/** \file crypt.c Openssl-based encryption/decryption routines. */
#include <regex.h>
-#include <dirent.h>
+#include <stdbool.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <openssl/rand.h>
#include <openssl/err.h>
#include <openssl/rc4.h>
#include <openssl/pem.h>
+#include <openssl/sha.h>
+#include <openssl/bn.h>
#include "para.h"
#include "error.h"
#include "string.h"
#include "crypt.h"
#include "fd.h"
+#include "crypt_backend.h"
struct asymmetric_key {
RSA *rsa;
srandom(seed);
}
-static int check_key_file(const char *file, int private)
-{
- struct stat st;
-
- if (stat(file, &st) != 0)
- return -ERRNO_TO_PARA_ERROR(errno);
- if (private != LOAD_PRIVATE_KEY)
- return 0;
- if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0)
- return -E_KEY_PERM;
- return 1;
-}
-
static EVP_PKEY *load_key(const char *file, int private)
{
BIO *key;
return pkey;
}
+static int get_openssl_key(const char *key_file, RSA **rsa, int private)
+{
+ EVP_PKEY *key = load_key(key_file, private);
+
+ if (!key)
+ return (private == LOAD_PRIVATE_KEY)? -E_PRIVATE_KEY
+ : -E_PUBLIC_KEY;
+ *rsa = EVP_PKEY_get1_RSA(key);
+ EVP_PKEY_free(key);
+ if (!*rsa)
+ return -E_RSA;
+ return RSA_size(*rsa);
+}
+
+/*
+ * The public key loading functions below were inspired by corresponding code
+ * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
+ * Finland. However, not much of the original code remains.
+ */
+
+static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
+{
+ const unsigned char *p = buf, *end = buf + len;
+ uint32_t bnsize;
+ BIGNUM *bn;
+
+ if (p + 4 < p)
+ return -E_BIGNUM;
+ if (p + 4 > end)
+ return -E_BIGNUM;
+ bnsize = read_ssh_u32(p);
+ PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
+ p += 4;
+ if (p + bnsize < p)
+ return -E_BIGNUM;
+ if (p + bnsize > end)
+ return -E_BIGNUM;
+ if (bnsize > 8192)
+ return -E_BIGNUM;
+ bn = BN_bin2bn(p, bnsize, NULL);
+ if (!bn)
+ return -E_BIGNUM;
+ *result = bn;
+ return bnsize + 4;
+}
+
+static int read_rsa_bignums(const unsigned char *blob, int blen, RSA **result)
+{
+ int ret;
+ RSA *rsa;
+ const unsigned char *p = blob, *end = blob + blen;
+
+ rsa = RSA_new();
+ if (!rsa)
+ return -E_BIGNUM;
+ ret = read_bignum(p, end - p, &rsa->e);
+ if (ret < 0)
+ goto fail;
+ p += ret;
+ ret = read_bignum(p, end - p, &rsa->n);
+ if (ret < 0)
+ goto fail;
+ *result = rsa;
+ return 1;
+fail:
+ if (rsa)
+ RSA_free(rsa);
+ return ret;
+}
+
/**
* Read an asymmetric key from a file.
