Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "config.h"
   3#include "run-command.h"
   4#include "strbuf.h"
   5#include "gpg-interface.h"
   6#include "sigchain.h"
   7#include "tempfile.h"
   8
   9static char *configured_signing_key;
  10struct gpg_format {
  11        const char *name;
  12        const char *program;
  13        const char **verify_args;
  14        const char **sigs;
  15};
  16
  17static const char *openpgp_verify_args[] = {
  18        "--keyid-format=long",
  19        NULL
  20};
  21static const char *openpgp_sigs[] = {
  22        "-----BEGIN PGP SIGNATURE-----",
  23        "-----BEGIN PGP MESSAGE-----",
  24        NULL
  25};
  26
  27static const char *x509_verify_args[] = {
  28        NULL
  29};
  30static const char *x509_sigs[] = {
  31        "-----BEGIN SIGNED MESSAGE-----",
  32        NULL
  33};
  34
  35static struct gpg_format gpg_format[] = {
  36        { .name = "openpgp", .program = "gpg",
  37          .verify_args = openpgp_verify_args,
  38          .sigs = openpgp_sigs
  39        },
  40        { .name = "x509", .program = "gpgsm",
  41          .verify_args = x509_verify_args,
  42          .sigs = x509_sigs
  43        },
  44};
  45
  46static struct gpg_format *use_format = &gpg_format[0];
  47
  48static struct gpg_format *get_format_by_name(const char *str)
  49{
  50        int i;
  51
  52        for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
  53                if (!strcmp(gpg_format[i].name, str))
  54                        return gpg_format + i;
  55        return NULL;
  56}
  57
  58static struct gpg_format *get_format_by_sig(const char *sig)
  59{
  60        int i, j;
  61
  62        for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
  63                for (j = 0; gpg_format[i].sigs[j]; j++)
  64                        if (starts_with(sig, gpg_format[i].sigs[j]))
  65                                return gpg_format + i;
  66        return NULL;
  67}
  68
  69void signature_check_clear(struct signature_check *sigc)
  70{
  71        FREE_AND_NULL(sigc->payload);
  72        FREE_AND_NULL(sigc->gpg_output);
  73        FREE_AND_NULL(sigc->gpg_status);
  74        FREE_AND_NULL(sigc->signer);
  75        FREE_AND_NULL(sigc->key);
  76}
  77
  78static struct {
  79        char result;
  80        const char *check;
  81} sigcheck_gpg_status[] = {
  82        { 'G', "\n[GNUPG:] GOODSIG " },
  83        { 'B', "\n[GNUPG:] BADSIG " },
  84        { 'U', "\n[GNUPG:] TRUST_NEVER" },
  85        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
  86        { 'E', "\n[GNUPG:] ERRSIG "},
  87        { 'X', "\n[GNUPG:] EXPSIG "},
  88        { 'Y', "\n[GNUPG:] EXPKEYSIG "},
  89        { 'R', "\n[GNUPG:] REVKEYSIG "},
  90};
  91
  92static void parse_gpg_output(struct signature_check *sigc)
  93{
  94        const char *buf = sigc->gpg_status;
  95        int i;
  96
  97        /* Iterate over all search strings */
  98        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
  99                const char *found, *next;
 100
 101                if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
 102                        found = strstr(buf, sigcheck_gpg_status[i].check);
 103                        if (!found)
 104                                continue;
 105                        found += strlen(sigcheck_gpg_status[i].check);
 106                }
 107                sigc->result = sigcheck_gpg_status[i].result;
 108                /* The trust messages are not followed by key/signer information */
 109                if (sigc->result != 'U') {
 110                        next = strchrnul(found, ' ');
 111                        sigc->key = xmemdupz(found, next - found);
 112                        /* The ERRSIG message is not followed by signer information */
 113                        if (*next && sigc-> result != 'E') {
 114                                found = next + 1;
 115                                next = strchrnul(found, '\n');
 116                                sigc->signer = xmemdupz(found, next - found);
 117                        }
 118                }
 119        }
 120}
 121
 122int check_signature(const char *payload, size_t plen, const char *signature,
 123        size_t slen, struct signature_check *sigc)
 124{
 125        struct strbuf gpg_output = STRBUF_INIT;
 126        struct strbuf gpg_status = STRBUF_INIT;
 127        int status;
 128
 129        sigc->result = 'N';
 130
 131        status = verify_signed_buffer(payload, plen, signature, slen,
 132                                      &gpg_output, &gpg_status);
 133        if (status && !gpg_output.len)
 134                goto out;
 135        sigc->payload = xmemdupz(payload, plen);
 136        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
 137        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
 138        parse_gpg_output(sigc);
 139
 140 out:
 141        strbuf_release(&gpg_status);
 142        strbuf_release(&gpg_output);
 143
 144        return sigc->result != 'G' && sigc->result != 'U';
 145}
 146
 147void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
 148{
 149        const char *output = flags & GPG_VERIFY_RAW ?
