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Diffstat (limited to 'agent/call-scd.c')
| -rw-r--r-- | agent/call-scd.c | 1167 |
1 files changed, 1167 insertions, 0 deletions
diff --git a/agent/call-scd.c b/agent/call-scd.c new file mode 100644 index 0000000..5a43377 --- /dev/null +++ b/agent/call-scd.c @@ -0,0 +1,1167 @@ +/* call-scd.c - fork of the scdaemon to do SC operations + * Copyright (C) 2001, 2002, 2005, 2007 Free Software Foundation, Inc. + * + * This file is part of GnuPG. + * + * GnuPG is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * GnuPG 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#include <config.h> +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <ctype.h> +#include <assert.h> +#include <unistd.h> +#include <signal.h> +#include <sys/stat.h> +#include <sys/types.h> +#ifndef HAVE_W32_SYSTEM +#include <sys/wait.h> +#endif +#include <pth.h> + +#include "agent.h" +#include <assuan.h> + +#ifdef _POSIX_OPEN_MAX +#define MAX_OPEN_FDS _POSIX_OPEN_MAX +#else +#define MAX_OPEN_FDS 20 +#endif + +/* This Assuan flag is only available since libassuan 2.0.2. Because + comments lines are comments anyway we can use a replacement which + might not do anything. assuan_{g,s}et_flag don't return an error + thus there won't be any ABI problem. */ +#ifndef ASSUAN_CONVEY_COMMENTS +#define ASSUAN_CONVEY_COMMENTS 4 +#endif + + +/* Definition of module local data of the CTRL structure. */ +struct scd_local_s +{ + /* We keep a list of all allocated context with a an achnor at + SCD_LOCAL_LIST (see below). */ + struct scd_local_s *next_local; + + /* We need to get back to the ctrl object actually referencing this + structure. This is really an awkward way of enumerint the lcoal + contects. A much cleaner way would be to keep a global list of + ctrl objects to enumerate them. */ + ctrl_t ctrl_backlink; + + assuan_context_t ctx; /* NULL or session context for the SCdaemon + used with this connection. */ + int locked; /* This flag is used to assert proper use of + start_scd and unlock_scd. */ + +}; + + +/* Callback parameter for learn card */ +struct learn_parm_s +{ + void (*kpinfo_cb)(void*, const char *); + void *kpinfo_cb_arg; + void (*certinfo_cb)(void*, const char *); + void *certinfo_cb_arg; + void (*sinfo_cb)(void*, const char *, size_t, const char *); + void *sinfo_cb_arg; +}; + +struct inq_needpin_s +{ + assuan_context_t ctx; + int (*getpin_cb)(void *, const char *, char*, size_t); + void *getpin_cb_arg; + assuan_context_t passthru; /* If not NULL, pass unknown inquiries + up to the caller. */ +}; + + +/* To keep track of all active SCD contexts, we keep a linked list + anchored at this variable. */ +static struct scd_local_s *scd_local_list; + +/* A Mutex used inside the start_scd function. */ +static pth_mutex_t start_scd_lock; + +/* A malloced string with the name of the socket to be used for + additional connections. May be NULL if not provided by + SCdaemon. */ +static char *socket_name; + +/* The context of the primary connection. This is also used as a flag + to indicate whether the scdaemon has been started. */ +static assuan_context_t primary_scd_ctx; + +/* To allow reuse of the primary connection, the following flag is set + to true if the primary context has been reset and is not in use by + any connection. */ +static int primary_scd_ctx_reusable; + + + +/* Local prototypes. */ +static gpg_error_t membuf_data_cb (void *opaque, + const void *buffer, size_t length); + + + + +/* This function must be called once to initialize this module. This + has to be done before a second thread is spawned. We can't do the + static initialization because Pth emulation code might not be able + to do a static init; in particular, it is not possible for W32. */ +void +initialize_module_call_scd (void) +{ + static int initialized; + + if (!initialized) + { + if (!pth_mutex_init (&start_scd_lock)) + log_fatal ("error initializing mutex: %s\n", strerror (errno)); + initialized = 1; + } +} + + +static void +dump_mutex_state (pth_mutex_t *m) +{ +#ifdef _W32_PTH_H + (void)m; + log_printf ("unknown under W32"); +#else + if (!