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![Henning Schild](/assets/img/avatar_default.png)
This commit allows git to create and check x509 type signatures using gpgsm. Signed-off-by: Henning Schild <henning.schild@siemens.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
313 lines
7.4 KiB
C
313 lines
7.4 KiB
C
#include "cache.h"
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#include "config.h"
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#include "run-command.h"
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#include "strbuf.h"
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#include "gpg-interface.h"
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#include "sigchain.h"
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#include "tempfile.h"
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static char *configured_signing_key;
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struct gpg_format {
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const char *name;
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const char *program;
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const char **verify_args;
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const char **sigs;
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};
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static const char *openpgp_verify_args[] = {
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"--keyid-format=long",
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NULL
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};
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static const char *openpgp_sigs[] = {
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"-----BEGIN PGP SIGNATURE-----",
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"-----BEGIN PGP MESSAGE-----",
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NULL
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};
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static const char *x509_verify_args[] = {
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NULL
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};
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static const char *x509_sigs[] = {
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"-----BEGIN SIGNED MESSAGE-----",
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NULL
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};
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static struct gpg_format gpg_format[] = {
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{ .name = "openpgp", .program = "gpg",
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.verify_args = openpgp_verify_args,
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.sigs = openpgp_sigs
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},
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{ .name = "x509", .program = "gpgsm",
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.verify_args = x509_verify_args,
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.sigs = x509_sigs
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},
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};
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static struct gpg_format *use_format = &gpg_format[0];
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static struct gpg_format *get_format_by_name(const char *str)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
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if (!strcmp(gpg_format[i].name, str))
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return gpg_format + i;
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return NULL;
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}
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static struct gpg_format *get_format_by_sig(const char *sig)
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{
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int i, j;
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for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
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for (j = 0; gpg_format[i].sigs[j]; j++)
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if (starts_with(sig, gpg_format[i].sigs[j]))
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return gpg_format + i;
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return NULL;
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}
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void signature_check_clear(struct signature_check *sigc)
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{
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FREE_AND_NULL(sigc->payload);
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FREE_AND_NULL(sigc->gpg_output);
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FREE_AND_NULL(sigc->gpg_status);
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FREE_AND_NULL(sigc->signer);
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FREE_AND_NULL(sigc->key);
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}
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static struct {
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char result;
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const char *check;
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} sigcheck_gpg_status[] = {
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{ 'G', "\n[GNUPG:] GOODSIG " },
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{ 'B', "\n[GNUPG:] BADSIG " },
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{ 'U', "\n[GNUPG:] TRUST_NEVER" },
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{ 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
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{ 'E', "\n[GNUPG:] ERRSIG "},
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{ 'X', "\n[GNUPG:] EXPSIG "},
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{ 'Y', "\n[GNUPG:] EXPKEYSIG "},
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{ 'R', "\n[GNUPG:] REVKEYSIG "},
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};
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static void parse_gpg_output(struct signature_check *sigc)
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{
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const char *buf = sigc->gpg_status;
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int i;
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/* Iterate over all search strings */
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for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
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const char *found, *next;
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if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
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found = strstr(buf, sigcheck_gpg_status[i].check);
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if (!found)
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continue;
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found += strlen(sigcheck_gpg_status[i].check);
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}
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sigc->result = sigcheck_gpg_status[i].result;
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/* The trust messages are not followed by key/signer information */
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if (sigc->result != 'U') {
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next = strchrnul(found, ' ');
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sigc->key = xmemdupz(found, next - found);
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/* The ERRSIG message is not followed by signer information */
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if (*next && sigc-> result != 'E') {
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found = next + 1;
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next = strchrnul(found, '\n');
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sigc->signer = xmemdupz(found, next - found);
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}
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}
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}
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}
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int check_signature(const char *payload, size_t plen, const char *signature,
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size_t slen, struct signature_check *sigc)
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{
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struct strbuf gpg_output = STRBUF_INIT;
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struct strbuf gpg_status = STRBUF_INIT;
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int status;
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sigc->result = 'N';
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status = verify_signed_buffer(payload, plen, signature, slen,
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&gpg_output, &gpg_status);
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if (status && !gpg_output.len)
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goto out;
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sigc->payload = xmemdupz(payload, plen);
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sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
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sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
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parse_gpg_output(sigc);
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out:
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strbuf_release(&gpg_status);
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strbuf_release(&gpg_output);
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return sigc->result != 'G' && sigc->result != 'U';
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}
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void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
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{
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const char *output = flags & GPG_VERIFY_RAW ?
