vss: Avoid use after free in vss_send().

[paraslash.git] / crypt.c

diff --git a/crypt.c b/crypt.c
index 5445138d53f6589ebce6645b027531f02b74c860..8116fb6eeacdbeaa0f1f22d14cfcc3726ee3bbbf 100644 (file)
--- a/crypt.c
+++ b/crypt.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -15,6 +15,7 @@
 #include <openssl/pem.h>
 #include <openssl/sha.h>
 #include <openssl/bn.h>
+#include <openssl/aes.h>
 
 #include "para.h"
 #include "error.h"
@@ -22,6 +23,7 @@
 #include "crypt.h"
 #include "fd.h"
 #include "crypt_backend.h"
+#include "base64.h"
 
 struct asymmetric_key {
        RSA *rsa;
@@ -132,18 +134,25 @@ static int read_rsa_bignums(const unsigned char *blob, int blen, RSA **result)
 {
        int ret;
        RSA *rsa;
+       BIGNUM *n, *e;
        const unsigned char *p = blob, *end = blob + blen;
 
        rsa = RSA_new();
        if (!rsa)
                return -E_BIGNUM;
-       ret = read_bignum(p, end - p, &rsa->e);
+       ret = read_bignum(p, end - p, &e);
        if (ret < 0)
                goto fail;
        p += ret;
-       ret = read_bignum(p, end - p, &rsa->n);
+       ret = read_bignum(p, end - p, &n);
        if (ret < 0)
                goto fail;
+#ifdef HAVE_RSA_SET0_KEY
+       RSA_set0_key(rsa, n, e, NULL);
+#else
+       rsa->n = n;
+       rsa->e = e;
+#endif
        *result = rsa;
        return 1;
 fail:
@@ -157,7 +166,7 @@ int get_asymmetric_key(const char *key_file, int private,
        struct asymmetric_key *key = NULL;
        void *map = NULL;
        unsigned char *blob = NULL;
-       size_t map_size, blob_size, decoded_size;
+       size_t map_size, encoded_size, decoded_size;
        int ret, ret2;
        char *cp;
 
@@ -179,16 +188,11 @@ int get_asymmetric_key(const char *key_file, int private,
                goto out;
        }
        cp = map + ret;
+       encoded_size = map_size - ret;
        PARA_INFO_LOG("decoding public rsa-ssh key %s\n", key_file);
-       ret = -ERRNO_TO_PARA_ERROR(EOVERFLOW);
-       if (map_size > INT_MAX / 4)
-               goto out_unmap;
-       blob_size = 2 * map_size;
-       blob = para_malloc(blob_size);
-       ret = uudecode(cp, blob, blob_size);
+       ret = uudecode(cp, encoded_size, (char **)&blob, &decoded_size);
        if (ret < 0)
                goto out_unmap;
-       decoded_size = ret;
        ret = check_ssh_key_header(blob, decoded_size);
        if (ret < 0)
                goto out_unmap;
@@ -260,18 +264,35 @@ int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
 }
 
 struct stream_cipher {
-       RC4_KEY key;
+       bool use_aes;
+       union {
+               RC4_KEY rc4_key;
+               EVP_CIPHER_CTX *aes;
+       } context;
 };
 
-struct stream_cipher *sc_new(const unsigned char *data, int len)
+struct stream_cipher *sc_new(const unsigned char *data, int len,
+               bool use_aes)
 {
        struct stream_cipher *sc = para_malloc(sizeof(*sc));
-       RC4_set_key(&sc->key, len, data);
+
+       sc->use_aes = use_aes;
+       if (!use_aes) {
+               RC4_set_key(&sc->context.rc4_key, len, data);
+               return sc;
+       }
+       assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
+       sc->context.aes = EVP_CIPHER_CTX_new();
+       EVP_EncryptInit_ex(sc->context.aes, EVP_aes_128_ctr(), NULL, data,
+               data + AES_CRT128_BLOCK_SIZE);
        return sc;
 }
 
 void sc_free(struct stream_cipher *sc)
 {
+       if (!sc)
+               return;
+       EVP_CIPHER_CTX_free(sc->context.aes);
        free(sc);
 }
 
@@ -282,10 +303,9 @@ void sc_free(struct stream_cipher *sc)
  */
 #define RC4_ALIGN 8
 
-void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
+static void rc4_crypt(RC4_KEY *key, struct iovec *src, struct iovec *dst)
 {
        size_t len = src->iov_len, l1, l2;
-       RC4_KEY *key = &sc->key;
 
        assert(len > 0);
        assert(len < ((typeof(src->iov_len))-1) / 2);
@@ -306,6 +326,32 @@ void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
        ((char *)dst->iov_base)[len] = '\0';
 }
 
+static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
+               struct iovec *dst)
+{
+       int ret, inlen = src->iov_len, outlen, tmplen;
+
+       *dst = (typeof(*dst)) {
+               /* Add one for the terminating zero byte. */
+               .iov_base = para_malloc(inlen + 1),
+               .iov_len = inlen
+       };
+       ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
+       assert(ret != 0);
+       ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
+       assert(ret != 0);
+       outlen += tmplen;
+       ((char *)dst->iov_base)[outlen] = '\0';
+       dst->iov_len = outlen;
+}
+
+void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
+{
+       if (sc->use_aes)
+               return aes_ctr128_crypt(sc->context.aes, src, dst);
+       return rc4_crypt(&sc->context.rc4_key, src, dst);
+}
+
 void hash_function(const char *data, unsigned long len, unsigned char *hash)
 {
        SHA_CTX c;