cifs: add IOCTL for QUERY_INFO passthrough to userspace

This allows userspace tools to query the raw info levels for cifs files
and process the response in userspace.
In particular this is useful for many of those data where there is no
corresponding native data structure in linux.
For example querying the security descriptor for a file and extract the
SIDs.

Signed-off-by: Ronnie Sahlberg <[email protected]>
Signed-off-by: Steve French <[email protected]>

Author: Ronnie Sahlberg

fs/cifs/cifs_ioctl.h

@@ -43,8 +43,19 @@ struct smb_snapshot_array {
 	/*	snapshots[]; */
 } __packed;
 
+struct smb_query_info {
+	__u32   info_type;
+	__u32   file_info_class;
+	__u32   additional_information;
+	__u32   flags;
+	__u32	input_buffer_length;
+	__u32	output_buffer_length;
+	/* char buffer[]; */
+} __packed;
+
 #define CIFS_IOCTL_MAGIC	0xCF
 #define CIFS_IOC_COPYCHUNK_FILE	_IOW(CIFS_IOCTL_MAGIC, 3, int)
 #define CIFS_IOC_SET_INTEGRITY  _IO(CIFS_IOCTL_MAGIC, 4)
 #define CIFS_IOC_GET_MNT_INFO _IOR(CIFS_IOCTL_MAGIC, 5, struct smb_mnt_fs_info)
 #define CIFS_ENUMERATE_SNAPSHOTS _IOR(CIFS_IOCTL_MAGIC, 6, struct smb_snapshot_array)
+#define CIFS_QUERY_INFO _IOWR(CIFS_IOCTL_MAGIC, 7, struct smb_query_info)

fs/cifs/cifsglob.h

@@ -465,6 +465,10 @@ struct smb_version_operations {
 	enum securityEnum (*select_sectype)(struct TCP_Server_Info *,
 			    enum securityEnum);
 	int (*next_header)(char *);
+	/* ioctl passthrough for query_info */
+	int (*ioctl_query_info)(const unsigned int xid,
+				struct cifsFileInfo *file,
+				unsigned long p);
 };
 
 struct smb_version_values {

fs/cifs/ioctl.c

@@ -34,6 +34,24 @@
 #include "cifs_ioctl.h"
 #include <linux/btrfs.h>
 
+static long cifs_ioctl_query_info(unsigned int xid, struct file *filep,
+				  unsigned long p)
+{
+	struct cifsFileInfo *pSMBFile = filep->private_data;
+	struct cifs_tcon *tcon;
+
+	cifs_dbg(FYI, "%s %p\n", __func__, pSMBFile);
+	if (pSMBFile == NULL)
+		return -EISDIR;
+	tcon = tlink_tcon(pSMBFile->tlink);
+
+	if (tcon->ses->server->ops->ioctl_query_info)
+		return tcon->ses->server->ops->ioctl_query_info(
+				xid, pSMBFile, p);
+	else
+		return -EOPNOTSUPP;
+}
+
 static long cifs_ioctl_copychunk(unsigned int xid, struct file *dst_file,
 			unsigned long srcfd)
 {
@@ -194,6 +212,9 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
 		case CIFS_IOC_COPYCHUNK_FILE:
 			rc = cifs_ioctl_copychunk(xid, filep, arg);
 			break;
+		case CIFS_QUERY_INFO:
+			rc = cifs_ioctl_query_info(xid, filep, arg);
+			break;
 		case CIFS_IOC_SET_INTEGRITY:
 			if (pSMBFile == NULL)
 				break;

fs/cifs/smb2inode.c

@@ -110,7 +110,7 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 				COMPOUND_FID, FILE_ALL_INFORMATION,
 				SMB2_O_INFO_FILE, 0,
 				sizeof(struct smb2_file_all_info) +
-					  PATH_MAX * 2);
+					  PATH_MAX * 2, 0, NULL);
 		smb2_set_next_command(server, &rqst[num_rqst]);
 		smb2_set_related(&rqst[num_rqst++]);
 		break;

fs/cifs/smb2ops.c

@@ -1118,6 +1118,86 @@ SMB2_request_res_key(const unsigned int xid, struct cifs_tcon *tcon,
 	return rc;
 }
 
