===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/ssh-rsa.c,v
retrieving revision 1.10.2.5
retrieving revision 1.10.2.6
diff -u -r1.10.2.5 -r1.10.2.6
--- src/usr.bin/ssh/ssh-rsa.c	2002/06/26 18:22:36	1.10.2.5
+++ src/usr.bin/ssh/ssh-rsa.c	2002/10/11 14:53:07	1.10.2.6
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh-rsa.c,v 1.10.2.5 2002/06/26 18:22:36 miod Exp $");
+RCSID("$OpenBSD: ssh-rsa.c,v 1.10.2.6 2002/10/11 14:53:07 miod Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -37,6 +37,8 @@
 #include "compat.h"
 #include "ssh.h"
 
+static int openssh_RSA_verify(int, u_char *, u_int, u_char *, u_int , RSA *);
+
 /* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
 int
 ssh_rsa_sign(Key *key, u_char **sigp, u_int *lenp,
@@ -44,7 +46,7 @@
 {
 	const EVP_MD *evp_md;
 	EVP_MD_CTX md;
-	u_char digest[EVP_MAX_MD_SIZE], *sig, *ret;
+	u_char digest[EVP_MAX_MD_SIZE], *sig;
 	u_int slen, dlen, len;
 	int ok, nid;
 	Buffer b;
@@ -76,7 +78,7 @@
 		return -1;
 	}
 	if (len < slen) {
-		int diff = slen - len;
+		u_int diff = slen - len;
 		debug("slen %u > len %u", slen, len);
 		memmove(sig + diff, sig, len);
 		memset(sig, 0, diff);
@@ -90,16 +92,16 @@
 	buffer_put_cstring(&b, "ssh-rsa");
 	buffer_put_string(&b, sig, slen);
 	len = buffer_len(&b);
-	ret = xmalloc(len);
-	memcpy(ret, buffer_ptr(&b), len);
+	if (lenp != NULL)
+		*lenp = len;
+	if (sigp != NULL) {
+		*sigp = xmalloc(len);
+		memcpy(*sigp, buffer_ptr(&b), len);
+	}
 	buffer_free(&b);
 	memset(sig, 's', slen);
 	xfree(sig);
 
-	if (lenp != NULL)
-		*lenp = len;
-	if (sigp != NULL)
-		*sigp = ret;
 	return 0;
 }
 
@@ -149,7 +151,7 @@
 		xfree(sigblob);
 		return -1;
 	} else if (len < modlen) {
-		int diff = modlen - len;
+		u_int diff = modlen - len;
 		debug("ssh_rsa_verify: add padding: modlen %u > len %u",
 		    modlen, len);
 		sigblob = xrealloc(sigblob, modlen);
@@ -167,15 +169,100 @@
 	EVP_DigestUpdate(&md, data, datalen);
 	EVP_DigestFinal(&md, digest, &dlen);
 
-	ret = RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
+	ret = openssh_RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
 	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));
-	}
 	debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
+	return ret;
+}
+
+/*
+ * See:
+ * http://www.rsasecurity.com/rsalabs/pkcs/pkcs-1/
+ * ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.asn
+ */
+/*
+ * id-sha1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
+ *	oiw(14) secsig(3) algorithms(2) 26 }
+ */
+static const u_char id_sha1[] = {
+	0x30, 0x21, /* type Sequence, length 0x21 (33) */
+	0x30, 0x09, /* type Sequence, length 0x09 */
+	0x06, 0x05, /* type OID, length 0x05 */
+	0x2b, 0x0e, 0x03, 0x02, 0x1a, /* id-sha1 OID */
+	0x05, 0x00, /* NULL */
+	0x04, 0x14  /* Octet string, length 0x14 (20), followed by sha1 hash */
+};
+/*
+ * id-md5 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
+ *	rsadsi(113549) digestAlgorithm(2) 5 }
+ */
+static const u_char id_md5[] = {
+	0x30, 0x20, /* type Sequence, length 0x20 (32) */
+	0x30, 0x0c, /* type Sequence, length 0x09 */
+	0x06, 0x08, /* type OID, length 0x05 */
+	0x2a, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* id-md5 */
+	0x05, 0x00, /* NULL */
+	0x04, 0x10  /* Octet string, length 0x10 (16), followed by md5 hash */
+};
+
+static int
+openssh_RSA_verify(int type, u_char *hash, u_int hashlen,
+    u_char *sigbuf, u_int siglen, RSA *rsa)
+{
+	u_int ret, rsasize, oidlen = 0, hlen = 0;
+	int len;
+	const u_char *oid = NULL;
+	u_char *decrypted = NULL;
+
+	ret = 0;
+	switch (type) {
+	case NID_sha1:
+		oid = id_sha1;
+		oidlen = sizeof(id_sha1);
+		hlen = 20;
+		break;
+	case NID_md5:
+		oid = id_md5;
+		oidlen = sizeof(id_md5);
+		hlen = 16;
+		break;
+	default:
+		goto done;
+		break;
+	}
+	if (hashlen != hlen) {
+		error("bad hashlen");
+		goto done;
+	}
+	rsasize = RSA_size(rsa);
+	if (siglen == 0 || siglen > rsasize) {
+		error("bad siglen");
+		goto done;
+	}
+	decrypted = xmalloc(rsasize);
+	if ((len = RSA_public_decrypt(siglen, sigbuf, decrypted, rsa,
+	    RSA_PKCS1_PADDING)) < 0) {
+		error("RSA_public_decrypt failed: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		goto done;
+	}
+	if (len != hlen + oidlen) {
+		error("bad decrypted len: %d != %d + %d", len, hlen, oidlen);
+		goto done;
+	}
+	if (memcmp(decrypted, oid, oidlen) != 0) {
+		error("oid mismatch");
+		goto done;
+	}
+	if (memcmp(decrypted + oidlen, hash, hlen) != 0) {
+		error("hash mismatch");
+		goto done;
+	}
+	ret = 1;
+done:
+	if (decrypted)
+		xfree(decrypted);
 	return ret;
 }