===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/ssh-rsa.c,v
retrieving revision 1.10
retrieving revision 1.10.2.5
diff -u -r1.10 -r1.10.2.5
--- src/usr.bin/ssh/ssh-rsa.c	2001/09/17 19:27:15	1.10
+++ src/usr.bin/ssh/ssh-rsa.c	2002/06/26 18:22:36	1.10.2.5
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh-rsa.c,v 1.10 2001/09/17 19:27:15 stevesk Exp $");
+RCSID("$OpenBSD: ssh-rsa.c,v 1.10.2.5 2002/06/26 18:22:36 miod Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -35,17 +35,16 @@
 #include "key.h"
 #include "ssh-rsa.h"
 #include "compat.h"
+#include "ssh.h"
 
 /* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
 int
-ssh_rsa_sign(
-    Key *key,
-    u_char **sigp, int *lenp,
-    u_char *data, int datalen)
+ssh_rsa_sign(Key *key, u_char **sigp, u_int *lenp,
+    u_char *data, u_int datalen)
 {
 	const EVP_MD *evp_md;
 	EVP_MD_CTX md;
-	u_char *digest, *sig, *ret;
+	u_char digest[EVP_MAX_MD_SIZE], *sig, *ret;
 	u_int slen, dlen, len;
 	int ok, nid;
 	Buffer b;
@@ -59,32 +58,30 @@
 		error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid);
 		return -1;
 	}
-	dlen = evp_md->md_size;
-	digest = xmalloc(dlen);
 	EVP_DigestInit(&md, evp_md);
 	EVP_DigestUpdate(&md, data, datalen);
-	EVP_DigestFinal(&md, digest, NULL);
+	EVP_DigestFinal(&md, digest, &dlen);
 
 	slen = RSA_size(key->rsa);
 	sig = xmalloc(slen);
 
 	ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa);
-	memset(digest, 'd', dlen);
-	xfree(digest);
+	memset(digest, 'd', sizeof(digest));
 
 	if (ok != 1) {
 		int ecode = ERR_get_error();
-		error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
+		error("ssh_rsa_sign: RSA_sign failed: %s",
+		    ERR_error_string(ecode, NULL));
 		xfree(sig);
 		return -1;
 	}
 	if (len < slen) {
 		int diff = slen - len;
-		debug("slen %d > len %d", slen, len);
+		debug("slen %u > len %u", slen, len);
 		memmove(sig + diff, sig, len);
 		memset(sig, 0, diff);
 	} else if (len > slen) {
-		error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
+		error("ssh_rsa_sign: slen %u slen2 %u", slen, len);
 		xfree(sig);
 		return -1;
 	}
@@ -107,26 +104,24 @@
 }
 
 int
-ssh_rsa_verify(
-    Key *key,
-    u_char *signature, int signaturelen,
-    u_char *data, int datalen)
+ssh_rsa_verify(Key *key, u_char *signature, u_int signaturelen,
+    u_char *data, u_int datalen)
 {
 	Buffer b;
 	const EVP_MD *evp_md;
 	EVP_MD_CTX md;
 	char *ktype;
-	u_char *sigblob, *digest;
-	u_int len, dlen;
+	u_char digest[EVP_MAX_MD_SIZE], *sigblob;
+	u_int len, dlen, modlen;
 	int rlen, ret, nid;
 
 	if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
 		error("ssh_rsa_verify: no RSA key");
 		return -1;
 	}
-	if (BN_num_bits(key->rsa->n) < 768) {
-		error("ssh_rsa_verify: n too small: %d bits",
-		    BN_num_bits(key->rsa->n));
+	if (BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
+		error("ssh_rsa_verify: RSA modulus too small: %d < minimum %d bits",
+		    BN_num_bits(key->rsa->n), SSH_RSA_MINIMUM_MODULUS_SIZE);
 		return -1;
 	}
 	buffer_init(&b);
@@ -142,31 +137,44 @@
 	sigblob = buffer_get_string(&b, &len);
 	rlen = buffer_len(&b);
 	buffer_free(&b);
-	if(rlen != 0) {
-		xfree(sigblob);
+	if (rlen != 0) {
 		error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
+		xfree(sigblob);
 		return -1;
 	}
+	/* RSA_verify expects a signature of RSA_size */
+	modlen = RSA_size(key->rsa);
+	if (len > modlen) {
+		error("ssh_rsa_verify: len %u > modlen %u", len, modlen);
+		xfree(sigblob);
+		return -1;
+	} else if (len < modlen) {
+		int diff = modlen - len;
+		debug("ssh_rsa_verify: add padding: modlen %u > len %u",
+		    modlen, len);
+		sigblob = xrealloc(sigblob, modlen);
+		memmove(sigblob + diff, sigblob, len);
+		memset(sigblob, 0, diff);
+		len = modlen;
+	}
 	nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
 	if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
-		xfree(sigblob);
 		error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid);
+		xfree(sigblob);
 		return -1;
 	}
-	dlen = evp_md->md_size;
-	digest = xmalloc(dlen);
 	EVP_DigestInit(&md, evp_md);
 	EVP_DigestUpdate(&md, data, datalen);
-	EVP_DigestFinal(&md, digest, NULL);
+	EVP_DigestFinal(&md, digest, &dlen);
 
 	ret = RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
-	memset(digest, 'd', dlen);
-	xfree(digest);
+	memset(digest, 'd', sizeof(digest));
 	memset(sigblob, 's', len);
 	xfree(sigblob);
 	if (ret == 0) {
 		int ecode = ERR_get_error();
-		error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
+		error("ssh_rsa_verify: RSA_verify failed: %s",
+		    ERR_error_string(ecode, NULL));
 	}
 	debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
 	return ret;