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pem.c
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953 lines (803 loc) · 27.1 KB
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/* Copyright (C) The Written Word, Inc.
* Copyright (C) Simon Josefsson
* All rights reserved.
*
* Redistribution and use in source and binary forms,
* with or without modification, are permitted provided
* that the following conditions are met:
*
* Redistributions of source code must retain the above
* copyright notice, this list of conditions and the
* following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* Neither the name of the copyright holder nor the names
* of any other contributors may be used to endorse or
* promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "libssh2_priv.h"
static int
readline(char *line, int line_size, FILE * fp)
{
size_t len;
if(!line) {
return -1;
}
if(!fgets(line, line_size, fp)) {
return -1;
}
if(*line) {
len = strlen(line);
if(len > 0 && line[len - 1] == '\n') {
line[len - 1] = '\0';
}
}
if(*line) {
len = strlen(line);
if(len > 0 && line[len - 1] == '\r') {
line[len - 1] = '\0';
}
}
return 0;
}
static int
readline_memory(char *line, size_t line_size,
const char *filedata, size_t filedata_len,
size_t *filedata_offset)
{
size_t off, len;
off = *filedata_offset;
for(len = 0; off + len < filedata_len && len < line_size - 1; len++) {
if(filedata[off + len] == '\n' ||
filedata[off + len] == '\r') {
break;
}
}
if(len) {
memcpy(line, filedata + off, len);
*filedata_offset += len;
}
line[len] = '\0';
*filedata_offset += 1;
return 0;
}
#define LINE_SIZE 128
static const char *crypt_annotation = "Proc-Type: 4,ENCRYPTED";
static unsigned char hex_decode(char digit)
{
return (unsigned char)
((digit >= 'A') ? (0xA + (digit - 'A')) : (digit - '0'));
}
int
_libssh2_pem_parse(LIBSSH2_SESSION * session,
const char *headerbegin,
const char *headerend,
const unsigned char *passphrase,
FILE * fp, unsigned char **data, size_t *datalen)
{
char line[LINE_SIZE];
unsigned char iv[LINE_SIZE];
char *b64data = NULL;
size_t b64datalen = 0;
int ret;
const LIBSSH2_CRYPT_METHOD *method = NULL;
do {
*line = '\0';
if(readline(line, LINE_SIZE, fp)) {
return -1;
}
}
while(strcmp(line, headerbegin) != 0);
if(readline(line, LINE_SIZE, fp)) {
return -1;
}
if(passphrase &&
memcmp(line, crypt_annotation, strlen(crypt_annotation)) == 0) {
const LIBSSH2_CRYPT_METHOD **all_methods, *cur_method;
int i;
if(readline(line, LINE_SIZE, fp)) {
ret = -1;
goto out;
}
all_methods = libssh2_crypt_methods();
/* !checksrc! disable EQUALSNULL 1 */
while((cur_method = *all_methods++) != NULL) {
if(*cur_method->pem_annotation &&
memcmp(line, cur_method->pem_annotation,
strlen(cur_method->pem_annotation)) == 0) {
method = cur_method;
memcpy(iv, line + strlen(method->pem_annotation) + 1,
2*method->iv_len);
}
}
/* None of the available crypt methods were able to decrypt the key */
if(!method)
return -1;
/* Decode IV from hex */
for(i = 0; i < method->iv_len; ++i) {
iv[i] = (unsigned char)(hex_decode(iv[2*i]) << 4);
iv[i] |= hex_decode(iv[2*i + 1]);
}
/* skip to the next line */
if(readline(line, LINE_SIZE, fp)) {
ret = -1;
goto out;
}
}
do {
if(*line) {
char *tmp;
