X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=crypt.c;h=7b602d995d3deccaba5e2e6ab76f4dec5570c95b;hp=6f7e611d0364035560819f7659bbb71d62d4f1b1;hb=6a7393e2abdcf30dd4201b84a417d08f6136e8d6;hpb=74f1e057c1579d880becb6a32acd43641b1a8c2b diff --git a/crypt.c b/crypt.c index 6f7e611d..7b602d99 100644 --- a/crypt.c +++ b/crypt.c @@ -7,6 +7,7 @@ /** \file crypt.c Openssl-based encryption/decryption routines. */ #include +#include #include #include #include @@ -21,6 +22,7 @@ #include "string.h" #include "crypt.h" #include "fd.h" +#include "crypt_backend.h" struct asymmetric_key { RSA *rsa; @@ -72,19 +74,6 @@ void init_random_seed_or_die(void) 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; @@ -122,203 +111,12 @@ static int get_openssl_key(const char *key_file, RSA **rsa, int private) 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 , 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; @@ -350,23 +148,6 @@ 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) @@ -403,7 +184,7 @@ int get_asymmetric_key(const char *key_file, int private, 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; @@ -434,7 +215,11 @@ int get_asymmetric_key(const char *key_file, int private, 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); @@ -600,39 +385,6 @@ int sc_send_bin_buffer(struct stream_cipher_context *scc, const char *buf, 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. * @@ -659,32 +411,6 @@ int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf, 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. *