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Diffstat (limited to 'agent/call-scd.c')
| -rw-r--r-- | agent/call-scd.c | 661 |
1 files changed, 661 insertions, 0 deletions
diff --git a/agent/call-scd.c b/agent/call-scd.c new file mode 100644 index 000000000..14487f1e3 --- /dev/null +++ b/agent/call-scd.c @@ -0,0 +1,661 @@ +/* call-scd.c - fork of the scdaemon to do SC operations + * Copyright (C) 2001, 2002 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 2 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, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +/* Fixme: For now we have serialized all access to the scdaemon which + make sense becuase the scdaemon can't handle concurrent connections + right now. We should however keep a list of connections and lock + just that connection - it migth make sense to implemtn parts of + this in Assuan.*/ + +#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 <sys/stat.h> +#ifdef USE_GNU_PTH +# include <pth.h> +#endif + +#include "agent.h" +#include <assuan.h> + +#ifdef _POSIX_OPEN_MAX +#define MAX_OPEN_FDS _POSIX_OPEN_MAX +#else +#define MAX_OPEN_FDS 20 +#endif + +static ASSUAN_CONTEXT scd_ctx = NULL; +#ifdef USE_GNU_PTH +static pth_mutex_t scd_lock = PTH_MUTEX_INIT; +#endif + +/* 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 ctx; + int (*getpin_cb)(void *, const char *, char*, size_t); + void *getpin_cb_arg; +}; + +struct membuf { + size_t len; + size_t size; + char *buf; + int out_of_core; +}; + + + +/* A simple implementation of a dynamic buffer. Use init_membuf() to + create a buffer, put_membuf to append bytes and get_membuf to + release and return the buffer. Allocation errors are detected but + only returned at the final get_membuf(), this helps not to clutter + the code with out of core checks. */ + +static void +init_membuf (struct membuf *mb, int initiallen) +{ + mb->len = 0; + mb->size = initiallen; + mb->out_of_core = 0; + mb->buf = xtrymalloc (initiallen); + if (!mb->buf) + mb->out_of_core = 1; +} + +static void +put_membuf (struct membuf *mb, const void *buf, size_t len) +{ + if (mb->out_of_core) + return; + + if (mb->len + len >= mb->size) + { + char *p; + + mb->size += len + 1024; + p = xtryrealloc (mb->buf, mb->size); + if (!p) + { + mb->out_of_core = 1; + return; + } + mb->buf = p; + } + memcpy (mb->buf + mb->len, buf, len); + mb->len += len; +} + +static void * +get_membuf (struct membuf *mb, size_t *len) +{ + char *p; + + if (mb->out_of_core) + { + xfree (mb->buf); + mb->buf = NULL; + return NULL; + } + + p = mb->buf; + *len = mb->len; + mb->buf = NULL; + mb->out_of_core = 1; /* don't allow a reuse */ + return p; +} + + + + +static int +unlock_scd (int rc) +{ +#ifdef USE_GNU_PTH + if (!pth_mutex_release (&scd_lock)) + { + log_error ("failed to release the SCD lock\n"); + if (!rc) + rc = gpg_error (GPG_ERR_INTERNAL); + } +#endif + return rc; +} + +/* Fork off the SCdaemon if this has not already been done */ +static int +start_scd (void) +{ + int rc; + const char *pgmname; + ASSUAN_CONTEXT ctx; + const char *argv[3]; + int no_close_list[3]; + int i; + +#ifdef USE_GNU_PTH + if (!pth_mutex_acquire (&scd_lock, 0, NULL)) + { + log_error ("failed to acquire the SCD lock\n"); + return gpg_error (GPG_ERR_INTERNAL); + } +#endif + + if (scd_ctx) + return 0; /* No need to serialize things because the agent is + expected to tun as a single-thread (or may be in + future using libpth) */ + + if (opt.verbose) + log_info ("no running SCdaemon - starting it\n"); + + if (fflush (NULL)) + { + gpg_error_t tmperr = gpg_error (gpg_err_code_from_errno (errno)); + log_error ("error flushing pending output: %s\n", strerror (errno)); + return unlock_scd (tmperr); + } + + if (!opt.scdaemon_program || !*opt.scdaemon_program) + opt.scdaemon_program = GNUPG_DEFAULT_SCDAEMON; + if ( !