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-rw-r--r--src/keyfiles.c1902
1 files changed, 1902 insertions, 0 deletions
diff --git a/src/keyfiles.c b/src/keyfiles.c
new file mode 100644
index 0000000..9512de0
--- /dev/null
+++ b/src/keyfiles.c
@@ -0,0 +1,1902 @@
+/*
+ * keyfiles.c - private and public key handling for authentication.
+ *
+ * This file is part of the SSH Library
+ *
+ * Copyright (c) 2003-2009 by Aris Adamantiadis
+ * Copyright (c) 2009 by Andreas Schneider <mail@cynapses.org>
+ *
+ * The SSH Library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ *
+ * The SSH Library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the SSH Library; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#ifndef _WIN32
+#if _MSC_VER >= 1400
+#include <io.h>
+#undef open
+#define open _open
+#undef close
+#define close _close
+#undef read
+#define read _read
+#endif /* _MSC_VER */
+#include <arpa/inet.h>
+#endif
+
+#include "libssh/priv.h"
+#include "libssh/buffer.h"
+#include "libssh/keyfiles.h"
+#include "libssh/session.h"
+#include "libssh/wrapper.h"
+#include "libssh/misc.h"
+#include "libssh/keys.h"
+
+/*todo: remove this include */
+#include "libssh/string.h"
+
+
+#ifdef HAVE_LIBGCRYPT
+#include <gcrypt.h>
+#elif defined HAVE_LIBCRYPTO
+#include <openssl/pem.h>
+#include <openssl/dsa.h>
+#include <openssl/err.h>
+#include <openssl/rsa.h>
+#endif /* HAVE_LIBCRYPTO */
+
+#define MAXLINESIZE 80
+#define RSA_HEADER_BEGIN "-----BEGIN RSA PRIVATE KEY-----"
+#define RSA_HEADER_END "-----END RSA PRIVATE KEY-----"
+#define DSA_HEADER_BEGIN "-----BEGIN DSA PRIVATE KEY-----"
+#define DSA_HEADER_END "-----END DSA PRIVATE KEY-----"
+
+#ifdef HAVE_LIBGCRYPT
+
+#define MAX_KEY_SIZE 32
+#define MAX_PASSPHRASE_SIZE 1024
+#define ASN1_INTEGER 2
+#define ASN1_SEQUENCE 48
+#define PKCS5_SALT_LEN 8
+
+static int load_iv(char *header, unsigned char *iv, int iv_len) {
+ int i;
+ int j;
+ int k;
+
+ memset(iv, 0, iv_len);
+ for (i = 0; i < iv_len; i++) {
+ if ((header[2*i] >= '0') && (header[2*i] <= '9'))
+ j = header[2*i] - '0';
+ else if ((header[2*i] >= 'A') && (header[2*i] <= 'F'))
+ j = header[2*i] - 'A' + 10;
+ else if ((header[2*i] >= 'a') && (header[2*i] <= 'f'))
+ j = header[2*i] - 'a' + 10;
+ else
+ return -1;
+ if ((header[2*i+1] >= '0') && (header[2*i+1] <= '9'))
+ k = header[2*i+1] - '0';
+ else if ((header[2*i+1] >= 'A') && (header[2*i+1] <= 'F'))
+ k = header[2*i+1] - 'A' + 10;
+ else if ((header[2*i+1] >= 'a') && (header[2*i+1] <= 'f'))
+ k = header[2*i+1] - 'a' + 10;
+ else
+ return -1;
+ iv[i] = (j << 4) + k;
+ }
+ return 0;
+}
+
+static uint32_t char_to_u32(unsigned char *data, uint32_t size) {
+ uint32_t ret;
+ uint32_t i;
+
+ for (i = 0, ret = 0; i < size; ret = ret << 8, ret += data[i++])
+ ;
+ return ret;
+}
+
+static uint32_t asn1_get_len(ssh_buffer buffer) {
+ uint32_t len;
+ unsigned char tmp[4];
+
+ if (buffer_get_data(buffer,tmp,1) == 0) {
+ return 0;
+ }
+
+ if (tmp[0] > 127) {
+ len = tmp[0] & 127;
+ if (len > 4) {
+ return 0; /* Length doesn't fit in u32. Can this really happen? */
+ }
+ if (buffer_get_data(buffer,tmp,len) == 0) {
+ return 0;
+ }
+ len = char_to_u32(tmp, len);
+ } else {
+ len = char_to_u32(tmp, 1);
+ }
+
+ return len;
+}
+
+static ssh_string asn1_get_int(ssh_buffer buffer) {
+ ssh_string str;
+ unsigned char type;
+ uint32_t size;
+
+ if (buffer_get_data(buffer, &type, 1) == 0 || type != ASN1_INTEGER) {
+ return NULL;
+ }
+ size = asn1_get_len(buffer);
+ if (size == 0) {
+ return NULL;
+ }
+
+ str = ssh_string_new(size);
+ if (str == NULL) {
+ return NULL;
+ }
+
+ if (buffer_get_data(buffer, str->string, size) == 0) {
+ ssh_string_free(str);
+ return NULL;
+ }
+
+ return str;
+}
+
+static int asn1_check_sequence(ssh_buffer buffer) {
+ unsigned char *j = NULL;
+ unsigned char tmp;
+ int i;
+ uint32_t size;
+ uint32_t padding;
+
+ if (buffer_get_data(buffer, &tmp, 1) == 0 || tmp != ASN1_SEQUENCE) {
+ return 0;
+ }
+
+ size = asn1_get_len(buffer);
+ if ((padding = ssh_buffer_get_len(buffer) - buffer->pos - size) > 0) {
+ for (i = ssh_buffer_get_len(buffer) - buffer->pos - size,
+ j = (unsigned char*)ssh_buffer_get_begin(buffer) + size + buffer->pos;
+ i;
+ i--, j++)
+ {
+ if (*j != padding) { /* padding is allowed */
+ return 0; /* but nothing else */
+ }
+ }
+ }
+
+ return 1;
+}
+
+static int read_line(char *data, unsigned int len, FILE *fp) {
+ char tmp;
+ unsigned int i;
+
+ for (i = 0; fread(&tmp, 1, 1, fp) && tmp != '\n' && i < len; data[i++] = tmp)
+ ;
+ if (tmp == '\n') {
+ return i;
+ }
+
+ if (i >= len) {
+ return -1;
+ }
+
+ return 0;
+}
+
+static int passphrase_to_key(char *data, unsigned int datalen,
+ unsigned char *salt, unsigned char *key, unsigned int keylen) {
+ MD5CTX md;
+ unsigned char digest[MD5_DIGEST_LEN] = {0};
+ unsigned int i;
+ unsigned int j;
+ unsigned int md_not_empty;
+
+ for (j = 0, md_not_empty = 0; j < keylen; ) {
+ md = md5_init();
+ if (md == NULL) {
+ return -1;
+ }
+
