+++ /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 <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"
-
-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;
-}
-
-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);
-}
-
-#define KEY_TYPE_TXT "ssh-rsa"
-
-/* check if it is an ssh rsa key */
-static size_t is_ssh_rsa_key(char *data, size_t size)
-{
- char *cp;
-
- if (size < strlen(KEY_TYPE_TXT) + 2)
- return 0;
- cp = memchr(data, ' ', size);
- if (cp == NULL)
- return 0;
- if (strncmp(KEY_TYPE_TXT, data, strlen(KEY_TYPE_TXT)))
- return 0;
- cp++;
- if (cp >= data + size)
- return 0;
- if (*cp == '\0')
- return 0;
- return cp - data;
-}
-
-/*
- * This base64/uudecode stuff below is taken from openssh-5.2p1, Copyright (c)
- * 1996 by Internet Software Consortium. Portions Copyright (c) 1995 by
- * International Business Machines, Inc.
- */
-
-static const char Base64[] =
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-static const char Pad64 = '=';
-/*
- * Skips all whitespace anywhere. Converts characters, four at a time, starting
- * at (or after) src from base - 64 numbers into three 8 bit bytes in the
- * target area. it returns the number of data bytes stored at the target, or -1
- * on error.
- */
-static int base64_decode(char const *src, unsigned char *target, size_t targsize)
-{
- unsigned int tarindex, state;
- int ch;
- char *pos;
-
- state = 0;
- tarindex = 0;
-
- while ((ch = *src++) != '\0') {
- if (para_isspace(ch)) /* Skip whitespace anywhere. */
- continue;
-
- if (ch == Pad64)
- break;
-
- pos = strchr(Base64, ch);
- if (pos == 0) /* A non-base64 character. */
- return -1;
-
- switch (state) {
- case 0:
- if (target) {
- if (tarindex >= targsize)
- return (-1);
- target[tarindex] = (pos - Base64) << 2;
- }
- state = 1;
- break;
- case 1:
- if (target) {
- if (tarindex + 1 >= targsize)
- return (-1);
- target[tarindex] |= (pos - Base64) >> 4;
- target[tarindex+1] = ((pos - Base64) & 0x0f)
- << 4 ;
- }
- tarindex++;
- state = 2;
- break;
- case 2:
- if (target) {
- if (tarindex + 1 >= targsize)
- return (-1);
- target[tarindex] |= (pos - Base64) >> 2;
- target[tarindex+1] = ((pos - Base64) & 0x03)
- << 6;
- }
- tarindex++;
- state = 3;
- break;
- case 3:
- if (target) {
- if (tarindex >= targsize)
- return (-1);
- target[tarindex] |= (pos - Base64);
- }
- tarindex++;
- state = 0;
- break;
- }
- }
-
- /*
- * We are done decoding Base-64 chars. Let's see if we ended
- * on a byte boundary, and/or with erroneous trailing characters.
- */
-
- if (ch == Pad64) { /* We got a pad char. */
- ch = *src++; /* Skip it, get next. */
- switch (state) {
- case 0: /* Invalid = in first position */
- case 1: /* Invalid = in second position */
- return (-1);
-
- case 2: /* Valid, means one byte of info */
- /* Skip any number of spaces. */
- for (; ch != '\0'; ch = *src++)
- if (!isspace(ch))
- break;
- /* Make sure there is another trailing = sign. */
- if (ch != Pad64)
- return (-1);
- ch = *src++; /* Skip the = */
- /* Fall through to "single trailing =" case. */
- /* FALLTHROUGH */
-
- case 3: /* Valid, means two bytes of info */
- /*
- * We know this char is an =. Is there anything but
- * whitespace after it?
- */
- for (; ch != '\0'; ch = *src++)
- if (!isspace(ch))
- return (-1);
-
- /*
- * Now make sure for cases 2 and 3 that the "extra"
- * bits that slopped past the last full byte were
- * zeros. If we don't check them, they become a
- * subliminal channel.
- */
- if (target && target[tarindex] != 0)
- return (-1);
- }
- } else {
- /*
- * We ended by seeing the end of the string. Make sure we
- * have no partial bytes lying around.