(m->mx_state & PTH_MUTEX_INITIALIZED)) + log_printf ("not_initialized"); + else if (!(m->mx_state & PTH_MUTEX_LOCKED)) + log_printf ("not_locked"); + else + log_printf ("locked tid=0x%lx count=%lu", (long)m->mx_owner, m->mx_count); +#endif +} + + +/* This function may be called to print infromation pertaining to the + current state of this module to the log. */ +void +agent_scd_dump_state (void) +{ + log_info ("agent_scd_dump_state: scd_lock="); + dump_mutex_state (&start_scd_lock); + log_printf ("\n"); + log_info ("agent_scd_dump_state: primary_scd_ctx=%p pid=%ld reusable=%d\n", + primary_scd_ctx, + (long)assuan_get_pid (primary_scd_ctx), + primary_scd_ctx_reusable); + if (socket_name) + log_info ("agent_scd_dump_state: socket=`%s'\n", socket_name); +} + + +/* The unlock_scd function shall be called after having accessed the + SCD. It is currently not very useful but gives an opportunity to + keep track of connections currently calling SCD. Note that the + "lock" operation is done by the start_scd() function which must be + called and error checked before any SCD operation. CTRL is the + usual connection context and RC the error code to be passed trhough + the function. */ +static int +unlock_scd (ctrl_t ctrl, int rc) +{ + if (gpg_err_code (rc) == GPG_ERR_NOT_OPERATIONAL + && gpg_err_source (rc) == GPG_ERR_SOURCE_SCD) + { + /* If the SCdaemon returned this error, it detected a major + problem, like no reader connected. To finish this we need to + stop the connection. This simulates an explicit killing of + the SCdaemon. */ + assuan_transact (primary_scd_ctx, "BYE", + NULL, NULL, NULL, NULL, NULL, NULL); + } + + if (ctrl->scd_local->locked != 1) + { + log_error ("unlock_scd: invalid lock count (%d)\n", + ctrl->scd_local->locked); + if (!rc) + rc = gpg_error (GPG_ERR_INTERNAL); + } + ctrl->scd_local->locked = 0; + return rc; +} + +/* To make sure we leave no secrets in our image after forking of the + scdaemon, we use this callback. */ +static void +atfork_cb (void *opaque, int where) +{ + (void)opaque; + + if (!where) + gcry_control (GCRYCTL_TERM_SECMEM); +} + + +/* Fork off the SCdaemon if this has not already been done. Lock the + daemon and make sure that a proper context has been setup in CTRL. + This function might also lock the daemon, which means that the + caller must call unlock_scd after this fucntion has returned + success and the actual Assuan transaction been done. */ +static int +start_scd (ctrl_t ctrl) +{ + gpg_error_t err = 0; + const char *pgmname; + assuan_context_t ctx = NULL; + const char *argv[3]; + int no_close_list[3]; + int i; + int rc; + + if (opt.disable_scdaemon) + return gpg_error (GPG_ERR_NOT_SUPPORTED); + + /* If this is the first call for this session, setup the local data + structure. */ + if (!ctrl->scd_local) + { + ctrl->scd_local = xtrycalloc (1, sizeof *ctrl->scd_local); + if (!ctrl->scd_local) + return gpg_error_from_syserror (); + ctrl->scd_local->ctrl_backlink = ctrl; + ctrl->scd_local->next_local = scd_local_list; + scd_local_list = ctrl->scd_local; + } + + + /* Assert that the lock count is as expected. */ + if (ctrl->scd_local->locked) + { + log_error ("start_scd: invalid lock count (%d)\n", + ctrl->scd_local->locked); + return gpg_error (GPG_ERR_INTERNAL); + } + ctrl->scd_local->locked++; + + if (ctrl->scd_local->ctx) + return 0; /* Okay, the context is fine. We used to test for an + alive context here and do an disconnect. Now that we + have a ticker function to check for it, it is easier + not to check here but to let the connection run on an + error instead. */ + + + /* We need to protect the following code. */ + if (!pth_mutex_acquire (&start_scd_lock, 0, NULL)) + { + log_error ("failed to acquire the start_scd lock: %s\n", + strerror (errno)); + return gpg_error (GPG_ERR_INTERNAL); + } + + /* Check whether the pipe server has already been started and in + this case either reuse a lingering pipe connection or establish a + new socket based one. */ + if (primary_scd_ctx && primary_scd_ctx_reusable) + { + ctx = primary_scd_ctx; + primary_scd_ctx_reusable = 0; + if (opt.verbose) + log_info ("new connection to SCdaemon established (reusing)\n"); + goto leave; + } + + rc = assuan_new (&ctx); + if (rc) + { + log_error ("can't allocate assuan context: %s\n", gpg_strerror (rc)); + err = rc; + goto leave; + } + + if (socket_name) + { + rc = assuan_socket_connect (ctx, socket_name, 0, 0); + if (rc) + { + log_error ("can't connect to socket `%s': %s\n", + socket_name, gpg_strerror (rc)); + err = gpg_error (GPG_ERR_NO_SCDAEMON); + goto leave; + } + + if (opt.verbose) + log_info ("new connection to SCdaemon established\n"); + goto leave; + } + + if (primary_scd_ctx) + { + log_info ("SCdaemon is running but won't accept further connections\n"); + err = gpg_error (GPG_ERR_NO_SCDAEMON); + goto leave; + } + + /* Nope, it has not been started. Fire it up now. */ + if (opt.verbose) + log_info ("no running SCdaemon - starting it\n"); + + if (fflush (NULL)) + { +#ifndef HAVE_W32_SYSTEM + err = gpg_error_from_syserror (); +#endif + log_error ("error flushing pending output: %s\n", strerror (errno)); + /* At least Windows XP fails here with EBADF. According to docs + and Wine an fflush(NULL) is the same as _flushall. However + the Wime implementaion does not flush stdin,stdout and stderr + - see above. Lets try to ignore the error. */ +#ifndef HAVE_W32_SYSTEM + goto leave; +#endif + } + + if (!opt.scdaemon_program || !*opt.scdaemon_program) + opt.scdaemon_program = gnupg_module_name (GNUPG_MODULE_NAME_SCDAEMON); + if ( !(pgmname = strrchr (opt.scdaemon_program, '/'))) + pgmname = opt.scdaemon_program; + else + pgmname++; + + argv[0] = pgmname; + argv[1] = "--multi-server"; + argv[2] = NULL; + + i=0; + if (!opt.running_detached) + { + if (log_get_fd () != -1) + no_close_list[i++] = assuan_fd_from_posix_fd (log_get_fd ()); + no_close_list[i++] = assuan_fd_from_posix_fd (fileno (stderr)); + } + no_close_list[i] = -1; + + /* Connect to the pinentry and perform initial handshaking. Use + detached flag (128) so that under W32 SCDAEMON does not show up a + new window. */ + rc = assuan_pipe_connect (ctx, opt.scdaemon_program, argv, + no_close_list, atfork_cb, NULL, 128); + if (rc) + { + log_error ("can't connect to the SCdaemon: %s\n", + gpg_strerror (rc)); + err = gpg_error (GPG_ERR_NO_SCDAEMON); + goto leave; + } + + if (opt.verbose) + log_debug ("first connection to SCdaemon established\n"); + + if (DBG_ASSUAN) + assuan_set_log_stream (ctx, log_get_stream ()); + + /* Get the name of the additional socket opened by scdaemon. */ + { + membuf_t data; + unsigned char *databuf; + size_t datalen; + + xfree (socket_name); + socket_name = NULL; + init_membuf (&data, 256); + assuan_transact (ctx, "GETINFO socket_name", + membuf_data_cb, &data, NULL, NULL, NULL, NULL); + + databuf = get_membuf (&data, &datalen); + if (databuf && datalen) + { + socket_name = xtrymalloc (datalen + 1); + if (!socket_name) + log_error ("warning: can't store socket name: %s\n", + strerror (errno)); + else + { + memcpy (socket_name, databuf, datalen); + socket_name[datalen] = 0; + if (DBG_ASSUAN) + log_debug ("additional connections at `%s'\n", socket_name); + } + } + xfree (databuf); + } + + /* Tell