+ if (md_not_empty) {
+ md5_update(md, digest, MD5_DIGEST_LEN);
+ } else {
+ md_not_empty = 1;
+ }
+
+ md5_update(md, data, datalen);
+ if (salt) {
+ md5_update(md, salt, PKCS5_SALT_LEN);
+ }
+ md5_final(digest, md);
+
+ for (i = 0; j < keylen && i < MD5_DIGEST_LEN; j++, i++) {
+ if (key) {
+ key[j] = digest[i];
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int privatekey_decrypt(int algo, int mode, unsigned int key_len,
+ unsigned char *iv, unsigned int iv_len,
+ ssh_buffer data, ssh_auth_callback cb,
+ void *userdata,
+ const char *desc)
+{
+ char passphrase[MAX_PASSPHRASE_SIZE] = {0};
+ unsigned char key[MAX_KEY_SIZE] = {0};
+ unsigned char *tmp = NULL;
+ gcry_cipher_hd_t cipher;
+ int rc = -1;
+
+ if (!algo) {
+ return -1;
+ }
+
+ if (cb) {
+ rc = (*cb)(desc, passphrase, MAX_PASSPHRASE_SIZE, 0, 0, userdata);
+ if (rc < 0) {
+ return -1;
+ }
+ } else if (cb == NULL && userdata != NULL) {
+ snprintf(passphrase, MAX_PASSPHRASE_SIZE, "%s", (char *) userdata);
+ }
+
+ if (passphrase_to_key(passphrase, strlen(passphrase), iv, key, key_len) < 0) {
+ return -1;
+ }
+
+ if (gcry_cipher_open(&cipher, algo, mode, 0)
+ || gcry_cipher_setkey(cipher, key, key_len)
+ || gcry_cipher_setiv(cipher, iv, iv_len)
+ || (tmp = malloc(ssh_buffer_get_len(data) * sizeof (char))) == NULL
+ || gcry_cipher_decrypt(cipher, tmp, ssh_buffer_get_len(data),
+ ssh_buffer_get_begin(data), ssh_buffer_get_len(data))) {
+ gcry_cipher_close(cipher);
+ return -1;
+ }
+
+ memcpy(ssh_buffer_get_begin(data), tmp, ssh_buffer_get_len(data));
+
+ SAFE_FREE(tmp);
+ gcry_cipher_close(cipher);
+
+ return 0;
+}
+
+static int privatekey_dek_header(char *header, unsigned int header_len,
+ int *algo, int *mode, unsigned int *key_len, unsigned char **iv,
+ unsigned int *iv_len) {
+ unsigned int iv_pos;
+
+ if (header_len > 13 && !strncmp("DES-EDE3-CBC", header, 12))
+ {
+ *algo = GCRY_CIPHER_3DES;
+ iv_pos = 13;
+ *mode = GCRY_CIPHER_MODE_CBC;
+ *key_len = 24;
+ *iv_len = 8;
+ }
+ else if (header_len > 8 && !strncmp("DES-CBC", header, 7))
+ {
+ *algo = GCRY_CIPHER_DES;
+ iv_pos = 8;
+ *mode = GCRY_CIPHER_MODE_CBC;
+ *key_len = 8;
+ *iv_len = 8;
+ }
+ else if (header_len > 12 && !strncmp("AES-128-CBC", header, 11))
+ {
+ *algo = GCRY_CIPHER_AES128;
+ iv_pos = 12;
+ *mode = GCRY_CIPHER_MODE_CBC;
+ *key_len = 16;
+ *iv_len = 16;
+ }
+ else if (header_len > 12 && !strncmp("AES-192-CBC", header, 11))
+ {
+ *algo = GCRY_CIPHER_AES192;
+ iv_pos = 12;
+ *mode = GCRY_CIPHER_MODE_CBC;
+ *key_len = 24;
+ *iv_len = 16;
+ }
+ else if (header_len > 12 && !strncmp("AES-256-CBC", header, 11))
+ {
+ *algo = GCRY_CIPHER_AES256;
+ iv_pos = 12;
+ *mode = GCRY_CIPHER_MODE_CBC;
+ *key_len = 32;
+ *iv_len = 16;
+ } else {
+ return -1;
+ }
+
+ *iv = malloc(*iv_len);
+ if (*iv == NULL) {
+ return -1;
+ }
+
+ return load_iv(header + iv_pos, *iv, *iv_len);
+}
+
+static ssh_buffer privatekey_file_to_buffer(FILE *fp, int type,
+ ssh_auth_callback cb, void *userdata, const char *desc) {
+ ssh_buffer buffer = NULL;
+ ssh_buffer out = NULL;
+ char buf[MAXLINESIZE] = {0};
+ unsigned char *iv = NULL;
+ const char *header_begin;
+ const char *header_end;
+ unsigned int header_begin_size;
+ unsigned int header_end_size;
+ unsigned int key_len = 0;
+ unsigned int iv_len = 0;
+ int algo = 0;
+ int mode = 0;
+ int len;
+
+ buffer = ssh_buffer_new();
+ if (buffer == NULL) {
+ return NULL;
+ }
+
+ switch(type) {
+ case SSH_KEYTYPE_DSS:
+ header_begin = DSA_HEADER_BEGIN;
+ header_end = DSA_HEADER_END;
+ break;
+ case SSH_KEYTYPE_RSA:
+ header_begin = RSA_HEADER_BEGIN;
+ header_end = RSA_HEADER_END;
+ break;
+ default:
+ ssh_buffer_free(buffer);
+ return NULL;
+ }
+
+ header_begin_size = strlen(header_begin);
+ header_end_size = strlen(header_end);
+
+ while (read_line(buf, MAXLINESIZE, fp) &&
+ strncmp(buf, header_begin, header_begin_size))
+ ;
+
+ len = read_line(buf, MAXLINESIZE, fp);
+ if (len > 11 && strncmp("Proc-Type: 4,ENCRYPTED", buf, 11) == 0) {
+ len = read_line(buf, MAXLINESIZE, fp);
+ if (len > 10 && strncmp("DEK-Info: ", buf, 10) == 0) {
+ if ((privatekey_dek_header(buf + 10, len - 10, &algo, &mode, &key_len,
+ &iv, &iv_len) < 0)
+ || read_line(buf, MAXLINESIZE, fp)) {
+ ssh_buffer_free(buffer);
+ SAFE_FREE(iv);
+ return NULL;
+ }
+ } else {
+ ssh_buffer_free(buffer);
+ SAFE_FREE(iv);
+ return NULL;
+ }
+ } else {
+ if (buffer_add_data(buffer, buf, len) < 0) {
+ ssh_buffer_free(buffer);
+ SAFE_FREE(iv);
+ return NULL;
+ }
+ }
+
+ while ((len = read_line(buf,MAXLINESIZE,fp)) &&
+ strncmp(buf, header_end, header_end_size) != 0) {
+ if (len == -1) {
+ ssh_buffer_free(buffer);
+ SAFE_FREE(iv);
+ return NULL;
+ }
+ if (buffer_add_data(buffer, buf, len) < 0) {
+ ssh_buffer_free(buffer);
+ SAFE_FREE(iv);
+ return NULL;
+ }
+ }
+
+ if (strncmp(buf,header_end,header_end_size) != 0) {
+ ssh_buffer_free(buffer);
+ SAFE_FREE(iv);
+ return NULL;
+ }
+
+ if (buffer_add_data(buffer, "\0", 1) < 0) {
+ ssh_buffer_free(buffer);
+ SAFE_FREE(iv);
