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, 9 insertions, 8 deletions

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index dacc3400eac6..1310bb355e32 100644
--- a/fs/cifs/smb2pdu.c
+++ b/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;