+static int
+smb2_ioctl_query_info(const unsigned int xid,
+		      struct cifsFileInfo *file,
+		      unsigned long p)
+{
+	struct cifs_tcon *tcon = tlink_tcon(file->tlink);
+	struct cifs_ses *ses = tcon->ses;
+	char __user *arg = (char __user *)p;
+	struct smb_query_info qi;
+	struct smb_query_info __user *pqi;
+	int rc = 0;
+	int flags = 0;
+	struct smb_rqst rqst;
+	struct kvec iov[1];
+	struct kvec rsp_iov;
+	int resp_buftype;
+	struct smb2_query_info_rsp *rsp = NULL;
+	void *buffer;
+
+	if (copy_from_user(&qi, arg, sizeof(struct smb_query_info)))
+		return -EFAULT;
+
+	if (qi.output_buffer_length > 1024)
+		return -EINVAL;
+
+	if (!ses || !(ses->server))
+		return -EIO;
+
+	if (smb3_encryption_required(tcon))
+		flags |= CIFS_TRANSFORM_REQ;
+
+	buffer = kmalloc(qi.output_buffer_length, GFP_KERNEL);
+	if (buffer == NULL)
+		return -ENOMEM;
+
+	if (copy_from_user(buffer, arg + sizeof(struct smb_query_info),
+			   qi.output_buffer_length)) {
+		kfree(buffer);
+		return -EFAULT;
+	}
+
+	memset(&rqst, 0, sizeof(struct smb_rqst));
+	memset(&iov, 0, sizeof(iov));
+	rqst.rq_iov = iov;
+	rqst.rq_nvec = 1;
+
+	rc = SMB2_query_info_init(tcon, &rqst, file->fid.persistent_fid,
+				  file->fid.volatile_fid,
+				  qi.file_info_class, qi.info_type,
+				  qi.additional_information,
+				  qi.input_buffer_length,
+				  qi.output_buffer_length, buffer);
+	kfree(buffer);
+	if (rc)
+		goto iqinf_exit;
+
+	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rsp = (struct smb2_query_info_rsp *)rsp_iov.iov_base;
+	if (rc)
+		goto iqinf_exit;
+
+	pqi = (struct smb_query_info __user *)arg;
+	if (le32_to_cpu(rsp->OutputBufferLength) < qi.input_buffer_length)
+		qi.input_buffer_length = le32_to_cpu(rsp->OutputBufferLength);
+	if (copy_to_user(&pqi->input_buffer_length, &qi.input_buffer_length,
+			 sizeof(qi.input_buffer_length))) {
+		rc = -EFAULT;
+		goto iqinf_exit;
+	}
+	if (copy_to_user(pqi + 1, rsp->Buffer, qi.input_buffer_length)) {
+		rc = -EFAULT;
+		goto iqinf_exit;
+	}
+
+ iqinf_exit:
+	SMB2_query_info_free(&rqst);
+	free_rsp_buf(resp_buftype, rsp);
+	return rc;
+}
+
 static ssize_t
 smb2_copychunk_range(const unsigned int xid,
 			struct cifsFileInfo *srcfile,
@@ -1697,7 +1777,8 @@ smb2_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
 	rc = SMB2_query_info_init(tcon, &rqst[1], COMPOUND_FID, COMPOUND_FID,
 				  FS_FULL_SIZE_INFORMATION,
 				  SMB2_O_INFO_FILESYSTEM, 0,
-				  sizeof(struct smb2_fs_full_size_info));
+				  sizeof(struct smb2_fs_full_size_info), 0,
+				  NULL);
 	if (rc)
 		goto qfs_exit;
 	smb2_set_next_command(server, &rqst[1]);
@@ -3364,6 +3445,7 @@ struct smb_version_operations smb20_operations = {
 	.set_acl = set_smb2_acl,
 #endif /* CIFS_ACL */
 	.next_header = smb2_next_header,
+	.ioctl_query_info = smb2_ioctl_query_info,
 };
 
 struct smb_version_operations smb21_operations = {
@@ -3459,6 +3541,7 @@ struct smb_version_operations smb21_operations = {
 	.set_acl = set_smb2_acl,
 #endif /* CIFS_ACL */
 	.next_header = smb2_next_header,
+	.ioctl_query_info = smb2_ioctl_query_info,
 };
 
 struct smb_version_operations smb30_operations = {
@@ -3563,6 +3646,7 @@ struct smb_version_operations smb30_operations = {
 	.set_acl = set_smb2_acl,
 #endif /* CIFS_ACL */
 	.next_header = smb2_next_header,
+	.ioctl_query_info = smb2_ioctl_query_info,
 };
 
 struct smb_version_operations smb311_operations = {
@@ -3668,6 +3752,7 @@ struct smb_version_operations smb311_operations = {
 	.set_acl = set_smb2_acl,
 #endif /* CIFS_ACL */
 	.next_header = smb2_next_header,
+	.ioctl_query_info = smb2_ioctl_query_info,
 };
 
 struct smb_version_values smb20_values = {

fs/cifs/smb2pdu.c

@@ -2651,7 +2651,7 @@ int
 SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
 		     u64 persistent_fid, u64 volatile_fid,
 		     u8 info_class, u8 info_type, u32 additional_info,
-		     size_t output_len)
+		     size_t output_len, size_t input_len, void *input)
 {
 	struct smb2_query_info_req *req;
 	struct kvec *iov = rqst->rq_iov;
@@ -2669,16 +2669,17 @@ SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
 	req->VolatileFileId = volatile_fid;
 	req->AdditionalInformation = cpu_to_le32(additional_info);
 
-	/*
-	 * We do not use the input buffer (do not send extra byte)
-	 */
-	req->InputBufferOffset = 0;
-
 	req->OutputBufferLength = cpu_to_le32(output_len);
+	if (input_len) {
+		req->InputBufferLength = cpu_to_le32(input_len);
+		/* total_len for smb query request never close to le16 max */
+		req->InputBufferOffset = cpu_to_le16(total_len - 1);
+		memcpy(req->Buffer, input, input_len);
+	}
 
 	iov[0].iov_base = (char *)req;
 	/* 1 for Buffer */
-	iov[0].iov_len = total_len - 1;
+	iov[0].iov_len = total_len - 1 + input_len;
 	return 0;
 }
 
@@ -2718,7 +2719,7 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon,
 
 	rc = SMB2_query_info_init(tcon, &rqst, persistent_fid, volatile_fid,
 				  info_class, info_type, additional_info,
-				  output_len);
+				  output_len, 0, NULL);
 	if (rc)
 		goto qinf_exit;
 

fs/cifs/smb2proto.h

@@ -163,7 +163,8 @@ extern int SMB2_query_info(const unsigned int xid, struct cifs_tcon *tcon,
 extern int SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
 				u64 persistent_fid, u64 volatile_fid,
 				u8 info_class, u8 info_type,
-				u32 additional_info, size_t output_len);
+				u32 additional_info, size_t output_len,
+				size_t input_len, void *input);
 extern void SMB2_query_info_free(struct smb_rqst *rqst);
 extern int SMB2_query_acl(const unsigned int xid, struct cifs_tcon *tcon,
 			   u64 persistent_file_id, u64 volatile_file_id,