X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/bccbeb7195c0a1b8bbc8a92f0c5f6e696c08cd8d..c570c83a03a82c066819cc8b02209e756b665f1e:/sshdss.c

diff --git a/sshdss.c b/sshdss.c
index 7c95d11b..1f15cee9 100644
--- a/sshdss.c
+++ b/sshdss.c
@@ -20,7 +20,7 @@ static void sha_mpint(SHA_State * s, Bignum b)
 	lenbuf[0] = bignum_byte(b, len);
 	SHA_Bytes(s, lenbuf, 1);
     }
-    memset(lenbuf, 0, sizeof(lenbuf));
+    smemclr(lenbuf, sizeof(lenbuf));
 }
 
 static void sha512_mpint(SHA512_State * s, Bignum b)
@@ -34,7 +34,7 @@ static void sha512_mpint(SHA512_State * s, Bignum b)
 	lenbuf[0] = bignum_byte(b, len);
 	SHA512_Bytes(s, lenbuf, 1);
     }
-    memset(lenbuf, 0, sizeof(lenbuf));
+    smemclr(lenbuf, sizeof(lenbuf));
 }
 
 static void getstring(char **data, int *datalen, char **p, int *length)
@@ -43,6 +43,8 @@ static void getstring(char **data, int *datalen, char **p, int *length)
     if (*datalen < 4)
 	return;
     *length = GET_32BIT(*data);
+    if (*length < 0)
+        return;
     *datalen -= 4;
     *data += 4;
     if (*datalen < *length)
@@ -98,7 +100,7 @@ static void *dss_newkey(char *data, int len)
     }
 #endif
 
-    if (!p || memcmp(p, "ssh-dss", 7)) {
+    if (!p || slen != 7 || memcmp(p, "ssh-dss", 7)) {
 	sfree(dss);
 	return NULL;
     }
@@ -575,7 +577,7 @@ static unsigned char *dss_sign(void *key, char *data, int datalen, int *siglen)
     SHA512_Bytes(&ss, digest, sizeof(digest));
     SHA512_Final(&ss, digest512);
 
-    memset(&ss, 0, sizeof(ss));
+    smemclr(&ss, sizeof(ss));
 
     /*
      * Now convert the result into a bignum, and reduce it mod q.
@@ -584,7 +586,7 @@ static unsigned char *dss_sign(void *key, char *data, int datalen, int *siglen)
     k = bigmod(proto_k, dss->q);
     freebn(proto_k);
 
-    memset(digest512, 0, sizeof(digest512));
+    smemclr(digest512, sizeof(digest512));
 
     /*
      * Now we have k, so just go ahead and compute the signature.