Andrew's git - gitweb.git/blob

a02db765807dfdcd14054b3641040e0e77256516
   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 struct gpg_format gpg_format[] = {
  28        { .name = "openpgp", .program = "gpg",
  29          .verify_args = openpgp_verify_args,
  30          .sigs = openpgp_sigs
  31        },
  32};
  33
  34static struct gpg_format *use_format = &gpg_format[0];
  35
  36static struct gpg_format *get_format_by_name(const char *str)
  37{
  38        int i;
  39
  40        for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
  41                if (!strcmp(gpg_format[i].name, str))
  42                        return gpg_format + i;
  43        return NULL;
  44}
  45
  46static struct gpg_format *get_format_by_sig(const char *sig)
  47{
  48        int i, j;
  49
  50        for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
  51                for (j = 0; gpg_format[i].sigs[j]; j++)
  52                        if (starts_with(sig, gpg_format[i].sigs[j]))
  53                                return gpg_format + i;
  54        return NULL;
  55}
  56
  57void signature_check_clear(struct signature_check *sigc)
  58{
  59        FREE_AND_NULL(sigc->payload);
  60        FREE_AND_NULL(sigc->gpg_output);
  61        FREE_AND_NULL(sigc->gpg_status);
  62        FREE_AND_NULL(sigc->signer);
  63        FREE_AND_NULL(sigc->key);
  64}
  65
  66static struct {
  67        char result;
  68        const char *check;
  69} sigcheck_gpg_status[] = {
  70        { 'G', "\n[GNUPG:] GOODSIG " },
  71        { 'B', "\n[GNUPG:] BADSIG " },
  72        { 'U', "\n[GNUPG:] TRUST_NEVER" },
  73        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
  74        { 'E', "\n[GNUPG:] ERRSIG "},
  75        { 'X', "\n[GNUPG:] EXPSIG "},
  76        { 'Y', "\n[GNUPG:] EXPKEYSIG "},
  77        { 'R', "\n[GNUPG:] REVKEYSIG "},
  78};
  79
  80static void parse_gpg_output(struct signature_check *sigc)
  81{
  82        const char *buf = sigc->gpg_status;
  83        int i;
  84
  85        /* Iterate over all search strings */
  86        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
  87                const char *found, *next;
  88
  89                if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
  90                        found = strstr(buf, sigcheck_gpg_status[i].check);
  91                        if (!found)
  92                                continue;
  93                        found += strlen(sigcheck_gpg_status[i].check);
  94                }
  95                sigc->result = sigcheck_gpg_status[i].result;
  96                /* The trust messages are not followed by key/signer information */
  97                if (sigc->result != 'U') {
  98                        sigc->key = xmemdupz(found, 16);
  99                        /* The ERRSIG message is not followed by signer information */
 100                        if (sigc-> result != 'E') {
 101                                found += 17;
 102                                next = strchrnul(found, '\n');
 103                                sigc->signer = xmemdupz(found, next - found);
 104                        }
 105                }
 106        }
 107}
 108
 109int check_signature(const char *payload, size_t plen, const char *signature,
 110        size_t slen, struct signature_check *sigc)
 111{
 112        struct strbuf gpg_output = STRBUF_INIT;
 113        struct strbuf gpg_status = STRBUF_INIT;
 114        int status;
 115
 116        sigc->result = 'N';
 117
 118        status = verify_signed_buffer(payload, plen, signature, slen,
 119                                      &gpg_output, &gpg_status);
 120        if (status && !gpg_output.len)
 121                goto out;
 122        sigc->payload = xmemdupz(payload, plen);
 123        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
 124        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
 125        parse_gpg_output(sigc);
 126
 127 out:
 128        strbuf_release(&gpg_status);
 129        strbuf_release(&gpg_output);
 130
 131        return sigc->result != 'G' && sigc->result != 'U';
 132}
 133
 134void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
 135{
 136        const char *output = flags & GPG_VERIFY_RAW ?
