git.oblomov.eu Git - git/blob - gpg-interface.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3 #include "strbuf.h"
   4 #include "gpg-interface.h"
   5 #include "sigchain.h"
   6
   7 static char *configured_signing_key;
   8 static const char *gpg_program = "gpg";
   9
  10 void signature_check_clear(struct signature_check *sigc)
  11 {
  12         free(sigc->payload);
  13         free(sigc->gpg_output);
  14         free(sigc->gpg_status);
  15         free(sigc->signer);
  16         free(sigc->key);
  17         sigc->payload = NULL;
  18         sigc->gpg_output = NULL;
  19         sigc->gpg_status = NULL;
  20         sigc->signer = NULL;
  21         sigc->key = NULL;
  22 }
  23
  24 static 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 };
  33
  34 void parse_gpg_output(struct signature_check *sigc)
  35 {
  36         const char *buf = sigc->gpg_status;
  37         int i;
  38
  39         /* Iterate over all search strings */
  40         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
  41                 const char *found, *next;
  42
  43                 if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
  44                         found = strstr(buf, sigcheck_gpg_status[i].check);
  45                         if (!found)
  46                                 continue;
  47                         found += strlen(sigcheck_gpg_status[i].check);
  48                 }
  49                 sigc->result = sigcheck_gpg_status[i].result;
  50                 /* The trust messages are not followed by key/signer information */
  51                 if (sigc->result != 'U') {
  52                         sigc->key = xmemdupz(found, 16);
  53                         found += 17;
  54                         next = strchrnul(found, '\n');
  55                         sigc->signer = xmemdupz(found, next - found);
  56                 }
  57         }
  58 }
  59
  60 void set_signing_key(const char *key)
  61 {
  62         free(configured_signing_key);
  63         configured_signing_key = xstrdup(key);
  64 }
  65
  66 int git_gpg_config(const char *var, const char *value, void *cb)
  67 {
  68         if (!strcmp(var, "user.signingkey")) {
  69                 set_signing_key(value);
  70         }
  71         if (!strcmp(var, "gpg.program")) {
  72                 if (!value)
  73                         return config_error_nonbool(var);
  74                 gpg_program = xstrdup(value);
  75         }
  76         return 0;
  77 }
  78
  79 const char *get_signing_key(void)
  80 {
  81         if (configured_signing_key)
  82                 return configured_signing_key;
  83         return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
  84 }
  85
  86 /*
  87  * Create a detached signature for the contents of "buffer" and append
  88  * it after "signature"; "buffer" and "signature" can be the same
  89  * strbuf instance, which would cause the detached signature appended
  90  * at the end.
  91  */
  92 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
  93 {
  94         struct child_process gpg;
  95         const char *args[4];
  96         ssize_t len;
  97         size_t i, j, bottom;
  98
  99         memset(&gpg, 0, sizeof(gpg));
 100         gpg.argv = args;
 101         gpg.in = -1;
 102         gpg.out = -1;
 103         args[0] = gpg_program;
 104         args[1] = "-bsau";
 105         args[2] = signing_key;
 106         args[3] = NULL;
 107
 108         if (start_command(&gpg))
 109                 return error(_("could not run gpg."));
 110
 111         /*
 112          * When the username signingkey is bad, program could be terminated
 113          * because gpg exits without reading and then write gets SIGPIPE.
 114          */
 115         sigchain_push(SIGPIPE, SIG_IGN);
 116
 117         if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
 118                 close(gpg.in);
 119                 close(gpg.out);
 120                 finish_command(&gpg);
 121                 return error(_("gpg did not accept the data"));
 122         }
 123         close(gpg.in);
 124
 125         bottom = signature->len;
 126         len = strbuf_read(signature, gpg.out, 1024);
 127         close(gpg.out);
 128
 129         sigchain_pop(SIGPIPE);
 130
 131         if (finish_command(&gpg) || !len || len < 0)
 132                 return error(_("gpg failed to sign the data"));
 133
 134         /* Strip CR from the line endings, in case we are on Windows. */
 135         for (i = j = bottom; i < signature->len; i++)
 136                 if (signature->buf[i] != '\r') {
 137                         if (i != j)
 138                                 signature->buf[j] = signature->buf[i];
 139                         j++;
 140                 }
 141         strbuf_setlen(signature, j);
 142
 143         return 0;
 144 }
 145
 146 /*
 147  * Run "gpg" to see if the payload matches the detached signature.
 148  * gpg_output, when set, receives the diagnostic output from GPG.
 149  * gpg_status, when set, receives the status output from GPG.
 150  */
 151 int verify_signed_buffer(const char *payload, size_t payload_size,
 152                          const char *signature, size_t signature_size,
 153                          struct strbuf *gpg_output, struct strbuf *gpg_status)
 154 {
 155         struct child_process gpg;
 156         const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
 157         char path[PATH_MAX];
 158         int fd, ret;
 159         struct strbuf buf = STRBUF_INIT;
 160         struct strbuf *pbuf = &buf;
 161
 162         args_gpg[0] = gpg_program;
 163         fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
 164         if (fd < 0)
 165                 return error(_("could not create temporary file '%s': %s"),
 166                              path, strerror(errno));
 167         if (write_in_full(fd, signature, signature_size) < 0)
 168                 return error(_("failed writing detached signature to '%s': %s"),
 169                              path, strerror(errno));
 170         close(fd);
 171
 172         memset(&gpg, 0, sizeof(gpg));
 173         gpg.argv = args_gpg;
 174         gpg.in = -1;
 175         gpg.out = -1;
 176         if (gpg_output)
 177                 gpg.err = -1;
 178         args_gpg[3] = path;
 179         if (start_command(&gpg)) {
 180                 unlink(path);
 181                 return error(_("could not run gpg."));
 182         }
 183
 184         write_in_full(gpg.in, payload, payload_size);
 185         close(gpg.in);
 186
 187         if (gpg_output) {
 188                 strbuf_read(gpg_output, gpg.err, 0);
 189                 close(gpg.err);
 190         }
 191         if (gpg_status)
 192                 pbuf = gpg_status;
 193         strbuf_read(pbuf, gpg.out, 0);
 194         close(gpg.out);
 195
 196         ret = finish_command(&gpg);
 197
 198         unlink_or_warn(path);
 199
 200         ret |= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
 201         strbuf_release(&buf); /* no matter it was used or not */
 202
 203         return ret;
 204 }