*
int get_asymmetric_key(const char *key_file, int private,
struct asymmetric_key **result)
{
- struct asymmetric_key *key;
- RSA *rsa;
- EVP_PKEY *pkey = load_key(key_file, private);
+ struct asymmetric_key *key = NULL;
+ void *map = NULL;
+ unsigned char *blob = NULL;
+ size_t map_size, blob_size, decoded_size;
+ int ret, ret2;
+ char *cp;
- if (!pkey)
- return (private == LOAD_PRIVATE_KEY)? -E_PRIVATE_KEY
- : -E_PUBLIC_KEY;
- rsa = EVP_PKEY_get1_RSA(pkey);
- EVP_PKEY_free(pkey);
- if (!rsa)
- return -E_RSA;
key = para_malloc(sizeof(*key));
- key->rsa = rsa;
- *result = key;
- return RSA_size(rsa);
+ if (private) {
+ ret = get_openssl_key(key_file, &key->rsa, LOAD_PRIVATE_KEY);
+ goto out;
+ }
+ ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
+ if (ret < 0)
+ goto out;
+ ret = is_ssh_rsa_key(map, map_size);
+ if (!ret) {
+ ret = para_munmap(map, map_size);
+ map = NULL;
+ if (ret < 0)
+ goto out;
+ ret = get_openssl_key(key_file, &key->rsa, LOAD_PUBLIC_KEY);
+ goto out;
+ }
+ cp = map + 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;
+ blob_size = 2 * map_size;
+ blob = para_malloc(blob_size);
+ ret = uudecode(cp, blob, blob_size);
+ if (ret < 0)
+ goto out;
+ decoded_size = ret;
+ ret = check_ssh_key_header(blob, decoded_size);
+ if (ret < 0)
+ goto out;
+ ret = read_rsa_bignums(blob + ret, decoded_size - ret, &key->rsa);
+ if (ret < 0)
+ goto out;
+ ret = RSA_size(key->rsa);
+out:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+ if (ret < 0) {
+ free(key);
+ result = NULL;
+ PARA_ERROR_LOG("key %s: %s\n", key_file, para_strerror(-ret));
+ } else
+ *result = key;
+ free(blob);
+ return ret;
}
/**
return ret < 0? -E_ENCRYPT : ret;
}
-#define RC4_ALIGN 8
struct stream_cipher {
RC4_KEY key;
};
free(sc);
}
+/**
+ * The RC4() implementation of openssl apparently reads and writes data in
+ * blocks of 8 bytes. So we have to make sure our buffer sizes are a multiple
+ * of this.
+ */
+#define RC4_ALIGN 8
+
/**
* Encrypt and send a buffer.
*
*
* \sa \ref write_all(), RC4(3).
*/
-int sc_send_bin_buffer(struct stream_cipher_context *scc, const char *buf,
+int sc_send_bin_buffer(struct stream_cipher_context *scc, char *buf,
size_t len)
{
int ret;
return ret;
}
-/**
- * Encrypt and send a \p NULL-terminated buffer.
- *
- * \param scc The context.
- * \param buf The buffer to send.
- *
- * \return The return value of the underyling call to sc_send_bin_buffer().
- */
-int sc_send_buffer(struct stream_cipher_context *scc, const char *buf)
-{
- return sc_send_bin_buffer(scc, buf, strlen(buf));
-}
-
-/**
- * Format, encrypt and send a buffer.
- *
- * \param scc The context.
- * \param fmt A format string.
- *
- * \return The return value of the underyling call to sc_send_buffer().
- */
-__printf_2_3 int sc_send_va_buffer(struct stream_cipher_context *scc,
- const char *fmt, ...)
-{
- char *msg;
- int ret;
-
- PARA_VSPRINTF(fmt, msg);
- ret = sc_send_buffer(scc, msg);
- free(msg);
- return ret;
-}
-
/**
* Receive a buffer and decrypt it.
*
}
/**
- * Receive a buffer, decrypt it and write terminating NULL byte.
+ * Compute the hash of the given input data.
*
- * \param scc The context.
- * \param buf The buffer to write the decrypted data to.
- * \param size The size of \a buf.
+ * \param data Pointer to the data to compute the hash value from.
+ * \param len The length of \a data in bytes.
+ * \param hash Result pointer.
*
- * Read at most \a size - 1 bytes from file descriptor given by \a scc, decrypt
- * the received data and write a NULL byte at the end of the decrypted data.
+ * \a hash must point to an area at least \p HASH_SIZE bytes large.
*
- * \return The return value of the underlying call to \ref
- * sc_recv_bin_buffer().
- */
-int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size)
+ * \sa sha(3), openssl(1).
+ * */
+void hash_function(const char *data, unsigned long len, unsigned char *hash)
{
- int n;
-
- assert(size);
- n = sc_recv_bin_buffer(scc, buf, size - 1);
- if (n >= 0)
- buf[n] = '\0';
- else
- *buf = '\0';
- return n;
+ SHA_CTX c;
+ SHA1_Init(&c);
+ SHA1_Update(&c, data, len);
+ SHA1_Final(hash, &c);
}
projects / paraslash.git / blobdiff