the scdaemon we want him to send us an event signal. */ + if (opt.sigusr2_enabled) + { + char buf[100]; + +#ifdef HAVE_W32_SYSTEM + snprintf (buf, sizeof buf, "OPTION event-signal=%lx", + (unsigned long)get_agent_scd_notify_event ()); +#else + snprintf (buf, sizeof buf, "OPTION event-signal=%d", SIGUSR2); +#endif + assuan_transact (ctx, buf, NULL, NULL, NULL, NULL, NULL, NULL); + } + + primary_scd_ctx = ctx; + primary_scd_ctx_reusable = 0; + + leave: + if (err) + { + unlock_scd (ctrl, err); + if (ctx) + assuan_release (ctx); + } + else + { + ctrl->scd_local->ctx = ctx; + } + if (!pth_mutex_release (&start_scd_lock)) + log_error ("failed to release the start_scd lock: %s\n", strerror (errno)); + return err; +} + + +/* Check whether the SCdaemon is active. This is a fast check without + any locking and might give a wrong result if another thread is about + to start the daemon or the daemon is about to be stopped.. */ +int +agent_scd_check_running (void) +{ + return !!primary_scd_ctx; +} + + +/* Check whether the Scdaemon is still alive and clean it up if not. */ +void +agent_scd_check_aliveness (void) +{ + pth_event_t evt; + pid_t pid; +#ifdef HAVE_W32_SYSTEM + DWORD rc; +#else + int rc; +#endif + + if (!primary_scd_ctx) + return; /* No scdaemon running. */ + + /* This is not a critical function so we use a short timeout while + acquiring the lock. */ + evt = pth_event (PTH_EVENT_TIME, pth_timeout (1, 0)); + if (!pth_mutex_acquire (&start_scd_lock, 0, evt)) + { + if (pth_event_occurred (evt)) + { + if (opt.verbose > 1) + log_info ("failed to acquire the start_scd lock while" + " doing an aliveness check: %s\n", "timeout"); + } + else + log_error ("failed to acquire the start_scd lock while" + " doing an aliveness check: %s\n", strerror (errno)); + pth_event_free (evt, PTH_FREE_THIS); + return; + } + pth_event_free (evt, PTH_FREE_THIS); + + if (primary_scd_ctx) + { + pid = assuan_get_pid (primary_scd_ctx); +#ifdef HAVE_W32_SYSTEM + /* If we have a PID we disconnect if either GetExitProcessCode + fails or if ir returns the exit code of the scdaemon. 259 is + the error code for STILL_ALIVE. */ + if (pid != (pid_t)(void*)(-1) && pid + && (!GetExitCodeProcess ((HANDLE)pid, &rc) || rc != 259)) +#else + if (pid != (pid_t)(-1) && pid + && ((rc=waitpid (pid, NULL, WNOHANG))==-1 || (rc == pid)) ) +#endif + { + /* Okay, scdaemon died. Disconnect the primary connection + now but take care that it won't do another wait. Also + cleanup all other connections and release their + resources. The next use will start a new daemon then. + Due to the use of the START_SCD_LOCAL we are sure that + none of these context are actually in use. */ + struct scd_local_s *sl; + + assuan_set_flag (primary_scd_ctx, ASSUAN_NO_WAITPID, 1); + assuan_release (primary_scd_ctx); + + for (sl=scd_local_list; sl; sl = sl->next_local) + { + if (sl->ctx) + { + if (sl->ctx != primary_scd_ctx) + assuan_release (sl->ctx); + sl->ctx = NULL; + } + } + + primary_scd_ctx = NULL; + primary_scd_ctx_reusable = 0; + + xfree (socket_name); + socket_name = NULL; + } + } + + if (!pth_mutex_release (&start_scd_lock)) + log_error ("failed to release the start_scd lock while" + " doing the aliveness check: %s\n", strerror (errno)); +} + + + +/* Reset the SCD if it has been used. Actually it is not a reset but + a cleanup of resources used by the current connection. */ +int +agent_reset_scd (ctrl_t ctrl) +{ + if (ctrl->scd_local) + { + if (ctrl->scd_local->ctx) + { + /* We can't disconnect the primary context because libassuan + does a waitpid on it and thus the system would hang. + Instead we send a reset and keep that connection for + reuse. */ + if (ctrl->scd_local->ctx == primary_scd_ctx) + { + /* Send a RESTART to the SCD. This is required for the + primary