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 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                        next = strchrnul(found, ' ');
  99                        sigc->key = xmemdupz(found, next - found);
 100                        /* The ERRSIG message is not followed by signer information */
 101                        if (*next && sigc-> result != 'E') {
 102                                found = next + 1;
 103                                next = strchrnul(found, '\n');
 104                                sigc->signer = xmemdupz(found, next - found);
 105                        }
 106                }
 107        }
 108}
 109
 110int check_signature(const char *payload, size_t plen, const char *signature,
 111        size_t slen, struct signature_check *sigc)
 112{
 113        struct strbuf gpg_output = STRBUF_INIT;
 114        struct strbuf gpg_status = STRBUF_INIT;
 115        int status;
 116
 117        sigc->result = 'N';
 118
 119        status = verify_signed_buffer(payload, plen, signature, slen,
 120                                      &gpg_output, &gpg_status);
 121        if (status && !gpg_output.len)
 122                goto out;
 123        sigc->payload = xmemdupz(payload, plen);
 124        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
 125        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
 126        parse_gpg_output(sigc);
 127
 128 out:
 129        strbuf_release(&gpg_status);
 130        strbuf_release(&gpg_output);
 131
 132        return sigc->result != 'G' && sigc->result != 'U';
 133}
 134
 135void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
 136{
 137        const char *output = flags & GPG_VERIFY_RAW ?
 138                sigc->gpg_status : sigc->gpg_output;
 139
 140        if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
 141                fputs(sigc->payload, stdout);
 142
 143        if (output)
 144                fputs(output, stderr);
 145}
 146
 147size_t parse_signature(const char *buf, size_t size)
 148{
 149        size_t len = 0;
 150        size_t match = size;
 151        while (len < size) {
 152                const char *eol;
 153
 154                if (get_format_by_sig(buf + len))
 155                        match = len;
 156
 157                eol = memchr(buf + len, '\n', size - len);
 158                len += eol ? eol - (buf + len) + 1 : size - len;
 159        }
 160        return match;
 161}
 162
 163void set_signing_key(const char *key)
 164{
 165        free(configured_signing_key);
 166        configured_signing_key = xstrdup(key);
 167}
 168
 169int git_gpg_config(const char *var, const char *value, void *cb)
 170{
 171        struct gpg_format *fmt = NULL;
 172        char *fmtname = NULL;
 173
 174        if (!strcmp(var, "user.signingkey")) {
 175                if (!value)
 176                        return config_error_nonbool(var);
 177                set_signing_key(value);
 178                return 0;
 179        }
 180
 181        if (!strcmp(var, "gpg.format")) {
 182                if (!value)
 183                        return config_error_nonbool(var);
 184                fmt = get_format_by_name(value);
 185                if (!fmt)
 186                        return error("unsupported value for %s: %s",
 187                                     var, value);
 188                use_format = fmt;
 189                return 0;
 190        }
 191
 192        if (!strcmp(var, "gpg.program"))
 193                fmtname = "openpgp";
 194
 195        if (fmtname) {
 196                fmt = get_format_by_name(fmtname);
 197                return git_config_string(&fmt->program, var, value);
 198        }
 199
 200        return 0;
 201}
 202
 203const char *get_signing_key(void)
 204{
 205        if (configured_signing_key)
 206                return configured_signing_key;
 207        return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
 208}
 209
 210int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 211{
 212        struct child_process gpg = CHILD_PROCESS_INIT;
 213        int ret;
 214        size_t i, j, bottom;
 215        struct strbuf gpg_status = STRBUF_INIT;
 216
 217        argv_array_pushl(&gpg.args,
 218                         use_format->program,
 219                         "--status-fd=2",
 220                         "-bsau", signing_key,
 221                         NULL);
 222
 223        bottom = signature->len;
 224
 225        /*
 226         * When the username signingkey is bad, program could be terminated
 227         * because gpg exits without reading and then write gets SIGPIPE.
 228         */
 229        sigchain_push(SIGPIPE, SIG_IGN);
 230        ret = pipe_command(&gpg, buffer->buf, buffer->len,
 231                           signature, 1024, &gpg_status, 0);
 232        sigchain_pop(SIGPIPE);
 233
 234        ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
 235        strbuf_release(&gpg_status);
 236        if (ret)
 237                return error(_("gpg failed to sign the data"));
 238
 239        /* Strip CR from the line endings, in case we are on Windows. */
 240        for (i = j = bottom; i < signature->len; i++)
 241                if (signature->buf[i] != '\r') {
 242                        if (i != j)
 243                                signature->buf[j] = signature->buf[i];
 244                        j++;
 245                }
 246        strbuf_setlen(signature, j);
 247
 248        return 0;
 249}
 250
 251int verify_signed_buffer(const char *payload, size_t payload_size,
 252                         const char *signature, size_t signature_size,
 253                         struct strbuf *gpg_output, struct strbuf *gpg_status)
 254{
 255        struct child_process gpg = CHILD_PROCESS_INIT;
 256        struct gpg_format *fmt;
 257        struct tempfile *temp;
 258        int ret;
 259        struct strbuf buf = STRBUF_INIT;
 260
 261        temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
 262        if (!temp)
 263                return error_errno(_("could not create temporary file"));
 264        if (write_in_full(temp->fd, signature, signature_size) < 0 ||
 265            close_tempfile_gently(temp) < 0) {
 266                error_errno(_("failed writing detached signature to '%s'"),
 267                            temp->filename.buf);
 268                delete_tempfile(&temp);
 269                return -1;
 270        }
 271
 272        fmt = get_format_by_sig(signature);
 273        if (!fmt)
 274                BUG("bad signature '%s'", signature);
 275
 276        argv_array_push(&gpg.args, fmt->program);
 277        argv_array_pushv(&gpg.args, fmt->verify_args);
 278        argv_array_pushl(&gpg.args,
 279                         "--status-fd=1",
 280                         "--verify", temp->filename.buf, "-",
 281                         NULL);
 282
 283        if (!gpg_status)
 284                gpg_status = &buf;
 285
 286        sigchain_push(SIGPIPE, SIG_IGN);
 287        ret = pipe_command(&gpg, payload, payload_size,
 288                           gpg_status, 0, gpg_output, 0);
 289        sigchain_pop(SIGPIPE);
 290
 291        delete_tempfile(&temp);
 292
 293        ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
 294        strbuf_release(&buf); /* no matter it was used or not */
 295
 296        return ret;
 297}