0.4.8 (to be announced) "nested assignment"
-------------------------------------------
+Gcrypt support, the overhauled osx writer and regex format specifiers
+are the highlights of this release.
+
+ - support for libgcrypt as a drop-in replacement for openssl.
+ Run configure --enable-cryptolib=gcrypt to link against
+ libgcrypt. The two crypto implementations are compatible to
+ each other, i.e. a para_client executable linked against
+ gcrypt can connect to para_server linked against libssl
+ and vice versa.
+ - Rewrite of the osx writer (output plugin for Mac OS).
- audiod: The format specifier for receivers, filters and
writers is now treated as a regular expression. This allows
to replace 5 lines in the config file (one for each audio
format) by one single line. See the manual for details.
- Compiles cleanly also with llvm/clang.
- - Rewrite of the osx writer (output plugin for Mac OS).
--------------------------------------
0.4.7 (2011-06-01) "infinite rollback"
all_errlist_objs="server mp3_afh afh_common vss command net string signal time
-daemon stat crypt http_send close_on_fork ipc acl afh fade amp_filter
+daemon stat http_send close_on_fork ipc acl afh fade amp_filter
dccp_send fd user_list chunk_queue afs aft mood score attribute blob ringbuffer
playlist sched audiod grab_client filter_common wav_filter compress_filter
http_recv dccp_recv recv_common write_common file_write audiod_command
client_common recv stdout filter stdin audioc write client exec send_common ggo
udp_recv udp_send color fec fecdec_filter prebuffer_filter mm
server_command_list afs_command_list audiod_command_list bitstream imdct wma_afh
-wma_common wmadec_filter buffer_tree
+wma_common wmadec_filter buffer_tree crypt_common
"
executables="recv filter audioc write client afh audiod"
audioc_ldflags=""
audiod_cmdline_objs="add_cmdline(audiod compress_filter http_recv dccp_recv file_write client amp_filter udp_recv prebuffer_filter)"
-audiod_errlist_objs="audiod signal string daemon stat net
+audiod_errlist_objs="audiod signal string daemon stat net crypt_common
time grab_client filter_common wav_filter compress_filter amp_filter http_recv dccp_recv
- recv_common fd sched write_common file_write audiod_command crypt fecdec_filter
+ recv_common fd sched write_common file_write audiod_command fecdec_filter
client_common ggo udp_recv color fec prebuffer_filter audiod_command_list
bitstream imdct wma_common wmadec_filter buffer_tree"
audiod_ldflags="-lm"
server_cmdline_objs="add_cmdline(server)"
server_errlist_objs="server afh_common mp3_afh vss command net string signal
- time daemon crypt http_send close_on_fork mm
+ time daemon http_send close_on_fork mm crypt_common
ipc dccp_send fd user_list chunk_queue afs aft mood score attribute
blob playlist sched acl send_common udp_send color fec
server_command_list afs_command_list wma_afh wma_common"
default_writer="FILE_WRITE"
client_cmdline_objs="add_cmdline(client)"
-client_errlist_objs="client net string crypt fd sched stdin stdout time
- client_common buffer_tree"
+client_errlist_objs="client net string fd sched stdin stdout time
+ client_common buffer_tree crypt_common"
client_ldflags=""
gui_cmdline_objs="add_cmdline(gui)"
CPPFLAGS="$OLD_CPPFLAGS"
LDFLAGS="$OLD_LDFLAGS"
LIBS="$OLD_LIBS"
+########################################################################### crypto
+AC_ARG_ENABLE(cryptolib, [AS_HELP_STRING(--enable-cryptolib=lib, [
+ Force using crypto library "lib". This package requires either
+ openssl or libgcrypt being installed. Possible values for "lib"
+ are thus "openssl" and "gcrypt". If this option is not given,
+ openssl is tried first. If openssl was not found, gcrypt is
+ tried next.])])
+
+case "$enable_cryptolib" in
+ "openssl") check_openssl="yes"; check_gcrypt="no";;
+ "gcrypt") check_openssl="no"; check_gcrypt="yes";;
+ "") check_openssl="yes"; check_gcrypt="yes";;
+ *) AC_MSG_ERROR([invalid value "$enable_cryptolib" for --enable-cryptolib]);;
+esac
###################################################################### openssl
-OLD_CPPFLAGS="$CPPFLAGS"
-OLD_LD_FLAGS="$LDFLAGS"
-OLD_LIBS="$LIBS"
-have_openssl="yes"
-AC_ARG_WITH(openssl_headers, [AC_HELP_STRING(--with-openssl-headers=dir,
- [look for openssl headers also in dir])])
-if test -n "$with_openssl_headers"; then
- openssl_cppflags="-I$with_openssl_headers"
- CPPFLAGS="$CPPFLAGS $openssl_cppflags"
-fi
-AC_ARG_WITH(openssl_libs, [AC_HELP_STRING(--with-openssl-libs=dir,
- [look for openssl libraries also in dir])])
-if test -n "$with_openssl_libs"; then
- openssl_libs="-L$with_openssl_libs"
- LDFLAGS="$LDFLAGS $openssl_libs"
-fi
-AC_CHECK_HEADER(openssl/ssl.h, [], [have_openssl="no"])
-AC_CHECK_LIB([crypto], [RAND_bytes], [], [have_openssl="no"])
-if test "$have_openssl" = "no" -a -z "$with_openssl_headers$with_openssl_libs"; then
- # try harder: openssl is sometimes installed in /usr/local/ssl
- openssl_cppflags="-I/usr/local/ssl/include"
- CPPFLAGS="$CPPFLAGS $openssl_cppflags"
- openssl_libs="-L/usr/local/ssl/lib"
- LDFLAGS="$LDFLAGS $openssl_libs"
- # clear cache
- unset ac_cv_header_openssl_ssl_h 2> /dev/null
- unset ac_cv_lib_crypto_RAND_bytes 2> /dev/null
- AC_CHECK_HEADER(openssl/ssl.h, [have_openssl="yes"], [])
+if test "$check_openssl" = "yes"; then
+ OLD_CPPFLAGS="$CPPFLAGS"
+ OLD_LD_FLAGS="$LDFLAGS"
+ OLD_LIBS="$LIBS"
+ have_openssl="yes"
+ AC_ARG_WITH(openssl_headers, [AC_HELP_STRING(--with-openssl-headers=dir,
+ [look for openssl headers also in dir])])
+ if test -n "$with_openssl_headers"; then
+ openssl_cppflags="-I$with_openssl_headers"
+ CPPFLAGS="$CPPFLAGS $openssl_cppflags"
+ fi
+ AC_ARG_WITH(openssl_libs, [AC_HELP_STRING(--with-openssl-libs=dir,
+ [look for openssl libraries also in dir])])
+ if test -n "$with_openssl_libs"; then
+ openssl_libs="-L$with_openssl_libs"
+ LDFLAGS="$LDFLAGS $openssl_libs"
+ fi
+ AC_CHECK_HEADER(openssl/ssl.h, [], [have_openssl="no"])
+ AC_CHECK_LIB([crypto], [RAND_bytes], [], [have_openssl="no"])
+ if test "$have_openssl" = "no" -a -z "$with_openssl_headers$with_openssl_libs"; then
+ # try harder: openssl is sometimes installed in /usr/local/ssl
+ openssl_cppflags="-I/usr/local/ssl/include"
+ CPPFLAGS="$CPPFLAGS $openssl_cppflags"
+ openssl_libs="-L/usr/local/ssl/lib"
+ LDFLAGS="$LDFLAGS $openssl_libs"
+ # clear cache
+ unset ac_cv_header_openssl_ssl_h 2> /dev/null
+ unset ac_cv_lib_crypto_RAND_bytes 2> /dev/null
+ AC_CHECK_HEADER(openssl/ssl.h, [have_openssl="yes"], [])
+ if test "$have_openssl" = "yes"; then
+ AC_CHECK_LIB([crypto], [RAND_bytes], [], [have_openssl="no"])
+ fi
+ fi
if test "$have_openssl" = "yes"; then
- AC_CHECK_LIB([crypto], [RAND_bytes], [], [have_openssl="no"])
+ AC_DEFINE(HAVE_OPENSSL, 1, [define to 1 to turn on openssl support])
+ AC_SUBST(openssl_cppflags)
+ openssl_libs="$openssl_libs -lssl -lcrypto"
+ server_ldflags="$server_ldflags $openssl_libs"
+ client_ldflags="$client_ldflags $openssl_libs"
+ audiod_ldflags="$audiod_ldflags $openssl_libs"
