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#include "cache.h"
#include "commit.h"
#include "config.h"
#include "run-command.h"
#include "strbuf.h"
#include "gpg-interface.h"
#include "sigchain.h"
#include "tempfile.h"
static char *configured_signing_key;
static enum signature_trust_level configured_min_trust_level = TRUST_UNDEFINED;
struct gpg_format {
const char *name;
const char *program;
const char **verify_args;
const char **sigs;
};
static const char *openpgp_verify_args[] = {
"--keyid-format=long",
NULL
};
static const char *openpgp_sigs[] = {
"-----BEGIN PGP SIGNATURE-----",
"-----BEGIN PGP MESSAGE-----",
NULL
};
static const char *x509_verify_args[] = {
NULL
};
static const char *x509_sigs[] = {
"-----BEGIN SIGNED MESSAGE-----",
NULL
};
static struct gpg_format gpg_format[] = {
{ .name = "openpgp", .program = "gpg",
.verify_args = openpgp_verify_args,
.sigs = openpgp_sigs
},
{ .name = "x509", .program = "gpgsm",
.verify_args = x509_verify_args,
.sigs = x509_sigs
},
};
static struct gpg_format *use_format = &gpg_format[0];
static struct gpg_format *get_format_by_name(const char *str)
{
int i;
for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
if (!strcmp(gpg_format[i].name, str))
return gpg_format + i;
return NULL;
}
static struct gpg_format *get_format_by_sig(const char *sig)
{
int i, j;
for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
for (j = 0; gpg_format[i].sigs[j]; j++)
if (starts_with(sig, gpg_format[i].sigs[j]))
return gpg_format + i;
return NULL;
}
void signature_check_clear(struct signature_check *sigc)
{
FREE_AND_NULL(sigc->payload);
FREE_AND_NULL(sigc->gpg_output);
FREE_AND_NULL(sigc->gpg_status);
FREE_AND_NULL(sigc->signer);
FREE_AND_NULL(sigc->key);
FREE_AND_NULL(sigc->fingerprint);
FREE_AND_NULL(sigc->primary_key_fingerprint);
}
/* An exclusive status -- only one of them can appear in output */
#define GPG_STATUS_EXCLUSIVE (1<<0)
/* The status includes key identifier */
#define GPG_STATUS_KEYID (1<<1)
/* The status includes user identifier */
#define GPG_STATUS_UID (1<<2)
/* The status includes key fingerprints */
#define GPG_STATUS_FINGERPRINT (1<<3)
/* The status includes trust level */
#define GPG_STATUS_TRUST_LEVEL (1<<4)
/* Short-hand for standard exclusive *SIG status with keyid & UID */
#define GPG_STATUS_STDSIG (GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID|GPG_STATUS_UID)
static struct {
char result;
const char *check;
unsigned int flags;
} sigcheck_gpg_status[] = {
{ 'G', "GOODSIG ", GPG_STATUS_STDSIG },
{ 'B', "BADSIG ", GPG_STATUS_STDSIG },
{ 'E', "ERRSIG ", GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID },
{ 'X', "EXPSIG ", GPG_STATUS_STDSIG },
{ 'Y', "EXPKEYSIG ", GPG_STATUS_STDSIG },
{ 'R', "REVKEYSIG ", GPG_STATUS_STDSIG },
{ 0, "VALIDSIG ", GPG_STATUS_FINGERPRINT },
{ 0, "TRUST_", GPG_STATUS_TRUST_LEVEL },
};
static struct {
const char *key;
enum signature_trust_level value;
} sigcheck_gpg_trust_level[] = {
{ "UNDEFINED", TRUST_UNDEFINED },
{ "NEVER", TRUST_NEVER },
{ "MARGINAL", TRUST_MARGINAL },
{ "FULLY", TRUST_FULLY },
{ "ULTIMATE", TRUST_ULTIMATE },
};
static void replace_cstring(char **field, const char *line, const char *next)
{
free(*field);
if (line && next)
*field = xmemdupz(line, next - line);
else
*field = NULL;
}
static int parse_gpg_trust_level(const char *level,
enum signature_trust_level *res)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_trust_level); i++) {
if (!strcmp(sigcheck_gpg_trust_level[i].key, level)) {
*res = sigcheck_gpg_trust_level[i].value;
return 0;
}
}
return 1;
}
static void parse_gpg_output(struct signature_check *sigc)
{
const char *buf = sigc->gpg_status;
const char *line, *next;
int i, j;
int seen_exclusive_status = 0;
/* Iterate over all lines */
for (line = buf; *line; line = strchrnul(line+1, '\n')) {
while (*line == '\n')
line++;
if (!*line)
break;
/* Skip lines that don't start with GNUPG status */
if (!skip_prefix(line, "[GNUPG:] ", &line))
continue;
/* Iterate over all search strings */
for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
if (skip_prefix(line, sigcheck_gpg_status[i].check, &line)) {
/*
* GOODSIG, BADSIG etc. can occur only once for
* each signature. Therefore, if we had more
* than one then we're dealing with multiple
* signatures. We don't support them
* currently, and they're rather hard to
* create, so something is likely fishy and we
* should reject them altogether.
