gpg-interface.c: use flags to determine key/signer info presence
[git/git.git] / gpg-interface.c
CommitLineData
2f47eae2 1#include "cache.h"
b2141fc1 2#include "config.h"
2f47eae2
JH
3#include "run-command.h"
4#include "strbuf.h"
5#include "gpg-interface.h"
6#include "sigchain.h"
4322353b 7#include "tempfile.h"
2f47eae2
JH
8
9static char *configured_signing_key;
58af57e1
HS
10struct gpg_format {
11 const char *name;
12 const char *program;
13 const char **verify_args;
14 const char **sigs;
15};
16
17static const char *openpgp_verify_args[] = {
18 "--keyid-format=long",
19 NULL
20};
21static const char *openpgp_sigs[] = {
22 "-----BEGIN PGP SIGNATURE-----",
23 "-----BEGIN PGP MESSAGE-----",
24 NULL
25};
26
1e7adb97
HS
27static const char *x509_verify_args[] = {
28 NULL
29};
30static const char *x509_sigs[] = {
31 "-----BEGIN SIGNED MESSAGE-----",
32 NULL
33};
34
58af57e1
HS
35static struct gpg_format gpg_format[] = {
36 { .name = "openpgp", .program = "gpg",
37 .verify_args = openpgp_verify_args,
38 .sigs = openpgp_sigs
39 },
1e7adb97
HS
40 { .name = "x509", .program = "gpgsm",
41 .verify_args = x509_verify_args,
42 .sigs = x509_sigs
43 },
58af57e1
HS
44};
45
46static struct gpg_format *use_format = &gpg_format[0];
2f47eae2 47
58af57e1
HS
48static struct gpg_format *get_format_by_name(const char *str)
49{
50 int i;
51
52 for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
53 if (!strcmp(gpg_format[i].name, str))
54 return gpg_format + i;
55 return NULL;
56}
57
58static struct gpg_format *get_format_by_sig(const char *sig)
59{
60 int i, j;
61
62 for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
63 for (j = 0; gpg_format[i].sigs[j]; j++)
64 if (starts_with(sig, gpg_format[i].sigs[j]))
65 return gpg_format + i;
66 return NULL;
67}
d7c67668 68
01e57b5d
MG
69void signature_check_clear(struct signature_check *sigc)
70{
88ce3ef6
ÆAB
71 FREE_AND_NULL(sigc->payload);
72 FREE_AND_NULL(sigc->gpg_output);
73 FREE_AND_NULL(sigc->gpg_status);
74 FREE_AND_NULL(sigc->signer);
75 FREE_AND_NULL(sigc->key);
01e57b5d
MG
76}
77
da6cf1b3
MG
78/* An exclusive status -- only one of them can appear in output */
79#define GPG_STATUS_EXCLUSIVE (1<<0)
0b11a84e
MG
80/* The status includes key identifier */
81#define GPG_STATUS_KEYID (1<<1)
82/* The status includes user identifier */
83#define GPG_STATUS_UID (1<<2)
84
85/* Short-hand for standard exclusive *SIG status with keyid & UID */
86#define GPG_STATUS_STDSIG (GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID|GPG_STATUS_UID)
da6cf1b3 87
a50e7ca3
JH
88static struct {
89 char result;
90 const char *check;
da6cf1b3 91 unsigned int flags;
a50e7ca3 92} sigcheck_gpg_status[] = {
0b11a84e
MG
93 { 'G', "GOODSIG ", GPG_STATUS_STDSIG },
94 { 'B', "BADSIG ", GPG_STATUS_STDSIG },
da6cf1b3
MG
95 { 'U', "TRUST_NEVER", 0 },
96 { 'U', "TRUST_UNDEFINED", 0 },
0b11a84e
MG
97 { 'E', "ERRSIG ", GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID },
98 { 'X', "EXPSIG ", GPG_STATUS_STDSIG },
99 { 'Y', "EXPKEYSIG ", GPG_STATUS_STDSIG },
100 { 'R', "REVKEYSIG ", GPG_STATUS_STDSIG },
a50e7ca3
JH
101};
102
fbd0f166 103static void parse_gpg_output(struct signature_check *sigc)
a50e7ca3
JH
104{
105 const char *buf = sigc->gpg_status;
da6cf1b3 106 const char *line, *next;
a50e7ca3 107 int i;
da6cf1b3
MG
108 int seen_exclusive_status = 0;
109
110 /* Iterate over all lines */
111 for (line = buf; *line; line = strchrnul(line+1, '\n')) {
112 while (*line == '\n')
113 line++;
114 /* Skip lines that don't start with GNUPG status */
115 if (!skip_prefix(line, "[GNUPG:] ", &line))
116 continue;
117
118 /* Iterate over all search strings */
119 for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
