First batch of misc patches for QEMU 8.1

[PULL 05/25] vnc: avoid underflow when accessing user-provided address

Paolo Bonzini posted 25 patches 2 years, 9 months ago

Download mbox

Maintainers: Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, "Alex Bennée" <alex.bennee@linaro.org>, Thomas Huth <thuth@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Helge Deller <deller@gmx.de>, Keith Busch <kbusch@kernel.org>, Klaus Jensen <its@irrelevant.dk>, "Daniel P. Berrangé" <berrange@redhat.com>, Juan Quintela <quintela@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Eric Blake <eblake@redhat.com>, Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>, Markus Armbruster <armbru@redhat.com>, Michael Roth <michael.roth@amd.com>, Peter Maydell <peter.maydell@linaro.org>, John Snow <jsnow@redhat.com>, Cleber Rosa <crosa@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Aurelien Jarno <aurelien@aurel32.net>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, Wainer dos Santos Moschetta <wainersm@redhat.com>, Beraldo Leal <bleal@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Ani Sinha <ani@anisinha.ca>, Gerd Hoffmann <kraxel@redhat.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>

Expand all Fold all

[PULL 05/25] vnc: avoid underflow when accessing user-provided address

Posted by Paolo Bonzini 2 years, 9 months ago

If hostlen is zero, there is a possibility that addrstr[hostlen - 1]
underflows and, if a closing bracked is there, hostlen - 2 is passed
to g_strndup() on the next line.  If websocket==false then
addrstr[0] would be a colon, but if websocket==true this could in
principle happen.

Fix it by checking hostlen.

Reported by Coverity.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 ui/vnc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ui/vnc.c b/ui/vnc.c
index bbd8b6baaeca..9d8a24dd8a69 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -3751,7 +3751,7 @@ static int vnc_display_get_address(const char *addrstr,
 
         addr->type = SOCKET_ADDRESS_TYPE_INET;
         inet = &addr->u.inet;
-        if (addrstr[0] == '[' && addrstr[hostlen - 1] == ']') {
+        if (hostlen && addrstr[0] == '[' && addrstr[hostlen - 1] == ']') {
             inet->host = g_strndup(addrstr + 1, hostlen - 2);
         } else {
             inet->host = g_strndup(addrstr, hostlen);
-- 
2.40.0