From 772a73692ecb52bace0cff6f95df62f59b8cabe0 Mon Sep 17 00:00:00 2001
From: Jan Dakinevich <jan.dakinevich@gmail.com>
Date: Wed, 20 Sep 2017 08:48:52 +0200
Subject: [PATCH] 9pfs: check the size of transport buffer before marshaling
v9fs_do_readdir_with_stat() should check for a maximum buffer size
before an attempt to marshal gathered data. Otherwise, buffers assumed
as misconfigured and the transport would be broken.
The patch brings v9fs_do_readdir_with_stat() in conformity with
v9fs_do_readdir() behavior.
Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
[groug, regression caused my commit 8d37de41cab1 # 2.10]
Signed-off-by: Greg Kurz <groug@kaod.org>
---
hw/9pfs/9p.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index cdd44bdc82e..23ac7bb532f 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1748,17 +1748,26 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu,
if (err < 0) {
break;
}
+ if ((count + v9stat.size + 2) > max_count) {
+ v9fs_readdir_unlock(&fidp->fs.dir);
+
+ /* Ran out of buffer. Set dir back to old position and return */
+ v9fs_co_seekdir(pdu, fidp, saved_dir_pos);
+ v9fs_stat_free(&v9stat);
+ v9fs_path_free(&path);
+ return count;
+ }
+
/* 11 = 7 + 4 (7 = start offset, 4 = space for storing count) */
len = pdu_marshal(pdu, 11 + count, "S", &v9stat);
v9fs_readdir_unlock(&fidp->fs.dir);
- if ((len != (v9stat.size + 2)) || ((count + len) > max_count)) {
- /* Ran out of buffer. Set dir back to old position and return */
+ if (len < 0) {
v9fs_co_seekdir(pdu, fidp, saved_dir_pos);
v9fs_stat_free(&v9stat);
v9fs_path_free(&path);
- return count;
+ return len;
}
count += len;
v9fs_stat_free(&v9stat);
--
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