[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PULL v2 09/11] ui/vnc: Fix problem with sending too many b

From: Gerd Hoffmann
Subject: [Qemu-devel] [PULL v2 09/11] ui/vnc: Fix problem with sending too many bytes as server name
Date: Mon, 9 Jan 2017 14:09:43 +0100

From: Thomas Huth <address@hidden>

If the buffer is not big enough, snprintf() does not return the number
of bytes that have been written to the buffer, but the number of bytes
that would be needed for writing the whole string. By using this value
for the following vnc_write() calls, we send some junk at the end of
the name in case the qemu_name is longer than 1017 bytes, which could
confuse the VNC clients. Fix this by adding an additional size check

Buglink: https://bugs.launchpad.net/qemu/+bug/1637447
Signed-off-by: Thomas Huth <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Message-id: address@hidden
Signed-off-by: Gerd Hoffmann <address@hidden>
 ui/vnc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/ui/vnc.c b/ui/vnc.c
index 2c28a59..29aa9c4 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -2459,10 +2459,14 @@ static int protocol_client_init(VncState *vs, uint8_t 
*data, size_t len)
-    if (qemu_name)
+    if (qemu_name) {
         size = snprintf(buf, sizeof(buf), "QEMU (%s)", qemu_name);
-    else
+        if (size > sizeof(buf)) {
+            size = sizeof(buf);
+        }
+    } else {
         size = snprintf(buf, sizeof(buf), "QEMU");
+    }
     vnc_write_u32(vs, size);
     vnc_write(vs, buf, size);

reply via email to

[Prev in Thread] Current Thread [Next in Thread]