[PATCH 1/2] smbd/reply: convert free space to 16bit in dskattr handler

[David Disseldorp]

The deprecated Core Protocol dskattr SMB_COM_QUERY_INFORMATION_DISK
command provides free space information in the form of 16-bit words.

Until now, this has been handled by passing the dskattr specific
small_query boolean through to disk_norm() via the SMB_VFS_DISK_FREE VFS
hook. disk_norm(small_query=true) then modifies the block size and free
space values such that they fit in the 16-bit field.

This change adds the command specific logic to the dskattr handler, so
that it can be removed from the SMB_VFS_DISK_FREE()->disk_norm() code
path. In doing so, it fixes dskattr request handling against opaque VFS
backends that don't call disk_norm(), such as vfs_glusterfs.

Signed-off-by: David Disseldorp <ddiss at samba.org>
---
 source3/smbd/reply.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/source3/smbd/reply.c b/source3/smbd/reply.c
index 0b6c102..b6199bb 100644
--- a/source3/smbd/reply.c
+++ b/source3/smbd/reply.c
@@ -1456,15 +1456,34 @@ void reply_setatr(struct smb_request *req)
 void reply_dskattr(struct smb_request *req)
 {
 	connection_struct *conn = req->conn;
+	uint64_t ret;
 	uint64_t dfree,dsize,bsize;
 	START_PROFILE(SMBdskattr);
 
-	if (get_dfree_info(conn,".",True,&bsize,&dfree,&dsize) == (uint64_t)-1) {
+	ret = get_dfree_info(conn, ".", false, &bsize, &dfree, &dsize);
+	if (ret == (uint64_t)-1) {
 		reply_nterror(req, map_nt_error_from_unix(errno));
 		END_PROFILE(SMBdskattr);
 		return;
 	}
 
+	/*
+	 * Force max to fit in 16 bit fields.
+	 */
+	while (dfree > WORDMAX || dsize > WORDMAX || bsize < 512) {
+		dfree /= 2;
+		dsize /= 2;
+		bsize *= 2;
+		if (bsize > (WORDMAX*512)) {
+			bsize = (WORDMAX*512);
+			if (dsize > WORDMAX)
+				dsize = WORDMAX;
+			if (dfree >  WORDMAX)
+				dfree = WORDMAX;
+			break;
+		}
+	}
+
 	reply_outbuf(req, 5, 0);
 
 	if (get_Protocol() <= PROTOCOL_LANMAN2) {
-- 
2.1.4