+ return NULL;
+ }
+
+ out = base64_to_bin(ssh_buffer_get_begin(buffer));
+ ssh_buffer_free(buffer);
+ if (out == NULL) {
+ SAFE_FREE(iv);
+ return NULL;
+ }
+
+ if (algo) {
+ if (privatekey_decrypt(algo, mode, key_len, iv, iv_len, out,
+ cb, userdata, desc) < 0) {
+ ssh_buffer_free(out);
+ SAFE_FREE(iv);
+ return NULL;
+ }
+ }
+ SAFE_FREE(iv);
+
+ return out;
+}
+
+static int read_rsa_privatekey(FILE *fp, gcry_sexp_t *r,
+ ssh_auth_callback cb, void *userdata, const char *desc) {
+ ssh_string n = NULL;
+ ssh_string e = NULL;
+ ssh_string d = NULL;
+ ssh_string p = NULL;
+ ssh_string q = NULL;
+ ssh_string unused1 = NULL;
+ ssh_string unused2 = NULL;
+ ssh_string u = NULL;
+ ssh_string v = NULL;
+ ssh_buffer buffer = NULL;
+ int rc = 1;
+
+ buffer = privatekey_file_to_buffer(fp, SSH_KEYTYPE_RSA, cb, userdata, desc);
+ if (buffer == NULL) {
+ return 0;
+ }
+
+ if (!asn1_check_sequence(buffer)) {
+ ssh_buffer_free(buffer);
+ return 0;
+ }
+
+ v = asn1_get_int(buffer);
+ if (ntohl(v->size) != 1 || v->string[0] != 0) {
+ ssh_buffer_free(buffer);
+ return 0;
+ }
+
+ n = asn1_get_int(buffer);
+ e = asn1_get_int(buffer);
+ d = asn1_get_int(buffer);
+ q = asn1_get_int(buffer);
+ p = asn1_get_int(buffer);
+ unused1 = asn1_get_int(buffer);
+ unused2 = asn1_get_int(buffer);
+ u = asn1_get_int(buffer);
+
+ ssh_buffer_free(buffer);
+
+ if (n == NULL || e == NULL || d == NULL || p == NULL || q == NULL ||
+ unused1 == NULL || unused2 == NULL|| u == NULL) {
+ rc = 0;
+ goto error;
+ }
+
+ if (gcry_sexp_build(r, NULL,
+ "(private-key(rsa(n %b)(e %b)(d %b)(p %b)(q %b)(u %b)))",
+ ntohl(n->size), n->string,
+ ntohl(e->size), e->string,
+ ntohl(d->size), d->string,
+ ntohl(p->size), p->string,
+ ntohl(q->size), q->string,
+ ntohl(u->size), u->string)) {
+ rc = 0;
+ }
+
+error:
+ ssh_string_free(n);
+ ssh_string_free(e);
+ ssh_string_free(d);
+ ssh_string_free(p);
+ ssh_string_free(q);
+ ssh_string_free(unused1);
+ ssh_string_free(unused2);
+ ssh_string_free(u);
+ ssh_string_free(v);
+
+ return rc;
+}
+
+static int read_dsa_privatekey(FILE *fp, gcry_sexp_t *r, ssh_auth_callback cb,
+ void *userdata, const char *desc) {
+ ssh_buffer buffer = NULL;
+ ssh_string p = NULL;
+ ssh_string q = NULL;
+ ssh_string g = NULL;
+ ssh_string y = NULL;
+ ssh_string x = NULL;
+ ssh_string v = NULL;
+ int rc = 1;
+
+ buffer = privatekey_file_to_buffer(fp, SSH_KEYTYPE_DSS, cb, userdata, desc);
+ if (buffer == NULL) {
+ return 0;
+ }
+
+ if (!asn1_check_sequence(buffer)) {
+ ssh_buffer_free(buffer);
+ return 0;
+ }
+
+ v = asn1_get_int(buffer);
+ if (ntohl(v->size) != 1 || v->string[0] != 0) {
+ ssh_buffer_free(buffer);
+ return 0;
+ }
+
+ p = asn1_get_int(buffer);
+ q = asn1_get_int(buffer);
+ g = asn1_get_int(buffer);
+ y = asn1_get_int(buffer);
+ x = asn1_get_int(buffer);
+ ssh_buffer_free(buffer);
+
+ if (p == NULL || q == NULL || g == NULL || y == NULL || x == NULL) {
+ rc = 0;
+ goto error;
+ }
+
+ if (gcry_sexp_build(r, NULL,
+ "(private-key(dsa(p %b)(q %b)(g %b)(y %b)(x %b)))",
+ ntohl(p->size), p->string,
+ ntohl(q->size), q->string,
+ ntohl(g->size), g->string,
+ ntohl(y->size), y->string,
+ ntohl(x->size), x->string)) {
+ rc = 0;
+ }
+
+error:
+ ssh_string_free(p);
+ ssh_string_free(q);
+ ssh_string_free(g);
+ ssh_string_free(y);
+ ssh_string_free(x);
+ ssh_string_free(v);
+
+ return rc;
+}
+#endif /* HAVE_LIBGCRYPT */
+
+#ifdef HAVE_LIBCRYPTO
+static int pem_get_password(char *buf, int size, int rwflag, void *userdata) {
+ ssh_session session = userdata;
+
+ /* unused flag */
+ (void) rwflag;
+ if(buf==NULL)
+ return 0;
+ memset(buf,'\0',size);
+ ssh_log(session, SSH_LOG_RARE,
+ "Trying to call external authentication function");
+
+ if (session && session->callbacks && session->callbacks->auth_function) {
+ if (session->callbacks->auth_function("Passphrase for private key:", buf, size, 0, 0,
+ session->callbacks->userdata) < 0) {
+ return 0;
+ }
+
+ return strlen(buf);
+ }
+
+ return 0;
+}
+#endif /* HAVE_LIBCRYPTO */
+
+static int privatekey_type_from_file(FILE *fp) {
+ char buffer[MAXLINESIZE] = {0};
+
+ if (!fgets(buffer, MAXLINESIZE, fp)) {
+ return 0;
+ }
+ fseek(fp, 0, SEEK_SET);
+ if (strncmp(buffer, DSA_HEADER_BEGIN, strlen(DSA_HEADER_BEGIN)) == 0) {
+ return SSH_KEYTYPE_DSS;
+ }
+ if (strncmp(buffer, RSA_HEADER_BEGIN, strlen(RSA_HEADER_BEGIN)) == 0) {
+ return SSH_KEYTYPE_RSA;
+ }
+ return 0;
+}
+
+/**
+ * @addtogroup libssh_auth
+ *
+ * @{
+ */
+
+/**
+ * @brief Reads a SSH private key from a file.
+ *
+ * @param[in] session The SSH Session to use.
+ *
+ * @param[in] filename The filename of the the private key.
+ *
+ * @param[in] type The type of the private key. This could be SSH_KEYTYPE_DSS or
+ * SSH_KEYTYPE_RSA. Pass 0 to automatically detect the type.
+ *
+ * @param[in] passphrase The passphrase to decrypt the private key. Set to null
+ * if none is needed or it is unknown.
+ *
+ * @return A private_key object containing the private key, or
+ * NULL on error.