size_t linelen;
linelen = strlen(line);
tmp = LIBSSH2_REALLOC(session, b64data, b64datalen + linelen);
if(!tmp) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for PEM parsing");
ret = -1;
goto out;
}
memcpy(tmp + b64datalen, line, linelen);
b64data = tmp;
b64datalen += linelen;
}
*line = '\0';
if(readline(line, LINE_SIZE, fp)) {
ret = -1;
goto out;
}
} while(strcmp(line, headerend) != 0);
if(!b64data) {
return -1;
}
if(_libssh2_base64_decode(session, (char **) data, datalen,
b64data, b64datalen)) {
ret = -1;
goto out;
}
if(method) {
#if LIBSSH2_MD5_PEM
/* Set up decryption */
int free_iv = 0, free_secret = 0, len_decrypted = 0, padding = 0;
int blocksize = method->blocksize;
void *abstract;
unsigned char secret[2*MD5_DIGEST_LENGTH];
libssh2_md5_ctx fingerprint_ctx;
/* Perform key derivation (PBKDF1/MD5) */
if(!libssh2_md5_init(&fingerprint_ctx)) {
ret = -1;
goto out;
}
libssh2_md5_update(fingerprint_ctx, passphrase,
strlen((char *)passphrase));
libssh2_md5_update(fingerprint_ctx, iv, 8);
libssh2_md5_final(fingerprint_ctx, secret);
if(method->secret_len > MD5_DIGEST_LENGTH) {
if(!libssh2_md5_init(&fingerprint_ctx)) {
ret = -1;
goto out;
}
libssh2_md5_update(fingerprint_ctx, secret, MD5_DIGEST_LENGTH);
libssh2_md5_update(fingerprint_ctx, passphrase,
strlen((char *)passphrase));
libssh2_md5_update(fingerprint_ctx, iv, 8);
libssh2_md5_final(fingerprint_ctx, secret + MD5_DIGEST_LENGTH);
}
/* Initialize the decryption */
if(method->init(session, method, iv, &free_iv, secret,
&free_secret, 0, &abstract)) {
_libssh2_explicit_zero((char *)secret, sizeof(secret));
LIBSSH2_FREE(session, data);
ret = -1;
goto out;
}
if(free_secret) {
_libssh2_explicit_zero((char *)secret, sizeof(secret));
}
/* Do the actual decryption */
if((*datalen % blocksize) != 0) {
_libssh2_explicit_zero((char *)secret, sizeof(secret));
method->dtor(session, &abstract);
_libssh2_explicit_zero(*data, *datalen);
LIBSSH2_FREE(session, *data);
ret = -1;
goto out;
}
while(len_decrypted <= (int)*datalen - blocksize) {
if(method->crypt(session, *data + len_decrypted, blocksize,
&abstract,
len_decrypted == 0 ? FIRST_BLOCK :
((len_decrypted == (int)*datalen - blocksize) ?
LAST_BLOCK : MIDDLE_BLOCK)
)) {
ret = LIBSSH2_ERROR_DECRYPT;
_libssh2_explicit_zero((char *)secret, sizeof(secret));
method->dtor(session, &abstract);
_libssh2_explicit_zero(*data, *datalen);
LIBSSH2_FREE(session, *data);
goto out;
}
len_decrypted += blocksize;
}
/* Account for padding */
padding = (*data)[*datalen - 1];
memset(&(*data)[*datalen-padding], 0, padding);
*datalen -= padding;
/* Clean up */
_libssh2_explicit_zero((char *)secret, sizeof(secret));
method->dtor(session, &abstract);
#else
ret = -1;
goto out;
#endif
}
ret = 0;
out:
if(b64data) {
_libssh2_explicit_zero(b64data, b64datalen);
LIBSSH2_FREE(session, b64data);
}
return ret;
}
int
_libssh2_pem_parse_memory(LIBSSH2_SESSION * session,
const char *headerbegin,
const char *headerend,
const char *filedata, size_t filedata_len,
unsigned char **data, size_t *datalen)
{
char line[LINE_SIZE];
char *b64data = NULL;
size_t b64datalen = 0;
size_t off = 0;
int ret;
do {
*line = '\0';
if(readline_memory(line, LINE_SIZE, filedata, filedata_len, &off)) {
return -1;
}
}
