X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=x11fwd.c;h=6cfec72824304b8e853802b599c12ed932802a91;hb=9f9d72ec58642e91b4f93ee4405a8086ee2fb2f0;hp=4a6d82704b7cdbccbed5a1dfcf964aaa2dda9cbd;hpb=a53e4e2cb6aa5b953fa0cdbef3b1702d0925f195;p=PuTTY.git

diff --git a/x11fwd.c b/x11fwd.c
index 4a6d8270..6cfec728 100644
--- a/x11fwd.c
+++ b/x11fwd.c
@@ -357,10 +357,10 @@ void x11_free_display(struct X11Display *disp)
 
 #define XDM_MAXSKEW 20*60      /* 20 minute clock skew should be OK */
 
-static char *x11_verify(unsigned long peer_ip, int peer_port,
-			tree234 *authtree, char *proto,
-			unsigned char *data, int dlen,
-                        struct X11FakeAuth **auth_ret)
+static const char *x11_verify(unsigned long peer_ip, int peer_port,
+                              tree234 *authtree, char *proto,
+                              unsigned char *data, int dlen,
+                              struct X11FakeAuth **auth_ret)
 {
     struct X11FakeAuth match_dummy;    /* for passing to find234 */
     struct X11FakeAuth *auth;
@@ -420,7 +420,8 @@ static char *x11_verify(unsigned long peer_ip, int peer_port,
 	    if (data[i] != 0)	       /* zero padding wrong */
 		return "XDM-AUTHORIZATION-1 data failed check";
 	tim = time(NULL);
-	if (abs(t - tim) > XDM_MAXSKEW)
+	if (((unsigned long)t - (unsigned long)tim
+             + XDM_MAXSKEW) > 2*XDM_MAXSKEW)
 	    return "XDM-AUTHORIZATION-1 time stamp was too far out";
 	seen = snew(struct XDMSeen);
 	seen->time = t;