+ * @see privatekey_free()
+ * @see publickey_from_privatekey()
+ */
+ssh_private_key privatekey_from_file(ssh_session session, const char *filename,
+ int type, const char *passphrase) {
+ ssh_private_key privkey = NULL;
+ FILE *file = NULL;
+#ifdef HAVE_LIBGCRYPT
+ ssh_auth_callback auth_cb = NULL;
+ void *auth_ud = NULL;
+
+ gcry_sexp_t dsa = NULL;
+ gcry_sexp_t rsa = NULL;
+ int valid;
+#elif defined HAVE_LIBCRYPTO
+ DSA *dsa = NULL;
+ RSA *rsa = NULL;
+#endif
+ /* TODO Implement to read both DSA and RSA at once. */
+
+ /* needed for openssl initialization */
+ ssh_init();
+ ssh_log(session, SSH_LOG_RARE, "Trying to open %s", filename);
+ file = fopen(filename,"r");
+ if (file == NULL) {
+ ssh_set_error(session, SSH_REQUEST_DENIED,
+ "Error opening %s: %s", filename, strerror(errno));
+ return NULL;
+ }
+
+ ssh_log(session, SSH_LOG_RARE, "Trying to read %s, passphase=%s, authcb=%s",
+ filename, passphrase ? "true" : "false",
+ session->callbacks && session->callbacks->auth_function ? "true" : "false");
+
+ if (type == 0) {
+ type = privatekey_type_from_file(file);
+ if (type == 0) {
+ fclose(file);
+ ssh_set_error(session, SSH_FATAL, "Invalid private key file.");
+ return NULL;
+ }
+ }
+ switch (type) {
+ case SSH_KEYTYPE_DSS:
+ if (passphrase == NULL) {
+ if (session->callbacks && session->callbacks->auth_function) {
+#ifdef HAVE_LIBGCRYPT
+ auth_cb = session->callbacks->auth_function;
+ auth_ud = session->callbacks->userdata;
+
+ valid = read_dsa_privatekey(file, &dsa, auth_cb, auth_ud,
+ "Passphrase for private key:");
+ } else { /* authcb */
+ valid = read_dsa_privatekey(file, &dsa, NULL, NULL, NULL);
+ } /* authcb */
+ } else { /* passphrase */
+ valid = read_dsa_privatekey(file, &dsa, NULL,
+ (void *) passphrase, NULL);
+ }
+
+ fclose(file);
+
+ if (!valid) {
+ ssh_set_error(session, SSH_FATAL, "Parsing private key %s", filename);
+#elif defined HAVE_LIBCRYPTO
+ dsa = PEM_read_DSAPrivateKey(file, NULL, pem_get_password, session);
+ } else { /* authcb */
+ /* openssl uses its own callback to get the passphrase here */
+ dsa = PEM_read_DSAPrivateKey(file, NULL, NULL, NULL);
+ } /* authcb */
+ } else { /* passphrase */
+ dsa = PEM_read_DSAPrivateKey(file, NULL, NULL, (void *) passphrase);
+ }
+
+ fclose(file);
+ if (dsa == NULL) {
+ ssh_set_error(session, SSH_FATAL,
+ "Parsing private key %s: %s",
+ filename, ERR_error_string(ERR_get_error(), NULL));
+#endif
+ return NULL;
+ }
+ break;
+ case SSH_KEYTYPE_RSA:
+ if (passphrase == NULL) {
+ if (session->callbacks && session->callbacks->auth_function) {
+#ifdef HAVE_LIBGCRYPT
+ auth_cb = session->callbacks->auth_function;
+ auth_ud = session->callbacks->userdata;
+ valid = read_rsa_privatekey(file, &rsa, auth_cb, auth_ud,
+ "Passphrase for private key:");
+ } else { /* authcb */
+ valid = read_rsa_privatekey(file, &rsa, NULL, NULL, NULL);
+ } /* authcb */
+ } else { /* passphrase */
+ valid = read_rsa_privatekey(file, &rsa, NULL,
+ (void *) passphrase, NULL);
+ }
+
+ fclose(file);
+
+ if (!valid) {
+ ssh_set_error(session,SSH_FATAL, "Parsing private key %s", filename);
+#elif defined HAVE_LIBCRYPTO
+ rsa = PEM_read_RSAPrivateKey(file, NULL, pem_get_password, session);
+ } else { /* authcb */
+ /* openssl uses its own callback to get the passphrase here */
+ rsa = PEM_read_RSAPrivateKey(file, NULL, NULL, NULL);
+ } /* authcb */
+ } else { /* passphrase */
+ rsa = PEM_read_RSAPrivateKey(file, NULL, NULL, (void *) passphrase);
+ }
+
+ fclose(file);
+
+ if (rsa == NULL) {
+ ssh_set_error(session, SSH_FATAL,
+ "Parsing private key %s: %s",
+ filename, ERR_error_string(ERR_get_error(),NULL));
+#endif
+ return NULL;
+ }
+ break;
+ default:
+ fclose(file);
+ ssh_set_error(session, SSH_FATAL, "Invalid private key type %d", type);
+ return NULL;
+ } /* switch */
+
+ privkey = malloc(sizeof(struct ssh_private_key_struct));
+ if (privkey == NULL) {
+#ifdef HAVE_LIBGCRYPT
+ gcry_sexp_release(dsa);
+ gcry_sexp_release(rsa);
+#elif defined HAVE_LIBCRYPTO
+ DSA_free(dsa);
+ RSA_free(rsa);
+#endif
+ return NULL;
+ }
+
+ privkey->type = type;
+ privkey->dsa_priv = dsa;
+ privkey->rsa_priv = rsa;
+
+ return privkey;
+}
+
+/**
+ * @brief returns the type of a private key
+ * @param[in] privatekey the private key handle
+ * @returns one of SSH_KEYTYPE_RSA,SSH_KEYTYPE_DSS,SSH_KEYTYPE_RSA1
+ * @returns SSH_KEYTYPE_UNKNOWN if the type is unknown
+ * @see privatekey_from_file
+ * @see ssh_userauth_offer_pubkey
+ */
+enum ssh_keytypes_e ssh_privatekey_type(ssh_private_key privatekey){
+ if (privatekey==NULL)
+ return SSH_KEYTYPE_UNKNOWN;
+ return privatekey->type;
+}
+
+/* same that privatekey_from_file() but without any passphrase things. */
+ssh_private_key _privatekey_from_file(void *session, const char *filename,
+ int type) {
+ ssh_private_key privkey = NULL;
+ FILE *file = NULL;
+#ifdef HAVE_LIBGCRYPT
+ gcry_sexp_t dsa = NULL;
+ gcry_sexp_t rsa = NULL;
+ int valid;
+#elif defined HAVE_LIBCRYPTO
+ DSA *dsa = NULL;
+ RSA *rsa = NULL;
+#endif
+
+ file = fopen(filename,"r");
+ if (file == NULL) {
+ ssh_set_error(session, SSH_REQUEST_DENIED,
+ "Error opening %s: %s", filename, strerror(errno));
+ return NULL;
+ }
+
+ switch (type) {
+ case SSH_KEYTYPE_DSS:
+#ifdef HAVE_LIBGCRYPT
+ valid = read_dsa_privatekey(file, &dsa, NULL, NULL, NULL);
+
+ fclose(file);
+
+ if (!valid) {
+ ssh_set_error(session, SSH_FATAL, "Parsing private key %s", filename);
+#elif defined HAVE_LIBCRYPTO
+ dsa = PEM_read_DSAPrivateKey(file, NULL, NULL, NULL);
+
+ fclose(file);
+
+ if (dsa == NULL) {
+ ssh_set_error(session, SSH_FATAL,
+ "Parsing private key %s: %s",
+ filename, ERR_error_string(ERR_get_error(), NULL));
+#endif
+ return NULL;
+ }
+ break;
+ case SSH_KEYTYPE_RSA:
+#ifdef HAVE_LIBGCRYPT
+ valid = read_rsa_privatekey(file, &rsa, NULL, NULL, NULL);
+
+ fclose(file);
+
+ if (!valid) {
+ ssh_set_error(session, SSH_FATAL, "Parsing private key %s", filename);
+#elif defined HAVE_LIBCRYPTO
+ rsa = PEM_read_RSAPrivateKey(file, NULL, NULL, NULL);
+
+ fclose(file);
+
+ if (rsa == NULL) {
+ ssh_set_error(session, SSH_FATAL,
+ "Parsing private key %s: %s",
+ filename, ERR_error_string(ERR_get_error(), NULL));
+#endif
+ return NULL;
+ }
+ break;
+ default:
+ ssh_set_error(session, SSH_FATAL, "Invalid private key type %d", type);
+ return NULL;
+ }
+
+ privkey = malloc(sizeof(struct ssh_private_key_struct));
+ if (privkey == NULL) {
+#ifdef HAVE_LIBGCRYPT
+ gcry_sexp_release(dsa);
+ gcry_sexp_release(rsa);
+#elif defined HAVE_LIBCRYPTO
+ DSA_free(dsa);
+ RSA_free(rsa);
+#endif
+ return NULL;
+ }
+
+ privkey->type = type;
+ privkey->dsa_priv = dsa;
+ privkey->rsa_priv = rsa;
+
+ return privkey;
+}
+
+/**
+ * @brief Deallocate a private key object.
+ *
+ * @param[in] prv The private_key object to free.
