSMBr->hdr.Protocol); 
+			cFYI(1,("num_referrals: %d dfs flags: 0x%x ... \nfor referral one refer size: 0x%x srv type: 0x%x refer flags: 0x%x ttl: 0x%x",pSMBr->NumberOfReferrals,pSMBr->DFSFlags, referrals->ReferralSize,referrals->ServerType,referrals->ReferralFlags,referrals->TimeToLive));
+			/* BB This field is actually two bytes in from start of
+			   data block so we could do safety check that DataBlock
+			   begins at address of pSMBr->NumberOfReferrals */
+			*number_of_UNC_in_array = le16_to_cpu(pSMBr->NumberOfReferrals);
+
+			/* BB Fix below so can return more than one referral */
+			if(*number_of_UNC_in_array > 1)
+				*number_of_UNC_in_array = 1;
+
+			/* get the length of the strings describing refs */
+			name_len = 0;
+			for(i=0;i<*number_of_UNC_in_array;i++) {
+				/* make sure that DfsPathOffset not past end */
+				referrals->DfsPathOffset = le16_to_cpu(referrals->DfsPathOffset);
+				if(referrals->DfsPathOffset > pSMBr->DataCount) {
+					/* if invalid referral, stop here and do 
+					not try to copy any more */
+					*number_of_UNC_in_array = i;
+					break;
+				} 
+				temp = ((char *)referrals) + referrals->DfsPathOffset;
+
+				if (pSMBr->hdr.Flags2 & SMBFLG2_UNICODE) {
+					name_len += UniStrnlen((wchar_t *)temp,pSMBr->DataCount);
+				} else {
+					name_len += strnlen(temp,pSMBr->DataCount);
+				}
+				referrals++;
+				/* BB add check that referral pointer does not fall off end PDU */
+				
+			}
+			/* BB add check for name_len bigger than bcc */
+			*targetUNCs = 
+				kmalloc(name_len+1+ (*number_of_UNC_in_array),GFP_KERNEL);
+			/* copy the ref strings */
+			referrals =  
+			    (struct dfs_referral_level_3 *) 
+					(8 /* sizeof data hdr */ +
+					pSMBr->DataOffset + 
+					(char *) &pSMBr->hdr.Protocol);
+
+			for(i=0;i<*number_of_UNC_in_array;i++) {
+				temp = ((char *)referrals) + referrals->DfsPathOffset;
+				if (pSMBr->hdr.Flags2 & SMBFLG2_UNICODE) {
+					cifs_strfromUCS_le(*targetUNCs,
+						(wchar_t *) temp, name_len, nls_codepage);
+				} else {
+					strncpy(*targetUNCs,temp,name_len);
+				}
+				/*  BB update target_uncs pointers */
+				referrals++;
+			}
+			temp = *targetUNCs;
+			temp[name_len] = 0;
+		}
+
 	}
 	if (pSMB)
 		buf_release(pSMB);

fs/cifs/connect.c

@@ -571,11 +571,32 @@ find_unc(__u32 new_target_ip_addr, char *uncName, char *userName)
 int
 connect_to_dfs_path(int xid, struct cifsSesInfo *pSesInfo,
 		    const char *old_path, const struct nls_table *nls_codepage)
+{
+	unsigned char *referrals = NULL;
+	unsigned int num_referrals;
+	int rc = 0;
+
+	rc = get_dfs_path(xid, pSesInfo,old_path, nls_codepage, 
+			&num_referrals, &referrals);
+
+	/* BB Add in code to: if valid refrl, if not ip address contact
+		the helper that resolves tcp names, mount to it, try to 
+		tcon to it unmount it if fail */
+
+	/* BB free memory for referrals string BB */
+
+	return rc;
+}
+
+int
+get_dfs_path(int xid, struct cifsSesInfo *pSesInfo,
+			const char *old_path, const struct nls_table *nls_codepage, 
+			unsigned int *pnum_referrals, unsigned char ** preferrals)
 {
 	char *temp_unc;
 	int rc = 0;
-	int num_referrals = 0;
-	unsigned char *referrals = NULL;
+
+	*pnum_referrals = 0;
 
 	if (pSesInfo->ipc_tid == 0) {
 		temp_unc = kmalloc(2 /* for slashes */ +
@@ -594,11 +615,10 @@ connect_to_dfs_path(int xid, struct cifsSesInfo *pSesInfo,
 		kfree(temp_unc);
 	}
 	if (rc == 0)
-		rc = CIFSGetDFSRefer(xid, pSesInfo, old_path, &referrals,
-				     &num_referrals, nls_codepage);
-
-	return -ENODEV;	/* BB remove and add return code processing */
+		rc = CIFSGetDFSRefer(xid, pSesInfo, old_path, preferrals,
+				     pnum_referrals, nls_codepage);
 