while(strcmp(line, headerbegin) != 0);
*line = '\0';
do {
if(*line) {
char *tmp;
size_t linelen;
linelen = strlen(line);
tmp = LIBSSH2_REALLOC(session, b64data, b64datalen + linelen);
if(!tmp) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for PEM parsing");
ret = -1;
goto out;
}
memcpy(tmp + b64datalen, line, linelen);
b64data = tmp;
b64datalen += linelen;
}
*line = '\0';
if(readline_memory(line, LINE_SIZE, filedata, filedata_len, &off)) {
ret = -1;
goto out;
}
} while(strcmp(line, headerend) != 0);
if(!b64data) {
return -1;
}
if(_libssh2_base64_decode(session, (char **) data, datalen,
b64data, b64datalen)) {
ret = -1;
goto out;
}
ret = 0;
out:
if(b64data) {
_libssh2_explicit_zero(b64data, b64datalen);
LIBSSH2_FREE(session, b64data);
}
return ret;
}
/* OpenSSH formatted keys */
#define AUTH_MAGIC "openssh-key-v1"
#define OPENSSH_HEADER_BEGIN "-----BEGIN OPENSSH PRIVATE KEY-----"
#define OPENSSH_HEADER_END "-----END OPENSSH PRIVATE KEY-----"
static int
_libssh2_openssh_pem_parse_data(LIBSSH2_SESSION * session,
const unsigned char *passphrase,
const char *b64data, size_t b64datalen,
struct string_buf **decrypted_buf)
{
const LIBSSH2_CRYPT_METHOD *method = NULL;
struct string_buf decoded, decrypted, kdf_buf;
unsigned char *ciphername = NULL;
unsigned char *kdfname = NULL;
unsigned char *kdf = NULL;
unsigned char *buf = NULL;
unsigned char *salt = NULL;
uint32_t nkeys, check1, check2;
uint32_t rounds = 0;
unsigned char *key = NULL;
unsigned char *key_part = NULL;
unsigned char *iv_part = NULL;
unsigned char *f = NULL;
size_t f_len = 0;
int ret = 0, keylen = 0, ivlen = 0, total_len = 0;
size_t kdf_len = 0, tmp_len = 0, salt_len = 0;
if(decrypted_buf)
*decrypted_buf = NULL;
/* decode file */
if(_libssh2_base64_decode(session, (char **)&f, &f_len,
b64data, b64datalen)) {
ret = -1;
goto out;
}
/* Parse the file */
decoded.data = (unsigned char *)f;
decoded.dataptr = (unsigned char *)f;
decoded.len = f_len;
if(decoded.len < strlen(AUTH_MAGIC)) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO, "key too short");
goto out;
}
if(strncmp((char *) decoded.dataptr, AUTH_MAGIC,
strlen(AUTH_MAGIC)) != 0) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"key auth magic mismatch");
goto out;
}
decoded.dataptr += strlen(AUTH_MAGIC) + 1;
if(_libssh2_get_string(&decoded, &ciphername, &tmp_len) ||
tmp_len == 0) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"ciphername is missing");
goto out;
}
if(_libssh2_get_string(&decoded, &kdfname, &tmp_len) ||
tmp_len == 0) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"kdfname is missing");
goto out;
}
if(_libssh2_get_string(&decoded, &kdf, &kdf_len)) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"kdf is missing");
goto out;
}
else {
kdf_buf.data = kdf;
kdf_buf.dataptr = kdf;
kdf_buf.len = kdf_len;
}
if((!passphrase || strlen((const char *)passphrase) == 0) &&
strcmp((const char *)ciphername, "none") != 0) {
/* passphrase required */
ret = LIBSSH2_ERROR_KEYFILE_AUTH_FAILED;
goto out;
}
if(strcmp((const char *)kdfname, "none") != 0 &&
strcmp((const char *)kdfname, "bcrypt") != 0) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"unknown cipher");
goto out;
}
if(!strcmp((const char *)kdfname, "none") &&