+ */
+void privatekey_free(ssh_private_key prv) {
+ if (prv == NULL) {
+ return;
+ }
+
+#ifdef HAVE_LIBGCRYPT
+ gcry_sexp_release(prv->dsa_priv);
+ gcry_sexp_release(prv->rsa_priv);
+#elif defined HAVE_LIBCRYPTO
+ DSA_free(prv->dsa_priv);
+ RSA_free(prv->rsa_priv);
+#endif
+ memset(prv, 0, sizeof(struct ssh_private_key_struct));
+ SAFE_FREE(prv);
+}
+
+/**
+ * @brief Write a public key to a file.
+ *
+ * @param[in] session The ssh session to use.
+ *
+ * @param[in] file The filename to write the key into.
+ *
+ * @param[in] pubkey The public key to write.
+ *
+ * @param[in] type The type of the public key.
+ *
+ * @return 0 on success, -1 on error.
+ */
+int ssh_publickey_to_file(ssh_session session, const char *file,
+ ssh_string pubkey, int type) {
+ FILE *fp;
+ char *user;
+ char buffer[1024];
+ char host[256];
+ unsigned char *pubkey_64;
+ size_t len;
+ int rc;
+
+ pubkey_64 = bin_to_base64(pubkey->string, ssh_string_len(pubkey));
+ if (pubkey_64 == NULL) {
+ return -1;
+ }
+
+ user = ssh_get_local_username(session);
+ if (user == NULL) {
+ SAFE_FREE(pubkey_64);
+ return -1;
+ }
+
+ rc = gethostname(host, sizeof(host));
+ if (rc < 0) {
+ SAFE_FREE(user);
+ SAFE_FREE(pubkey_64);
+ return -1;
+ }
+
+ snprintf(buffer, sizeof(buffer), "%s %s %s@%s\n",
+ ssh_type_to_char(type),
+ pubkey_64,
+ user,
+ host);
+
+ SAFE_FREE(pubkey_64);
+ SAFE_FREE(user);
+
+ ssh_log(session, SSH_LOG_RARE, "Trying to write public key file: %s", file);
+ ssh_log(session, SSH_LOG_PACKET, "public key file content: %s", buffer);
+
+ fp = fopen(file, "w+");
+ if (fp == NULL) {
+ ssh_set_error(session, SSH_REQUEST_DENIED,
+ "Error opening %s: %s", file, strerror(errno));
+ return -1;
+ }
+
+ len = strlen(buffer);
+ if (fwrite(buffer, len, 1, fp) != 1 || ferror(fp)) {
+ ssh_set_error(session, SSH_REQUEST_DENIED,
+ "Unable to write to %s", file);
+ fclose(fp);
+ unlink(file);
+ return -1;
+ }
+
+ fclose(fp);
+ return 0;
+}
+
+/**
+ * @brief Retrieve a public key from a file.
+ *
+ * @param[in] session The SSH session to use.
+ *
+ * @param[in] filename The filename of the public key.
+ *
+ * @param[out] type The Pointer to a integer. If it is not NULL, it will
+ * contain the type of the key after execution.
+ *
+ * @return A SSH String containing the public key, or NULL if it
+ * failed.
+ *
+ * @see string_free()
+ * @see publickey_from_privatekey()
+ */
+ssh_string publickey_from_file(ssh_session session, const char *filename,
+ int *type) {
+ ssh_buffer buffer = NULL;
+ char buf[4096] = {0};
+ ssh_string str = NULL;
+ char *ptr = NULL;
+ int key_type;
+ int fd = -1;
+ int r;
+
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ ssh_set_error(session, SSH_REQUEST_DENIED, "Public key file doesn't exist");
+ return NULL;
+ }
+
+ if (read(fd, buf, 8) != 8) {
+ close(fd);
+ ssh_set_error(session, SSH_REQUEST_DENIED, "Invalid public key file");
+ return NULL;
+ }
+
+ buf[7] = '\0';
+
+ key_type = ssh_type_from_name(buf);
+ if (key_type == -1) {
+ close(fd);
+ ssh_set_error(session, SSH_REQUEST_DENIED, "Invalid public key file");
+ return NULL;
+ }
+
+ r = read(fd, buf, sizeof(buf) - 1);
+ close(fd);
+ if (r <= 0) {
+ ssh_set_error(session, SSH_REQUEST_DENIED, "Invalid public key file");
+ return NULL;
+ }
+
+ buf[r] = 0;
+ ptr = strchr(buf, ' ');
+
+ /* eliminate the garbage at end of file */
+ if (ptr) {
+ *ptr = '\0';
+ }
+
+ buffer = base64_to_bin(buf);
+ if (buffer == NULL) {
+ ssh_set_error(session, SSH_REQUEST_DENIED, "Invalid public key file");
+ return NULL;
+ }
+
+ str = ssh_string_new(ssh_buffer_get_len(buffer));
+ if (str == NULL) {
+ ssh_set_error(session, SSH_FATAL, "Not enough space");
+ ssh_buffer_free(buffer);
+ return NULL;
+ }
+
+ ssh_string_fill(str, ssh_buffer_get_begin(buffer), ssh_buffer_get_len(buffer));
+ ssh_buffer_free(buffer);
+
+ if (type) {
+ *type = key_type;
+ }
+
+ return str;
+}
+
+/**
+ * @brief Try to read the public key from a given file.
+ *
+ * @param[in] session The ssh session to use.
+ *
+ * @param[in] keyfile The name of the private keyfile.
+ *
+ * @param[out] publickey A ssh_string to store the public key.
+ *
+ * @param[out] type A pointer to an integer to store the type.
+ *
+ * @return 0 on success, -1 on error or the private key doesn't
+ * exist, 1 if the public key doesn't exist.