+
+ all_errlist_objs="$all_errlist_objs crypt"
+ server_errlist_objs="$server_errlist_objs crypt"
+ client_errlist_objs="$client_errlist_objs crypt"
+ audiod_errlist_objs="$audiod_errlist_objs crypt"
+
+ check_gcrypt="no"
+ else
+ AC_MSG_WARN([openssl libraries not found])
fi
-fi
-if test "$have_openssl" = "yes"; then
- AC_DEFINE(HAVE_OPENSSL, 1, [define to 1 to turn on openssl support])
- AC_SUBST(openssl_cppflags)
- openssl_libs="$openssl_libs -lssl -lcrypto"
- server_ldflags="$server_ldflags $openssl_libs"
- client_ldflags="$client_ldflags $openssl_libs"
- audiod_ldflags="$audiod_ldflags $openssl_libs"
+ CPPFLAGS="$OLD_CPPFLAGS"
+ LDFLAGS="$OLD_LDFLAGS"
+ LIBS="$OLD_LIBS"
else
- AC_MSG_ERROR([openssl libraries not found])
+ have_openssl="no"
+fi
+########################################################################### gcrypt
+if test "$check_gcrypt" = "yes"; then
+ OLD_CPPFLAGS="$CPPFLAGS"
+ OLD_LD_FLAGS="$LDFLAGS"
+ OLD_LIBS="$LIBS"
+ have_gcrypt="yes"
+ AC_ARG_WITH(gcrypt_headers, [AC_HELP_STRING(--with-gcrypt-headers=dir,
+ [look for gcrypt headers also in dir])])
+ if test -n "$with_gcrypt_headers"; then
+ gcrypt_cppflags="-I$with_gcrypt_headers"
+ CPPFLAGS="$CPPFLAGS $gcrypt_cppflags"
+ fi
+ AC_ARG_WITH(gcrypt_libs, [AC_HELP_STRING(--with-gcrypt-libs=dir,
+ [look for libgcrypt also in dir])])
+ if test -n "$with_gcrypt_libs"; then
+ gcrypt_libs="-L$with_gcrypt_libs"
+ LDFLAGS="$LDFLAGS $gcrypt_libs"
+ fi
+ AC_CHECK_HEADER(gcrypt.h, [], [have_gcrypt="no"])
+ AC_CHECK_LIB([gcrypt], [gcry_randomize], [], [have_gcrypt="no"])
+ if test "$have_gcrypt" = "yes"; then
+ AC_DEFINE(HAVE_GCRYPT, 1, [define to 1 to turn on gcrypt support])
+ AC_SUBST(gcrypt_cppflags)
+ gcrypt_libs="$gcrypt_libs -lgcrypt"
+ server_ldflags="$server_ldflags $gcrypt_libs"
+ client_ldflags="$client_ldflags $gcrypt_libs"
+ audiod_ldflags="$audiod_ldflags $gcrypt_libs"
+
+ all_errlist_objs="$all_errlist_objs gcrypt"
+ server_errlist_objs="$server_errlist_objs gcrypt"
+ client_errlist_objs="$client_errlist_objs gcrypt"
+ audiod_errlist_objs="$audiod_errlist_objs gcrypt"
+ else
+ AC_MSG_WARN([gcrypt library not found])
+ fi
+ CPPFLAGS="$OLD_CPPFLAGS"
+ LDFLAGS="$OLD_LDFLAGS"
+ LIBS="$OLD_LIBS"
+else
+ have_gcrypt="no"
+fi
+###########################################################################
+if test "$have_openssl" = "no" -a "$have_gcrypt" = "no"; then
+ AC_MSG_ERROR([neither openssl nor gcrypt usable])
fi
-CPPFLAGS="$OLD_CPPFLAGS"
-LDFLAGS="$OLD_LDFLAGS"
-LIBS="$OLD_LIBS"
########################################################################### libsocket
AC_CHECK_LIB([c], [socket],
[socket_lib=],
done
AC_DEFINE_UNQUOTED(DEFINE_ERRLIST_OBJECT_ENUM,
[enum {$SS NUM_SS}],
- [list of all objects that use paraslash's error facility]
+ [list of all objects that use the paraslash error facility]
)
################################################################## status items
/** \file crypt.c Openssl-based encryption/decryption routines. */
#include <regex.h>
+#include <stdbool.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <openssl/rand.h>
#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)
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;
ret = uudecode(cp, blob, blob_size);
if (ret < 0)
goto out;
- ret = read_rsa_bignums(blob, ret, &key->rsa);
+ 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);
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,
+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.
- *
- * \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)
{
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;
* Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file crypt.h Prototypes for paraslash crypto functions. */
+/** \file crypt.h Public crypto interface. */
+
+
+/** \cond used to distinguish between loading of private/public key */
+#define LOAD_PUBLIC_KEY 0
+#define LOAD_PRIVATE_KEY 1
+#define CHALLENGE_SIZE 64
+/** \endcond **/
+
+/* asymetric (public key) crypto */
/** Opaque structure for public and private keys. */
struct asymmetric_key;
+/**
+ * Encrypt a buffer using asymmetric keys.
+ *
+ * \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.
+ */
int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
unsigned len, unsigned char *outbuf);
+
+/**
+ * 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.
+ *
+ * The \a outbuf must be large enough to hold at least 512 bytes.
+ *
+ * \return The size of the recovered plaintext on success, negative on errors.
+ */
int priv_decrypt(const char *key_file, unsigned char *outbuf,
unsigned char *inbuf, int inlen);
+
+/**
+ * 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.
+ */
int get_asymmetric_key(const char *key_file, int private,
struct asymmetric_key **result);
+
+/**
+ * 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);
+
+/**
+ * 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 it 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);
+
+/**
+ * Seed pseudo random number generators.
+ *
+ * This function seeds the PRNG used by random() with a random seed obtained
+ * from the crypto implementation. On errors, an error message is logged and
+ * the function calls exit().
+ *
+ * \sa \ref get_random_bytes_or_die(), srandom(3), random(3), \ref
+ * para_random().
+ */
void init_random_seed_or_die(void);
-/** Opaque structure for stream cipher crypto. */
+
+/** Opaque structure for stream ciphers. */
struct stream_cipher;
-/** Number of bytes of the session key. */
+/** Number of bytes of the session key for stream ciphers. */
#define SESSION_KEY_LEN 32
/**
- * Used on the server-side for client-server communication encryption.
+ * Used for client-server communication encryption.
*
* The traffic between (the forked child of) para_server and the remote client
* process is crypted by a symmetric session key. This structure contains the
struct stream_cipher *send;
};
+/**
+ * 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);
+
+/**
+ * Deallocate a stream cipher structure.
+ *
+ * \param sc A stream cipher previously obtained by sc_new().
+ */
void sc_free(struct stream_cipher *sc);
-int sc_send_bin_buffer(struct stream_cipher_context *scc, const char *buf,
+/**
+ * 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, char *buf,
size_t len);
-int sc_send_buffer(struct stream_cipher_context *scc, const char *buf);
+
+/**
+ * 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, char *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, ...);
+
+/**
+ * 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);
+
+/**
+ * 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);
-/** \cond used to distinguish between loading of private/public key */
-#define LOAD_PUBLIC_KEY 0
-#define LOAD_PRIVATE_KEY 1
-#define CHALLENGE_SIZE 64
-/** \endcond **/
/** Size of the hash value in bytes. */
#define HASH_SIZE 20
-void hash_function(const char *data, unsigned long len, unsigned char *hash);
/**
- * Compare two hashes.