(pgmname = strrchr (opt.scdaemon_program, '/'))) + pgmname = opt.scdaemon_program; + else + pgmname++; + + argv[0] = pgmname; + argv[1] = "--server"; + argv[2] = NULL; + + i=0; + if (!opt.running_detached) + { + if (log_get_fd () != -1) + no_close_list[i++] = log_get_fd (); + no_close_list[i++] = fileno (stderr); + } + no_close_list[i] = -1; + + /* connect to the pinentry and perform initial handshaking */ + rc = assuan_pipe_connect (&ctx, opt.scdaemon_program, (char**)argv, + no_close_list); + if (rc) + { + log_error ("can't connect to the SCdaemon: %s\n", + assuan_strerror (rc)); + return unlock_scd (gpg_error (GPG_ERR_NO_SCDAEMON)); + } + scd_ctx = ctx; + + if (DBG_ASSUAN) + log_debug ("connection to SCdaemon established\n"); + return 0; +} + + + +static AssuanError +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 (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 (); + 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 (scd_ctx, "LEARN --force", + NULL, NULL, NULL, NULL, + learn_status_cb, &parm); + if (rc) + return unlock_scd (map_assuan_err (rc)); + + return unlock_scd (0); +} + + + +static AssuanError +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 ASSUAN_Unexpected_Status; + for (n=0,s=line; hexdigitp (s); s++, n++) + ; + if (!n || (n&1)|| !(spacep (s) || !*s) ) + return ASSUAN_Invalid_Status; + *serialno = xtrymalloc (n+1); + if (!*serialno) + return ASSUAN_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 (char **r_serialno) +{ + int rc; + char *serialno = NULL; + + rc = start_scd (); + if (rc) + return rc; + + /* Hmm, do we really need this reset - scddaemon should do this or + we can do this if we for some reason figure out that the + operation might have failed due to a missing RESET. Hmmm, I feel + this is really SCdaemon's duty */ +/* rc = assuan_transact (scd_ctx, "RESET", NULL, NULL, NULL, NULL, NULL, NULL); */ +/* if (rc) */ +/* return unlock_scd (map_assuan_err (rc)); */ + + rc = assuan_transact (scd_ctx, "SERIALNO", + NULL, NULL, NULL, NULL, + get_serialno_cb, &serialno); + if (rc) + { + xfree (serialno); + return unlock_scd (map_assuan_err (rc)); + } + *r_serialno = serialno; + return unlock_scd (0); +} + + +static AssuanError +membuf_data_cb (void *opaque, const void *buffer, size_t length) +{ + struct membuf *data = opaque; + + if (buffer) + put_membuf (data, buffer, length); + return 0; +} + +/* Handle the NEEDPIN inquiry. */ +static AssuanError +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]))) + { + log_error ("unsupported inquiry `%s'\n", line); + return ASSUAN_Inquire_Unknown; + } + line += 7; + + pinlen = 90; + pin = gcry_malloc_secure (pinlen); + if (!pin) + return ASSUAN_Out_Of_Core; + + rc = parm->getpin_cb (parm->getpin_cb_arg, line, pin, pinlen); + if (rc) + rc = ASSUAN_Canceled; + if (!rc) + rc = assuan_send_data (parm->ctx, pin, pinlen); + xfree (pin); + + return rc; +} + + + +/* Create a signature using the current card */ +int +agent_card_pksign (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]; + struct membuf data; + struct inq_needpin_s inqparm; + size_t len; + unsigned char *sigbuf; + size_t sigbuflen; + + *r_buf = NULL; + rc = start_scd (); + if (rc) + return rc; + + if (indatalen*2 + 50 > DIM(line)) + return unlock_scd (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 (scd_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL); + if (rc) + return unlock_scd (map_assuan_err (rc)); + + init_membuf (&data, 1024); + inqparm.ctx = scd_ctx; + inqparm.getpin_cb = getpin_cb; + inqparm.getpin_cb_arg = getpin_cb_arg; + snprintf (line, DIM(line)-1, "PKSIGN %s", keyid); + line[DIM(line)-1] = 0; + rc = assuan_transact (scd_ctx, line, + membuf_data_cb, &data, + inq_needpin, &inqparm, + NULL, NULL); + if (rc) + { + xfree (get_membuf (&data, &len)); + return unlock_scd (map_assuan_err (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; + *r_buf = xtrymalloc (*r_buflen); + if (!