smb: client: implement ->query_reparse_point() for SMB1

Reparse points are not limited to symlinks, so implement
->query_reparse_point() in order to handle different file types.

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: Paulo Alcantara

fs/smb/client/cifspdu.h

@@ -1356,7 +1356,7 @@ typedef struct smb_com_transaction_ioctl_rsp {
 	__le32 DataDisplacement;
 	__u8 SetupCount;	/* 1 */
 	__le16 ReturnedDataLen;
-	__u16 ByteCount;
+	__le16 ByteCount;
 } __attribute__((packed)) TRANSACT_IOCTL_RSP;
 
 #define CIFS_ACL_OWNER 1

fs/smb/client/cifsproto.h

@@ -458,6 +458,12 @@ extern int CIFSSMBUnixQuerySymLink(const unsigned int xid,
 			struct cifs_tcon *tcon,
 			const unsigned char *searchName, char **syminfo,
 			const struct nls_table *nls_codepage, int remap);
+extern int cifs_query_reparse_point(const unsigned int xid,
+				    struct cifs_tcon *tcon,
+				    struct cifs_sb_info *cifs_sb,
+				    const char *full_path,
+				    u32 *tag, struct kvec *rsp,
+				    int *rsp_buftype);
 extern int CIFSSMBQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon,
 			       __u16 fid, char **symlinkinfo,
 			       const struct nls_table *nls_codepage);
@@ -659,6 +665,9 @@ void cifs_put_tcp_super(struct super_block *sb);
 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix);
 char *extract_hostname(const char *unc);
 char *extract_sharename(const char *unc);
+int parse_reparse_point(struct reparse_data_buffer *buf,
+			u32 plen, struct cifs_sb_info *cifs_sb,
+			bool unicode, char **target_path);
 
 #ifdef CONFIG_CIFS_DFS_UPCALL
 static inline int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,

fs/smb/client/cifssmb.c

@@ -2690,136 +2690,97 @@ CIFSSMBUnixQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon,
 	return rc;
 }
 
-/*
- *	Recent Windows versions now create symlinks more frequently
- *	and they use the "reparse point" mechanism below.  We can of course
- *	do symlinks nicely to Samba and other servers which support the
- *	CIFS Unix Extensions and we can also do SFU symlinks and "client only"
- *	"MF" symlinks optionally, but for recent Windows we really need to
- *	reenable the code below and fix the cifs_symlink callers to handle this.
- *	In the interim this code has been moved to its own config option so
- *	it is not compiled in by default until callers fixed up and more tested.
- */
-int
-CIFSSMBQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon,
-		    __u16 fid, char **symlinkinfo,
-		    const struct nls_table *nls_codepage)
+int cifs_query_reparse_point(const unsigned int xid,
+			     struct cifs_tcon *tcon,
+			     struct cifs_sb_info *cifs_sb,
+			     const char *full_path,
+			     u32 *tag, struct kvec *rsp,
+			     int *rsp_buftype)
 {
-	int rc = 0;
-	int bytes_returned;
-	struct smb_com_transaction_ioctl_req *pSMB;
-	struct smb_com_transaction_ioctl_rsp *pSMBr;
-	bool is_unicode;
-	unsigned int sub_len;
-	char *sub_start;
-	struct reparse_symlink_data *reparse_buf;
-	struct reparse_posix_data *posix_buf;
+	struct cifs_open_parms oparms;
+	TRANSACT_IOCTL_REQ *io_req = NULL;
+	TRANSACT_IOCTL_RSP *io_rsp = NULL;
+	struct cifs_fid fid;
 	__u32 data_offset, data_count;
-	char *end_of_smb;
+	__u8 *start, *end;
+	int io_rsp_len;
+	int oplock = 0;
+	int rc;
 
-	cifs_dbg(FYI, "In Windows reparse style QueryLink for fid %u\n", fid);
-	rc = smb_init(SMB_COM_NT_TRANSACT, 23, tcon, (void **) &pSMB,
-		      (void **) &pSMBr);
+	cifs_tcon_dbg(FYI, "%s: path=%s\n", __func__, full_path);
+
+	if (cap_unix(tcon->ses))
+		return -EOPNOTSUPP;
+
+	oparms = (struct cifs_open_parms) {
+		.tcon = tcon,
+		.cifs_sb = cifs_sb,
+		.desired_access = FILE_READ_ATTRIBUTES,
+		.create_options = cifs_create_options(cifs_sb,
+						      OPEN_REPARSE_POINT),
+		.disposition = FILE_OPEN,
+		.path = full_path,
+		.fid = &fid,
+	};
+
+	rc = CIFS_open(xid, &oparms, &oplock, NULL);
 	if (rc)
 		return rc;
 