 150                sigc->gpg_status : sigc->gpg_output;
 151
 152        if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
 153                fputs(sigc->payload, stdout);
 154
 155        if (output)
 156                fputs(output, stderr);
 157}
 158
 159size_t parse_signature(const char *buf, size_t size)
 160{
 161        size_t len = 0;
 162        size_t match = size;
 163        while (len < size) {
 164                const char *eol;
 165
 166                if (get_format_by_sig(buf + len))
 167                        match = len;
 168
 169                eol = memchr(buf + len, '\n', size - len);
 170                len += eol ? eol - (buf + len) + 1 : size - len;
 171        }
 172        return match;
 173}
 174
 175void set_signing_key(const char *key)
 176{
 177        free(configured_signing_key);
 178        configured_signing_key = xstrdup(key);
 179}
 180
 181int git_gpg_config(const char *var, const char *value, void *cb)
 182{
 183        struct gpg_format *fmt = NULL;
 184        char *fmtname = NULL;
 185
 186        if (!strcmp(var, "user.signingkey")) {
 187                if (!value)
 188                        return config_error_nonbool(var);
 189                set_signing_key(value);
 190                return 0;
 191        }
 192
 193        if (!strcmp(var, "gpg.format")) {
 194                if (!value)
 195                        return config_error_nonbool(var);
 196                fmt = get_format_by_name(value);
 197                if (!fmt)
 198                        return error("unsupported value for %s: %s",
 199                                     var, value);
 200                use_format = fmt;
 201                return 0;
 202        }
 203
 204        if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
 205                fmtname = "openpgp";
 206
 207        if (!strcmp(var, "gpg.x509.program"))
 208                fmtname = "x509";
 209
 210        if (fmtname) {
 211                fmt = get_format_by_name(fmtname);
 212                return git_config_string(&fmt->program, var, value);
 213        }
 214
 215        return 0;
 216}
 217
 218const char *get_signing_key(void)
 219{
 220        if (configured_signing_key)
 221                return configured_signing_key;
 222        return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
 223}
 224
 225int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 226{
 227        struct child_process gpg = CHILD_PROCESS_INIT;
 228        int ret;
 229        size_t i, j, bottom;
 230        struct strbuf gpg_status = STRBUF_INIT;
 231
 232        argv_array_pushl(&gpg.args,
 233                         use_format->program,
 234                         "--status-fd=2",
 235                         "-bsau", signing_key,
 236                         NULL);
 237
 238        bottom = signature->len;
 239
 240        /*
 241         * When the username signingkey is bad, program could be terminated
 242         * because gpg exits without reading and then write gets SIGPIPE.
 243         */
 244        sigchain_push(SIGPIPE, SIG_IGN);
 245        ret = pipe_command(&gpg, buffer->buf, buffer->len,
 246                           signature, 1024, &gpg_status, 0);
 247        sigchain_pop(SIGPIPE);
 248
 249        ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
 250        strbuf_release(&gpg_status);
 251        if (ret)
 252                return error(_("gpg failed to sign the data"));
 253
 254        /* Strip CR from the line endings, in case we are on Windows. */
 255        for (i = j = bottom; i < signature->len; i++)
 256                if (signature->buf[i] != '\r') {
 257                        if (i != j)
 258                                signature->buf[j] = signature->buf[i];
 259                        j++;
 260                }
 261        strbuf_setlen(signature, j);
 262
 263        return 0;
 264}
 265
 266int verify_signed_buffer(const char *payload, size_t payload_size,
 267                         const char *signature, size_t signature_size,
 268                         struct strbuf *gpg_output, struct strbuf *gpg_status)
 269{
 270        struct child_process gpg = CHILD_PROCESS_INIT;
 271        struct gpg_format *fmt;
 272        struct tempfile *temp;
 273        int ret;
 274        struct strbuf buf = STRBUF_INIT;
 275
 276        temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
 277        if (!temp)
 278                return error_errno(_("could not create temporary file"));
 279        if (write_in_full(temp->fd, signature, signature_size) < 0 ||
 280            close_tempfile_gently(temp) < 0) {
 281                error_errno(_("failed writing detached signature to '%s'"),
 282                            temp->filename.buf);
 283                delete_tempfile(&temp);
 284                return -1;
 285        }
 286
 287        fmt = get_format_by_sig(signature);
 288        if (!fmt)
 289                BUG("bad signature '%s'", signature);
 290
 291        argv_array_push(&gpg.args, fmt->program);
 292        argv_array_pushv(&gpg.args, fmt->verify_args);
 293        argv_array_pushl(&gpg.args,
 294                         "--status-fd=1",
 295                         "--verify", temp->filename.buf, "-",
 296                         NULL);
 297
 298        if (!gpg_status)
 299                gpg_status = &buf;
 300
 301        sigchain_push(SIGPIPE, SIG_IGN);
 302        ret = pipe_command(&gpg, payload, payload_size,
 303                           gpg_status, 0, gpg_output, 0);
 304        sigchain_pop(SIGPIPE);
 305
 306        delete_tempfile(&temp);
 307
 308        ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
 309        strbuf_release(&buf); /* no matter it was used or not */
 310
 311        return ret;
 312}