+++ /dev/null
-/*
- * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
-
-/** \file crypt.c Openssl-based encryption/decryption routines. */
-
-#include <regex.h>
-#include <dirent.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 "para.h"
-#include "error.h"
-#include "string.h"
-#include "crypt.h"
-#include "fd.h"
-
-struct asymmetric_key {
- RSA *rsa;
-};
-
-/**
- * Fill a buffer with random content.
- *
- * \param buf The buffer to fill.
- * \param num The size of \a buf in bytes.
- *
- * This function puts \a num cryptographically strong pseudo-random bytes into
- * buf. If libssl can not guarantee an unpredictable byte sequence (for example
- * because the PRNG has not been seeded with enough randomness) the function
- * logs an error message and calls exit().
- */
-void get_random_bytes_or_die(unsigned char *buf, int num)
-{
- unsigned long err;
-
- /* RAND_bytes() returns 1 on success, 0 otherwise. */
- if (RAND_bytes(buf, num) == 1)
- return;
- err = ERR_get_error();
- PARA_EMERG_LOG("%s\n", ERR_reason_error_string(err));
- exit(EXIT_FAILURE);
-}
-
-/**
- * Seed pseudo random number generators.
- *
- * This function reads 64 bytes from /dev/urandom and adds them to the SSL
- * PRNG. It also seeds the PRNG used by random() with a random seed obtained
- * from SSL. If /dev/random could not be read, an error message is logged and
- * the function calls exit().
- *
- * \sa RAND_load_file(3), \ref get_random_bytes_or_die(), srandom(3),
- * random(3), \ref para_random().
- */
-void init_random_seed_or_die(void)
-{
- int seed, ret = RAND_load_file("/dev/urandom", 64);
-
- if (ret != 64) {
- PARA_EMERG_LOG("could not seed PRNG (ret = %d)\n", ret);
- exit(EXIT_FAILURE);
- }
- get_random_bytes_or_die((unsigned char *)&seed, sizeof(seed));
- 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;
- EVP_PKEY *pkey = NULL;
- int ret = check_key_file(file, private);
-
- if (ret < 0) {
- PARA_ERROR_LOG("%s\n", para_strerror(-ret));
- return NULL;
- }
- key = BIO_new(BIO_s_file());
- if (!key)
- return NULL;
- if (BIO_read_filename(key, file) > 0) {
- if (private == LOAD_PRIVATE_KEY)
- pkey = PEM_read_bio_PrivateKey(key, NULL, NULL, NULL);
- else
- pkey = PEM_read_bio_PUBKEY(key, NULL, NULL, NULL);
- }
- BIO_free(key);
- return pkey;
-}
-
-/**
- * Read an asymmetric key from a file.
- *
- * \param key_file The file containing the key.
- * \param private if non-zero, read the private key, otherwise the public key.
- * \param result The key structure is returned here.
- *
- * \return The size of the key on success, negative on errors.
- *
- * \sa openssl(1), rsa(1).
- */
-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);
-
- 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);
-}
-
-/**
- * Deallocate an asymmetric key structure.
- *
- * \param key Pointer to the key structure to free.
- *
- * This must be called for any key obtained by get_asymmetric_key().
- */
-void free_asymmetric_key(struct asymmetric_key *key)
-{
- if (!key)
- return;
- RSA_free(key->rsa);
- free(key);
-}
-
-/**
- * Decrypt a buffer using a private key.
- *
- * \param key_file Full path of the key.
- * \param outbuf The output buffer.
- * \param inbuf The encrypted input buffer.
- * \param inlen The length of \a inbuf in bytes.
- *
- * The \a outbuf must be large enough to hold at least \a rsa_inlen bytes.
- *
- * \return The size of the recovered plaintext on success, negative on errors.
- *
- * \sa RSA_private_decrypt(3)
- **/
-int priv_decrypt(const char *key_file, unsigned char *outbuf,
- unsigned char *inbuf, int inlen)
-{
- struct asymmetric_key *priv;
- int ret;
-
- if (inlen < 0)
- return -E_RSA;
- ret = get_asymmetric_key(key_file, LOAD_PRIVATE_KEY, &priv);
- if (ret < 0)
- return ret;
- /*
- * RSA is vulnerable to timing attacks. Generate a random blinding
- * factor to protect against this kind of attack.
- */
- ret = -E_BLINDING;
- if (RSA_blinding_on(priv->rsa, NULL) == 0)
- goto out;
- ret = RSA_private_decrypt(inlen, inbuf, outbuf, priv->rsa,
- RSA_PKCS1_OAEP_PADDING);
- RSA_blinding_off(priv->rsa);
- if (ret <= 0)
- ret = -E_DECRYPT;
-out:
- free_asymmetric_key(priv);
- return ret;
-}
-
-/**
- * Encrypt a buffer using an RSA key
- *
- * \param pub: The public key.