120 if (skip_prefix(line, sigcheck_gpg_status[i].check, &line)) {
121 if (sigcheck_gpg_status[i].flags & GPG_STATUS_EXCLUSIVE) {
122 if (++seen_exclusive_status > 1)
123 goto found_duplicate_status;
124 }
125
126 sigc->result = sigcheck_gpg_status[i].result;
0b11a84e
MG
127 /* Do we have key information? */
128 if (sigcheck_gpg_status[i].flags & GPG_STATUS_KEYID) {
da6cf1b3
MG
129 next = strchrnul(line, ' ');
130 free(sigc->key);
131 sigc->key = xmemdupz(line, next - line);
0b11a84e
MG
132 /* Do we have signer information? */
133 if (*next && (sigcheck_gpg_status[i].flags & GPG_STATUS_UID)) {
da6cf1b3
MG
134 line = next + 1;
135 next = strchrnul(line, '\n');
136 free(sigc->signer);
137 sigc->signer = xmemdupz(line, next - line);
138 }
139 }
140
141 break;
661a1806 142 }
a50e7ca3
JH
143 }
144 }
da6cf1b3
MG
145 return;
146
147found_duplicate_status:
148 /*
149 * GOODSIG, BADSIG etc. can occur only once for each signature.
150 * Therefore, if we had more than one then we're dealing with multiple
151 * signatures. We don't support them currently, and they're rather
152 * hard to create, so something is likely fishy and we should reject
153 * them altogether.
154 */
155 sigc->result = 'E';
156 /* Clear partial data to avoid confusion */
157 FREE_AND_NULL(sigc->signer);
158 FREE_AND_NULL(sigc->key);
a50e7ca3
JH
159}
160
434060ec 161int check_signature(const char *payload, size_t plen, const char *signature,
a4cc18f2 162 size_t slen, struct signature_check *sigc)
163{
164 struct strbuf gpg_output = STRBUF_INIT;
165 struct strbuf gpg_status = STRBUF_INIT;
166 int status;
167
168 sigc->result = 'N';
169
170 status = verify_signed_buffer(payload, plen, signature, slen,
171 &gpg_output, &gpg_status);
172 if (status && !gpg_output.len)
173 goto out;
174 sigc->payload = xmemdupz(payload, plen);
175 sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
176 sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
177 parse_gpg_output(sigc);
4e5dc9ca 178 status |= sigc->result != 'G' && sigc->result != 'U';
a4cc18f2 179
180 out:
181 strbuf_release(&gpg_status);
182 strbuf_release(&gpg_output);
434060ec 183
4e5dc9ca 184 return !!status;
a4cc18f2 185}
186
ca194d50 187void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
188{
aeff29dd 189 const char *output = flags & GPG_VERIFY_RAW ?
190 sigc->gpg_status : sigc->gpg_output;
191
ca194d50 192 if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
193 fputs(sigc->payload, stdout);
194
aeff29dd 195 if (output)
196 fputs(output, stderr);
ca194d50 197}
198
e6fa6cde 199size_t parse_signature(const char *buf, size_t size)
d7c67668 200{
d7c67668 201 size_t len = 0;
8b44b2be
JK
202 size_t match = size;
203 while (len < size) {
204 const char *eol;
205
58af57e1 206 if (get_format_by_sig(buf + len))
8b44b2be
JK
207 match = len;
208
209 eol = memchr(buf + len, '\n', size - len);
d7c67668
JH
210 len += eol ? eol - (buf + len) + 1 : size - len;
211 }
8b44b2be 212 return match;
d7c67668
JH
213}
214
2f47eae2
JH
215void set_signing_key(const char *key)
216{
217 free(configured_signing_key);
218 configured_signing_key = xstrdup(key);
219}
220
221int git_gpg_config(const char *var, const char *value, void *cb)
222{
58af57e1
HS
223 struct gpg_format *fmt = NULL;
224 char *fmtname = NULL;
225
2f47eae2 226 if (!strcmp(var, "user.signingkey")) {
1b0eeec3
JK
227 if (!value)
228 return config_error_nonbool(var);
0c5e70f0 229 set_signing_key(value);
1b0eeec3 230 return 0;
0c5e70f0 231 }
1b0eeec3 232
57a8dd75
HS
233 if (!strcmp(var, "gpg.format")) {
234 if (!value)
235 return config_error_nonbool(var);
58af57e1
HS
236 fmt = get_format_by_name(value);
237 if (!fmt)
57a8dd75
HS
238 return error("unsupported value for %s: %s",