+ * Compute the hash of the given input data.
*
- * \param h1 Pointer to the first hash value.
- * \param h2 Pointer to the second hash value.
+ * \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.
*
- * \return 1, -1, or zero, depending on whether \a h1 is greater than,
- * less than or equal to h2, respectively.
- */
-_static_inline_ int hash_compare(unsigned char *h1, unsigned char *h2)
-{
- int i;
-
- for (i = 0; i < HASH_SIZE; i++) {
- if (h1[i] < h2[i])
- return -1;
- if (h1[i] > h2[i])
- return 1;
- }
- return 0;
-}
+ * \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);
/**
* Convert a hash value to ascii format.
* will be filled by the function with the ascii representation of the hash
* value given by \a hash, and a terminating \p NULL byte.
*/
-_static_inline_ void hash_to_asc(unsigned char *hash, char *asc)
-{
- int i;
- const char hexchar[] = "0123456789abcdef";
-
- for (i = 0; i < HASH_SIZE; i++) {
- asc[2 * i] = hexchar[hash[i] >> 4];
- asc[2 * i + 1] = hexchar[hash[i] & 0xf];
- }
- asc[2 * HASH_SIZE] = '\0';
-}
+void hash_to_asc(unsigned char *hash, char *asc);
+
+/**
+ * Compare two hashes.
+ *
+ * \param h1 Pointer to the first hash value.
+ * \param h2 Pointer to the second hash value.
+ *
+ * \return 1, -1, or zero, depending on whether \a h1 is greater than,
+ * less than or equal to h2, respectively.
+ */
+int hash_compare(unsigned char *h1, unsigned char *h2);
--- /dev/null
+/*
+ * Copyright (C) 2011 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file crypt_backend.h Non-public crypto interface. */
+
+/* This should only be incuded from files which provide crypto functions. */
+
+size_t is_ssh_rsa_key(char *data, size_t size);
+uint32_t read_ssh_u32(const void *vp);
+int uudecode(const char *src, unsigned char *target, size_t targsize);
+int check_ssh_key_header(const unsigned char *blob, int blen);
+int check_key_file(const char *file, bool private_key);
+int base64_decode(char const *src, unsigned char *target, size_t targsize);
--- /dev/null
+/*
+ * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file crypt_common.c Crypto functions independent of openssl/libgcrypt. */
+
+#include <regex.h>
+#include <stdbool.h>
+
+#include "para.h"
+#include "error.h"
+#include "string.h"
+#include "crypt_backend.h"
+#include "crypt.h"
+
+/** If the key begins with this text, we treat it as an ssh key. */
+#define KEY_TYPE_TXT "ssh-rsa"
+
+/**
+ * Check if given buffer starts with a ssh rsa key signature.
+ *
+ * \param data The buffer.
+ * \param size Number of data bytes.
+ *
+ * \return Number of header bytes to be skipped on success, zero if
+ * ssh rsa signature was not found.
+ */
+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 = '=';
+
+/**
+ * base64-decode a buffer.
+ *
+ * \param src The buffer to decode.
+ * \param target Result is stored here.
+ * \param targsize Number of bytes of \a target.
+ *
+ * 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.
+ *
+ * \return The number of data bytes stored at the target, -E_BASE64 on errors.
+ */
+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 -E_BASE64;
+
+ switch (state) {
+ case 0:
+ if (target) {
+ if (tarindex >= targsize)
+ return -E_BASE64;
+ target[tarindex] = (pos - Base64) << 2;
+ }
+ state = 1;
+ break;
+ case 1:
+ if (target) {
+ if (tarindex + 1 >= targsize)
+ return -E_BASE64;
+ 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 -E_BASE64;
+ target[tarindex] |= (pos - Base64) >> 2;
+ target[tarindex+1] = ((pos - Base64) & 0x03)
+ << 6;
+ }
+ tarindex++;
+ state = 3;
+ break;
+ case 3:
+ if (target) {
+ if (tarindex >= targsize)
+ return -E_BASE64;
+ 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 -E_BASE64;
+
+ 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 -E_BASE64;
+ 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 -E_BASE64;
+
+ /*
+ * 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 -E_BASE64;
+ }
+ } else {
+ /*
+ * We ended by seeing the end of the string. Make sure we
+ * have no partial bytes lying around.
+ */
+ if (state != 0)
+ return -E_BASE64;
+ }
+
+ return tarindex;
+}
+
+/**
+ * uudecode a buffer.
+ *
+ * \param src The buffer to decode.
+ * \param target Result buffer.
+ * \param targsize The length of \a target in bytes.
+ *
+ * This is just a simple wrapper for base64_decode() which strips whitespace.
+ *
+ * \return The return value of the underlying call to base64_decode().
+ */
+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;
+}
+
+/**
+ * Read a 4-byte number from a buffer in big-endian format.
+ *
+ * \param vp The buffer.
+ *
+ * The byte-order of the buffer is expected to be big-endian, unlike read_u32()
+ * of portable_io.h which expects little endian.
+ *
+ * \return The 32 bit number given by \a vp.
+ */
+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;
+}
+
+/**
+ * Sanity checks for the header of an ssh key.
+ *
+ * \param blob The buffer.
+ * \param blen The number of bytes of \a blob.
+ *
+ * This performs some checks to make sure we really have an ssh key. It also
+ * computes the offset in bytes of the start of the key values (modulus,
+ * exponent..).
+ *
+ * \return The number of bytes to skip until the start of the first encoded
+ * number (usually 11).
+ */
+int check_ssh_key_header(const unsigned char *blob, int blen)
+{
+ const unsigned char *p = blob, *end = blob + blen;
+ uint32_t rlen;
+
+ if (p + 4 > end)
+ return -E_SSH_KEY_HEADER;
+ rlen = read_ssh_u32(p);
+ p += 4;
+ if (p + rlen < p)
+ return -E_SSH_KEY_HEADER;
+ if (p + rlen > end)
+ return -E_SSH_KEY_HEADER;
+ if (rlen < strlen(KEY_TYPE_TXT))
+ return -E_SSH_KEY_HEADER;
+ PARA_DEBUG_LOG("type: %s, rlen: %d\n", p, rlen);
+ if (strncmp((char *)p, KEY_TYPE_TXT, strlen(KEY_TYPE_TXT)))
+ return -E_SSH_KEY_HEADER;
+ return 4 + rlen;
+}
+
+/**
+ * Check existence and permissions of a key file.
+ *
+ * \param file The path of the key file.
+ * \param private_key Whether this is a private key.
+ *
+ * This checks whether the file exists. If it is a private key, we additionally
+ * check that the permissions are restrictive enough. It is considered an error
+ * if we own the file and it is readable for others.
+ *
+ * \return Standard.
