git/gpg-interface.c
Junio C Hamano af2b21ec3c Merge branch 'lt/gpg-show-long-key-in-signature-verification-maint' into lt/gpg-show-long-key-in-signature-verification
Linus's original was rebased to apply to the maintenance track just
in case binary distributors that are stuck in the past want to take
it to their older codebase.  Let's merge it up to more modern
codebase that has Peff's gpg-interface clean-up topic that appeared
after Git 2.9 was tagged.

* lt/gpg-show-long-key-in-signature-verification-maint:
  gpg-interface: prefer "long" key format output when verifying pgp signatures
2016-08-16 15:04:13 -07:00

239 lines
6.1 KiB
C

#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;
}