connection as a kind of virtual EOF; we don't + have another way to tell it that the next command + should be viewed as if a new connection has been + made. For the non-primary connections this is not + needed as we simply close the socket. We don't check + for an error here because the RESTART may fail for + example if the scdaemon has already been terminated. + Anyway, we need to set the reusable flag to make sure + that the aliveness check can clean it up. */ + assuan_transact (primary_scd_ctx, "RESTART", + NULL, NULL, NULL, NULL, NULL, NULL); + primary_scd_ctx_reusable = 1; + } + else + assuan_release (ctrl->scd_local->ctx); + ctrl->scd_local->ctx = NULL; + } + + /* Remove the local context from our list and release it. */ + if (!scd_local_list) + BUG (); + else if (scd_local_list == ctrl->scd_local) + scd_local_list = ctrl->scd_local->next_local; + else + { + struct scd_local_s *sl; + + for (sl=scd_local_list; sl->next_local; sl = sl->next_local) + if (sl->next_local == ctrl->scd_local) + break; + if (!sl->next_local) + BUG (); + sl->next_local = ctrl->scd_local->next_local; + } + xfree (ctrl->scd_local); + ctrl->scd_local = NULL; + } + + return 0; +} + + + +static gpg_error_t +learn_status_cb (void *opaque, const char *line) +{ + struct learn_parm_s *parm = opaque; + const char *keyword = line; + int keywordlen; + + for (keywordlen=0; *line && !spacep (line); line++, keywordlen++) + ; + while (spacep (line)) + line++; + if (keywordlen == 8 && !memcmp (keyword, "CERTINFO", keywordlen)) + { + parm->certinfo_cb (parm->certinfo_cb_arg, line); + } + else if (keywordlen == 11 && !memcmp (keyword, "KEYPAIRINFO", keywordlen)) + { + parm->kpinfo_cb (parm->kpinfo_cb_arg, line); + } + else if (keywordlen && *line) + { + parm->sinfo_cb (parm->sinfo_cb_arg, keyword, keywordlen, line); + } + + return 0; +} + +/* Perform the LEARN command and return a list of all private keys + stored on the card. */ +int +agent_card_learn (ctrl_t ctrl, + void (*kpinfo_cb)(void*, const char *), + void *kpinfo_cb_arg, + void (*certinfo_cb)(void*, const char *), + void *certinfo_cb_arg, + void (*sinfo_cb)(void*, const char *, size_t, const char *), + void *sinfo_cb_arg) +{ + int rc; + struct learn_parm_s parm; + + rc = start_scd (ctrl); + if (rc) + return rc; + + memset (&parm, 0, sizeof parm); + parm.kpinfo_cb = kpinfo_cb; + parm.kpinfo_cb_arg = kpinfo_cb_arg; + parm.certinfo_cb = certinfo_cb; + parm.certinfo_cb_arg = certinfo_cb_arg; + parm.sinfo_cb = sinfo_cb; + parm.sinfo_cb_arg = sinfo_cb_arg; + rc = assuan_transact (ctrl->scd_local->ctx, "LEARN --force", + NULL, NULL, NULL, NULL, + learn_status_cb, &parm); + if (rc) + return unlock_scd (ctrl, rc); + + return unlock_scd (ctrl, 0); +} + + + +static gpg_error_t +get_serialno_cb (void *opaque, const char *line) +{ + char **serialno = opaque; + const char *keyword = line; + const char *s; + int keywordlen, n; + + for (keywordlen=0; *line && !spacep (line); line++, keywordlen++) + ; + while (spacep (line)) + line++; + + if (keywordlen == 8 && !memcmp (keyword, "SERIALNO", keywordlen)) + { + if (*serialno) + return gpg_error (GPG_ERR_CONFLICT); /* Unexpected status line. */ + for (n=0,s=line; hexdigitp (s); s++, n++) + ; + if (!n || (n&1)|| !(spacep (s) || !*s) ) + return gpg_error (GPG_ERR_ASS_PARAMETER); + *serialno = xtrymalloc (n+1); + if (!