X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/5ca51e190d8991e7cf2e8076dbd4d3dfbb50c966..0073b70fa18e81070f70ab64bc95d89f866b23fe:/ssh-rsa.c

diff --git a/ssh-rsa.c b/ssh-rsa.c
index 9de0e7b0..458c9c84 100644
--- a/ssh-rsa.c
+++ b/ssh-rsa.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh-rsa.c,v 1.6 2001/02/08 19:30:52 itojun Exp $");
+RCSID("$OpenBSD: ssh-rsa.c,v 1.19 2002/05/31 13:20:50 markus Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -34,37 +34,41 @@ RCSID("$OpenBSD: ssh-rsa.c,v 1.6 2001/02/08 19:30:52 itojun Exp $");
 #include "bufaux.h"
 #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)
+    u_char **sigp, u_int *lenp,
+    u_char *data, u_int datalen)
 {
-	EVP_MD *evp_md = EVP_sha1();
+	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;
+	int ok, nid;
 	Buffer b;
 
 	if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
 		error("ssh_rsa_sign: no RSA key");
 		return -1;
 	}
-	slen = RSA_size(key->rsa);
-	sig = xmalloc(slen);
-
-	dlen = evp_md->md_size;
-	digest = xmalloc(dlen);
+	nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
+	if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
+		error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid);
+		return -1;
+	}
 	EVP_DigestInit(&md, evp_md);
 	EVP_DigestUpdate(&md, data, datalen);
-	EVP_DigestFinal(&md, digest, NULL);
+	EVP_DigestFinal(&md, digest, &dlen);
 
-	ok = RSA_sign(NID_sha1, digest, dlen, sig, &len, key->rsa);
-	memset(digest, 'd', dlen);
-	xfree(digest);
+	slen = RSA_size(key->rsa);
+	sig = xmalloc(slen);
+
+	ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa);
+	memset(digest, 'd', sizeof(digest));
 
 	if (ok != 1) {
 		int ecode = ERR_get_error();
@@ -97,36 +101,34 @@ ssh_rsa_sign(
 		*lenp = len;
 	if (sigp != NULL)
 		*sigp = ret;
-	debug2("ssh_rsa_sign: done");
 	return 0;
 }
 
 int
 ssh_rsa_verify(
     Key *key,
-    u_char *signature, int signaturelen,
-    u_char *data, int datalen)
+    u_char *signature, u_int signaturelen,
+    u_char *data, u_int datalen)
 {
 	Buffer b;
-	EVP_MD *evp_md = EVP_sha1();
+	const EVP_MD *evp_md;
 	EVP_MD_CTX md;
 	char *ktype;
-	u_char *sigblob, *digest;
-	u_int len, dlen;
-	int rlen;
-	int ret;
+	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) {
+	if (BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
 		error("ssh_rsa_verify: n too small: %d bits",
 		    BN_num_bits(key->rsa->n));
 		return -1;
 	}
 	buffer_init(&b);
-	buffer_append(&b, (char *) signature, signaturelen);
+	buffer_append(&b, signature, signaturelen);
 	ktype = buffer_get_string(&b, NULL);
 	if (strcmp("ssh-rsa", ktype) != 0) {
 		error("ssh_rsa_verify: cannot handle type %s", ktype);
@@ -135,23 +137,41 @@ ssh_rsa_verify(
 		return -1;
 	}
 	xfree(ktype);
-	sigblob = (u_char *)buffer_get_string(&b, &len);
+	sigblob = buffer_get_string(&b, &len);
 	rlen = buffer_len(&b);
 	buffer_free(&b);
-	if(rlen != 0) {
+	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 %d > modlen %d", len, modlen);
+		xfree(sigblob);
+		return -1;
+	} else if (len < modlen) {
+		int diff = modlen - len;
+		debug("ssh_rsa_verify: add padding: modlen %d > len %d",
+		    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) {
+		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_sha1, digest, dlen, sigblob, len, key->rsa);
-	memset(digest, 'd', dlen);
-	xfree(digest);
+	ret = RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
+	memset(digest, 'd', sizeof(digest));
 	memset(sigblob, 's', len);
 	xfree(sigblob);
 	if (ret == 0) {