From: Stefan Metzmacher <metze@samba.org>
Date: Mon, 11 May 2020 16:18:24 +0000 (+0200)
Subject: s3:smbd: handle 0 length writes as no-op.
X-Git-Tag: ldb-2.2.0~545
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ba68f21286c2c2f1fef8bf8c9cd500a622077887;p=thirdparty%2Fsamba.git

s3:smbd: handle 0 length writes as no-op.

They should never touch the SMB_VFS layer
and they never trigger an DISK_FULL error.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14361

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
---

diff --git a/source3/smbd/aio.c b/source3/smbd/aio.c
index 7ed2691cfbf..f89ce8537a0 100644
--- a/source3/smbd/aio.c
+++ b/source3/smbd/aio.c
@@ -337,6 +337,11 @@ static struct tevent_req *pwrite_fsync_send(TALLOC_CTX *mem_ctx,
 	state->fsp = fsp;
 	state->write_through = write_through;
 
+	if (n == 0) {
+		tevent_req_done(req);
+		return tevent_req_post(req, ev);
+	}
+
 	subreq = SMB_VFS_PWRITE_SEND(state, ev, fsp, data, n, offset);
 	if (tevent_req_nomem(subreq, req)) {
 		return tevent_req_post(req, ev);
diff --git a/source3/smbd/fileio.c b/source3/smbd/fileio.c
index 6d58bdbbc97..079d414db05 100644
--- a/source3/smbd/fileio.c
+++ b/source3/smbd/fileio.c
@@ -70,6 +70,10 @@ static ssize_t real_write_file(struct smb_request *req,
 {
 	ssize_t ret;
 
+	if (n == 0) {
+		return 0;
+	}
+
 	fsp->fh->pos = pos;
 	if (pos &&
 	    lp_strict_allocate(SNUM(fsp->conn)) &&