*serialno) + return out_of_core (); + memcpy (*serialno, line, n); + (*serialno)[n] = 0; + } + + return 0; +} + +/* Return the serial number of the card or an appropriate error. The + serial number is returned as a hexstring. */ +int +agent_card_serialno (ctrl_t ctrl, char **r_serialno) +{ + int rc; + char *serialno = NULL; + + rc = start_scd (ctrl); + if (rc) + return rc; + + rc = assuan_transact (ctrl->scd_local->ctx, "SERIALNO", + NULL, NULL, NULL, NULL, + get_serialno_cb, &serialno); + if (rc) + { + xfree (serialno); + return unlock_scd (ctrl, rc); + } + *r_serialno = serialno; + return unlock_scd (ctrl, 0); +} + + + + +static gpg_error_t +membuf_data_cb (void *opaque, const void *buffer, size_t length) +{ + membuf_t *data = opaque; + + if (buffer) + put_membuf (data, buffer, length); + return 0; +} + +/* Handle the NEEDPIN inquiry. */ +static gpg_error_t +inq_needpin (void *opaque, const char *line) +{ + struct inq_needpin_s *parm = opaque; + char *pin; + size_t pinlen; + int rc; + + if (!strncmp (line, "NEEDPIN", 7) && (line[7] == ' ' || !line[7])) + { + line += 7; + while (*line == ' ') + line++; + + pinlen = 90; + pin = gcry_malloc_secure (pinlen); + if (!pin) + return out_of_core (); + + rc = parm->getpin_cb (parm->getpin_cb_arg, line, pin, pinlen); + if (!rc) + rc = assuan_send_data (parm->ctx, pin, pinlen); + xfree (pin); + } + else if (!strncmp (line, "POPUPKEYPADPROMPT", 17) + && (line[17] == ' ' || !line[17])) + { + line += 17; + while (*line == ' ') + line++; + + rc = parm->getpin_cb (parm->getpin_cb_arg, line, NULL, 1); + } + else if (!strncmp (line, "DISMISSKEYPADPROMPT", 19) + && (line[19] == ' ' || !line[19])) + { + rc = parm->getpin_cb (parm->getpin_cb_arg, "", NULL, 0); + } + else if (parm->passthru) + { + unsigned char *value; + size_t valuelen; + int rest; + int needrest = !strncmp (line, "KEYDATA", 8); + + /* Pass the inquiry up to our caller. We limit the maximum + amount to an arbitrary value. As we know that the KEYDATA + enquiry is pretty sensitive we disable logging then */ + if ((rest = (needrest + && !assuan_get_flag (parm->passthru, ASSUAN_CONFIDENTIAL)))) + assuan_begin_confidential (parm->passthru); + rc = assuan_inquire (parm->passthru, line, &value, &valuelen, 8096); + if (rest) + assuan_end_confidential (parm->passthru); + if (!rc) + { + if ((rest = (needrest + && !assuan_get_flag (parm->ctx, ASSUAN_CONFIDENTIAL)))) + assuan_begin_confidential (parm->ctx); + rc = assuan_send_data (parm->ctx, value, valuelen); + if (rest) + assuan_end_confidential (parm->ctx); + xfree (value); + } + else + log_error ("error forwarding inquiry `%s': %s\n", + line, gpg_strerror (rc)); + } + else + { + log_error ("unsupported inquiry `%s'\n", line); + rc = gpg_error (GPG_ERR_ASS_UNKNOWN_INQUIRE); + } + + return rc; +} + + + +/* Create a signature using the current card */ +int +agent_card_pksign (ctrl_t ctrl, + const char *keyid, + int (*getpin_cb)(void *, const char *, char*, size_t), + void *getpin_cb_arg, + const unsigned char *indata, size_t indatalen, + unsigned char **r_buf, size_t *r_buflen) +{ + int rc, i; + char *p, line[ASSUAN_LINELENGTH]; + membuf_t data; + struct inq_needpin_s inqparm; + size_t len; + unsigned char *sigbuf; + size_t sigbuflen; + + *r_buf = NULL; + rc = start_scd (ctrl); + if (rc) + return rc; + + if (indatalen*2 + 50 > DIM(line)) + return unlock_scd (ctrl, gpg_error (GPG_ERR_GENERAL)); + + sprintf (line, "SETDATA "); + p = line + strlen (line); + for (i=0; i < indatalen ; i++, p += 2 ) + sprintf (p, "%02X", indata[i]); + rc = assuan_transact (ctrl->scd_local->ctx, line, + NULL, NULL, NULL, NULL, NULL, NULL); + if (rc) + return unlock_scd (ctrl, rc); + + init_membuf (&data, 1024); + inqparm.ctx = ctrl->scd_local->ctx; + inqparm.getpin_cb = getpin_cb; + inqparm.getpin_cb_arg = getpin_cb_arg; + inqparm.passthru = 0; + snprintf (line, DIM(line)-1, + ctrl->use_auth_call? "PKAUTH %s":"PKSIGN %s", keyid); + line[DIM(line)-1] = 0; + rc = assuan_transact (ctrl->scd_local->ctx, line, + membuf_data_cb, &data, + inq_needpin, &inqparm, + NULL, NULL); + if (rc) + { + xfree (get_membuf (&data, &len)); + return unlock_scd (ctrl, rc); + } + sigbuf = get_membuf (&data, &sigbuflen); + + /* Create an S-expression