strcmp((const char *)ciphername, "none") != 0) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"invalid format");
goto out;
}
if(_libssh2_get_u32(&decoded, &nkeys) != 0 || nkeys != 1) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Multiple keys are unsupported");
goto out;
}
/* unencrypted public key */
if(_libssh2_get_string(&decoded, &buf, &tmp_len) || tmp_len == 0) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Invalid private key; "
"expect embedded public key");
goto out;
}
if(_libssh2_get_string(&decoded, &buf, &tmp_len) || tmp_len == 0) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Private key data not found");
goto out;
}
/* decode encrypted private key */
decrypted.data = decrypted.dataptr = buf;
decrypted.len = tmp_len;
if(ciphername && strcmp((const char *)ciphername, "none") != 0) {
const LIBSSH2_CRYPT_METHOD **all_methods, *cur_method;
all_methods = libssh2_crypt_methods();
/* !checksrc! disable EQUALSNULL 1 */
while((cur_method = *all_methods++) != NULL) {
if(*cur_method->name &&
memcmp(ciphername, cur_method->name,
strlen(cur_method->name)) == 0) {
method = cur_method;
}
}
/* None of the available crypt methods were able to decrypt the key */
if(!method) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"No supported cipher found");
goto out;
}
}
if(method) {
int free_iv = 0, free_secret = 0, len_decrypted = 0;
int blocksize;
void *abstract = NULL;
keylen = method->secret_len;
ivlen = method->iv_len;
total_len = keylen + ivlen;
key = LIBSSH2_CALLOC(session, total_len);
if(!key) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Could not alloc key");
goto out;
}
if(strcmp((const char *)kdfname, "bcrypt") == 0 && passphrase) {
if((_libssh2_get_string(&kdf_buf, &salt, &salt_len)) ||
(_libssh2_get_u32(&kdf_buf, &rounds) != 0)) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"kdf contains unexpected values");
LIBSSH2_FREE(session, key);
goto out;
}
if(_libssh2_bcrypt_pbkdf((const char *)passphrase,
strlen((const char *)passphrase),
salt, salt_len, key,
keylen + ivlen, rounds) < 0) {
ret = _libssh2_error(session, LIBSSH2_ERROR_DECRYPT,
"invalid format");
LIBSSH2_FREE(session, key);
goto out;
}
}
else {
ret = _libssh2_error(session, LIBSSH2_ERROR_KEYFILE_AUTH_FAILED,
"bcrypted without passphrase");
LIBSSH2_FREE(session, key);
goto out;
}
/* Set up decryption */
blocksize = method->blocksize;
key_part = LIBSSH2_CALLOC(session, keylen);
if(!key_part) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Could not alloc key part");
goto out;
}
iv_part = LIBSSH2_CALLOC(session, ivlen);
if(!iv_part) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Could not alloc iv part");
goto out;
}
memcpy(key_part, key, keylen);
memcpy(iv_part, key + keylen, ivlen);
/* Initialize the decryption */
if(method->init(session, method, iv_part, &free_iv, key_part,
&free_secret, 0, &abstract)) {
ret = LIBSSH2_ERROR_DECRYPT;
goto out;
}
/* Do the actual decryption */
if((decrypted.len % blocksize) != 0) {
method->dtor(session, &abstract);
ret = LIBSSH2_ERROR_DECRYPT;
goto out;
}
while((size_t)len_decrypted <= decrypted.len - blocksize) {
/* We always pass MIDDLE_BLOCK here because OpenSSH Key Files
* do not use AAD to authenticate the length.