- * \param inbuf The input buffer.
- * \param len The length of \a inbuf.
- * \param outbuf The output buffer.
- *
- * \return The size of the encrypted data on success, negative on errors.
- *
- * \sa RSA_public_encrypt(3)
- */
-int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
- unsigned len, unsigned char *outbuf)
-{
- int ret, flen = len; /* RSA_public_encrypt expects a signed int */
-
- if (flen < 0)
- return -E_ENCRYPT;
- ret = RSA_public_encrypt(flen, inbuf, outbuf, pub->rsa,
- RSA_PKCS1_OAEP_PADDING);
- return ret < 0? -E_ENCRYPT : ret;
-}
-
-#define RC4_ALIGN 8
-
-/**
- * Encrypt and send a buffer.
- *
- * \param rc4c The rc4 crypt context.
- * \param buf The buffer to send.
- * \param len The size of \a buf in bytes.
- *
- * \return The return value of the underyling call to write_all().
- *
- * \sa \ref write_all(), RC4(3).
- */
-int rc4_send_bin_buffer(struct rc4_context *rc4c, const char *buf, size_t len)
-{
- int ret;
- unsigned char *tmp;
- static unsigned char remainder[RC4_ALIGN];
- size_t l1 = ROUND_DOWN(len, RC4_ALIGN), l2 = ROUND_UP(len, RC4_ALIGN);
-
- assert(len);
- tmp = para_malloc(l2);
- RC4(&rc4c->send_key, l1, (const unsigned char *)buf, tmp);
- if (len > l1) {
- memcpy(remainder, buf + l1, len - l1);
- RC4(&rc4c->send_key, len - l1, remainder, tmp + l1);
- }
- ret = write_all(rc4c->fd, (char *)tmp, &len);
- free(tmp);
- return ret;
-}
-
-/**
- * Encrypt and send a \p NULL-terminated buffer.
- *
- * \param rc4c The rc4 crypt context.
- * \param buf The buffer to send.
- *
- * \return The return value of the underyling call to rc4_send_bin_buffer().
- */
-int rc4_send_buffer(struct rc4_context *rc4c, const char *buf)
-{
- return rc4_send_bin_buffer(rc4c, buf, strlen(buf));
-}
-
-/**
- * Format, encrypt and send a buffer.
- *
- * \param rc4c The rc4 crypt context.
- * \param fmt A format string.
- *
- * \return The return value of the underyling call to rc4_send_buffer().
- */
-__printf_2_3 int rc4_send_va_buffer(struct rc4_context *rc4c, const char *fmt, ...)
-{
- char *msg;
- int ret;
-
- PARA_VSPRINTF(fmt, msg);
- ret = rc4_send_buffer(rc4c, msg);
- free(msg);
- return ret;
-}
-
-/**
- * Receive a buffer and decrypt it.
- *
- * \param rc4c The rc4 crypt context.
- * \param buf The buffer to write the decrypted data to.
- * \param size The size of \a buf.
- *
- * \return The number of bytes received on success, negative on errors, zero if
- * the peer has performed an orderly shutdown.
- *
- * \sa recv(2), RC4(3).
- */
-int rc4_recv_bin_buffer(struct rc4_context *rc4c, char *buf, size_t size)
-{
- unsigned char *tmp = para_malloc(size);
- ssize_t ret = recv(rc4c->fd, tmp, size, 0);
-
- if (ret > 0)
- RC4(&rc4c->recv_key, ret, tmp, (unsigned char *)buf);
- else if (ret < 0)
- ret = -ERRNO_TO_PARA_ERROR(errno);
- free(tmp);
- return ret;
-}
-
-/**
- * Receive a buffer, decrypt it and write terminating NULL byte.
- *
- * \param rc4c The rc4 crypt context.
- * \param buf The buffer to write the decrypted data to.
- * \param size The size of \a buf.
- *
- * Read at most \a size - 1 bytes from file descriptor given by \a rc4c,
- * decrypt the received data and write a NULL byte at the end of the decrypted
- * data.
- *
- * \return The return value of the underlying call to \ref
- * rc4_recv_bin_buffer().
- */
-int rc4_recv_buffer(struct rc4_context *rc4c, char *buf, size_t size)
-{
- int n;
-
- assert(size);
- n = rc4_recv_bin_buffer(rc4c, buf, size - 1);
- if (n >= 0)
- buf[n] = '\0';
- else
- *buf = '\0';
- return n;
-}
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