 137                sigc->gpg_status : sigc->gpg_output;
 138
 139        if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
 140                fputs(sigc->payload, stdout);
 141
 142        if (output)
 143                fputs(output, stderr);
 144}
 145
 146size_t parse_signature(const char *buf, size_t size)
 147{
 148        size_t len = 0;
 149        size_t match = size;
 150        while (len < size) {
 151                const char *eol;
 152
 153                if (get_format_by_sig(buf + len))
 154                        match = len;
 155
 156                eol = memchr(buf + len, '\n', size - len);
 157                len += eol ? eol - (buf + len) + 1 : size - len;
 158        }
 159        return match;
 160}
 161
 162void set_signing_key(const char *key)
 163{
 164        free(configured_signing_key);
 165        configured_signing_key = xstrdup(key);
 166}
 167
 168int git_gpg_config(const char *var, const char *value, void *cb)
 169{
 170        struct gpg_format *fmt = NULL;
 171        char *fmtname = NULL;
 172
 173        if (!strcmp(var, "user.signingkey")) {
 174                if (!value)
 175                        return config_error_nonbool(var);
 176                set_signing_key(value);
 177                return 0;
 178        }
 179
 180        if (!strcmp(var, "gpg.format")) {
 181                if (!value)
 182                        return config_error_nonbool(var);
 183                fmt = get_format_by_name(value);
 184                if (!fmt)
 185                        return error("unsupported value for %s: %s",
 186                                     var, value);
 187                use_format = fmt;
 188                return 0;
 189        }
 190
 191        if (!strcmp(var, "gpg.program"))
 192                fmtname = "openpgp";
 193
 194        if (fmtname) {
 195                fmt = get_format_by_name(fmtname);
 196                return git_config_string(&fmt->program, var, value);
 197        }
 198
 199        return 0;
 200}
 201
 202const char *get_signing_key(void)
 203{
 204        if (configured_signing_key)
 205                return configured_signing_key;
 206        return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
 207}
 208
 209int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 210{
 211        struct child_process gpg = CHILD_PROCESS_INIT;
 212        int ret;
 213        size_t i, j, bottom;
 214        struct strbuf gpg_status = STRBUF_INIT;
 215
 216        argv_array_pushl(&gpg.args,
 217                         use_format->program,
 218                         "--status-fd=2",
 219                         "-bsau", signing_key,
 220                         NULL);
 221
 222        bottom = signature->len;
 223
 224        /*
 225         * When the username signingkey is bad, program could be terminated
 226         * because gpg exits without reading and then write gets SIGPIPE.
 227         */
 228        sigchain_push(SIGPIPE, SIG_IGN);
 229        ret = pipe_command(&gpg, buffer->buf, buffer->len,
 230                           signature, 1024, &gpg_status, 0);
 231        sigchain_pop(SIGPIPE);
 232
 233        ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
 234        strbuf_release(&gpg_status);
 235        if (ret)
 236                return error(_("gpg failed to sign the data"));
 237
 238        /* Strip CR from the line endings, in case we are on Windows. */
 239        for (i = j = bottom; i < signature->len; i++)
 240                if (signature->buf[i] != '\r') {
 241                        if (i != j)
 242                                signature->buf[j] = signature->buf[i];
 243                        j++;
 244                }
 245        strbuf_setlen(signature, j);
 246
 247        return 0;
 248}
 249
 250int verify_signed_buffer(const char *payload, size_t payload_size,
 251                         const char *signature, size_t signature_size,
 252                         struct strbuf *gpg_output, struct strbuf *gpg_status)
 253{
 254        struct child_process gpg = CHILD_PROCESS_INIT;
 255        struct gpg_format *fmt;
 256        struct tempfile *temp;
 257        int ret;
 258        struct strbuf buf = STRBUF_INIT;
 259
 260        temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
 261        if (!temp)
 262                return error_errno(_("could not create temporary file"));
 263        if (write_in_full(temp->fd, signature, signature_size) < 0 ||
 264            close_tempfile_gently(temp) < 0) {
 265                error_errno(_("failed writing detached signature to '%s'"),
 266                            temp->filename.buf);
 267                delete_tempfile(&temp);
 268                return -1;
 269        }
 270
 271        fmt = get_format_by_sig(signature);
 272        if (!fmt)
 273                BUG("bad signature '%s'", signature);
 274
 275        argv_array_push(&gpg.args, fmt->program);
 276        argv_array_pushv(&gpg.args, fmt->verify_args);
 277        argv_array_pushl(&gpg.args,
 278                         "--status-fd=1",
 279                         "--verify", temp->filename.buf, "-",
 280                         NULL);
 281
 282        if (!gpg_status)
 283                gpg_status = &buf;
 284
 285        sigchain_push(SIGPIPE, SIG_IGN);
 286        ret = pipe_command(&gpg, payload, payload_size,
 287                           gpg_status, 0, gpg_output, 0);
 288        sigchain_pop(SIGPIPE);
 289
 290        delete_tempfile(&temp);
 291
 292        ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
 293        strbuf_release(&buf); /* no matter it was used or not */
 294
 295        return ret;
 296}