*/
if (sigcheck_gpg_status[i].flags & GPG_STATUS_EXCLUSIVE) {
if (seen_exclusive_status++)
goto error;
}
if (sigcheck_gpg_status[i].result)
sigc->result = sigcheck_gpg_status[i].result;
/* Do we have key information? */
if (sigcheck_gpg_status[i].flags & GPG_STATUS_KEYID) {
next = strchrnul(line, ' ');
replace_cstring(&sigc->key, line, next);
/* Do we have signer information? */
if (*next && (sigcheck_gpg_status[i].flags & GPG_STATUS_UID)) {
line = next + 1;
next = strchrnul(line, '\n');
replace_cstring(&sigc->signer, line, next);
}
}
/* Do we have trust level? */
if (sigcheck_gpg_status[i].flags & GPG_STATUS_TRUST_LEVEL) {
/*
* GPG v1 and v2 differs in how the
* TRUST_ lines are written. Some
* trust lines contain no additional
* space-separated information for v1.
*/
size_t trust_size = strcspn(line, " \n");
char *trust = xmemdupz(line, trust_size);
if (parse_gpg_trust_level(trust, &sigc->trust_level)) {
free(trust);
goto error;
}
free(trust);
}
/* Do we have fingerprint? */
if (sigcheck_gpg_status[i].flags & GPG_STATUS_FINGERPRINT) {
const char *limit;
char **field;
next = strchrnul(line, ' ');
replace_cstring(&sigc->fingerprint, line, next);
/*
* Skip interim fields. The search is
* limited to the same line since only
* OpenPGP signatures has a field with
* the primary fingerprint.
*/
limit = strchrnul(line, '\n');
for (j = 9; j > 0; j--) {
if (!*next || limit <= next)
break;
line = next + 1;
next = strchrnul(line, ' ');
}
field = &sigc->primary_key_fingerprint;
if (!j) {
next = strchrnul(line, '\n');
replace_cstring(field, line, next);
} else {
replace_cstring(field, NULL, NULL);
}
}
break;
}
}
}
return;
error:
sigc->result = 'E';
/* Clear partial data to avoid confusion */
FREE_AND_NULL(sigc->primary_key_fingerprint);
FREE_AND_NULL(sigc->fingerprint);
FREE_AND_NULL(sigc->signer);
FREE_AND_NULL(sigc->key);
}
static 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;
struct gpg_format *fmt;
struct tempfile *temp;
int ret;
struct strbuf buf = STRBUF_INIT;
temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
if (!temp)
return error_errno(_("could not create temporary file"));
if (write_in_full(temp->fd, signature, signature_size) < 0 ||
close_tempfile_gently(temp) < 0) {
error_errno(_("failed writing detached signature to '%s'"),
temp->filename.buf);
delete_tempfile(&temp);
return -1;
}
fmt = get_format_by_sig(signature);
if (!fmt)
BUG("bad signature '%s'", signature);
strvec_push(&gpg.args, fmt->program);
strvec_pushv(&gpg.args, fmt->verify_args);
strvec_pushl(&gpg.args,
"--status-fd=1",
"--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;
}
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';
sigc->trust_level = -1;
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);
status |= sigc->result != 'G';
status |= sigc->trust_level < configured_min_trust_level;
out:
strbuf_release(&gpg_status);
strbuf_release(&gpg_output);
return !!status;
}
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);
}
size_t parse_signed_buffer(const char *buf, size_t size)
{
size_t len = 0;
size_t match = size;
while (len < size) {
const char *eol;
if (get_format_by_sig(buf + len))
match = len;
eol = memchr(buf + len, '\n', size - len);
len += eol ? eol - (buf + len) + 1 : size - len;
}
return match;
}
int parse_signature(const char *buf, size_t size, struct strbuf *payload, struct strbuf *signature)
{
size_t match = parse_signed_buffer(buf, size);
if (match != size) {
strbuf_add(payload, buf, match);
remove_signature(payload);
strbuf_add(signature, buf + match, size - match);
return 1;
}
return 0;
}
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)
{
struct gpg_format *fmt = NULL;
char *fmtname = NULL;
char *trust;
int ret;
if (!strcmp(var, "user.signingkey")) {
if (!value)
return config_error_nonbool(var);
set_signing_key(value);
return 0;
}
if (!strcmp(var, "gpg.format")) {
if (!value)
return config_error_nonbool(var);
fmt = get_format_by_name(value);
if (!fmt)
return error("unsupported value for %s: %s",
var, value);
use_format = fmt;
return 0;
}
if (!strcmp(var, "gpg.mintrustlevel")) {
if (!value)
return config_error_nonbool(var);
trust = xstrdup_toupper(value);
ret = parse_gpg_trust_level(trust, &configured_min_trust_level);
free(trust);
if (ret)
return error("unsupported value for %s: %s", var,
value);
return 0;
}
if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
fmtname = "openpgp";
if (!strcmp(var, "gpg.x509.program"))
fmtname = "x509";
if (fmtname) {
fmt = get_format_by_name(fmtname);
return git_config_string(&fmt->program, var, 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);
}
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;
strvec_pushl(&gpg.args,
use_format->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;
}
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