+ */
+int check_key_file(const char *file, bool private_key)
+{
+ struct stat st;
+
+ if (stat(file, &st) != 0)
+ return -ERRNO_TO_PARA_ERROR(errno);
+ if (!private_key)
+ return 0;
+ if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0)
+ return -E_KEY_PERM;
+ return 1;
+}
+
+void hash_to_asc(unsigned char *hash, char *asc)
+{
+ int i;
+ const char hexchar[] = "0123456789abcdef";
+
+ for (i = 0; i < HASH_SIZE; i++) {
+ asc[2 * i] = hexchar[hash[i] >> 4];
+ asc[2 * i + 1] = hexchar[hash[i] & 0xf];
+ }
+ asc[2 * HASH_SIZE] = '\0';
+}
+
+int hash_compare(unsigned char *h1, unsigned char *h2)
+{
+ int i;
+
+ for (i = 0; i < HASH_SIZE; i++) {
+ if (h1[i] < h2[i])
+ return -1;
+ if (h1[i] > h2[i])
+ return 1;
+ }
+ return 0;
+}
+
+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;
+}
+
+int sc_send_buffer(struct stream_cipher_context *scc, char *buf)
+{
+ return sc_send_bin_buffer(scc, buf, strlen(buf));
+}
+
+__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;
+}
PARA_ERROR(AFS_SHORT_READ, "short read from afs socket"), \
+#define CRYPT_COMMON_ERRORS \
+ PARA_ERROR(SSH_KEY_HEADER, "ssh key header not found"), \
+ PARA_ERROR(BASE64, "failed to base64-decode ssh public key"), \
+ PARA_ERROR(KEY_PERM, "unprotected private key"), \
+
+
#define CRYPT_ERRORS \
PARA_ERROR(PRIVATE_KEY, "can not read private key"), \
PARA_ERROR(PUBLIC_KEY, "can not read public key"), \
PARA_ERROR(ENCRYPT, "encrypt error"), \
PARA_ERROR(DECRYPT, "decrypt error"), \
PARA_ERROR(BLINDING, "failed to activate key blinding"), \
- PARA_ERROR(KEY_PERM, "unprotected private key"), \
- PARA_ERROR(BASE64, "failed to base64-decode ssh private key"), \
PARA_ERROR(BIGNUM, "bignum error"), \
+#define GCRYPT_ERRORS \
+ PARA_ERROR(MPI_SCAN, "could not scan multi-precision integer"), \
+ PARA_ERROR(MPI_PRINT, "could not convert multi-precision integer"), \
+ PARA_ERROR(SEXP_FIND, "could not find sublist in S-expression"), \
+ PARA_ERROR(SEXP_BUILD, "could not build S-expression"), \
+ PARA_ERROR(SEXP_ENCRYPT, "could not encrypt S-expression"), \
+ PARA_ERROR(SEXP_DECRYPT, "could not decrypt S-expression"), \
+ PARA_ERROR(MD_OPEN, "could not open message digest object"), \
+ PARA_ERROR(CIPHER_OPEN, "could not create stream cipher handle"), \
+ PARA_ERROR(BAD_PRIVATE_KEY, "invalid private key"), \
+ PARA_ERROR(KEY_MARKER, "invalid/missing key header or footer"), \
+ PARA_ERROR(ASN1_PARSE, "could not parse ASN.1 key"), \
+ PARA_ERROR(SSH_PARSE, "could not parse ssh public key"), \
+ PARA_ERROR(OEAP, "error during oeap (un)padding"), \
+
#define COMMAND_ERRORS \
PARA_ERROR(COMMAND_SYNTAX, "syntax error in command"), \
--- /dev/null
+/*
+ * Copyright (C) 2011 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file gcrypt.c Libgrcypt-based encryption/decryption routines. */
+
+#include <regex.h>
+#include <stdbool.h>
+#include <gcrypt.h>
+
+#include "para.h"
+#include "error.h"
+#include "string.h"
+#include "crypt.h"
+#include "crypt_backend.h"
+#include "fd.h"
+
+//#define GCRYPT_DEBUG 1
+
+static bool libgcrypt_has_oaep;
+static const char *rsa_decrypt_sexp;
+
+#ifdef GCRYPT_DEBUG
+static void dump_buffer(const char *msg, unsigned char *buf, int len)
+{
+ int i;
+
+ fprintf(stderr, "%s (%u bytes): ", msg, len);
+ for (i = 0; i < len; i++)
+ fprintf(stderr, "%02x ", buf[i]);
+ fprintf(stderr, "\n");
+}
+#else
+/** Empty. Define GCRYPT_DEBUG to dump buffers. */
+#define dump_buffer(a, b, c)
+#endif
+
+void hash_function(const char *data, unsigned long len, unsigned char *hash)
+{
+ gcry_error_t gret;
+ gcry_md_hd_t handle;
+ unsigned char *md;
+
+ gret = gcry_md_open(&handle, GCRY_MD_SHA1, 0);
+ assert(gret == 0);
+ gcry_md_write(handle, data, (size_t)len);
+ gcry_md_final(handle);
+ md = gcry_md_read(handle, GCRY_MD_SHA1);
+ assert(md);
+ memcpy(hash, md, HASH_SIZE);
+ gcry_md_close(handle);
+}
+
+void get_random_bytes_or_die(unsigned char *buf, int num)
+{
+ gcry_randomize(buf, (size_t)num, GCRY_STRONG_RANDOM);
+}
+
+/*
+ * This is called at the beginning of every program that uses libgcrypt. We
+ * don't have to initialize any random seed here, but we must initialize the
+ * gcrypt library. This task is performed by gcry_check_version() which can
+ * also check that the gcrypt library version is at least the minimal required
+ * version. This function also tells us whether we have to use our own OAEP
+ * padding code.
+ */
+void init_random_seed_or_die(void)
+{
+ const char *ver, *req_ver;
+
+ ver = gcry_check_version(NULL);
+ req_ver = "1.4.0";
+ if (!gcry_check_version(req_ver)) {
+ PARA_EMERG_LOG("fatal: need at least libgcrypt-%s, have: %s\n",
+ req_ver, ver);
+ exit(EXIT_FAILURE);
+ }
+ req_ver = "1.5.0";
+ if (gcry_check_version(req_ver)) {
+ libgcrypt_has_oaep = true;
+ rsa_decrypt_sexp = "(enc-val(flags oaep)(rsa(a %m)))";
+ } else {
+ libgcrypt_has_oaep = false;
+ rsa_decrypt_sexp = "(enc-val(rsa(a %m)))";
+ }
+}
+
+/** S-expression for the public part of an RSA key. */
+#define RSA_PUBKEY_SEXP "(public-key (rsa (n %m) (e %m)))"
+/** S-expression for a private RSA key. */
+#define RSA_PRIVKEY_SEXP "(private-key (rsa (n %m) (e %m) (d %m) (p %m) (q %m) (u %m)))"
+
+/* rfc 3447, appendix B.2 */
+static void mgf1(unsigned char *seed, size_t seed_len, unsigned result_len,
+ unsigned char *result)
+{
+ gcry_error_t gret;
+ gcry_md_hd_t handle;
+ size_t n;;
+ unsigned char *md;
+ unsigned char octet_string[4], *rp = result, *end = rp + result_len;
+
+ assert(result_len / HASH_SIZE < 1ULL << 31);
+ gret = gcry_md_open(&handle, GCRY_MD_SHA1, 0);
+ assert(gret == 0);
+ for (n = 0; rp < end; n++) {
+ gcry_md_write(handle, seed, seed_len);
+ octet_string[0] = (unsigned char)((n >> 24) & 255);
+ octet_string[1] = (unsigned char)((n >> 16) & 255);
+ octet_string[2] = (unsigned char)((n >> 8)) & 255;
+ octet_string[3] = (unsigned char)(n & 255);
+ gcry_md_write(handle, octet_string, 4);
+ gcry_md_final(handle);
+ md = gcry_md_read(handle, GCRY_MD_SHA1);
+ memcpy(rp, md, PARA_MIN(HASH_SIZE, (int)(end - rp)));
+ rp += HASH_SIZE;
+ gcry_md_reset(handle);
+ }
+ gcry_md_close(handle);
+}
+
+/** The sha1 hash of an empty file. */
+static const unsigned char empty_hash[HASH_SIZE] =
+ "\xda" "\x39" "\xa3" "\xee" "\x5e"
