From 772a73692ecb52bace0cff6f95df62f59b8cabe0 Mon Sep 17 00:00:00 2001 From: Jan Dakinevich 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 [groug, regression caused my commit 8d37de41cab1 # 2.10] Signed-off-by: Greg Kurz --- hw/9pfs/9p.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index cdd44bdc82..23ac7bb532 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -1748,18 +1748,27 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu, if (err < 0) { break; } - /* 11 = 7 + 4 (7 = start offset, 4 = space for storing count) */ - len = pdu_marshal(pdu, 11 + count, "S", &v9stat); + if ((count + v9stat.size + 2) > max_count) { + v9fs_readdir_unlock(&fidp->fs.dir); - 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 */ 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 < 0) { + v9fs_co_seekdir(pdu, fidp, saved_dir_pos); + v9fs_stat_free(&v9stat); + v9fs_path_free(&path); + return len; + } count += len; v9fs_stat_free(&v9stat); v9fs_path_free(&path);