+ */
+int ssh_try_publickey_from_file(ssh_session session, const char *keyfile,
+ ssh_string *publickey, int *type) {
+ char *pubkey_file;
+ size_t len;
+ ssh_string pubkey_string;
+ int pubkey_type;
+
+ if (session == NULL || keyfile == NULL || publickey == NULL || type == NULL) {
+ return -1;
+ }
+
+ if (session->sshdir == NULL) {
+ if (ssh_options_apply(session) < 0) {
+ return -1;
+ }
+ }
+
+ ssh_log(session, SSH_LOG_PACKET, "Trying to open privatekey %s", keyfile);
+ if (!ssh_file_readaccess_ok(keyfile)) {
+ ssh_log(session, SSH_LOG_PACKET, "Failed to open privatekey %s", keyfile);
+ return -1;
+ }
+
+ len = strlen(keyfile) + 5;
+ pubkey_file = malloc(len);
+ if (pubkey_file == NULL) {
+ return -1;
+ }
+ snprintf(pubkey_file, len, "%s.pub", keyfile);
+
+ ssh_log(session, SSH_LOG_PACKET, "Trying to open publickey %s",
+ pubkey_file);
+ if (!ssh_file_readaccess_ok(pubkey_file)) {
+ ssh_log(session, SSH_LOG_PACKET, "Failed to open publickey %s",
+ pubkey_file);
+ SAFE_FREE(pubkey_file);
+ return 1;
+ }
+
+ ssh_log(session, SSH_LOG_PACKET, "Success opening public and private key");
+
+ /*
+ * We are sure both the private and public key file is readable. We return
+ * the public as a string, and the private filename as an argument
+ */
+ pubkey_string = publickey_from_file(session, pubkey_file, &pubkey_type);
+ if (pubkey_string == NULL) {
+ ssh_log(session, SSH_LOG_PACKET,
+ "Wasn't able to open public key file %s: %s",
+ pubkey_file,
+ ssh_get_error(session));
+ SAFE_FREE(pubkey_file);
+ return -1;
+ }
+
+ SAFE_FREE(pubkey_file);
+
+ *publickey = pubkey_string;
+ *type = pubkey_type;
+
+ return 0;
+}
+
+ssh_string try_publickey_from_file(ssh_session session, struct ssh_keys_struct keytab,
+ char **privkeyfile, int *type) {
+ const char *priv;
+ const char *pub;
+ char *new;
+ ssh_string pubkey=NULL;
+
+ pub = keytab.publickey;
+ if (pub == NULL) {
+ return NULL;
+ }
+ priv = keytab.privatekey;
+ if (priv == NULL) {
+ return NULL;
+ }
+
+ if (session->sshdir == NULL) {
+ if (ssh_options_apply(session) < 0) {
+ return NULL;
+ }
+ }
+
+ ssh_log(session, SSH_LOG_PACKET, "Trying to open publickey %s", pub);
+ if (!ssh_file_readaccess_ok(pub)) {
+ ssh_log(session, SSH_LOG_PACKET, "Failed to open publickey %s", pub);
+ goto error;
+ }
+
+ ssh_log(session, SSH_LOG_PACKET, "Trying to open privatekey %s", priv);
+ if (!ssh_file_readaccess_ok(priv)) {
+ ssh_log(session, SSH_LOG_PACKET, "Failed to open privatekey %s", priv);
+ goto error;
+ }
+
+ ssh_log(session, SSH_LOG_PACKET, "Success opening public and private key");
+
+ /*
+ * We are sure both the private and public key file is readable. We return
+ * the public as a string, and the private filename as an argument
+ */
+ pubkey = publickey_from_file(session, pub, type);
+ if (pubkey == NULL) {
+ ssh_log(session, SSH_LOG_PACKET,
+ "Wasn't able to open public key file %s: %s",
+ pub,
+ ssh_get_error(session));
+ goto error;
+ }
+
+ new = realloc(*privkeyfile, strlen(priv) + 1);
+ if (new == NULL) {
+ ssh_string_free(pubkey);
+ goto error;
+ }
+
+ strcpy(new, priv);
+ *privkeyfile = new;
+error:
+ return pubkey;
+}
+
+static int alldigits(const char *s) {
+ while (*s) {
+ if (isdigit(*s)) {
+ s++;
+ } else {
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+/** @} */
+
+
+/**
+ * @addtogroup libssh_session
+ *
+ * @{
+ */
+
+/**
+ * @internal
+ *
+ * @brief Free a token array.
+ */
+static void tokens_free(char **tokens) {
+ if (tokens == NULL) {
+ return;
+ }
+
+ SAFE_FREE(tokens[0]);
+ /* It's not needed to free other pointers because tokens generated by
+ * space_tokenize fit all in one malloc
+ */
+ SAFE_FREE(tokens);
+}
+
+/**
+ * @internal
+ *
+ * @brief Return one line of known host file.
+ *
+ * This will return a token array containing (host|ip), keytype and key.
+ *
+ * @param[out] file A pointer to the known host file. Could be pointing to
+ * NULL at start.
+ *
+ * @param[in] filename The file name of the known host file.
+ *
+ * @param[out] found_type A pointer to a string to be set with the found key
+ * type.
+ *
+ * @returns The found_type type of key (ie "dsa","ssh-rsa1"). Don't
+ * free that value. NULL if no match was found or the file
+ * was not found.
+ */
+static char **ssh_get_knownhost_line(ssh_session session, FILE **file,
+ const char *filename, const char **found_type) {
+ char buffer[4096] = {0};
+ char *ptr;
+ char **tokens;
+
+ enter_function();
+
+ if(*file == NULL){
+ *file = fopen(filename,"r");
+ if (*file == NULL) {
+ leave_function();
+ return NULL;
+ }
+ }
+
+ while (fgets(buffer, sizeof(buffer), *file)) {
+ ptr = strchr(buffer, '\n');
+ if (ptr) {
+ *ptr = '\0';
+ }
+
+ ptr = strchr(buffer,'\r');
+ if (ptr) {
+ *ptr = '\0';
+ }
+
+ if (!buffer[0] || buffer[0] == '#') {
+ continue; /* skip empty lines */
+ }
+
+ tokens = space_tokenize(buffer);
+ if (tokens == NULL) {
+ fclose(*file);
+ *file = NULL;
+ leave_function();
+ return NULL;
+ }
+
+ if(!tokens[0] || !tokens[1] || !tokens[2]) {
+ /* it should have at least 3 tokens */
+ tokens_free(tokens);
+ continue;
+ }
+
+ *found_type = tokens[1];
+ if (tokens[3]) {
+ /* openssh rsa1 format has 4 tokens on the line. Recognize it
+ by the fact that everything is all digits */
+ if (tokens[4]) {
+ /* that's never valid */
+ tokens_free(tokens);
+ continue;
+ }
+ if (alldigits(tokens[1]) && alldigits(tokens[2]) && alldigits(tokens[3])) {
+ *found_type = "ssh-rsa1";
+ } else {
+ /* 3 tokens only, not four */
+ tokens_free(tokens);
+ continue;
+ }
+ }
+ leave_function();
+ return tokens;
+ }
+
+ fclose(*file);
+ *file = NULL;
+
+ /* we did not find anything, end of file*/
+ leave_function();
+ return NULL;
+}
+
+/**
+ * @brief Check the public key in the known host line matches the public key of
+ * the currently connected server.
+ *
+ * @param[in] session The SSH session to use.
+ *
+ * @param[in] tokens A list of tokens in the known_hosts line.
+ *
+ * @returns 1 if the key matches, 0 if the key doesn't match and -1
+ * on error.
+ */
+static int check_public_key(ssh_session session, char **tokens) {
+ ssh_string pubkey = session->current_crypto->server_pubkey;
+ ssh_buffer pubkey_buffer;
+ char *pubkey_64;
+
+ /* ok we found some public key in known hosts file. now un-base64it */
+ if (alldigits(tokens[1])) {
+ /* openssh rsa1 format */
+ bignum tmpbn;
+ ssh_string tmpstring;
+ unsigned int len;
+ int i;
+
+ pubkey_buffer = ssh_buffer_new();
+ if (pubkey_buffer == NULL) {
+ return -1;
+ }
+
+ tmpstring = ssh_string_from_char("ssh-rsa1");
+ if (tmpstring == NULL) {
+ ssh_buffer_free(pubkey_buffer);
+ return -1;
+ }
+
+ if (buffer_add_ssh_string(pubkey_buffer, tmpstring) < 0) {
+ ssh_buffer_free(pubkey_buffer);
+ ssh_string_free(tmpstring);
+ return -1;
+ }
+ ssh_string_free(tmpstring);
+
+ for (i = 2; i < 4; i++) { /* e, then n */
+ tmpbn = NULL;
+ bignum_dec2bn(tokens[i], &tmpbn);
+ if (tmpbn == NULL) {
+ ssh_buffer_free(pubkey_buffer);
+ return -1;
+ }
+ /* for some reason, make_bignum_string does not work
+ because of the padding which it does --kv */
+ /* tmpstring = make_bignum_string(tmpbn); */
+ /* do it manually instead */
+ len = bignum_num_bytes(tmpbn);
+ tmpstring = malloc(4 + len);
+ if (tmpstring == NULL) {
+ ssh_buffer_free(pubkey_buffer);
+ bignum_free(tmpbn);
+ return -1;
+ }
+ /* TODO: fix the hardcoding */
+ tmpstring->size = htonl(len);
+#ifdef HAVE_LIBGCRYPT
+ bignum_bn2bin(tmpbn, len, tmpstring->string);
+#elif defined HAVE_LIBCRYPTO
+ bignum_bn2bin(tmpbn, tmpstring->string);
+#endif
+ bignum_free(tmpbn);
+ if (buffer_add_ssh_string(pubkey_buffer, tmpstring) < 0) {
+ ssh_buffer_free(pubkey_buffer);
+ ssh_string_free(tmpstring);
+ bignum_free(tmpbn);
+ return -1;
+ }
+ ssh_string_free(tmpstring);
+ }
+ } else {
+ /* ssh-dss or ssh-rsa */
+ pubkey_64 = tokens[2];
+ pubkey_buffer = base64_to_bin(pubkey_64);
+ }
+
+ if (pubkey_buffer == NULL) {
+ ssh_set_error(session, SSH_FATAL,
+ "Verifying that server is a known host: base64 error");
+ return -1;
+ }
+
+ if (ssh_buffer_get_len(pubkey_buffer) != ssh_string_len(pubkey)) {
+ ssh_buffer_free(pubkey_buffer);
+ return 0;
+ }
+
+ /* now test that they are identical */
+ if (memcmp(ssh_buffer_get_begin(pubkey_buffer), pubkey->string,
+ ssh_buffer_get_len(pubkey_buffer)) != 0) {
+ ssh_buffer_free(pubkey_buffer);
+ return 0;
+ }
+
+ ssh_buffer_free(pubkey_buffer);
+ return 1;
+}
+
+/**
+ * @brief Check if a hostname matches a openssh-style hashed known host.