*r_buf) + { + gpg_error_t tmperr = out_of_core (); + xfree (*r_buf); + return unlock_scd (tmperr); + } + p = stpcpy (*r_buf, "(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 (0); +} + +/* Decipher INDATA using the current card. Note that the returned value is */ +int +agent_card_pkdecrypt (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]; + struct membuf data; + struct inq_needpin_s inqparm; + size_t len; + + *r_buf = NULL; + rc = start_scd (); + if (rc) + return rc; + + /* FIXME: use secure memory where appropriate */ + if (indatalen*2 + 50 > DIM(line)) + return unlock_scd (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 (scd_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL); + if (rc) + return unlock_scd (map_assuan_err (rc)); + + init_membuf (&data, 1024); + inqparm.ctx = scd_ctx; + inqparm.getpin_cb = getpin_cb; + inqparm.getpin_cb_arg = getpin_cb_arg; + snprintf (line, DIM(line)-1, "PKDECRYPT %s", keyid); + line[DIM(line)-1] = 0; + rc = assuan_transact (scd_ctx, line, + membuf_data_cb, &data, + inq_needpin, &inqparm, + NULL, NULL); + if (rc) + { + xfree (get_membuf (&data, &len)); + return unlock_scd (map_assuan_err (rc)); + } + *r_buf = get_membuf (&data, r_buflen); + if (!*r_buf) + return unlock_scd (gpg_error (GPG_ERR_ENOMEM)); + + return unlock_scd (0); +} + + + +/* Read a certificate with ID into R_BUF and R_BUFLEN. */ +int +agent_card_readcert (const char *id, char **r_buf, size_t *r_buflen) +{ + int rc; + char line[ASSUAN_LINELENGTH]; + struct membuf data; + size_t len; + + *r_buf = NULL; + rc = start_scd (); + if (rc) + return rc; + + init_membuf (&data, 1024); + snprintf (line, DIM(line)-1, "READCERT %s", id); + line[DIM(line)-1] = 0; + rc = assuan_transact (scd_ctx, line, + membuf_data_cb, &data, + NULL, NULL, + NULL, NULL); + if (rc) + { + xfree (get_membuf (&data, &len)); + return unlock_scd (map_assuan_err (rc)); + } + *r_buf = get_membuf (&data, r_buflen); + if (!*r_buf) + return unlock_scd (gpg_error (GPG_ERR_ENOMEM)); + + return unlock_scd (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 (const char *id, unsigned char **r_buf) +{ + int rc; + char line[ASSUAN_LINELENGTH]; + struct membuf data; + size_t len, buflen; + + *r_buf = NULL; + rc = start_scd (); + if (rc) + return rc; + + init_membuf (&data, 1024); + snprintf (line, DIM(line)-1, "READKEY %s", id); + line[DIM(line)-1] = 0; + rc = assuan_transact (scd_ctx, line, + membuf_data_cb, &data, + NULL, NULL, + NULL, NULL); + if (rc) + { + xfree (get_membuf (&data, &len)); + return unlock_scd (map_assuan_err (rc)); + } + *r_buf = get_membuf (&data, &buflen); + if (!*r_buf) + return unlock_scd (gpg_error (GPG_ERR_ENOMEM)); + + if (!gcry_sexp_canon_len (*r_buf, buflen, NULL, NULL)) + { + xfree (*r_buf); *r_buf = NULL; + return unlock_scd (gpg_error (GPG_ERR_INV_VALUE)); + } + + return unlock_scd (0); +} + + + + +static AssuanError +pass_status_thru (void *opaque, const char *line) +{ + ASSUAN_CONTEXT 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 AssuanError +pass_data_thru (void *opaque, const void *buffer, size_t length) +{ + ASSUAN_CONTEXT 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 SCDAEMOPN. The PIN + inquirey is handled inside gpg-agent. */ +int +agent_card_scd (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; + + rc = start_scd (); + if (rc) + return rc; + + inqparm.ctx = scd_ctx; + inqparm.getpin_cb = getpin_cb; + inqparm.getpin_cb_arg = getpin_cb_arg; + rc = assuan_transact (scd_ctx, cmdline, + pass_data_thru, assuan_context, + inq_needpin, &inqparm, + pass_status_thru, assuan_context); + if (rc) + { + return unlock_scd (map_assuan_err (rc)); + } + + return unlock_scd (0); +} + + |