3414af38b9d1b7ff8be0f3d24e9086a1059b1717
   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;
  10static const char *gpg_program = "gpg";
  11
  12#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
  13#define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
  14
  15void signature_check_clear(struct signature_check *sigc)
  16{
  17        FREE_AND_NULL(sigc->payload);
  18        FREE_AND_NULL(sigc->gpg_output);
  19        FREE_AND_NULL(sigc->gpg_status);
  20        FREE_AND_NULL(sigc->signer);
  21        FREE_AND_NULL(sigc->key);
  22}
  23
  24static struct {
  25        char result;
  26        const char *check;
  27} sigcheck_gpg_status[] = {
  28        { 'G', "\n[GNUPG:] GOODSIG " },
  29        { 'B', "\n[GNUPG:] BADSIG " },
  30        { 'U', "\n[GNUPG:] TRUST_NEVER" },
  31        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
  32        { 'E', "\n[GNUPG:] ERRSIG "},
  33        { 'X', "\n[GNUPG:] EXPSIG "},
  34        { 'Y', "\n[GNUPG:] EXPKEYSIG "},
  35        { 'R', "\n[GNUPG:] REVKEYSIG "},
  36};
  37
  38void parse_gpg_output(struct signature_check *sigc)
  39{
  40        const char *buf = sigc->gpg_status;
  41        int i;
  42
  43        /* Iterate over all search strings */
  44        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
  45                const char *found, *next;
  46
  47                if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
  48                        found = strstr(buf, sigcheck_gpg_status[i].check);
  49                        if (!found)
  50                                continue;
  51                        found += strlen(sigcheck_gpg_status[i].check);
  52                }
  53                sigc->result = sigcheck_gpg_status[i].result;
  54                /* The trust messages are not followed by key/signer information */
  55                if (sigc->result != 'U') {
  56                        sigc->key = xmemdupz(found, 16);
  57                        /* The ERRSIG message is not followed by signer information */
  58                        if (sigc-> result != 'E') {
  59                                found += 17;
  60                                next = strchrnul(found, '\n');
  61                                sigc->signer = xmemdupz(found, next - found);
  62                        }
  63                }
  64        }
  65}
  66
  67int check_signature(const char *payload, size_t plen, const char *signature,
  68        size_t slen, struct signature_check *sigc)
  69{
  70        struct strbuf gpg_output = STRBUF_INIT;
  71        struct strbuf gpg_status = STRBUF_INIT;
  72        int status;
  73
  74        sigc->result = 'N';
  75
  76        status = verify_signed_buffer(payload, plen, signature, slen,
  77                                      &gpg_output, &gpg_status);
  78        if (status && !gpg_output.len)
  79                goto out;
  80        sigc->payload = xmemdupz(payload, plen);
  81        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
  82        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
  83        parse_gpg_output(sigc);
  84
  85 out:
  86        strbuf_release(&gpg_status);
  87        strbuf_release(&gpg_output);
  88
  89        return sigc->result != 'G' && sigc->result != 'U';
  90}
  91
  92void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
  93{
  94        const char *output = flags & GPG_VERIFY_RAW ?
  95                sigc->gpg_status : sigc->gpg_output;
  96
  97        if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
  98                fputs(sigc->payload, stdout);
  99
 100        if (output)
 101                fputs(output, stderr);
 102}
 103
 104size_t parse_signature(const char *buf, size_t size)
 105{
 106        size_t len = 0;
 107        while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
 108                        !starts_with(buf + len, PGP_MESSAGE)) {
 109                const char *eol = memchr(buf + len, '\n', size - len);
 110                len += eol ? eol - (buf + len) + 1 : size - len;
 111        }
 112        return len;
 113}
 114
 115void set_signing_key(const char *key)
 116{
 117        free(configured_signing_key);
 118        configured_signing_key = xstrdup(key);
 119}
 120
 121int git_gpg_config(const char *var, const char *value, void *cb)
 122{
 123        if (!strcmp(var, "user.signingkey")) {
 124                if (!value)
 125                        return config_error_nonbool(var);
 126                set_signing_key(value);
 127                return 0;
 128        }
 129
 130        if (!strcmp(var, "gpg.program")) {
 131                if (!value)
 132                        return config_error_nonbool(var);
 133                gpg_program = xstrdup(value);
 134                return 0;
 135        }
 136
 137        return 0;
 138}
 139
 140const char *get_signing_key(void)
 141{
 142        if (configured_signing_key)
 143                return configured_signing_key;
 144        return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
 145}
 146
 147int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 148{
 149        struct child_process gpg = CHILD_PROCESS_INIT;
 150        int ret;
 151        size_t i, j, bottom;
 152        struct strbuf gpg_status = STRBUF_INIT;
 153
 154        argv_array_pushl(&gpg.args,
 155                         gpg_program,
 156                         "--status-fd=2",
 157                         "-bsau", signing_key,
 158                         NULL);
 159
 160        bottom = signature->len;
 161
 162        /*
 163         * When the username signingkey is bad, program could be terminated
 164         * because gpg exits without reading and then write gets SIGPIPE.
 165         */
 166        sigchain_push(SIGPIPE, SIG_IGN);
 167        ret = pipe_command(&gpg, buffer->buf, buffer->len,
 168                           signature, 1024, &gpg_status, 0);
 169        sigchain_pop(SIGPIPE);
 170
 171        ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
 172        strbuf_release(&gpg_status);
 173        if (ret)
 174                return error(_("gpg failed to sign the data"));
 175
 176        /* Strip CR from the line endings, in case we are on Windows. */
 177        for (i = j = bottom; i < signature->len; i++)
 178                if (signature->buf[i] != '\r') {
 179                        if (i != j)
 180                                signature->buf[j] = signature->buf[i];
 181                        j++;
 182                }
 183        strbuf_setlen(signature, j);
 184
 185        return 0;
 186}
 187
 188int verify_signed_buffer(const char *payload, size_t payload_size,
 189                         const char *signature, size_t signature_size,
 190                         struct strbuf *gpg_output, struct strbuf *gpg_status)
 191{
 192        struct child_process gpg = CHILD_PROCESS_INIT;
 193        struct tempfile *temp;
 194        int ret;
 195        struct strbuf buf = STRBUF_INIT;
 196
 197        temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
 198        if (!temp)
 199                return error_errno(_("could not create temporary file"));
 200        if (write_in_full(temp->fd, signature, signature_size) < 0 ||
 201            close_tempfile_gently(temp) < 0) {
 202                error_errno(_("failed writing detached signature to '%s'"),
 203                            temp->filename.buf);
 204                delete_tempfile(&temp);
 205                return -1;
 206        }
 207
 208        argv_array_pushl(&gpg.args,
 209                         gpg_program,
 210                         "--status-fd=1",
 211                         "--keyid-format=long",
 212                         "--verify", temp->filename.buf, "-",
 213                         NULL);
 214
 215        if (!gpg_status)
 216                gpg_status = &buf;
 217
 218        sigchain_push(SIGPIPE, SIG_IGN);
 219        ret = pipe_command(&gpg, payload, payload_size,
 220                           gpg_status, 0, gpg_output, 0);
 221        sigchain_pop(SIGPIPE);
 222
 223        delete_tempfile(&temp);
 224
 225        ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
 226        strbuf_release(&buf); /* no matter it was used or not */
 227
 228        return ret;
 229}