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#include "cache.h"
#include "run-command.h"
#include "strbuf.h"
#include "gpg-interface.h"
#include "sigchain.h"
#include "tempfile.h"
static char *configured_signing_key;
static const char *gpg_program = "gpg";
#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
#define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
void signature_check_clear(struct signature_check *sigc)
{
free(sigc->payload);
free(sigc->gpg_output);
free(sigc->gpg_status);
free(sigc->signer);
free(sigc->key);
sigc->payload = NULL;
sigc->gpg_output = NULL;
sigc->gpg_status = NULL;
sigc->signer = NULL;
sigc->key = NULL;
}
static struct {
char result;
const char *check;
} sigcheck_gpg_status[] = {
{ 'G', "\n[GNUPG:] GOODSIG " },
{ 'B', "\n[GNUPG:] BADSIG " },
{ 'U', "\n[GNUPG:] TRUST_NEVER" },
{ 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
};
void parse_gpg_output(struct signature_check *sigc)
{
const char *buf = sigc->gpg_status;
int i;
/* Iterate over all search strings */
for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
const char *found, *next;
if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
found = strstr(buf, sigcheck_gpg_status[i].check);
if (!found)
continue;
found += strlen(sigcheck_gpg_status[i].check);
}
sigc->result = sigcheck_gpg_status[i].result;
/* The trust messages are not followed by key/signer information */
if (sigc->result != 'U') {
sigc->key = xmemdupz(found, 16);
found += 17;
next = strchrnul(found, '\n');
sigc->signer = xmemdupz(found, next - found);
}
}
}
int check_signature(const char *payload, size_t plen, const char *signature,
size_t slen, struct signature_check *sigc)
{
struct strbuf gpg_output = STRBUF_INIT;
struct strbuf gpg_status = STRBUF_INIT;
int status;
sigc->result = 'N';
status = verify_signed_buffer(payload, plen, signature, slen,
&gpg_output, &gpg_status);
if (status && !gpg_output.len)
goto out;
sigc->payload = xmemdupz(payload, plen);
sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
parse_gpg_output(sigc);
out:
strbuf_release(&gpg_status);
strbuf_release(&gpg_output);
return sigc->result != 'G' && sigc->result != 'U';
}
void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
{
const char *output = flags & GPG_VERIFY_RAW ?
sigc->gpg_status : sigc->gpg_output;
if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
fputs(sigc->payload, stdout);
if (output)
fputs(output, stderr);
}
/*
* Look at GPG signed content (e.g. a signed tag object), whose
* payload is followed by a detached signature on it. Return the
* offset where the embedded detached signature begins, or the end of
* the data when there is no such signature.
*/
size_t parse_signature(const char *buf, unsigned long size)
{
char *eol;
size_t len = 0;
while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
!starts_with(buf + len, PGP_MESSAGE)) {
eol = memchr(buf + len, '\n', size - len);
len += eol ? eol - (buf + len) + 1 : size - len;
}
return len;
}
void set_signing_key(const char *key)
{
free(configured_signing_key);
configured_signing_key = xstrdup(key);
}
int git_gpg_config(const char *var, const char *value, void *cb)
{
if (!strcmp(var, "user.signingkey")) {
set_signing_key(value);
}
if (!strcmp(var, "gpg.program")) {
if (!value)
return config_error_nonbool(var);
gpg_program = xstrdup(value);
}
return 0;
}
const char *get_signing_key(void)
{
if (configured_signing_key)
return configured_signing_key;
return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
}
/*
* Create a detached signature for the contents of "buffer" and append
* it after "signature"; "buffer" and "signature" can be the same
* strbuf instance, which would cause the detached signature appended
* at the end.
*/
int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
{
struct child_process gpg = CHILD_PROCESS_INIT;
int ret;
size_t i, j, bottom;
struct strbuf gpg_status = STRBUF_INIT;
argv_array_pushl(&gpg.args,
gpg_program,
"--status-fd=2",
"-bsau", signing_key,
NULL);
bottom = signature->len;
/*
* When the username signingkey is bad, program could be terminated
* because gpg exits without reading and then write gets SIGPIPE.
*/
sigchain_push(SIGPIPE, SIG_IGN);
ret = pipe_command(&gpg, buffer->buf, buffer->len,
signature, 1024, &gpg_status, 0);
sigchain_pop(SIGPIPE);
ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
strbuf_release(&gpg_status);
if (ret)
return error(_("gpg failed to sign the data"));
/* Strip CR from the line endings, in case we are on Windows. */
for (i = j = bottom; i < signature->len; i++)
if (signature->buf[i] != '\r') {
if (i != j)
signature->buf[j] = signature->buf[i];
j++;
}
strbuf_setlen(signature, j);
return 0;
}
/*
* Run "gpg" to see if the payload matches the detached signature.
* gpg_output, when set, receives the diagnostic output from GPG.
* gpg_status, when set, receives the status output from GPG.
*/
int verify_signed_buffer(const char *payload, size_t payload_size,
const char *signature, size_t signature_size,
struct strbuf *gpg_output, struct strbuf *gpg_status)
{
struct child_process gpg = CHILD_PROCESS_INIT;
static struct tempfile temp;
int fd, ret;
struct strbuf buf = STRBUF_INIT;
fd = mks_tempfile_t(&temp, ".git_vtag_tmpXXXXXX");
if (fd < 0)
return error_errno(_("could not create temporary file"));
if (write_in_full(fd, signature, signature_size) < 0) {
error_errno(_("failed writing detached signature to '%s'"),
temp.filename.buf);
delete_tempfile(&temp);
return -1;
}
close(fd);
argv_array_pushl(&gpg.args,
gpg_program,
"--status-fd=1",
"--keyid-format=long",
"--verify", temp.filename.buf, "-",
NULL);
if (!gpg_status)
gpg_status = &buf;
sigchain_push(SIGPIPE, SIG_IGN);
ret = pipe_command(&gpg, payload, payload_size,
gpg_status, 0, gpg_output, 0);
sigchain_pop(SIGPIPE);
delete_tempfile(&temp);
ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
strbuf_release(&buf); /* no matter it was used or not */
return ret;
}
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