diff options
author | Daniel P. Berrangé <berrange@redhat.com> | 2018-02-05 11:49:35 +0000 |
---|---|---|
committer | Gerd Hoffmann <kraxel@redhat.com> | 2018-02-16 12:33:02 +0100 |
commit | dffa1de071aa956308172170107b7b60d99bf34b (patch) | |
tree | 35de430dfbd92dd728d336c34b7b0b85891cb3f4 | |
parent | 8dfa3061ce56d871dc9df1e264f05e7ec2fb50c1 (diff) |
ui: avoid risk of 32-bit int overflow in VNC buffer check
For very large framebuffers, it is theoretically possible for the result
of 'vs->throttle_output_offset * VNC_THROTTLE_OUTPUT_LIMIT_SCALE' to
exceed the size of a 32-bit int. For this to happen in practice, the
video RAM would have to be set to a large enough value, which is not
likely today. None the less we can be paranoid against future growth by
using division instead of multiplication when checking the limits.
Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180205114938.15784-2-berrange@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
-rw-r--r-- | ui/vnc.c | 4 |
1 files changed, 2 insertions, 2 deletions
@@ -1579,8 +1579,8 @@ void vnc_write(VncState *vs, const void *data, size_t len) * handshake, or from the job thread's VncState clone */ if (vs->throttle_output_offset != 0 && - vs->output.offset > (vs->throttle_output_offset * - VNC_THROTTLE_OUTPUT_LIMIT_SCALE)) { + (vs->output.offset / VNC_THROTTLE_OUTPUT_LIMIT_SCALE) > + vs->throttle_output_offset) { trace_vnc_client_output_limit(vs, vs->ioc, vs->output.offset, vs->throttle_output_offset); vnc_disconnect_start(vs); |