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        status |= sigc->result != 'G' && sigc->result != 'U';
 140
 141 out:
 142        strbuf_release(&gpg_status);
 143        strbuf_release(&gpg_output);
 144
 145        return !!status;
 146}
 147
 148void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
 149{
 150        const char *output = flags & GPG_VERIFY_RAW ?
 151                sigc->gpg_status : sigc->gpg_output;
 152
 153        if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
 154                fputs(sigc->payload, stdout);
 155
 156        if (output)
 157                fputs(output, stderr);
 158}
 159
 160size_t parse_signature(const char *buf, size_t size)
 161{
 162        size_t len = 0;
 163        size_t match = size;
 164        while (len < size) {
 165                const char *eol;
 166
 167                if (get_format_by_sig(buf + len))
 168                        match = len;
 169
 170                eol = memchr(buf + len, '\n', size - len);
 171                len += eol ? eol - (buf + len) + 1 : size - len;
 172        }
 173        return match;
 174}
 175
 176void set_signing_key(const char *key)
 177{
 178        free(configured_signing_key);
 179        configured_signing_key = xstrdup(key);
 180}
 181
 182int git_gpg_config(const char *var, const char *value, void *cb)
 183{
 184        struct gpg_format *fmt = NULL;
 185        char *fmtname = NULL;
 186
 187        if (!strcmp(var, "user.signingkey")) {
 188                if (!value)
 189                        return config_error_nonbool(var);
 190                set_signing_key(value);
 191                return 0;
 192        }
 193
 194        if (!strcmp(var, "gpg.format")) {
 195                if (!value)
 196                        return config_error_nonbool(var);
 197                fmt = get_format_by_name(value);
 198                if (!fmt)
 199                        return error("unsupported value for %s: %s",
 200                                     var, value);
 201                use_format = fmt;
 202                return 0;
 203        }
 204
 205        if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
 206                fmtname = "openpgp";
 207
 208        if (!strcmp(var, "gpg.x509.program"))
 209                fmtname = "x509";
 210
 211        if (fmtname) {
 212                fmt = get_format_by_name(fmtname);
 213                return git_config_string(&fmt->program, var, value);
 214        }
 215
 216        return 0;
 217}
 218
 219const char *get_signing_key(void)
 220{
 221        if (configured_signing_key)
 222                return configured_signing_key;
 223        return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
 224}
 225
 226int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 227{
 228        struct child_process gpg = CHILD_PROCESS_INIT;
 229        int ret;
 230        size_t i, j, bottom;
 231        struct strbuf gpg_status = STRBUF_INIT;
 232
 233        argv_array_pushl(&gpg.args,
 234                         use_format->program,
 235                         "--status-fd=2",
 236                         "-bsau", signing_key,
 237                         NULL);
 238
 239        bottom = signature->len;
 240
 241        /*
 242         * When the username signingkey is bad, program could be terminated
 243         * because gpg exits without reading and then write gets SIGPIPE.
 244         */
 245        sigchain_push(SIGPIPE, SIG_IGN);
 246        ret = pipe_command(&gpg, buffer->buf, buffer->len,
 247                           signature, 1024, &gpg_status, 0);
 248        sigchain_pop(SIGPIPE);
 249
 250        ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
 251        strbuf_release(&gpg_status);
 252        if (ret)
 253                return error(_("gpg failed to sign the data"));
 254
 255        /* Strip CR from the line endings, in case we are on Windows. */
 256        for (i = j = bottom; i < signature->len; i++)
 257                if (signature->buf[i] != '\r') {
 258                        if (i != j)
 259                                signature->buf[j] = signature->buf[i];
 260                        j++;
 261                }
 262        strbuf_setlen(signature, j);
 263
 264        return 0;
 265}
 266
 267int verify_signed_buffer(const char *payload, size_t payload_size,
 268                         const char *signature, size_t signature_size,
 269                         struct strbuf *gpg_output, struct strbuf *gpg_status)
 270{
 271        struct child_process gpg = CHILD_PROCESS_INIT;
 272        struct gpg_format *fmt;
 273        struct tempfile *temp;
 274        int ret;
 275        struct strbuf buf = STRBUF_INIT;
 276
 277        temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
 278        if (!temp)
 279                return error_errno(_("could not create temporary file"));
 280        if (write_in_full(temp->fd, signature, signature_size) < 0 ||
 281            close_tempfile_gently(temp) < 0) {
 282                error_errno(_("failed writing detached signature to '%s'"),
 283                            temp->filename.buf);
 284                delete_tempfile(&temp);
 285                return -1;
 286        }
 287
 288        fmt = get_format_by_sig(signature);
 289        if (!fmt)
 290                BUG("bad signature '%s'", signature);
 291
 292        argv_array_push(&gpg.args, fmt->program);
 293        argv_array_pushv(&gpg.args, fmt->verify_args);
 294        argv_array_pushl(&gpg.args,
 295                         "--status-fd=1",
 296                         "--verify", temp->filename.buf, "-",
 297                         NULL);
 298
 299        if (!gpg_status)
 300                gpg_status = &buf;
 301
 302        sigchain_push(SIGPIPE, SIG_IGN);
 303        ret = pipe_command(&gpg, payload, payload_size,
 304                           gpg_status, 0, gpg_output, 0);
 305        sigchain_pop(SIGPIPE);
 306
 307        delete_tempfile(&temp);
 308
 309        ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
 310        strbuf_release(&buf); /* no matter it was used or not */
 311
 312        return ret;
 313}