+ *
+ * @param[in] host The host to check.
+ *
+ * @param[in] hashed The hashed value.
+ *
+ * @returns 1 if it matches, 0 otherwise.
+ */
+static int match_hashed_host(ssh_session session, const char *host,
+ const char *sourcehash) {
+ /* Openssh hash structure :
+ * |1|base64 encoded salt|base64 encoded hash
+ * hash is produced that way :
+ * hash := HMAC_SHA1(key=salt,data=host)
+ */
+ unsigned char buffer[256] = {0};
+ ssh_buffer salt;
+ ssh_buffer hash;
+ HMACCTX mac;
+ char *source;
+ char *b64hash;
+ int match;
+ unsigned int size;
+
+ enter_function();
+
+ if (strncmp(sourcehash, "|1|", 3) != 0) {
+ leave_function();
+ return 0;
+ }
+
+ source = strdup(sourcehash + 3);
+ if (source == NULL) {
+ leave_function();
+ return 0;
+ }
+
+ b64hash = strchr(source, '|');
+ if (b64hash == NULL) {
+ /* Invalid hash */
+ SAFE_FREE(source);
+ leave_function();
+ return 0;
+ }
+
+ *b64hash = '\0';
+ b64hash++;
+
+ salt = base64_to_bin(source);
+ if (salt == NULL) {
+ SAFE_FREE(source);
+ leave_function();
+ return 0;
+ }
+
+ hash = base64_to_bin(b64hash);
+ SAFE_FREE(source);
+ if (hash == NULL) {
+ ssh_buffer_free(salt);
+ leave_function();
+ return 0;
+ }
+
+ mac = hmac_init(ssh_buffer_get_begin(salt), ssh_buffer_get_len(salt), HMAC_SHA1);
+ if (mac == NULL) {
+ ssh_buffer_free(salt);
+ ssh_buffer_free(hash);
+ leave_function();
+ return 0;
+ }
+ size = sizeof(buffer);
+ hmac_update(mac, host, strlen(host));
+ hmac_final(mac, buffer, &size);
+
+ if (size == ssh_buffer_get_len(hash) &&
+ memcmp(buffer, ssh_buffer_get_begin(hash), size) == 0) {
+ match = 1;
+ } else {
+ match = 0;
+ }
+
+ ssh_buffer_free(salt);
+ ssh_buffer_free(hash);
+
+ ssh_log(session, SSH_LOG_PACKET,
+ "Matching a hashed host: %s match=%d", host, match);
+
+ leave_function();
+ return match;
+}
+
+/* How it's working :
+ * 1- we open the known host file and bitch if it doesn't exist
+ * 2- we need to examine each line of the file, until going on state SSH_SERVER_KNOWN_OK:
+ * - there's a match. if the key is good, state is SSH_SERVER_KNOWN_OK,
+ * else it's SSH_SERVER_KNOWN_CHANGED (or SSH_SERVER_FOUND_OTHER)
+ * - there's no match : no change
+ */
+
+/**
+ * @brief Check if the server is known.
+ *
+ * Checks the user's known host file for a previous connection to the
+ * current server.
+ *
+ * @param[in] session The SSH session to use.
+ *
+ * @returns SSH_SERVER_KNOWN_OK: The server is known and has not changed.\n
+ * SSH_SERVER_KNOWN_CHANGED: The server key has changed. Either you
+ * are under attack or the administrator
+ * changed the key. You HAVE to warn the
+ * user about a possible attack.\n
+ * SSH_SERVER_FOUND_OTHER: The server gave use a key of a type while
+ * we had an other type recorded. It is a
+ * possible attack.\n
+ * SSH_SERVER_NOT_KNOWN: The server is unknown. User should
+ * confirm the MD5 is correct.\n
+ * SSH_SERVER_FILE_NOT_FOUND: The known host file does not exist. The
+ * host is thus unknown. File will be
+ * created if host key is accepted.\n
+ * SSH_SERVER_ERROR: Some error happened.
+ *
+ * @see ssh_get_pubkey_hash()
+ *
+ * @bug There is no current way to remove or modify an entry into the known
+ * host table.
+ */
+int ssh_is_server_known(ssh_session session) {
+ FILE *file = NULL;
+ char **tokens;
+ char *host;
+ char *hostport;
+ const char *type;
+ int match;
+ int ret = SSH_SERVER_NOT_KNOWN;
+
+ enter_function();
+
+ if (session->knownhosts == NULL) {
+ if (ssh_options_apply(session) < 0) {
+ ssh_set_error(session, SSH_REQUEST_DENIED,
+ "Can't find a known_hosts file");
+ leave_function();
+ return SSH_SERVER_FILE_NOT_FOUND;
+ }
+ }
+
+ if (session->host == NULL) {
+ ssh_set_error(session, SSH_FATAL,
+ "Can't verify host in known hosts if the hostname isn't known");
+ leave_function();
+ return SSH_SERVER_ERROR;
+ }
+
+ if (session->current_crypto == NULL){
+ ssh_set_error(session, SSH_FATAL,
+ "ssh_is_host_known called without cryptographic context");
+ leave_function();
+ return SSH_SERVER_ERROR;
+ }
+ host = ssh_lowercase(session->host);
+ hostport = ssh_hostport(host,session->port);
+ if (host == NULL || hostport == NULL) {
+ ssh_set_error_oom(session);
+ SAFE_FREE(host);
+ SAFE_FREE(hostport);
+ leave_function();
+ return SSH_SERVER_ERROR;
+ }
+
+ do {
+ tokens = ssh_get_knownhost_line(session, &file,
+ session->knownhosts, &type);
+
+ /* End of file, return the current state */
+ if (tokens == NULL) {
+ break;
+ }
+ match = match_hashed_host(session, host, tokens[0]);
+ if (match == 0){
+ match = match_hostname(hostport, tokens[0], strlen(tokens[0]));
+ }
+ if (match == 0) {
+ match = match_hostname(host, tokens[0], strlen(tokens[0]));
+ }
+ if (match == 0) {
+ match = match_hashed_host(session, hostport, tokens[0]);
+ }
+ if (match) {
+ /* We got a match. Now check the key type */
+ if (strcmp(session->current_crypto->server_pubkey_type, type) != 0) {
+ /* Different type. We don't override the known_changed error which is
+ * more important */
+ if (ret != SSH_SERVER_KNOWN_CHANGED)
+ ret = SSH_SERVER_FOUND_OTHER;
+ tokens_free(tokens);
+ continue;
+ }
+ /* so we know the key type is good. We may get a good key or a bad key. */
+ match = check_public_key(session, tokens);
+ tokens_free(tokens);
+
+ if (match < 0) {
+ ret = SSH_SERVER_ERROR;
+ break;
+ } else if (match == 1) {
+ ret = SSH_SERVER_KNOWN_OK;
+ break;
+ } else if(match == 0) {
+ /* We override the status with the wrong key state */
+ ret = SSH_SERVER_KNOWN_CHANGED;
+ }
+ } else {
+ tokens_free(tokens);
+ }
+ } while (1);
+
+ if ( (ret == SSH_SERVER_NOT_KNOWN) && (session->StrictHostKeyChecking == 0) ) {
+ ssh_write_knownhost(session);
+ ret = SSH_SERVER_KNOWN_OK;
+ }
+
+ SAFE_FREE(host);
+ SAFE_FREE(hostport);
+ if (file != NULL) {
+ fclose(file);
+ }
+
+ /* Return the current state at end of file */
+ leave_function();
+ return ret;
+}
+
+/**
+ * @brief Write the current server as known in the known hosts file.
