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 set_signing_key(const char *key)
  11{
  12        free(configured_signing_key);
  13        configured_signing_key = xstrdup(key);
  14}
  15
  16int git_gpg_config(const char *var, const char *value, void *cb)
  17{
  18        if (!strcmp(var, "user.signingkey")) {
  19                set_signing_key(value);
  20        }
  21        if (!strcmp(var, "gpg.program")) {
  22                if (!value)
  23                        return config_error_nonbool(var);
  24                gpg_program = xstrdup(value);
  25        }
  26        return 0;
  27}
  28
  29const char *get_signing_key(void)
  30{
  31        if (configured_signing_key)
  32                return configured_signing_key;
  33        return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
  34}
  35
  36/*
  37 * Create a detached signature for the contents of "buffer" and append
  38 * it after "signature"; "buffer" and "signature" can be the same
  39 * strbuf instance, which would cause the detached signature appended
  40 * at the end.
  41 */
  42int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
  43{
  44        struct child_process gpg;
  45        const char *args[4];
  46        ssize_t len;
  47        size_t i, j, bottom;
  48
  49        memset(&gpg, 0, sizeof(gpg));
  50        gpg.argv = args;
  51        gpg.in = -1;
  52        gpg.out = -1;
  53        args[0] = gpg_program;
  54        args[1] = "-bsau";
  55        args[2] = signing_key;
  56        args[3] = NULL;
  57
  58        if (start_command(&gpg))
  59                return error(_("could not run gpg."));
  60
  61        /*
  62         * When the username signingkey is bad, program could be terminated
  63         * because gpg exits without reading and then write gets SIGPIPE.
  64         */
  65        sigchain_push(SIGPIPE, SIG_IGN);
  66
  67        if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
  68                close(gpg.in);
  69                close(gpg.out);
  70                finish_command(&gpg);
  71                return error(_("gpg did not accept the data"));
  72        }
  73        close(gpg.in);
  74
  75        bottom = signature->len;
  76        len = strbuf_read(signature, gpg.out, 1024);
  77        close(gpg.out);
  78
  79        sigchain_pop(SIGPIPE);
  80
  81        if (finish_command(&gpg) || !len || len < 0)
  82                return error(_("gpg failed to sign the data"));
  83
  84        /* Strip CR from the line endings, in case we are on Windows. */
  85        for (i = j = bottom; i < signature->len; i++)
  86                if (signature->buf[i] != '\r') {
  87                        if (i != j)
  88                                signature->buf[j] = signature->buf[i];
  89                        j++;
  90                }
  91        strbuf_setlen(signature, j);
  92
  93        return 0;
  94}
  95
  96/*
  97 * Run "gpg" to see if the payload matches the detached signature.
  98 * gpg_output, when set, receives the diagnostic output from GPG.
  99 * gpg_status, when set, receives the status output from GPG.
 100 */
 101int verify_signed_buffer(const char *payload, size_t payload_size,
 102                         const char *signature, size_t signature_size,
 103                         struct strbuf *gpg_output, struct strbuf *gpg_status)
 104{
 105        struct child_process gpg;
 106        const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
 107        char path[PATH_MAX];
 108        int fd, ret;
 109        struct strbuf buf = STRBUF_INIT;
 110        struct strbuf *pbuf = &buf;
 111
 112        args_gpg[0] = gpg_program;
 113        fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
 114        if (fd < 0)
 115                return error(_("could not create temporary file '%s': %s"),
 116                             path, strerror(errno));
 117        if (write_in_full(fd, signature, signature_size) < 0)
 118                return error(_("failed writing detached signature to '%s': %s"),
 119                             path, strerror(errno));
 120        close(fd);
 121
 122        memset(&gpg, 0, sizeof(gpg));
 123        gpg.argv = args_gpg;
 124        gpg.in = -1;
 125        gpg.out = -1;
 126        if (gpg_output)
 127                gpg.err = -1;
 128        args_gpg[3] = path;
 129        if (start_command(&gpg)) {
 130                unlink(path);
 131                return error(_("could not run gpg."));
 132        }
 133
 134        write_in_full(gpg.in, payload, payload_size);
 135        close(gpg.in);
 136
 137        if (gpg_output) {
 138                strbuf_read(gpg_output, gpg.err, 0);
 139                close(gpg.err);
 140        }
 141        if (gpg_status)
 142                pbuf = gpg_status;
 143        strbuf_read(pbuf, gpg.out, 0);
 144        close(gpg.out);
 145
 146        ret = finish_command(&gpg);
 147
 148        unlink_or_warn(path);
 149
 150        ret |= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
 151        strbuf_release(&buf); /* no matter it was used or not */
 152
 153        return ret;
 154}