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[Qemu-devel] [PATCH] vnc: fix use-after-free in vnc_update_client_sync
From: |
Gerd Hoffmann |
Subject: |
[Qemu-devel] [PATCH] vnc: fix use-after-free in vnc_update_client_sync |
Date: |
Thu, 6 Mar 2014 15:02:33 +0100 |
Spotted by Coverity:
876 static int vnc_update_client_sync(VncState *vs, int has_dirty)
877 {
(1) Event freed_arg: "vnc_update_client(VncState *, int)" frees "vs".
[details]
Also see events: [deref_arg]
878 int ret = vnc_update_client(vs, has_dirty);
(2) Event deref_arg: Calling "vnc_jobs_join(VncState *)" dereferences freed
pointer "vs". [details]
Also see events: [freed_arg]
879 vnc_jobs_join(vs);
880 return ret;
881 }
Remove vnc_update_client_sync wrapper, replace it with an additional
argument to vnc_update_client, so we can so the sync properly in
vnc_update_client (i.e. skip it in case of a client disconnect).
Cc: Markus Armbruster <address@hidden>
Signed-off-by: Gerd Hoffmann <address@hidden>
---
ui/vnc.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff --git a/ui/vnc.c b/ui/vnc.c
index 5601cc3..b0efb1f 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -416,8 +416,7 @@ out_error:
3) resolutions > 1024
*/
-static int vnc_update_client(VncState *vs, int has_dirty);
-static int vnc_update_client_sync(VncState *vs, int has_dirty);
+static int vnc_update_client(VncState *vs, int has_dirty, bool sync);
static void vnc_disconnect_start(VncState *vs);
static void vnc_colordepth(VncState *vs);
@@ -750,7 +749,7 @@ static void vnc_dpy_copy(DisplayChangeListener *dcl,
QTAILQ_FOREACH_SAFE(vs, &vd->clients, next, vn) {
if (vnc_has_feature(vs, VNC_FEATURE_COPYRECT)) {
vs->force_update = 1;
- vnc_update_client_sync(vs, 1);
+ vnc_update_client(vs, 1, true);
/* vs might be free()ed here */
}
}
@@ -873,14 +872,7 @@ static int find_and_clear_dirty_height(struct VncState *vs,
return h;
}
-static int vnc_update_client_sync(VncState *vs, int has_dirty)
-{
- int ret = vnc_update_client(vs, has_dirty);
- vnc_jobs_join(vs);
- return ret;
-}
-
-static int vnc_update_client(VncState *vs, int has_dirty)
+static int vnc_update_client(VncState *vs, int has_dirty, bool sync)
{
if (vs->need_update && vs->csock != -1) {
VncDisplay *vd = vs->vd;
@@ -939,8 +931,11 @@ static int vnc_update_client(VncState *vs, int has_dirty)
return n;
}
- if (vs->csock == -1)
+ if (vs->csock == -1) {
vnc_disconnect_finish(vs);
+ } else if (sync) {
+ vnc_jobs_join(vs);
+ }
return 0;
}
@@ -2749,7 +2744,7 @@ static void vnc_refresh(DisplayChangeListener *dcl)
vnc_unlock_display(vd);
QTAILQ_FOREACH_SAFE(vs, &vd->clients, next, vn) {
- rects += vnc_update_client(vs, has_dirty);
+ rects += vnc_update_client(vs, has_dirty, false);
/* vs might be free()ed here */
}
--
1.8.3.1
- [Qemu-devel] [PATCH] vnc: fix use-after-free in vnc_update_client_sync,
Gerd Hoffmann <=