+ "\x6b" "\x4b" "\x0d" "\x32" "\x55"
+ "\xbf" "\xef" "\x95" "\x60" "\x18"
+ "\x90" "\xaf" "\xd8" "\x07" "\x09";
+
+/* rfc3447, section 7.1.1 */
+static void pad_oaep(unsigned char *in, size_t in_len, unsigned char *out,
+ size_t out_len)
+{
+ size_t ps_len = out_len - in_len - 2 * HASH_SIZE - 2;
+ size_t n, mask_len = out_len - HASH_SIZE - 1;
+ unsigned char *seed = out + 1, *db = seed + HASH_SIZE,
+ *ps = db + HASH_SIZE, *one = ps + ps_len;
+ unsigned char *db_mask, seed_mask[HASH_SIZE];
+
+ assert(in_len <= out_len - 2 - 2 * HASH_SIZE);
+ assert(out_len > 2 * HASH_SIZE + 2);
+ PARA_DEBUG_LOG("padding %zu byte input -> %zu byte output\n",
+ in_len, out_len);
+ dump_buffer("unpadded buffer", in, in_len);
+
+ out[0] = '\0';
+ get_random_bytes_or_die(seed, HASH_SIZE);
+ memcpy(db, empty_hash, HASH_SIZE);
+ memset(ps, 0, ps_len);
+ *one = 0x01;
+ memcpy(one + 1, in, in_len);
+ db_mask = para_malloc(mask_len);
+ mgf1(seed, HASH_SIZE, mask_len, db_mask);
+ for (n = 0; n < mask_len; n++)
+ db[n] ^= db_mask[n];
+ mgf1(db, mask_len, HASH_SIZE, seed_mask);
+ for (n = 0; n < HASH_SIZE; n++)
+ seed[n] ^= seed_mask[n];
+ free(db_mask);
+ dump_buffer("padded buffer", out, out_len);
+}
+
+/* rfc 3447, section 7.1.2 */
+static int unpad_oaep(unsigned char *in, size_t in_len, unsigned char *out,
+ size_t *out_len)
+{ int ret;
+ unsigned char *masked_seed = in + 1;
+ unsigned char *db = in + 1 + HASH_SIZE;
+ unsigned char seed[HASH_SIZE], seed_mask[HASH_SIZE];
+ unsigned char *db_mask, *p;
+ size_t n, mask_len = in_len - HASH_SIZE - 1;
+
+ mgf1(db, mask_len, HASH_SIZE, seed_mask);
+ for (n = 0; n < HASH_SIZE; n++)
+ seed[n] = masked_seed[n] ^ seed_mask[n];
+ db_mask = para_malloc(mask_len);
+ mgf1(seed, HASH_SIZE, mask_len, db_mask);
+ for (n = 0; n < mask_len; n++)
+ db[n] ^= db_mask[n];
+ free(db_mask);
+ if (memcmp(db, empty_hash, HASH_SIZE))
+ return -E_OEAP;
+ for (p = db + HASH_SIZE; p < in + in_len - 1; p++)
+ if (*p != '\0')
+ break;
+ if (p >= in + in_len - 1)
+ return -E_OEAP;
+ p++;
+ *out_len = in + in_len - p;
+ memcpy(out, p, *out_len);
+ return ret;
+}
+
+struct asymmetric_key {
+ gcry_sexp_t sexp;
+ int num_bytes;
+};
+
+static const char *gcrypt_strerror(gcry_error_t gret)
+{
+ return gcry_strerror(gcry_err_code(gret));
+}
+
+static int decode_key(const char *key_file, const char *header_str,
+ const char *footer_str, unsigned char **result)
+{
+ int ret, ret2, i, j;
+ void *map;
+ size_t map_size, key_size, blob_size;
+ unsigned char *blob = NULL;
+ char *begin, *footer, *key;
+
+ ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
+ if (ret < 0)
+ return ret;
+ ret = -E_KEY_MARKER;
+ if (strncmp(map, header_str, strlen(header_str)))
+ goto unmap;
+ footer = strstr(map, footer_str);
+ ret = -E_KEY_MARKER;
+ if (!footer)
+ goto unmap;
+ begin = map + strlen(header_str);
+ /* skip whitespace at the beginning */
+ for (; begin < footer; begin++) {
+ if (para_isspace(*begin))
+ continue;
+ break;
+ }
+ ret = -E_KEY_MARKER;
+ if (begin >= footer)
+ goto unmap;
+
+ key_size = footer - begin;
+ key = para_malloc(key_size + 1);
+ for (i = 0, j = 0; begin + i < footer; i++) {
+ if (para_isspace(begin[i]))
+ continue;
+ key[j++] = begin[i];
+ }
+ key[j] = '\0';
+ //PARA_CRIT_LOG("key: %s\n", key);
+ blob_size = key_size * 2;
+ blob = para_malloc(blob_size);
+ ret = base64_decode(key, blob, blob_size);
+ free(key);
+ if (ret < 0)
+ goto free_unmap;
+ goto unmap;
+free_unmap:
+ free(blob);
+ blob = NULL;
+unmap:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+ if (ret < 0) {
+ free(blob);
+ blob = NULL;
+ }
+ *result = blob;
+ return ret;
+}
+
+/** ASN Types and their code. */
+enum asn1_types {
+ /** The next object is an integer. */
+ ASN1_TYPE_INTEGER = 0x2,
+ /** Bit string object. */
+ ASN1_TYPE_BIT_STRING = 0x03,
+ /** Keys start with one big type sequence. */
+ ASN1_TYPE_SEQUENCE = 0x30,
+};
+
+/* bit 6 has value 0 */
+static inline bool is_primitive(unsigned char c)
+{
+ return ((c & (1<<6)) == 0);
+}
+
+static inline bool is_primitive_integer(unsigned char c)
+{
+ if (!is_primitive(c))
+ return false;
+ return ((c & 0x1f) == ASN1_TYPE_INTEGER);
+}
+
+/* Bit 8 is zero (and bits 7-1 give the length) */
+static inline bool is_short_form(unsigned char c)
+{
+ return (c & 0x80) == 0;
+}
+
+static inline int get_short_form_length(unsigned char c)
+{
+ return c & 0x7f;
+}
+
+static inline int get_long_form_num_length_bytes(unsigned char c)
+{
+ return c & 0x7f;
+}
+
+static int find_pubkey_bignum_offset(const unsigned char *data, int len)
+{
+ const unsigned char *p = data, *end = data + len;
+
+ /* the whole thing istarts with one sequence */
+ if (*p != ASN1_TYPE_SEQUENCE)
+ return -E_ASN1_PARSE;
+ p++;
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ if (is_short_form(*p))
+ p++;
+ else
+ p += 1 + get_long_form_num_length_bytes(*p);
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ /* another sequence containing the object id, skip it */
+ if (*p != ASN1_TYPE_SEQUENCE)
+ return -E_ASN1_PARSE;
+ p++;
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ if (!is_short_form(*p))
+ return -E_ASN1_PARSE;
+ p += 1 + get_short_form_length(*p);
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ /* all numbers are wrapped in a bit string object that follows */
+ if (*p != ASN1_TYPE_BIT_STRING)
+ return -E_ASN1_PARSE;
+ p++;
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ if (is_short_form(*p))
+ p++;
+ else
+ p += 1 + get_long_form_num_length_bytes(*p);
+ p++; /* skip number of unused bits in the bit string */
+ if (p >= end)
+ return -E_ASN1_PARSE;
+
+ /* next, we have a sequence of two integers (n and e) */
+ if (*p != ASN1_TYPE_SEQUENCE)
+ return -E_ASN1_PARSE;
+ p++;
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ if (is_short_form(*p))
+ p++;
+ else
+ p += 1 + get_long_form_num_length_bytes(*p);
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ if (*p != ASN1_TYPE_INTEGER)
+ return -E_ASN1_PARSE;
+ return p - data;
+}
+
+/*
+ * Returns: Number of bytes scanned. This may differ from the value returned via
+ * bn_bytes because the latter does not include the ASN.1 prefix and a leading
+ * zero is not considered as an additional byte for bn_bytes.
