/*
- * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
#include "string.h"
#include "crypt.h"
#include "fd.h"
+#include "crypt_backend.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;
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().
+/*
+ * Read 64 bytes from /dev/urandom and adds them to the SSL PRNG. Seed the PRNG
+ * used by random() with a random seed obtained from SSL. If /dev/random is not
+ * readable the function calls exit().
*
* \sa RAND_load_file(3), \ref get_random_bytes_or_die(), srandom(3),
* random(3), \ref para_random().
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 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;
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)
*result = rsa;
return 1;
fail:
- if (rsa)
- RSA_free(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;
+ size_t map_size, blob_size, decoded_size;
int ret, ret2;
char *cp;
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;
+ goto out_unmap;
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);
+ goto out_unmap;
+ decoded_size = ret;
+ ret = check_ssh_key_header(blob, decoded_size);
if (ret < 0)
- goto out;
+ goto out_unmap;
+ ret = read_rsa_bignums(blob + ret, decoded_size - ret, &key->rsa);
+ if (ret < 0)
+ goto out_unmap;
ret = RSA_size(key->rsa);
-out:
+out_unmap:
ret2 = para_munmap(map, map_size);
if (ret >= 0 && ret2 < 0)
ret = ret2;
+out:
if (ret < 0) {
free(key);
- result = NULL;
+ *result = NULL;
PARA_ERROR_LOG("key %s: %s\n", key_file, para_strerror(-ret));
} else
*result = key;
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)
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)
{
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)
{
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));
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);
*/
#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)
+void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
{
- 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);
+ size_t len = src->iov_len, l1, l2;
+ RC4_KEY *key = &sc->key;
+
+ assert(len > 0);
+ assert(len < ((typeof(src->iov_len))-1) / 2);
+ l1 = ROUND_DOWN(len, RC4_ALIGN);
+ l2 = ROUND_UP(len, RC4_ALIGN);
+
+ *dst = (typeof(*dst)) {
+ /* Add one for the terminating zero byte. */
+ .iov_base = para_malloc(l2 + 1),
+ .iov_len = len
+ };
+ RC4(key, l1, src->iov_base, dst->iov_base);
if (len > l1) {
- memcpy(remainder, buf + l1, len - l1);
- RC4(&scc->send->key, len - l1, remainder, tmp + l1);
+ unsigned char remainder[RC4_ALIGN] = "";
+ memcpy(remainder, src->iov_base + l1, len - l1);
+ RC4(key, len - l1, remainder, dst->iov_base + 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;
+ ((char *)dst->iov_base)[len] = '\0';
}
-/**
- * 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;
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