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 <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 86 insertions, 1 deletions

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index b744221f685d..c6c6450d0f38 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1118,6 +1118,86 @@ req_res_key_exit:
 	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 = {