+ */
+static int read_bignum(unsigned char *start, unsigned char *end, gcry_mpi_t *bn,
+ int *bn_bytes)
+{
+ int i, bn_size;
+ gcry_error_t gret;
+ unsigned char *cp = start;
+
+ if (!is_primitive_integer(*cp))
+ return -E_BAD_PRIVATE_KEY;
+ cp++;
+ if (is_short_form(*cp)) {
+ bn_size = get_short_form_length(*cp);
+ cp++;
+ } else {
+ int num_bytes = get_long_form_num_length_bytes(*cp);
+ if (cp + num_bytes > end)
+ return -E_BAD_PRIVATE_KEY;
+ if (num_bytes > 4) /* nobody has such a large modulus */
+ return -E_BAD_PRIVATE_KEY;
+ cp++;
+ bn_size = 0;
+ for (i = 0; i < num_bytes; i++, cp++)
+ bn_size = (bn_size << 8) + *cp;
+ }
+ PARA_DEBUG_LOG("bn_size %d (0x%x)\n", bn_size, bn_size);
+ gret = gcry_mpi_scan(bn, GCRYMPI_FMT_STD, cp, bn_size, NULL);
+ if (gret) {
+ PARA_ERROR_LOG("%s while scanning n\n",
+ gcry_strerror(gcry_err_code(gret)));
+ return-E_MPI_SCAN;
+ }
+ /*
+ * Don't take the first leading zero into account for the size of the
+ * bignum.
+ */
+ if (*cp == '\0') {
+ cp++;
+ bn_size--;
+ }
+ if (bn_bytes)
+ *bn_bytes = bn_size;
+ cp += bn_size;
+// unsigned char *buf;
+// gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, *bn);
+// PARA_CRIT_LOG("bn: %s\n", buf);
+ return cp - start;
+}
+
+static int find_privkey_bignum_offset(const unsigned char *data, int len)
+{
+ const unsigned char *p = data, *end = data + len;
+
+ /* like the public key, the whole thing is contained in a sequence */
+ if (*p != ASN1_TYPE_SEQUENCE)
+ return -E_ASN1_PARSE;
+ p++;
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ if (is_short_form(*p))
+ p++;
+ else
+ p += 1 + get_long_form_num_length_bytes(*p);
+ if (p >= end)
+ return -E_ASN1_PARSE;
+
+ /* Skip next integer */
+ if (*p != ASN1_TYPE_INTEGER)
+ return -E_ASN1_PARSE;
+ p++;
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ if (is_short_form(*p))
+ p += 1 + get_short_form_length(*p);
+ else
+ p += 1 + get_long_form_num_length_bytes(*p);
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ return p - data;
+}
+
+/** Private keys start with this header. */
+#define PRIVATE_KEY_HEADER "-----BEGIN RSA PRIVATE KEY-----"
+/** Private keys end with this footer. */
+#define PRIVATE_KEY_FOOTER "-----END RSA PRIVATE KEY-----"
+
+static int get_private_key(const char *key_file, struct asymmetric_key **result)
+{
+ gcry_mpi_t n = NULL, e = NULL, d = NULL, p = NULL, q = NULL,
+ u = NULL;
+ unsigned char *blob, *cp, *end;
+ int blob_size, ret, n_size;
+ gcry_error_t gret;
+ size_t erroff;
+ gcry_sexp_t sexp;
+ struct asymmetric_key *key;
+
+ ret = decode_key(key_file, PRIVATE_KEY_HEADER, PRIVATE_KEY_FOOTER,
+ &blob);
+ if (ret < 0)
+ return ret;
+ blob_size = ret;
+ end = blob + blob_size;
+ ret = find_privkey_bignum_offset(blob, blob_size);
+ if (ret < 0)
+ goto free_blob;
+ PARA_INFO_LOG("reading RSA params at offset %d\n", ret);
+ cp = blob + ret;
+
+ ret = read_bignum(cp, end, &n, &n_size);
+ if (ret < 0)
+ goto free_blob;
+ cp += ret;
+
+ ret = read_bignum(cp, end, &e, NULL);
+ if (ret < 0)
+ goto release_n;
+ cp += ret;
+
+ ret = read_bignum(cp, end, &d, NULL);
+ if (ret < 0)
+ goto release_e;
+ cp += ret;
+
+ ret = read_bignum(cp, end, &p, NULL);
+ if (ret < 0)
+ goto release_d;
+ cp += ret;
+
+ ret = read_bignum(cp, end, &q, NULL);
+ if (ret < 0)
+ goto release_p;
+ cp += ret;
+ ret = read_bignum(cp, end, &u, NULL);
+ if (ret < 0)
+ goto release_q;
+ cp += ret;
+ /*
+ * OpenSSL uses slightly different parameters than gcrypt. To use these
+ * parameters we need to swap the values of p and q and recompute u.
+ */
+ if (gcry_mpi_cmp(p, q) > 0) {
+ gcry_mpi_swap(p, q);
+ gcry_mpi_invm(u, p, q);
+ }
+ gret = gcry_sexp_build(&sexp, &erroff, RSA_PRIVKEY_SEXP,
+ n, e, d, p, q, u);
+
+ if (gret) {
+ PARA_ERROR_LOG("offset %zu: %s\n", erroff,
+ gcry_strerror(gcry_err_code(gret)));
+ ret = -E_SEXP_BUILD;
+ goto release_u;
+ }
+ key = para_malloc(sizeof(*key));
+ key->sexp = sexp;
+ *result = key;
+ ret = n_size * 8;
+ PARA_INFO_LOG("succesfully read %d bit private key\n", ret);
+release_u:
+ gcry_mpi_release(u);
+release_q:
+ gcry_mpi_release(q);
+release_p:
+ gcry_mpi_release(p);
+release_d:
+ gcry_mpi_release(d);
+release_e:
+ gcry_mpi_release(e);
+release_n:
+ gcry_mpi_release(n);
+free_blob:
+ free(blob);
+ return ret;
+}
+
+/** Public keys start with this header. */
+#define PUBLIC_KEY_HEADER "-----BEGIN PUBLIC KEY-----"
+/** Public keys end with this footer. */
+#define PUBLIC_KEY_FOOTER "-----END PUBLIC KEY-----"
+
+static int get_asn_public_key(const char *key_file, struct asymmetric_key **result)
+{
+ gcry_mpi_t n = NULL, e = NULL;
+ unsigned char *blob, *cp, *end;
+ int blob_size, ret, n_size;
+ gcry_error_t gret;
+ size_t erroff;
+ gcry_sexp_t sexp;
+ struct asymmetric_key *key;
+
+ ret = decode_key(key_file, PUBLIC_KEY_HEADER, PUBLIC_KEY_FOOTER,
+ &blob);
+ if (ret < 0)
+ return ret;
+ blob_size = ret;
+ end = blob + blob_size;
+ ret = find_pubkey_bignum_offset(blob, blob_size);
+ if (ret < 0)
+ goto free_blob;
+ PARA_DEBUG_LOG("decoding public RSA params at offset %d\n", ret);