* Furthermore, the authentication tag is appended after the
* encrypted key, and the length of the authentication tag is
* not included in the key length, so we check it after the
* loop.
*/
if(method->crypt(session, decrypted.data + len_decrypted,
blocksize,
&abstract,
MIDDLE_BLOCK)) {
ret = LIBSSH2_ERROR_DECRYPT;
method->dtor(session, &abstract);
goto out;
}
len_decrypted += blocksize;
}
/* No padding */
/* for the AES GCM methods, the 16 byte authentication tag is
* appended to the encrypted key */
if(strcmp(method->name, "aes256-gcm@openssh.com") == 0 ||
strcmp(method->name, "aes128-gcm@openssh.com") == 0) {
if(!_libssh2_check_length(&decoded, 16)) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"GCM auth tag missing");
method->dtor(session, &abstract);
goto out;
}
if(method->crypt(session, decoded.dataptr, 16, &abstract,
LAST_BLOCK)) {
ret = _libssh2_error(session, LIBSSH2_ERROR_DECRYPT,
"GCM auth tag invalid");
method->dtor(session, &abstract);
goto out;
}
decoded.dataptr += 16;
}
method->dtor(session, &abstract);
}
/* Check random bytes match */
if(_libssh2_get_u32(&decrypted, &check1) != 0 ||
_libssh2_get_u32(&decrypted, &check2) != 0 ||
check1 != check2) {
_libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Private key unpack failed (correct password?)");
ret = LIBSSH2_ERROR_KEYFILE_AUTH_FAILED;
goto out;
}
if(decrypted_buf) {
/* copy data to out-going buffer */
struct string_buf *out_buf = _libssh2_string_buf_new(session);
if(!out_buf) {
ret = _libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for "
"decrypted struct");
goto out;
}
out_buf->data = LIBSSH2_CALLOC(session, decrypted.len);
if(!out_buf->data) {
ret = _libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for "
"decrypted struct");
_libssh2_string_buf_free(session, out_buf);
goto out;
}
memcpy(out_buf->data, decrypted.data, decrypted.len);
out_buf->dataptr = out_buf->data +
(decrypted.dataptr - decrypted.data);
out_buf->len = decrypted.len;
*decrypted_buf = out_buf;
}
out:
/* Clean up */
if(key) {
_libssh2_explicit_zero(key, total_len);
LIBSSH2_FREE(session, key);
}
if(key_part) {
_libssh2_explicit_zero(key_part, keylen);
LIBSSH2_FREE(session, key_part);
}
if(iv_part) {
_libssh2_explicit_zero(iv_part, ivlen);
LIBSSH2_FREE(session, iv_part);
}
if(f) {
_libssh2_explicit_zero(f, f_len);
LIBSSH2_FREE(session, f);
}
return ret;
}
int
_libssh2_openssh_pem_parse(LIBSSH2_SESSION * session,
const unsigned char *passphrase,
FILE * fp, struct string_buf **decrypted_buf)
{
char line[LINE_SIZE];
char *b64data = NULL;
size_t b64datalen = 0;
int ret = 0;
/* read file */
do {
*line = '\0';
if(readline(line, LINE_SIZE, fp)) {
return -1;
}
}
while(strcmp(line, OPENSSH_HEADER_BEGIN) != 0);
if(readline(line, LINE_SIZE, fp)) {
return -1;
}
do {
if(*line) {
char *tmp;
size_t linelen;
linelen = strlen(line);
tmp = LIBSSH2_REALLOC(session, b64data, b64datalen + linelen);
if(!tmp) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for PEM parsing");
ret = -1;
goto out;
}
memcpy(tmp + b64datalen, line, linelen);
b64data = tmp;
b64datalen += linelen;
}
*line = '\0';
if(readline(line, LINE_SIZE, fp)) {
ret = -1;
goto out;
}