-	pSMB->TotalParameterCount = 0 ;
-	pSMB->TotalDataCount = 0;
-	pSMB->MaxParameterCount = cpu_to_le32(2);
-	/* BB find exact data count max from sess structure BB */
-	pSMB->MaxDataCount = cpu_to_le32(CIFSMaxBufSize & 0xFFFFFF00);
-	pSMB->MaxSetupCount = 4;
-	pSMB->Reserved = 0;
-	pSMB->ParameterOffset = 0;
-	pSMB->DataCount = 0;
-	pSMB->DataOffset = 0;
-	pSMB->SetupCount = 4;
-	pSMB->SubCommand = cpu_to_le16(NT_TRANSACT_IOCTL);
-	pSMB->ParameterCount = pSMB->TotalParameterCount;
-	pSMB->FunctionCode = cpu_to_le32(FSCTL_GET_REPARSE_POINT);
-	pSMB->IsFsctl = 1; /* FSCTL */
-	pSMB->IsRootFlag = 0;
-	pSMB->Fid = fid; /* file handle always le */
-	pSMB->ByteCount = 0;
+	rc = smb_init(SMB_COM_NT_TRANSACT, 23, tcon,
+		      (void **)&io_req, (void **)&io_rsp);
+	if (rc)
+		goto error;
 
-	rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB,
-			 (struct smb_hdr *) pSMBr, &bytes_returned, 0);
-	if (rc) {
-		cifs_dbg(FYI, "Send error in QueryReparseLinkInfo = %d\n", rc);
-		goto qreparse_out;
-	}
+	io_req->TotalParameterCount = 0;
+	io_req->TotalDataCount = 0;
+	io_req->MaxParameterCount = cpu_to_le32(2);
+	/* BB find exact data count max from sess structure BB */
+	io_req->MaxDataCount = cpu_to_le32(CIFSMaxBufSize & 0xFFFFFF00);
+	io_req->MaxSetupCount = 4;
+	io_req->Reserved = 0;
+	io_req->ParameterOffset = 0;
+	io_req->DataCount = 0;
+	io_req->DataOffset = 0;
+	io_req->SetupCount = 4;
+	io_req->SubCommand = cpu_to_le16(NT_TRANSACT_IOCTL);
+	io_req->ParameterCount = io_req->TotalParameterCount;
+	io_req->FunctionCode = cpu_to_le32(FSCTL_GET_REPARSE_POINT);
+	io_req->IsFsctl = 1;
+	io_req->IsRootFlag = 0;
+	io_req->Fid = fid.netfid;
+	io_req->ByteCount = 0;
+
+	rc = SendReceive(xid, tcon->ses, (struct smb_hdr *)io_req,
+			 (struct smb_hdr *)io_rsp, &io_rsp_len, 0);
+	if (rc)
+		goto error;
 
-	data_offset = le32_to_cpu(pSMBr->DataOffset);
-	data_count = le32_to_cpu(pSMBr->DataCount);
-	if (get_bcc(&pSMBr->hdr) < 2 || data_offset > 512) {
-		/* BB also check enough total bytes returned */
-		rc = -EIO;	/* bad smb */
-		goto qreparse_out;
-	}
-	if (!data_count || (data_count > 2048)) {
+	data_offset = le32_to_cpu(io_rsp->DataOffset);
+	data_count = le32_to_cpu(io_rsp->DataCount);
+	if (get_bcc(&io_rsp->hdr) < 2 || data_offset > 512 ||
+	    !data_count || data_count > 2048) {
 		rc = -EIO;
-		cifs_dbg(FYI, "Invalid return data count on get reparse info ioctl\n");
-		goto qreparse_out;
-	}
-	end_of_smb = 2 + get_bcc(&pSMBr->hdr) + (char *)&pSMBr->ByteCount;
-	reparse_buf = (struct reparse_symlink_data *)
-				((char *)&pSMBr->hdr.Protocol + data_offset);
-	if ((char *)reparse_buf >= end_of_smb) {
-		rc = -EIO;
-		goto qreparse_out;
-	}
-	if (reparse_buf->ReparseTag == cpu_to_le32(IO_REPARSE_TAG_NFS)) {
-		cifs_dbg(FYI, "NFS style reparse tag\n");
-		posix_buf =  (struct reparse_posix_data *)reparse_buf;
-
-		if (posix_buf->InodeType != cpu_to_le64(NFS_SPECFILE_LNK)) {
-			cifs_dbg(FYI, "unsupported file type 0x%llx\n",
-				 le64_to_cpu(posix_buf->InodeType));
-			rc = -EOPNOTSUPP;
-			goto qreparse_out;
-		}
-		is_unicode = true;
-		sub_len = le16_to_cpu(reparse_buf->ReparseDataLength);
-		if (posix_buf->PathBuffer + sub_len > end_of_smb) {
-			cifs_dbg(FYI, "reparse buf beyond SMB\n");
-			rc = -EIO;
-			goto qreparse_out;
-		}
-		*symlinkinfo = cifs_strndup_from_utf16(posix_buf->PathBuffer,
-				sub_len, is_unicode, nls_codepage);
-		goto qreparse_out;
-	} else if (reparse_buf->ReparseTag !=
-			cpu_to_le32(IO_REPARSE_TAG_SYMLINK)) {
-		rc = -EOPNOTSUPP;
-		goto qreparse_out;
+		goto error;
 	}
 