+ cp = blob + ret;
+
+ ret = read_bignum(cp, end, &n, &n_size);
+ if (ret < 0)
+ goto free_blob;
+ cp += ret;
+
+ ret = read_bignum(cp, end, &e, NULL);
+ if (ret < 0)
+ goto release_n;
+ cp += ret;
+
+ gret = gcry_sexp_build(&sexp, &erroff, RSA_PUBKEY_SEXP, n, e);
+ if (gret) {
+ PARA_ERROR_LOG("offset %zu: %s\n", erroff,
+ gcry_strerror(gcry_err_code(gret)));
+ ret = -E_SEXP_BUILD;
+ goto release_e;
+ }
+ key = para_malloc(sizeof(*key));
+ key->sexp = sexp;
+ *result = key;
+ ret = n_size;
+ PARA_INFO_LOG("successfully read %u bit asn public key\n", n_size * 8);
+
+release_e:
+ gcry_mpi_release(e);
+release_n:
+ gcry_mpi_release(n);
+free_blob:
+ free(blob);
+ return ret;
+}
+
+static int get_ssh_public_key(unsigned char *data, int size, gcry_sexp_t *result)
+{
+ int ret;
+ gcry_error_t gret;
+ unsigned char *blob = NULL, *p, *end;
+ size_t nr_scanned, erroff, decoded_size;
+ gcry_mpi_t e = NULL, n = NULL;
+
+ PARA_DEBUG_LOG("decoding %d byte public rsa-ssh key\n", size);
+ if (size > INT_MAX / 4)
+ return -ERRNO_TO_PARA_ERROR(EOVERFLOW);
+ blob = para_malloc(2 * size);
+ ret = uudecode((char *)data, blob, 2 * size);
+ if (ret < 0)
+ goto free_blob;
+ decoded_size = ret;
+ end = blob + decoded_size;
+ dump_buffer("decoded key", blob, decoded_size);
+ ret = check_ssh_key_header(blob, decoded_size);
+ if (ret < 0)
+ goto free_blob;
+ p = blob + ret;
+ ret = -E_SSH_PARSE;
+ if (p >= end)
+ goto free_blob;
+ PARA_DEBUG_LOG("scanning modulus and public exponent\n");
+ gret = gcry_mpi_scan(&e, GCRYMPI_FMT_SSH, p, end - p, &nr_scanned);
+ if (gret) {
+ ret = -E_MPI_SCAN;
+ PARA_CRIT_LOG("%s\n", gcry_strerror(gcry_err_code(gret)));
+ goto free_blob;
+ }
+ PARA_DEBUG_LOG("scanned e (%zu bytes)\n", nr_scanned);
+// gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, rsa_e);
+// PARA_CRIT_LOG("e: %s\n", buf);
+ p += nr_scanned;
+ if (p >= end)
+ goto release_e;
+ gret = gcry_mpi_scan(&n, GCRYMPI_FMT_SSH, p, end - p, &nr_scanned);
+ if (gret) {
+ ret = -E_MPI_SCAN;
+ PARA_ERROR_LOG("%s\n", gcry_strerror(gcry_err_code(gret)));
+ goto release_e;
+ }
+ PARA_DEBUG_LOG("scanned n (%zu bytes)\n", nr_scanned);
+// gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, rsa_n);
+// PARA_CRIT_LOG("n: %s\n", buf);
+ gret = gcry_sexp_build(result, &erroff, RSA_PUBKEY_SEXP, n, e);
+ if (gret) {
+ PARA_ERROR_LOG("offset %zu: %s\n", erroff,
+ gcry_strerror(gcry_err_code(gret)));
+ ret = -E_SEXP_BUILD;
+ goto release_n;
+ }
+ ret = nr_scanned / 32 * 32;
+ PARA_INFO_LOG("successfully read %u bit ssh public key\n", ret * 8);
+release_n:
+ gcry_mpi_release(n);
+release_e:
+ gcry_mpi_release(e);
+free_blob:
+ free(blob);
+ return ret;
+}
+
+int get_asymmetric_key(const char *key_file, int private,
+ struct asymmetric_key **result)
+{
+ int ret, ret2;
+ void *map;
+ size_t map_size;
+ unsigned char *start, *end;
+ gcry_sexp_t sexp;
+ struct asymmetric_key *key;
+
+ if (private)
+ return get_private_key(key_file, result);
+ ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
+ if (ret < 0)
+ return ret;
+ ret = is_ssh_rsa_key(map, map_size);
+ if (!ret) {
+ ret = para_munmap(map, map_size);
+ if (ret < 0)
+ return ret;
+ return get_asn_public_key(key_file, result);
+ }
+ start = map + ret;
+ end = map + map_size;
+ ret = -E_SSH_PARSE;
+ if (start >= end)
+ goto unmap;
+ ret = get_ssh_public_key(start, end - start, &sexp);
+ if (ret < 0)
+ goto unmap;
+ key = para_malloc(sizeof(*key));
+ key->num_bytes = ret;
+ key->sexp = sexp;
+ *result = key;
+ ret = key->num_bytes;
+unmap:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+ return ret;
+}
+
+void free_asymmetric_key(struct asymmetric_key *key)
+{
+ if (!key)
+ return;
+ gcry_sexp_release(key->sexp);
+ free(key);
+}
+
+static int decode_rsa(gcry_sexp_t sexp, int key_size, unsigned char *outbuf,
+ size_t *nbytes)
+{
+ int ret;
+ gcry_error_t gret;
+ unsigned char oaep_buf[512];
+ gcry_mpi_t out_mpi;
+
+ if (libgcrypt_has_oaep) {
+ const char *p = gcry_sexp_nth_data(sexp, 1, nbytes);
+
+ if (!p) {
+ PARA_ERROR_LOG("could not get data from list\n");
+ return -E_OEAP;
+ }
+ memcpy(outbuf, p, *nbytes);
+ return 1;
+ }
+ out_mpi = gcry_sexp_nth_mpi(sexp, 0, GCRYMPI_FMT_USG);
+ if (!out_mpi)
+ return -E_SEXP_FIND;
+ gret = gcry_mpi_print(GCRYMPI_FMT_USG, oaep_buf, sizeof(oaep_buf),
+ nbytes, out_mpi);
+ if (gret) {
+ PARA_ERROR_LOG("mpi_print: %s\n", gcrypt_strerror(gret));
+ ret = -E_MPI_PRINT;
+ goto out_mpi_release;
+ }
+ /*
+ * An oaep-encoded buffer always starts with at least one zero byte.
+ * However, leading zeroes in an mpi are omitted in the output of
+ * gcry_mpi_print() when using the GCRYMPI_FMT_USG format. The
+ * alternative, GCRYMPI_FMT_STD, does not work either because here the
+ * leading zero(es) might also be omitted, depending on the value of
+ * the second byte.
+ *
+ * To circumvent this, we shift the oaep buffer to the right. But first
+ * we check that the buffer actually started with a zero byte, i.e. that
+ * nbytes < key_size. Otherwise a decoding error occurred.