from it which is formatted like this: + "(7:sig-val(3:rsa(1:sSIGBUFLEN:SIGBUF)))" */ + *r_buflen = 21 + 11 + sigbuflen + 4; + p = xtrymalloc (*r_buflen); + *r_buf = (unsigned char*)p; + if (!p) + return unlock_scd (ctrl, out_of_core ()); + p = stpcpy (p, "(7:sig-val(3:rsa(1:s" ); + sprintf (p, "%u:", (unsigned int)sigbuflen); + p += strlen (p); + memcpy (p, sigbuf, sigbuflen); + p += sigbuflen; + strcpy (p, ")))"); + xfree (sigbuf); + + assert (gcry_sexp_canon_len (*r_buf, *r_buflen, NULL, NULL)); + return unlock_scd (ctrl, 0); +} + +/* Decipher INDATA using the current card. Note that the returned value is */ +int +agent_card_pkdecrypt (ctrl_t ctrl, + const char *keyid, + int (*getpin_cb)(void *, const char *, char*, size_t), + void *getpin_cb_arg, + const unsigned char *indata, size_t indatalen, + char **r_buf, size_t *r_buflen) +{ + int rc, i; + char *p, line[ASSUAN_LINELENGTH]; + membuf_t data; + struct inq_needpin_s inqparm; + size_t len; + + *r_buf = NULL; + rc = start_scd (ctrl); + if (rc) + return rc; + + /* FIXME: use secure memory where appropriate */ + if (indatalen*2 + 50 > DIM(line)) + return unlock_scd (ctrl, gpg_error (GPG_ERR_GENERAL)); + + sprintf (line, "SETDATA "); + p = line + strlen (line); + for (i=0; i < indatalen ; i++, p += 2 ) + sprintf (p, "%02X", indata[i]); + rc = assuan_transact (ctrl->scd_local->ctx, line, + NULL, NULL, NULL, NULL, NULL, NULL); + if (rc) + return unlock_scd (ctrl, rc); + + init_membuf (&data, 1024); + inqparm.ctx = ctrl->scd_local->ctx; + inqparm.getpin_cb = getpin_cb; + inqparm.getpin_cb_arg = getpin_cb_arg; + inqparm.passthru = 0; + snprintf (line, DIM(line)-1, "PKDECRYPT %s", keyid); + line[DIM(line)-1] = 0; + rc = assuan_transact (ctrl->scd_local->ctx, line, + membuf_data_cb, &data, + inq_needpin, &inqparm, + NULL, NULL); + if (rc) + { + xfree (get_membuf (&data, &len)); + return unlock_scd (ctrl, rc); + } + *r_buf = get_membuf (&data, r_buflen); + if (!*r_buf) + return unlock_scd (ctrl, gpg_error (GPG_ERR_ENOMEM)); + + return unlock_scd (ctrl, 0); +} + + + +/* Read a certificate with ID into R_BUF and R_BUFLEN. */ +int +agent_card_readcert (ctrl_t ctrl, + const char *id, char **r_buf, size_t *r_buflen) +{ + int rc; + char line[ASSUAN_LINELENGTH]; + membuf_t data; + size_t len; + + *r_buf = NULL; + rc = start_scd (ctrl); + if (rc) + return rc; + + init_membuf (&data, 1024); + snprintf (line, DIM(line)-1, "READCERT %s", id); + line[DIM(line)-1] = 0; + rc = assuan_transact (ctrl->scd_local->ctx, line, + membuf_data_cb, &data, + NULL, NULL, + NULL, NULL); + if (rc) + { + xfree (get_membuf (&data, &len)); + return unlock_scd (ctrl, rc); + } + *r_buf = get_membuf (&data, r_buflen); + if (!*r_buf) + return unlock_scd (ctrl, gpg_error (GPG_ERR_ENOMEM)); + + return unlock_scd (ctrl, 0); +} + + + +/* Read a key with ID and return it in an allocate buffer pointed to + by r_BUF as a valid S-expression. */ +int +agent_card_readkey (ctrl_t ctrl, const char *id, unsigned char **r_buf) +{ + int rc; + char line[ASSUAN_LINELENGTH]; + membuf_t data; + size_t len, buflen; + + *r_buf = NULL; + rc = start_scd (ctrl); + if (rc) + return rc; + + init_membuf (&data, 1024); + snprintf (line, DIM(line)-1, "READKEY %s", id); + line[DIM(line)-1] = 0; + rc = assuan_transact (ctrl->scd_local->ctx, line, + membuf_data_cb, &data, + NULL, NULL, + NULL, NULL); + if (rc) + { + xfree (get_membuf (&data, &len)); + return unlock_scd (ctrl, rc); + } + *r_buf = get_membuf (&data, &buflen); + if (!