X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/0016d70b76e2706064b54c9dd24d45a45646b0de..71ed591e9e049cf1c64ec9ddc10e2158c2f76c89:/sshrsa.c

diff --git a/sshrsa.c b/sshrsa.c
index e7fca008..4f95fb38 100644
--- a/sshrsa.c
+++ b/sshrsa.c
@@ -54,7 +54,7 @@ int makekey(unsigned char *data, int len, struct RSAKey *result,
     }
 
     n = ssh1_read_bignum(p, len, result ? &result->modulus : NULL);
-    if (n < 0) return -1;
+    if (n < 0 || (result && bignum_bitcount(result->modulus) == 0)) return -1;
     if (result)
 	result->bytes = n - 2;
     if (keystr)
@@ -802,6 +802,7 @@ static unsigned char *rsa2_sign(void *key, char *data, int datalen,
     SHA_Simple(data, datalen, hash);
 
     nbytes = (bignum_bitcount(rsa->modulus) - 1) / 8;
+    assert(1 <= nbytes - 20 - ASN1_LEN);
     bytes = snewn(nbytes, unsigned char);
 
     bytes[0] = 1;