+ */
+ ret = -E_SEXP_DECRYPT;
+ if (*nbytes >= key_size)
+ goto out_mpi_release;
+ memmove(oaep_buf + key_size - *nbytes, oaep_buf, *nbytes);
+ memset(oaep_buf, 0, key_size - *nbytes);
+
+ PARA_DEBUG_LOG("decrypted buffer before unpad (%d bytes):\n",
+ key_size);
+ dump_buffer("non-unpadded decrypted buffer", oaep_buf, key_size);;
+ unpad_oaep(oaep_buf, key_size, outbuf, nbytes);
+ PARA_DEBUG_LOG("decrypted buffer after unpad (%zu bytes):\n",
+ *nbytes);
+ dump_buffer("unpadded decrypted buffer", outbuf, *nbytes);;
+ ret = 1;
+out_mpi_release:
+ gcry_mpi_release(out_mpi);
+ return ret;
+}
+
+int priv_decrypt(const char *key_file, unsigned char *outbuf,
+ unsigned char *inbuf, int inlen)
+{
+ gcry_error_t gret;
+ int ret, key_size;
+ struct asymmetric_key *priv;
+ gcry_mpi_t in_mpi = NULL;
+ gcry_sexp_t in, out, priv_key;
+ size_t nbytes;
+
+ PARA_INFO_LOG("decrypting %d byte input\n", inlen);
+ /* key_file -> asymmetric key priv */
+ ret = get_private_key(key_file, &priv);
+ if (ret < 0)
+ return ret;
+ key_size = ret / 8;
+
+ /* asymmetric key priv -> sexp priv_key */
+ ret = -E_SEXP_FIND;
+ priv_key = gcry_sexp_find_token(priv->sexp, "private-key", 0);
+ if (!priv_key)
+ goto free_key;
+
+ /* inbuf -> in_mpi */
+ gret = gcry_mpi_scan(&in_mpi, GCRYMPI_FMT_USG, inbuf,
+ inlen, NULL);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_MPI_SCAN;
+ goto key_release;
+ }
+ /* in_mpi -> in sexp */
+ gret = gcry_sexp_build(&in, NULL, rsa_decrypt_sexp, in_mpi);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_BUILD;
+ goto in_mpi_release;
+ }
+
+ /* rsa decryption: in sexp -> out sexp */
+ gret = gcry_pk_decrypt(&out, in, priv_key);
+ if (gret) {
+ PARA_ERROR_LOG("decrypt: %s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_DECRYPT;
+ goto in_release;
+ }
+ ret = decode_rsa(out, key_size, outbuf, &nbytes);
+ if (ret < 0)
+ goto out_release;
+ PARA_INFO_LOG("successfully decrypted %zu byte message\n", nbytes);
+ ret = nbytes;
+out_release:
+ gcry_sexp_release(out);
+in_release:
+ gcry_sexp_release(in);
+in_mpi_release:
+ gcry_mpi_release(in_mpi);
+key_release:
+ gcry_sexp_release(priv_key);
+free_key:
+ free_asymmetric_key(priv);
+ return ret;
+}
+
+int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
+ unsigned len, unsigned char *outbuf)
+{
+ gcry_error_t gret;
+ gcry_sexp_t pub_key, in, out, out_a;
+ gcry_mpi_t out_mpi = NULL;
+ size_t nbytes;
+ int ret;
+
+ PARA_INFO_LOG("encrypting %u byte input with %d-byte key\n", len, pub->num_bytes);
+
+ /* get pub key */
+ pub_key = gcry_sexp_find_token(pub->sexp, "public-key", 0);
+ if (!pub_key)
+ return -E_SEXP_FIND;
+ if (libgcrypt_has_oaep) {
+ gret = gcry_sexp_build(&in, NULL,
+ "(data(flags oaep)(value %b))", len, inbuf);
+ } else {
+ unsigned char padded_input[256];
+ const size_t pad_size = 256;
+ /* inbuf -> padded inbuf */
+ pad_oaep(inbuf, len, padded_input, pad_size);
+ /* padded inbuf -> in sexp */
+ gret = gcry_sexp_build(&in, NULL,
+ "(data(flags raw)(value %b))", pad_size, padded_input);
+ }
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_BUILD;
+ goto key_release;
+ }
+ /* rsa sexp encryption: in -> out */
+ gret = gcry_pk_encrypt(&out, in, pub_key);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_ENCRYPT;
+ goto in_release;
+ }
+ /* extract a, an MPI with the result of the RSA operation */
+ ret = -E_SEXP_FIND;
+ out_a = gcry_sexp_find_token(out, "a", 0);
+ if (!out_a)
+ goto out_release;
+ /* convert sexp out_a -> out_mpi */
+ out_mpi = gcry_sexp_nth_mpi(out_a, 1, GCRYMPI_FMT_USG);
+ if (!out_mpi) {
+ ret = -E_SEXP_FIND;
+ goto out_a_release;
+ }
+ gret = gcry_mpi_print(GCRYMPI_FMT_USG, outbuf, 512 /* FIXME */, &nbytes, out_mpi);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_ENCRYPT;
+ goto out_mpi_release;
+ }
+ PARA_INFO_LOG("encrypted buffer is %zu bytes\n", nbytes);
+ dump_buffer("enc buf", outbuf, nbytes);
+ ret = nbytes;
+
+out_mpi_release:
+ gcry_mpi_release(out_mpi);
+out_a_release:
+ gcry_sexp_release(out_a);
+out_release:
+ gcry_sexp_release(out);
+in_release:
+ gcry_sexp_release(in);
+key_release:
+ gcry_sexp_release(pub_key);
+ return ret;
+}
+
+struct stream_cipher {
+ gcry_cipher_hd_t handle;
+};
+
+struct stream_cipher *sc_new(const unsigned char *data, int len)
+{
+ gcry_error_t gret;
+
+ struct stream_cipher *sc = para_malloc(sizeof(*sc));
+ gret = gcry_cipher_open(&sc->handle, GCRY_CIPHER_ARCFOUR,
+ GCRY_CIPHER_MODE_STREAM, 0);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ free(sc);
+ return NULL;
+ }
+ gret = gcry_cipher_setkey(sc->handle, data, (size_t)len);
+ assert(gret == 0);
+ return sc;
+}
+
+void sc_free(struct stream_cipher *sc)
+{
+ if (!sc)
+ return;
+ gcry_cipher_close(sc->handle);
+ free(sc);
+}
+
+int sc_send_bin_buffer(struct stream_cipher_context *scc, char *buf,
+ size_t size)
+{
+ gcry_error_t gret;
+ int ret;
+ unsigned char *tmp = para_malloc(size);
+
+ assert(size);
+ gret = gcry_cipher_encrypt(scc->send->handle, tmp, size,
+ (unsigned char *)buf, size);
+ assert(gret == 0);
+ ret = write_all(scc->fd, (char *)tmp, &size);
+ free(tmp);
+ return ret;
+}
+
+int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf,
+ size_t size)
+{
+ gcry_error_t gret;
+ ssize_t ret = recv(scc->fd, buf, size, 0);
+
+ if (ret < 0)
+ ret = -ERRNO_TO_PARA_ERROR(errno);
+ if (ret <= 0)
+ return ret;
+ /* perform in-place encryption */
+ gret = gcry_cipher_encrypt(scc->recv->handle, (unsigned char *)buf, ret,
+ NULL, 0);
+ assert(gret == 0);
+ return ret;
+}
* - Blob tables: \ref blob.c,
* - The error subssystem: \ref error.h.
* - Access control for paraslash senders: \ref acl.c, \ref acl.h.
+ * - Internal crypto API: \ref crypt.h.
*
* Low-level data structures:
*
* - Doubly linked lists: \ref list.h,
* - Ring buffer: \ref ringbuffer.c, \ref ringbuffer.h,
- * - Crypto: \ref crypt.c, \ref crypt.h.
+ * - openssl: \ref crypt.c
+ * - libgcrypt: \ref gcrypt.c
* - Forward error correction: \ref fec.c.
*/
scripts which run during compilation require the EMPH(Bourne
again shell). It is most likely already installed.
- - XREFERENCE(http://www.openssl.org/, openssl). The EMPH(Secure
- Sockets Layer) library is needed for cryptographic routines
- on both the server and the client side. It is usually shipped
- with the distro, but you might have to install the "development
- package" (called libssl-dev on debian systems) as well.
+ - XREFERENCE(http://www.openssl.org/, openssl) or
+ XREFERENCE(ftp://ftp.gnupg.org/gcrypt/libgcrypt/, libgcrypt).
+ At least one of these two libraries is needed as the backend
+ for cryptographic routines on both the server and the client
+ side. Both openssl and libgcrypt are usually shipped with the
+ distro, but you might have to install the development package
+ (libssl-dev or libgcrypt-dev on debian systems) as well.
- XREFERENCE(ftp://ftp.gnu.org/pub/gnu/help2man, help2man)
is used to create the man pages.
this point on the communication is encrypted using the RC4
stream cipher with the session key known to both peers.
-paraslash relies on the quality of openssl's cryptographically strong
-pseudo-random bytes, on the security of the implementation of the
-openssl RSA and RC4 crypto routines and on the infeasibility to invert
-the SHA1 function.
+paraslash relies on the quality of the pseudo-random bytes provided
+by the crypto library (openssl or libgcrypt), on the security of
+the implementation of the RSA and RC4 crypto routines and on the
+infeasibility to invert the SHA1 function.
Neither para_server or para_client create RSA keys on their own. This
has to be done once for each user as sketched in REFERENCE(Quick start,
projects / paraslash.git / commitdiff