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sigc->gpg_status : sigc->gpg_output;
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if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
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fputs(sigc->payload, stdout);
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if (output)
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fputs(output, stderr);
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}
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size_t parse_signature(const char *buf, size_t size)
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{
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size_t len = 0;
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size_t match = size;
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while (len < size) {
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const char *eol;
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if (get_format_by_sig(buf + len))
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match = len;
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eol = memchr(buf + len, '\n', size - len);
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len += eol ? eol - (buf + len) + 1 : size - len;
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}
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return match;
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}
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void set_signing_key(const char *key)
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{
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free(configured_signing_key);
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configured_signing_key = xstrdup(key);
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}
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int git_gpg_config(const char *var, const char *value, void *cb)
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{
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struct gpg_format *fmt = NULL;
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char *fmtname = NULL;
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if (!strcmp(var, "user.signingkey")) {
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if (!value)
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return config_error_nonbool(var);
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set_signing_key(value);
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return 0;
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}
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if (!strcmp(var, "gpg.format")) {
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if (!value)
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return config_error_nonbool(var);
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fmt = get_format_by_name(value);
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if (!fmt)
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return error("unsupported value for %s: %s",
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var, value);
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use_format = fmt;
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return 0;
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}
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if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
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fmtname = "openpgp";
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if (!strcmp(var, "gpg.x509.program"))
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fmtname = "x509";
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if (fmtname) {
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fmt = get_format_by_name(fmtname);
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return git_config_string(&fmt->program, var, value);
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}
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return 0;
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}
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const char *get_signing_key(void)
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{
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if (configured_signing_key)
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return configured_signing_key;
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return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
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}
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int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
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{
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struct child_process gpg = CHILD_PROCESS_INIT;
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int ret;
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size_t i, j, bottom;
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struct strbuf gpg_status = STRBUF_INIT;
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argv_array_pushl(&gpg.args,
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use_format->program,
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"--status-fd=2",
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"-bsau", signing_key,
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NULL);
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bottom = signature->len;
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/*
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* When the username signingkey is bad, program could be terminated
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* because gpg exits without reading and then write gets SIGPIPE.
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*/
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sigchain_push(SIGPIPE, SIG_IGN);
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ret = pipe_command(&gpg, buffer->buf, buffer->len,
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signature, 1024, &gpg_status, 0);
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sigchain_pop(SIGPIPE);
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ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
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strbuf_release(&gpg_status);
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if (ret)
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return error(_("gpg failed to sign the data"));
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/* Strip CR from the line endings, in case we are on Windows. */
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for (i = j = bottom; i < signature->len; i++)
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if (signature->buf[i] != '\r') {
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if (i != j)
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signature->buf[j] = signature->buf[i];
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j++;
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}
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strbuf_setlen(signature, j);
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return 0;
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}
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int verify_signed_buffer(const char *payload, size_t payload_size,
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const char *signature, size_t signature_size,
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struct strbuf *gpg_output, struct strbuf *gpg_status)
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{
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struct child_process gpg = CHILD_PROCESS_INIT;
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struct gpg_format *fmt;
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struct tempfile *temp;
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int ret;
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struct strbuf buf = STRBUF_INIT;
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temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
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if (!temp)
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return error_errno(_("could not create temporary file"));
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if (write_in_full(temp->fd, signature, signature_size) < 0 ||
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close_tempfile_gently(temp) < 0) {
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error_errno(_("failed writing detached signature to '%s'"),
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temp->filename.buf);
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delete_tempfile(&temp);
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return -1;
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}
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fmt = get_format_by_sig(signature);
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if (!fmt)
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BUG("bad signature '%s'", signature);
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argv_array_push(&gpg.args, fmt->program);
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argv_array_pushv(&gpg.args, fmt->verify_args);
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argv_array_pushl(&gpg.args,
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"--status-fd=1",
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"--verify", temp->filename.buf, "-",
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NULL);
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if (!gpg_status)
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gpg_status = &buf;
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sigchain_push(SIGPIPE, SIG_IGN);
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ret = pipe_command(&gpg, payload, payload_size,
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gpg_status, 0, gpg_output, 0);
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sigchain_pop(SIGPIPE);
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delete_tempfile(&temp);
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ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
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strbuf_release(&buf); /* no matter it was used or not */
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return ret;
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}
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