} while(strcmp(line, OPENSSH_HEADER_END) != 0);
if(!b64data) {
return -1;
}
ret = _libssh2_openssh_pem_parse_data(session,
passphrase,
(const char *)b64data,
b64datalen,
decrypted_buf);
if(b64data) {
_libssh2_explicit_zero(b64data, b64datalen);
LIBSSH2_FREE(session, b64data);
}
out:
return ret;
}
int
_libssh2_openssh_pem_parse_memory(LIBSSH2_SESSION * session,
const unsigned char *passphrase,
const char *filedata, size_t filedata_len,
struct string_buf **decrypted_buf)
{
char line[LINE_SIZE];
char *b64data = NULL;
size_t b64datalen = 0;
size_t off = 0;
int ret;
if(!filedata || filedata_len <= 0)
return _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Error parsing PEM: filedata missing");
do {
*line = '\0';
if(off >= filedata_len)
return _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Error parsing PEM: "
"OpenSSH header not found");
if(readline_memory(line, LINE_SIZE, filedata, filedata_len, &off)) {
return -1;
}
}
while(strcmp(line, OPENSSH_HEADER_BEGIN) != 0);
*line = '\0';
do {
if(*line) {
char *tmp;
size_t linelen;
linelen = strlen(line);
tmp = LIBSSH2_REALLOC(session, b64data, b64datalen + linelen);
if(!tmp) {
ret = _libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for "
"PEM parsing");
goto out;
}
memcpy(tmp + b64datalen, line, linelen);
b64data = tmp;
b64datalen += linelen;
}
*line = '\0';
if(off >= filedata_len) {
ret = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Error parsing PEM: offset out of bounds");
goto out;
}
if(readline_memory(line, LINE_SIZE, filedata, filedata_len, &off)) {
ret = -1;
goto out;
}
} while(strcmp(line, OPENSSH_HEADER_END) != 0);
if(!b64data)
return _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Error parsing PEM: base 64 data missing");
ret = _libssh2_openssh_pem_parse_data(session, passphrase, b64data,
b64datalen, decrypted_buf);
out:
if(b64data) {
_libssh2_explicit_zero(b64data, b64datalen);
LIBSSH2_FREE(session, b64data);
}
return ret;
}
static int
read_asn1_length(const unsigned char *data,
size_t datalen, size_t *len)
{
unsigned int lenlen;
int nextpos;
if(datalen < 1) {
return -1;
}
*len = data[0];
if(*len >= 0x80) {
lenlen = *len & 0x7F;
*len = data[1];
if(1 + lenlen > datalen) {
return -1;
}
if(lenlen > 1) {
*len <<= 8;
*len |= data[2];
}
}
else {
lenlen = 0;
}
nextpos = 1 + lenlen;
if(lenlen > 2 || 1 + lenlen + *len > datalen) {
return -1;
}
return nextpos;
}
int
_libssh2_pem_decode_sequence(unsigned char **data, size_t *datalen)
{
size_t len;
int lenlen;
if(*datalen < 1) {
return -1;
}
if((*data)[0] != '\x30') {
return -1;
}
(*data)++;
(*datalen)--;
lenlen = read_asn1_length(*data, *datalen, &len);
if(lenlen < 0 || lenlen + len != *datalen) {
return -1;
}
*data += lenlen;
*datalen -= lenlen;
return 0;
}
int
_libssh2_pem_decode_integer(unsigned char **data, size_t *datalen,
unsigned char **i, unsigned int *ilen)
{
size_t len;
int lenlen;
if(*datalen < 1) {
return -1;
}
if((*data)[0] != '\x02') {
return -1;
}
(*data)++;
(*datalen)--;
lenlen = read_asn1_length(*data, *datalen, &len);
if(lenlen < 0 || lenlen + len > *datalen) {
return -1;
}
*data += lenlen;
*datalen -= lenlen;
*i = *data;
*ilen = (unsigned int)len;
*data += len;
*datalen -= len;
return 0;
}