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/* $OpenBSD: ssh-pkcs11-client.c,v 1.7 2017/05/30 08:52:19 markus Exp $ */ |
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/* |
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* Copyright (c) 2010 Markus Friedl. All rights reserved. |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include <sys/types.h> |
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#include <sys/time.h> |
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#include <sys/socket.h> |
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#include <stdarg.h> |
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#include <string.h> |
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#include <unistd.h> |
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#include <errno.h> |
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#include <openssl/rsa.h> |
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#include "pathnames.h" |
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#include "xmalloc.h" |
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#include "buffer.h" |
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#include "log.h" |
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#include "misc.h" |
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#include "key.h" |
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#include "authfd.h" |
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#include "atomicio.h" |
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#include "ssh-pkcs11.h" |
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/* borrows code from sftp-server and ssh-agent */ |
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int fd = -1; |
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pid_t pid = -1; |
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static void |
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send_msg(Buffer *m) |
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{ |
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u_char buf[4]; |
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int mlen = buffer_len(m); |
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put_u32(buf, mlen); |
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if (atomicio(vwrite, fd, buf, 4) != 4 || |
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atomicio(vwrite, fd, buffer_ptr(m), |
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buffer_len(m)) != buffer_len(m)) |
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error("write to helper failed"); |
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buffer_consume(m, mlen); |
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} |
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static int |
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recv_msg(Buffer *m) |
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{ |
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u_int l, len; |
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u_char buf[1024]; |
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if ((len = atomicio(read, fd, buf, 4)) != 4) { |
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error("read from helper failed: %u", len); |
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return (0); /* XXX */ |
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} |
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len = get_u32(buf); |
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if (len > 256 * 1024) |
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fatal("response too long: %u", len); |
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/* read len bytes into m */ |
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buffer_clear(m); |
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while (len > 0) { |
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l = len; |
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if (l > sizeof(buf)) |
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l = sizeof(buf); |
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if (atomicio(read, fd, buf, l) != l) { |
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error("response from helper failed."); |
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return (0); /* XXX */ |
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} |
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buffer_append(m, buf, l); |
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len -= l; |
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} |
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return (buffer_get_char(m)); |
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} |
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int |
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pkcs11_init(int interactive) |
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{ |
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return (0); |
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} |
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void |
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pkcs11_terminate(void) |
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{ |
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close(fd); |
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} |
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static int |
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pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, |
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int padding) |
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{ |
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struct sshkey key; /* XXX */ |
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u_char *blob, *signature = NULL; |
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u_int blen, slen = 0; |
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int ret = -1; |
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Buffer msg; |
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if (padding != RSA_PKCS1_PADDING) |
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return (-1); |
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key.type = KEY_RSA; |
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key.rsa = rsa; |
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if (key_to_blob(&key, &blob, &blen) == 0) |
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return -1; |
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buffer_init(&msg); |
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buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST); |
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buffer_put_string(&msg, blob, blen); |
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buffer_put_string(&msg, from, flen); |
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buffer_put_int(&msg, 0); |
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free(blob); |
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send_msg(&msg); |
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buffer_clear(&msg); |
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if (recv_msg(&msg) == SSH2_AGENT_SIGN_RESPONSE) { |
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signature = buffer_get_string(&msg, &slen); |
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if (slen <= (u_int)RSA_size(rsa)) { |
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memcpy(to, signature, slen); |
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ret = slen; |
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} |
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free(signature); |
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} |
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buffer_free(&msg); |
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return (ret); |
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} |
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/* redirect the private key encrypt operation to the ssh-pkcs11-helper */ |
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static int |
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wrap_key(RSA *rsa) |
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{ |
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static RSA_METHOD helper_rsa; |
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memcpy(&helper_rsa, RSA_get_default_method(), sizeof(helper_rsa)); |
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helper_rsa.name = "ssh-pkcs11-helper"; |
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helper_rsa.rsa_priv_enc = pkcs11_rsa_private_encrypt; |
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RSA_set_method(rsa, &helper_rsa); |
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return (0); |
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} |
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static int |
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pkcs11_start_helper(void) |
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{ |
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int pair[2]; |
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if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) { |
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error("socketpair: %s", strerror(errno)); |
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return (-1); |
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} |
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if ((pid = fork()) == -1) { |
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error("fork: %s", strerror(errno)); |
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return (-1); |
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} else if (pid == 0) { |
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if ((dup2(pair[1], STDIN_FILENO) == -1) || |
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(dup2(pair[1], STDOUT_FILENO) == -1)) { |
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fprintf(stderr, "dup2: %s\n", strerror(errno)); |
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_exit(1); |
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} |
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close(pair[0]); |
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close(pair[1]); |
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execlp(_PATH_SSH_PKCS11_HELPER, _PATH_SSH_PKCS11_HELPER, |
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(char *)NULL); |
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fprintf(stderr, "exec: %s: %s\n", _PATH_SSH_PKCS11_HELPER, |
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strerror(errno)); |
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_exit(1); |
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} |
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close(pair[1]); |
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fd = pair[0]; |
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return (0); |
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} |
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int |
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pkcs11_add_provider(char *name, char *pin, Key ***keysp) |
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{ |
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struct sshkey *k; |
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int i, nkeys; |
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u_char *blob; |
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u_int blen; |
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Buffer msg; |
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if (fd < 0 && pkcs11_start_helper() < 0) |
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return (-1); |
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buffer_init(&msg); |
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buffer_put_char(&msg, SSH_AGENTC_ADD_SMARTCARD_KEY); |
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buffer_put_cstring(&msg, name); |
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buffer_put_cstring(&msg, pin); |
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send_msg(&msg); |
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buffer_clear(&msg); |
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if (recv_msg(&msg) == SSH2_AGENT_IDENTITIES_ANSWER) { |
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nkeys = buffer_get_int(&msg); |
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*keysp = xcalloc(nkeys, sizeof(Key *)); |
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for (i = 0; i < nkeys; i++) { |
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blob = buffer_get_string(&msg, &blen); |
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free(buffer_get_string(&msg, NULL)); |
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k = key_from_blob(blob, blen); |
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wrap_key(k->rsa); |
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(*keysp)[i] = k; |
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free(blob); |
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} |
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} else { |
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nkeys = -1; |
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} |
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buffer_free(&msg); |
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return (nkeys); |
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} |
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int |
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pkcs11_del_provider(char *name) |
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{ |
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int ret = -1; |
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Buffer msg; |
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buffer_init(&msg); |
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buffer_put_char(&msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY); |
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buffer_put_cstring(&msg, name); |
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buffer_put_cstring(&msg, ""); |
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send_msg(&msg); |
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buffer_clear(&msg); |
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if (recv_msg(&msg) == SSH_AGENT_SUCCESS) |
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ret = 0; |
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buffer_free(&msg); |
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return (ret); |
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} |