[libvirt] [PATCH 01/10] uml: fix logic bug in checking reply length

[Eric Blake]

* src/uml/uml_driver.c (umlMonitorCommand): Validate that enough
bytes were read to dereference both res.length, and that many
bytes from res.data.
Reported by Soren Hansen.
---

Whoops; this is a resend of an unrelated issue, but it is still
sitting on my tree, and the original email has no review yet,
perhaps because it was in a reply to a longish thread.

 src/uml/uml_driver.c |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/uml/uml_driver.c b/src/uml/uml_driver.c
index 04493ba..37ddc39 100644
--- a/src/uml/uml_driver.c
+++ b/src/uml/uml_driver.c
@@ -737,14 +737,11 @@ static int umlMonitorCommand(const struct uml_driver *driver,
             virReportSystemError(errno, _("cannot read reply %s"), cmd);
             goto error;
         }
-        if (nbytes < sizeof res) {
+        if (nbytes < offsetof(struct monitor_request, data) ||
+            nbytes < res.length + offsetof(struct monitor_request, data)) {
             virReportSystemError(0, _("incomplete reply %s"), cmd);
             goto error;
         }
-        if (sizeof res.data < res.length) {
-            virReportSystemError(0, _("invalid length in reply %s"), cmd);
-            goto error;
-        }

         if (VIR_REALLOC_N(retdata, retlen + res.length) < 0) {
             virReportOOMError();
-- 
1.7.2.1