X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/putty/blobdiff_plain/a03c9f9c9d2b4961fc334bebecf8f404a811ef28..c4c04facf82078b66673e1dfc607ee27f1adc490:/ssh.c

diff --git a/ssh.c b/ssh.c
index 174efe91..9661e2af 100644
--- a/ssh.c
+++ b/ssh.c
@@ -6418,9 +6418,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 #define CHECK_HYPOTHESIS(offset, result) \
     do { \
 	long q = offset; \
-	if (q+4 <= len) { \
+	if (q >= 0 && q+4 <= len) { \
 	    q = q + 4 + GET_32BIT(p+q); \
-	    if (q+4 <= len && (q = q + 4 + GET_32BIT(p+q)) && q == len) \
+	    if (q >= 0 && q+4 <= len && \
+		    (q = q + 4 + GET_32BIT(p+q)) && q == len) \
 		result = TRUE; \
 	} \
     } while(0)