239 var, value);
58af57e1
HS
240 use_format = fmt;
241 return 0;
57a8dd75
HS
242 }
243
b02f51b1 244 if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
58af57e1
HS
245 fmtname = "openpgp";
246
1e7adb97
HS
247 if (!strcmp(var, "gpg.x509.program"))
248 fmtname = "x509";
249
58af57e1
HS
250 if (fmtname) {
251 fmt = get_format_by_name(fmtname);
252 return git_config_string(&fmt->program, var, value);
2f47eae2 253 }
1b0eeec3 254
2f47eae2
JH
255 return 0;
256}
257
258const char *get_signing_key(void)
259{
260 if (configured_signing_key)
261 return configured_signing_key;
f9bc573f 262 return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
2f47eae2
JH
263}
264
2f47eae2
JH
265int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
266{
d3180279 267 struct child_process gpg = CHILD_PROCESS_INIT;
0581b546 268 int ret;
2f47eae2 269 size_t i, j, bottom;
efee9553 270 struct strbuf gpg_status = STRBUF_INIT;
2f47eae2 271
aedb5dc3 272 argv_array_pushl(&gpg.args,
58af57e1 273 use_format->program,
efee9553 274 "--status-fd=2",
aedb5dc3
JK
275 "-bsau", signing_key,
276 NULL);
2f47eae2 277
0581b546 278 bottom = signature->len;
2f47eae2
JH
279
280 /*
281 * When the username signingkey is bad, program could be terminated
282 * because gpg exits without reading and then write gets SIGPIPE.
283 */
284 sigchain_push(SIGPIPE, SIG_IGN);
0581b546 285 ret = pipe_command(&gpg, buffer->buf, buffer->len,
efee9553 286 signature, 1024, &gpg_status, 0);
2f47eae2
JH
287 sigchain_pop(SIGPIPE);
288
efee9553
MG
289 ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
290 strbuf_release(&gpg_status);
291 if (ret)
2f47eae2
JH
292 return error(_("gpg failed to sign the data"));
293
294 /* Strip CR from the line endings, in case we are on Windows. */
295 for (i = j = bottom; i < signature->len; i++)
296 if (signature->buf[i] != '\r') {
297 if (i != j)
298 signature->buf[j] = signature->buf[i];
299 j++;
300 }
301 strbuf_setlen(signature, j);
302
303 return 0;
304}
305
2f47eae2
JH
306int verify_signed_buffer(const char *payload, size_t payload_size,
307 const char *signature, size_t signature_size,
9cc4ac8f 308 struct strbuf *gpg_output, struct strbuf *gpg_status)
2f47eae2 309{
d3180279 310 struct child_process gpg = CHILD_PROCESS_INIT;
58af57e1 311 struct gpg_format *fmt;
076aa2cb
JK
312 struct tempfile *temp;
313 int ret;
b60b7566 314 struct strbuf buf = STRBUF_INIT;
2f47eae2 315
076aa2cb
JK
316 temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
317 if (!temp)
4322353b 318 return error_errno(_("could not create temporary file"));
076aa2cb
JK
319 if (write_in_full(temp->fd, signature, signature_size) < 0 ||
320 close_tempfile_gently(temp) < 0) {
4322353b 321 error_errno(_("failed writing detached signature to '%s'"),
076aa2cb 322 temp->filename.buf);
4322353b
JK
323 delete_tempfile(&temp);
324 return -1;
325 }
2f47eae2 326
58af57e1
HS
327 fmt = get_format_by_sig(signature);
328 if (!fmt)
329 BUG("bad signature '%s'", signature);
330
331 argv_array_push(&gpg.args, fmt->program);
332 argv_array_pushv(&gpg.args, fmt->verify_args);
aedb5dc3 333 argv_array_pushl(&gpg.args,
aedb5dc3 334 "--status-fd=1",
076aa2cb 335 "--verify", temp->filename.buf, "-",
aedb5dc3 336 NULL);
2f47eae2 337
c752fcc8
JK
338 if (!gpg_status)
339 gpg_status = &buf;
b60b7566 340
0d2b664e
JK
341 sigchain_push(SIGPIPE, SIG_IGN);
342 ret = pipe_command(&gpg, payload, payload_size,
343 gpg_status, 0, gpg_output, 0);
d281b45d 344 sigchain_pop(SIGPIPE);
2f47eae2 345
4322353b 346 delete_tempfile(&temp);
2f47eae2 347
c752fcc8 348 ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
9cc4ac8f 349 strbuf_release(&buf); /* no matter it was used or not */
b60b7566 350
2f47eae2
JH
351 return ret;
352}