-	/* Reparse tag is NTFS symlink */
-	sub_start = le16_to_cpu(reparse_buf->SubstituteNameOffset) +
-				reparse_buf->PathBuffer;
-	sub_len = le16_to_cpu(reparse_buf->SubstituteNameLength);
-	if (sub_start + sub_len > end_of_smb) {
-		cifs_dbg(FYI, "reparse buf beyond SMB\n");
+	end = 2 + get_bcc(&io_rsp->hdr) + (__u8 *)&io_rsp->ByteCount;
+	start = (__u8 *)&io_rsp->hdr.Protocol + data_offset;
+	if (start >= end) {
 		rc = -EIO;
-		goto qreparse_out;
+		goto error;
 	}
-	if (pSMBr->hdr.Flags2 & SMBFLG2_UNICODE)
-		is_unicode = true;
-	else
-		is_unicode = false;
-
-	/* BB FIXME investigate remapping reserved chars here */
-	*symlinkinfo = cifs_strndup_from_utf16(sub_start, sub_len, is_unicode,
-					       nls_codepage);
-	if (!*symlinkinfo)
-		rc = -ENOMEM;
-qreparse_out:
-	cifs_buf_release(pSMB);
 
-	/*
-	 * Note: On -EAGAIN error only caller can retry on handle based calls
-	 * since file handle passed in no longer valid.
-	 */
+	*tag = le32_to_cpu(((struct reparse_data_buffer *)start)->ReparseTag);
+	rsp->iov_base = io_rsp;
+	rsp->iov_len = io_rsp_len;
+	*rsp_buftype = CIFS_LARGE_BUFFER;
+	CIFSSMBClose(xid, tcon, fid.netfid);
+	return 0;
+
+error:
+	cifs_buf_release(io_req);
+	CIFSSMBClose(xid, tcon, fid.netfid);
 	return rc;
 }
 

fs/smb/client/smb1ops.c

@@ -979,18 +979,13 @@ static int cifs_query_symlink(const unsigned int xid,
 			      char **target_path,
 			      struct kvec *rsp_iov)
 {
+	struct reparse_data_buffer *buf;
+	TRANSACT_IOCTL_RSP *io = rsp_iov->iov_base;
+	bool unicode = !!(io->hdr.Flags2 & SMBFLG2_UNICODE);
+	u32 plen = le16_to_cpu(io->ByteCount);
 	int rc;
-	int oplock = 0;
-	bool is_reparse_point = !!rsp_iov;
-	struct cifs_fid fid;
-	struct cifs_open_parms oparms;
 
-	cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);
-
-	if (is_reparse_point) {
-		cifs_dbg(VFS, "reparse points not handled for SMB1 symlinks\n");
-		return -EOPNOTSUPP;
-	}
+	cifs_tcon_dbg(FYI, "%s: path=%s\n", __func__, full_path);
 
 	/* Check for unix extensions */
 	if (cap_unix(tcon->ses)) {
@@ -1001,37 +996,12 @@ static int cifs_query_symlink(const unsigned int xid,
 			rc = cifs_unix_dfs_readlink(xid, tcon, full_path,
 						    target_path,
 						    cifs_sb->local_nls);
-
-		goto out;
+		return rc;
 	}
 
-	oparms = (struct cifs_open_parms) {
-		.tcon = tcon,
-		.cifs_sb = cifs_sb,
-		.desired_access = FILE_READ_ATTRIBUTES,
-		.create_options = cifs_create_options(cifs_sb,
-						      OPEN_REPARSE_POINT),
-		.disposition = FILE_OPEN,
-		.path = full_path,
-		.fid = &fid,
-	};
-
-	rc = CIFS_open(xid, &oparms, &oplock, NULL);
-	if (rc)
-		goto out;
-
-	rc = CIFSSMBQuerySymLink(xid, tcon, fid.netfid, target_path,
-				 cifs_sb->local_nls);
-	if (rc)
-		goto out_close;
-
-	convert_delimiter(*target_path, '/');
-out_close:
-	CIFSSMBClose(xid, tcon, fid.netfid);
-out:
-	if (!rc)
-		cifs_dbg(FYI, "%s: target path: %s\n", __func__, *target_path);
-	return rc;
+	buf = (struct reparse_data_buffer *)((__u8 *)&io->hdr.Protocol +
+					     le32_to_cpu(io->DataOffset));
+	return parse_reparse_point(buf, plen, cifs_sb, unicode, target_path);
 }
 
 static bool
@@ -1214,6 +1184,7 @@ struct smb_version_operations smb1_operations = {
 	.is_path_accessible = cifs_is_path_accessible,
 	.can_echo = cifs_can_echo,
 	.query_path_info = cifs_query_path_info,
+	.query_reparse_point = cifs_query_reparse_point,
 	.query_file_info = cifs_query_file_info,
 	.get_srv_inum = cifs_get_srv_inum,
 	.set_path_size = CIFSSMBSetEOF,