*r_buf) + return unlock_scd (ctrl, gpg_error (GPG_ERR_ENOMEM)); + + if (!gcry_sexp_canon_len (*r_buf, buflen, NULL, NULL)) + { + xfree (*r_buf); *r_buf = NULL; + return unlock_scd (ctrl, gpg_error (GPG_ERR_INV_VALUE)); + } + + return unlock_scd (ctrl, 0); +} + + + +/* Type used with the card_getattr_cb. */ +struct card_getattr_parm_s { + const char *keyword; /* Keyword to look for. */ + size_t keywordlen; /* strlen of KEYWORD. */ + char *data; /* Malloced and unescaped data. */ + int error; /* ERRNO value or 0 on success. */ +}; + +/* Callback function for agent_card_getattr. */ +static gpg_error_t +card_getattr_cb (void *opaque, const char *line) +{ + struct card_getattr_parm_s *parm = opaque; + const char *keyword = line; + int keywordlen; + + if (parm->data) + return 0; /* We want only the first occurrence. */ + + for (keywordlen=0; *line && !spacep (line); line++, keywordlen++) + ; + while (spacep (line)) + line++; + + if (keywordlen == parm->keywordlen + && !memcmp (keyword, parm->keyword, keywordlen)) + { + parm->data = percent_plus_unescape ((const unsigned char*)line, 0xff); + if (!parm->data) + parm->error = errno; + } + + return 0; +} + + +/* Call the agent to retrieve a single line data object. On success + the object is malloced and stored at RESULT; it is guaranteed that + NULL is never stored in this case. On error an error code is + returned and NULL stored at RESULT. */ +gpg_error_t +agent_card_getattr (ctrl_t ctrl, const char *name, char **result) +{ + int err; + struct card_getattr_parm_s parm; + char line[ASSUAN_LINELENGTH]; + + *result = NULL; + + if (!*name) + return gpg_error (GPG_ERR_INV_VALUE); + + memset (&parm, 0, sizeof parm); + parm.keyword = name; + parm.keywordlen = strlen (name); + + /* We assume that NAME does not need escaping. */ + if (8 + strlen (name) > DIM(line)-1) + return gpg_error (GPG_ERR_TOO_LARGE); + stpcpy (stpcpy (line, "GETATTR "), name); + + err = start_scd (ctrl); + if (err) + return err; + + err = assuan_transact (ctrl->scd_local->ctx, line, + NULL, NULL, NULL, NULL, + card_getattr_cb, &parm); + if (!err && parm.error) + err = gpg_error_from_errno (parm.error); + + if (!err && !parm.data) + err = gpg_error (GPG_ERR_NO_DATA); + + if (!err) + *result = parm.data; + else + xfree (parm.data); + + return unlock_scd (ctrl, err); +} + + + + +static gpg_error_t +pass_status_thru (void *opaque, const char *line) +{ + assuan_context_t ctx = opaque; + char keyword[200]; + int i; + + for (i=0; *line && !spacep (line) && i < DIM(keyword)-1; line++, i++) + keyword[i] = *line; + keyword[i] = 0; + /* truncate any remaining keyword stuff. */ + for (; *line && !spacep (line); line++) + ; + while (spacep (line)) + line++; + + assuan_write_status (ctx, keyword, line); + return 0; +} + +static gpg_error_t +pass_data_thru (void *opaque, const void *buffer, size_t length) +{ + assuan_context_t ctx = opaque; + + assuan_send_data (ctx, buffer, length); + return 0; +} + + +/* Send the line CMDLINE with command for the SCDdaemon to it and send + all status messages back. This command is used as a general quoting + mechanism to pass everything verbatim to SCDAEMON. The PIN + inquiry is handled inside gpg-agent. */ +int +agent_card_scd (ctrl_t ctrl, const char *cmdline, + int (*getpin_cb)(void *, const char *, char*, size_t), + void *getpin_cb_arg, void *assuan_context) +{ + int rc; + struct inq_needpin_s inqparm; + int saveflag; + + rc = start_scd (ctrl); + if (rc) + return rc; + + inqparm.ctx = ctrl->scd_local->ctx; + inqparm.getpin_cb = getpin_cb; + inqparm.getpin_cb_arg = getpin_cb_arg; + inqparm.passthru = assuan_context; + saveflag = assuan_get_flag (ctrl->scd_local->ctx, ASSUAN_CONVEY_COMMENTS); + assuan_set_flag (ctrl->scd_local->ctx, ASSUAN_CONVEY_COMMENTS, 1); + rc = assuan_transact (ctrl->scd_local->ctx, cmdline, + pass_data_thru, assuan_context, + inq_needpin, &inqparm, + pass_status_thru, assuan_context); + assuan_set_flag (ctrl->scd_local->ctx, ASSUAN_CONVEY_COMMENTS, saveflag); + if (rc) + { + return unlock_scd (ctrl, rc); + } + + return unlock_scd (ctrl, 0); +} + + |