Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "run-command.h"
   3#include "strbuf.h"
   4#include "gpg-interface.h"
   5#include "sigchain.h"
   6
   7static char *configured_signing_key;
   8static const char *gpg_program = "gpg";
   9
  10void 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
  24void set_signing_key(const char *key)
  25{
  26        free(configured_signing_key);
  27        configured_signing_key = xstrdup(key);
  28}
  29
  30int git_gpg_config(const char *var, const char *value, void *cb)
  31{
  32        if (!strcmp(var, "user.signingkey")) {
  33                set_signing_key(value);
  34        }
  35        if (!strcmp(var, "gpg.program")) {
  36                if (!value)
  37                        return config_error_nonbool(var);
  38                gpg_program = xstrdup(value);
  39        }
  40        return 0;
  41}
  42
  43const char *get_signing_key(void)
  44{
  45        if (configured_signing_key)
  46                return configured_signing_key;
  47        return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
  48}
  49
  50/*
  51 * Create a detached signature for the contents of "buffer" and append
  52 * it after "signature"; "buffer" and "signature" can be the same
  53 * strbuf instance, which would cause the detached signature appended
  54 * at the end.
  55 */
  56int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
  57{
  58        struct child_process gpg;
  59        const char *args[4];
  60        ssize_t len;
  61        size_t i, j, bottom;
  62
  63        memset(&gpg, 0, sizeof(gpg));
  64        gpg.argv = args;
  65        gpg.in = -1;
  66        gpg.out = -1;
  67        args[0] = gpg_program;
  68        args[1] = "-bsau";
  69        args[2] = signing_key;
  70        args[3] = NULL;
  71
  72        if (start_command(&gpg))
  73                return error(_("could not run gpg."));
  74
  75        /*
  76         * When the username signingkey is bad, program could be terminated
  77         * because gpg exits without reading and then write gets SIGPIPE.
  78         */
  79        sigchain_push(SIGPIPE, SIG_IGN);
  80
  81        if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
  82                close(gpg.in);
  83                close(gpg.out);
  84                finish_command(&gpg);
  85                return error(_("gpg did not accept the data"));
  86        }
  87        close(gpg.in);
  88
  89        bottom = signature->len;
  90        len = strbuf_read(signature, gpg.out, 1024);
  91        close(gpg.out);
  92
  93        sigchain_pop(SIGPIPE);
  94
  95        if (finish_command(&gpg) || !len || len < 0)
  96                return error(_("gpg failed to sign the data"));
  97
  98        /* Strip CR from the line endings, in case we are on Windows. */
  99        for (i = j = bottom; i < signature->len; i++)
 100                if (signature->buf[i] != '\r') {
 101                        if (i != j)
 102                                signature->buf[j] = signature->buf[i];
 103                        j++;
 104                }
 105        strbuf_setlen(signature, j);
 106
 107        return 0;
 108}
 109
 110/*
 111 * Run "gpg" to see if the payload matches the detached signature.
 112 * gpg_output, when set, receives the diagnostic output from GPG.
 113 * gpg_status, when set, receives the status output from GPG.
 114 */
 115int verify_signed_buffer(const char *payload, size_t payload_size,
 116                         const char *signature, size_t signature_size,
 117                         struct strbuf *gpg_output, struct strbuf *gpg_status)
 118{
 119        struct child_process gpg;
 120        const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
 121        char path[PATH_MAX];
 122        int fd, ret;
 123        struct strbuf buf = STRBUF_INIT;
 124        struct strbuf *pbuf = &buf;
 125
 126        args_gpg[0] = gpg_program;
 127        fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
 128        if (fd < 0)
 129                return error(_("could not create temporary file '%s': %s"),
 130                             path, strerror(errno));
 131        if (write_in_full(fd, signature, signature_size) < 0)
 132                return error(_("failed writing detached signature to '%s': %s"),
 133                             path, strerror(errno));
 134        close(fd);
 135
 136        memset(&gpg, 0, sizeof(gpg));
 137        gpg.argv = args_gpg;
 138        gpg.in = -1;
 139        gpg.out = -1;
 140        if (gpg_output)
 141                gpg.err = -1;
 142        args_gpg[3] = path;
 143        if (start_command(&gpg)) {
 144                unlink(path);
 145                return error(_("could not run gpg."));
 146        }
 147
 148        write_in_full(gpg.in, payload, payload_size);
 149        close(gpg.in);
 150
 151        if (gpg_output) {
 152                strbuf_read(gpg_output, gpg.err, 0);
 153                close(gpg.err);
 154        }
 155        if (gpg_status)
 156                pbuf = gpg_status;
 157        strbuf_read(pbuf, gpg.out, 0);
 158        close(gpg.out);
 159
 160        ret = finish_command(&gpg);
 161
 162        unlink_or_warn(path);
 163
 164        ret |= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
 165        strbuf_release(&buf); /* no matter it was used or not */
 166
 167        return ret;
 168}