+ *
+ * This will create the known hosts file if it does not exist. You generaly use
+ * it when ssh_is_server_known() answered SSH_SERVER_NOT_KNOWN.
+ *
+ * @param[in] session The ssh session to use.
+ *
+ * @return SSH_OK on success, SSH_ERROR on error.
+ */
+int ssh_write_knownhost(ssh_session session) {
+ ssh_string pubkey;
+ unsigned char *pubkey_64;
+ char buffer[4096] = {0};
+ FILE *file;
+ char *dir;
+ char *host;
+ char *hostport;
+ size_t len = 0;
+
+ if (session->host == NULL) {
+ ssh_set_error(session, SSH_FATAL,
+ "Can't write host in known hosts if the hostname isn't known");
+ return SSH_ERROR;
+ }
+
+ host = ssh_lowercase(session->host);
+ /* If using a nonstandard port, save the host in the [host]:port format */
+ if(session->port != 22){
+ hostport = ssh_hostport(host,session->port);
+ SAFE_FREE(host);
+ host=hostport;
+ hostport=NULL;
+ }
+
+ if (session->knownhosts == NULL) {
+ if (ssh_options_apply(session) < 0) {
+ ssh_set_error(session, SSH_FATAL, "Can't find a known_hosts file");
+ return SSH_ERROR;
+ }
+ }
+
+ if(session->current_crypto==NULL) {
+ ssh_set_error(session, SSH_FATAL, "No current crypto context");
+ return SSH_ERROR;
+ }
+
+ pubkey = session->current_crypto->server_pubkey;
+ if(pubkey == NULL){
+ ssh_set_error(session, SSH_FATAL, "No public key present");
+ return SSH_ERROR;
+ }
+
+ /* Check if ~/.ssh exists and create it if not */
+ dir = ssh_dirname(session->knownhosts);
+ if (dir == NULL) {
+ ssh_set_error(session, SSH_FATAL, "%s", strerror(errno));
+ return -1;
+ }
+ if (! ssh_file_readaccess_ok(dir)) {
+ if (ssh_mkdir(dir, 0700) < 0) {
+ ssh_set_error(session, SSH_FATAL,
+ "Cannot create %s directory.", dir);
+ SAFE_FREE(dir);
+ return -1;
+ }
+ }
+ SAFE_FREE(dir);
+
+ file = fopen(session->knownhosts, "a");
+ if (file == NULL) {
+ ssh_set_error(session, SSH_FATAL,
+ "Couldn't open known_hosts file %s for appending: %s",
+ session->knownhosts, strerror(errno));
+ SAFE_FREE(host);
+ return -1;
+ }
+
+ if (strcmp(session->current_crypto->server_pubkey_type, "ssh-rsa1") == 0) {
+ /* openssh uses a different format for ssh-rsa1 keys.
+ Be compatible --kv */
+ ssh_public_key key;
+ char *e_string = NULL;
+ char *n_string = NULL;
+ bignum e = NULL;
+ bignum n = NULL;
+ int rsa_size;
+#ifdef HAVE_LIBGCRYPT
+ gcry_sexp_t sexp;
+#endif
+
+ key = publickey_from_string(session, pubkey);
+ if (key == NULL) {
+ fclose(file);
+ SAFE_FREE(host);
+ return -1;
+ }
+
+#ifdef HAVE_LIBGCRYPT
+ sexp = gcry_sexp_find_token(key->rsa_pub, "e", 0);
+ if (sexp == NULL) {
+ publickey_free(key);
+ fclose(file);
+ SAFE_FREE(host);
+ return -1;
+ }
+ e = gcry_sexp_nth_mpi(sexp, 1, GCRYMPI_FMT_USG);
+ gcry_sexp_release(sexp);
+ if (e == NULL) {
+ publickey_free(key);
+ fclose(file);
+ SAFE_FREE(host);
+ return -1;
+ }
+
+ sexp = gcry_sexp_find_token(key->rsa_pub, "n", 0);
+ if (sexp == NULL) {
+ publickey_free(key);
+ bignum_free(e);
+ fclose(file);
+ SAFE_FREE(host);
+ return -1;
+ }
+ n = gcry_sexp_nth_mpi(sexp, 1, GCRYMPI_FMT_USG);
+ gcry_sexp_release(sexp);
+ if (n == NULL) {
+ publickey_free(key);
+ bignum_free(e);
+ fclose(file);
+ SAFE_FREE(host);
+ return -1;
+ }
+
+ rsa_size = (gcry_pk_get_nbits(key->rsa_pub) + 7) / 8;
+#elif defined HAVE_LIBCRYPTO
+ e = key->rsa_pub->e;
+ n = key->rsa_pub->n;
+ rsa_size = RSA_size(key->rsa_pub);
+#endif
+
+ e_string = bignum_bn2dec(e);
+ n_string = bignum_bn2dec(n);
+ if (e_string == NULL || n_string == NULL) {
+#ifdef HAVE_LIBGCRYPT
+ bignum_free(e);
+ bignum_free(n);
+ SAFE_FREE(e_string);
+ SAFE_FREE(n_string);
+#elif defined HAVE_LIBCRYPTO
+ OPENSSL_free(e_string);
+ OPENSSL_free(n_string);
+#endif
+ publickey_free(key);
+ fclose(file);
+ SAFE_FREE(host);
+ return -1;
+ }
+
+ snprintf(buffer, sizeof(buffer),
+ "%s %d %s %s\n",
+ host,
+ rsa_size << 3,
+ e_string,
+ n_string);
+
+#ifdef HAVE_LIBGCRYPT
+ bignum_free(e);
+ bignum_free(n);
+ SAFE_FREE(e_string);
+ SAFE_FREE(n_string);
+#elif defined HAVE_LIBCRYPTO
+ OPENSSL_free(e_string);
+ OPENSSL_free(n_string);
+#endif
+
+ publickey_free(key);
+ } else {
+ pubkey_64 = bin_to_base64(pubkey->string, ssh_string_len(pubkey));
+ if (pubkey_64 == NULL) {
+ fclose(file);
+ SAFE_FREE(host);
+ return -1;
+ }
+
+ snprintf(buffer, sizeof(buffer),
+ "%s %s %s\n",
+ host,
+ session->current_crypto->server_pubkey_type,
+ pubkey_64);
+
+ SAFE_FREE(pubkey_64);
+ }
+ SAFE_FREE(host);
+ len = strlen(buffer);
+ if (fwrite(buffer, len, 1, file) != 1 || ferror(file)) {
+ fclose(file);
+ return -1;
+ }
+
+ fclose(file);
+ return 0;
+}
+
+/** @} */
+
+/* vim: set ts=4 sw=4 et cindent: */
generated by cgit (git 2.34.1) at 2024-11-11 12:48:48 +0000