+	return rc;
 }
 
 int setup_session(unsigned int xid, struct cifsSesInfo *pSesInfo, struct nls_table * nls_info)

fs/cifs/inode.c

@@ -53,10 +53,6 @@ cifs_get_inode_info_unix(struct inode **pinode,
 	/* dump_mem("\nUnixQPathInfo return data", &findData, sizeof(findData)); */
 	if (rc) {
 		if (rc == -EREMOTE) {
-/* rc = *//* CIFSGetDFSRefer(xid, pTcon->ses, search_path,
-	&referrals,
-	&num_referrals,
-	cifs_sb->local_nls); */
 			tmp_path =
 			    kmalloc(strnlen
 				    (pTcon->treeName,
@@ -180,11 +176,6 @@ cifs_get_inode_info(struct inode **pinode,
 	/* dump_mem("\nQPathInfo return data",&findData, sizeof(findData)); */
 	if (rc) {
 		if (rc == -EREMOTE) {
-			/* BB add call to new func rc = GetDFSReferral(); */
-/* rc = *//* CIFSGetDFSRefer(xid, pTcon->ses, search_path,
-	&referrals,
-	&num_referrals,
-	cifs_sb->local_nls); */
 			tmp_path =
 			    kmalloc(strnlen
 				    (pTcon->treeName,

fs/cifs/link.c

@@ -113,6 +113,9 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 	/* BB Should we be using page symlink ops here? */
 
 	if (rc == 0) {
+
+/* BB Add special case check for Samba DFS symlinks */
+
 		target_path[PATH_MAX-1] = 0;
 		rc = vfs_follow_link(nd, target_path);
 	}
@@ -186,7 +189,10 @@ cifs_readlink(struct dentry *direntry, char *pBuffer, int buflen)
 	struct cifs_sb_info *cifs_sb;
 	struct cifsTconInfo *pTcon;
 	char *full_path = NULL;
+	char *tmp_path =  NULL;
 	char * tmpbuffer;
+	unsigned char * referrals = NULL;
+	int num_referrals = 0;
 	int len;
 	__u16 fid;
 
@@ -206,6 +212,7 @@ cifs_readlink(struct dentry *direntry, char *pBuffer, int buflen)
 		FreeXid(xid);
 		return -ENOMEM;
 	}
+
 /* BB add read reparse point symlink code and Unix extensions symlink code here BB */
 	if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
 		rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
@@ -224,8 +231,36 @@ cifs_readlink(struct dentry *direntry, char *pBuffer, int buflen)
 			if(CIFSSMBClose(xid, pTcon, fid)) {
 				cFYI(1,("Error closing junction point (open for ioctl)"));
 			}
+			if(rc == -EIO) {
+				/* Query if DFS Junction */
+				tmp_path =
+					kmalloc(MAX_TREE_SIZE + MAX_PATHCONF + 1,
+						GFP_KERNEL);
+				if (tmp_path) {
+					strncpy(tmp_path, pTcon->treeName, MAX_TREE_SIZE);
+					strncat(tmp_path, full_path, MAX_PATHCONF);
+					rc = get_dfs_path(xid, pTcon->ses, tmp_path,
+						cifs_sb->local_nls, &num_referrals, &referrals);
+					cFYI(1,("Get DFS for %s rc = %d ",tmp_path, rc));
+					if((num_referrals == 0) && (rc == 0))
+						rc = -EACCES;
+					else {
+						cFYI(1,("num referral: %d",num_referrals));
+						if(referrals) {
+							cFYI(1,("referral string: %s ",referrals));
+							strncpy(tmpbuffer, referrals, len-1);
+						}
 					}
 
+					kfree(tmp_path);
+					if(referrals) {
+						kfree(referrals);
+					}
+				}
+				/* BB add code like else decode referrals then memcpy to
+				  tmpbuffer and free referrals string array BB */
+			}
+		}
 	}
 	/* BB Anything else to do to handle recursive links? */
 	/* BB Should we be using page ops here? */
@@ -238,10 +273,12 @@ cifs_readlink(struct dentry *direntry, char *pBuffer, int buflen)
 		      rc));
 	}
 
-	if (tmpbuffer)
+	if (tmpbuffer) {
 		kfree(tmpbuffer);
-	if (full_path)
+	}
+	if (full_path) {
 		kfree(full_path);
+	}
 	FreeXid(xid);
 	return rc;
 }