- */
- if (state != 0)
- return (-1);
- }
-
- return (tarindex);
-}
-
-static int uudecode(const char *src, unsigned char *target, size_t targsize)
-{
- int len;
- char *encoded, *p;
-
- /* copy the 'readonly' source */
- encoded = para_strdup(src);
- /* skip whitespace and data */
- for (p = encoded; *p == ' ' || *p == '\t'; p++)
- ;
- for (; *p != '\0' && *p != ' ' && *p != '\t'; p++)
- ;
- /* and remove trailing whitespace because base64_decode needs this */
- *p = '\0';
- len = base64_decode(encoded, target, targsize);
- free(encoded);
- return len >= 0? len : -E_BASE64;
-}
-
-/*
- * 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.
- */
-
-
-/*
- * Can not use the inline functions of portable_io.h here because the byte
- * order is different.
- */
-static uint32_t read_ssh_u32(const void *vp)
-{
- const unsigned char *p = (const unsigned char *)vp;
- uint32_t v;
-
- v = (uint32_t)p[0] << 24;
- v |= (uint32_t)p[1] << 16;
- v |= (uint32_t)p[2] << 8;
- v |= (uint32_t)p[3];
-
- return v;
-}
-
-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;
- uint32_t rlen;
-
- *result = NULL;
- if (p + 4 > end)
- return -E_BIGNUM;
- rlen = read_ssh_u32(p);
- p += 4;
- if (p + rlen < p)
- return -E_BIGNUM;
- if (p + rlen > end)
- return -E_BIGNUM;
- if (rlen < strlen(KEY_TYPE_TXT))
- return -E_BIGNUM;
- PARA_DEBUG_LOG("type: %s, rlen: %d\n", p, rlen);
- if (strncmp((char *)p, KEY_TYPE_TXT, strlen(KEY_TYPE_TXT)))
- return -E_BIGNUM;
- p += rlen;
-
- 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.
- *
- * \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 = NULL;
- void *map = NULL;
- unsigned char *blob = NULL;
- size_t map_size, blob_size;
- int ret, ret2;
- char *cp;
-
- key = para_malloc(sizeof(*key));
- 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;
- ret = read_rsa_bignums(blob, 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;
-}
-
-/**
- * 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;
-}
-
-struct stream_cipher {
- RC4_KEY key;
-};
-
-/**
- * Allocate and initialize a stream cipher structure.
- *
- * \param data The key.
- * \param len The size of the key.
- *
- * \return A new stream cipher structure.
- */
-struct stream_cipher *sc_new(const unsigned char *data, int len)
-{
- struct stream_cipher *sc = para_malloc(sizeof(*sc));
- RC4_set_key(&sc->key, len, data);
- return sc;
-}
-
-/**
- * Deallocate a stream cipher structure.
- *
- * \param sc A stream cipher previously obtained by sc_new().
- */
-void sc_free(struct stream_cipher *sc)
-{
- 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.
- *
- * \param scc The 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 sc_send_bin_buffer(struct stream_cipher_context *scc, 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(&scc->send->key, l1, (const unsigned char *)buf, tmp);
- if (len > l1) {
- memcpy(remainder, buf + l1, len - l1);
- RC4(&scc->send->key, len - l1, remainder, tmp + l1);
- }
- ret = write_all(scc->fd, (char *)tmp, &len);
- free(tmp);
- 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.
- *
- * \param scc The 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 sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf,
- size_t size)
-{
- unsigned char *tmp = para_malloc(size);
- ssize_t ret = recv(scc->fd, tmp, size, 0);
-
- if (ret > 0)
- RC4(&scc->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 scc The 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 scc, 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
- * sc_recv_bin_buffer().
- */
-int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size)
-{
- int n;
-
- assert(size);
- n = sc_recv_bin_buffer(scc, buf, size - 1);
- if (n >= 0)
- buf[n] = '\0';
- else
- *buf = '\0';
- return n;
-}
-
-/**
- * Compute the hash of the given input data.
- *
- * \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.
- *
- * \a hash must point to an area at least \p HASH_SIZE bytes large.
- *
- * \sa sha(3), openssl(1).
- * */
-void hash_function(const char *data, unsigned long len, unsigned char *hash)
-{
- SHA_CTX c;
- SHA1_Init(&c);
- SHA1_Update(&c, data, len);
- SHA1_Final(hash, &c);
-}
projects / paraslash.git / blobdiff