Merge branch 'jc/gpg-status'
[git/git.git] / gpg-interface.c
1 #include "cache.h"
2 #include "config.h"
3 #include "run-command.h"
4 #include "strbuf.h"
5 #include "gpg-interface.h"
6 #include "sigchain.h"
7 #include "tempfile.h"
8
9 static char *configured_signing_key;
10 struct gpg_format {
11 const char *name;
12 const char *program;
13 const char **verify_args;
14 const char **sigs;
15 };
16
17 static const char *openpgp_verify_args[] = {
18 "--keyid-format=long",
19 NULL
20 };
21 static const char *openpgp_sigs[] = {
22 "-----BEGIN PGP SIGNATURE-----",
23 "-----BEGIN PGP MESSAGE-----",
24 NULL
25 };
26
27 static const char *x509_verify_args[] = {
28 NULL
29 };
30 static const char *x509_sigs[] = {
31 "-----BEGIN SIGNED MESSAGE-----",
32 NULL
33 };
34
35 static struct gpg_format gpg_format[] = {
36 { .name = "openpgp", .program = "gpg",
37 .verify_args = openpgp_verify_args,
38 .sigs = openpgp_sigs
39 },
40 { .name = "x509", .program = "gpgsm",
41 .verify_args = x509_verify_args,
42 .sigs = x509_sigs
43 },
44 };
45
46 static struct gpg_format *use_format = &gpg_format[0];
47
48 static 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
58 static 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 }
68
69 void signature_check_clear(struct signature_check *sigc)
70 {
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);
76 }
77
78 static struct {
79 char result;
80 const char *check;
81 } sigcheck_gpg_status[] = {
82 { 'G', "\n[GNUPG:] GOODSIG " },
83 { 'B', "\n[GNUPG:] BADSIG " },
84 { 'U', "\n[GNUPG:] TRUST_NEVER" },
85 { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
86 { 'E', "\n[GNUPG:] ERRSIG "},
87 { 'X', "\n[GNUPG:] EXPSIG "},
88 { 'Y', "\n[GNUPG:] EXPKEYSIG "},
89 { 'R', "\n[GNUPG:] REVKEYSIG "},
90 };
91
92 static void parse_gpg_output(struct signature_check *sigc)
93 {
94 const char *buf = sigc->gpg_status;
95 int i;
96
97 /* Iterate over all search strings */
98 for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
99 const char *found, *next;
100
101 if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
102 found = strstr(buf, sigcheck_gpg_status[i].check);
103 if (!found)
104 continue;
105 found += strlen(sigcheck_gpg_status[i].check);
106 }
107 sigc->result = sigcheck_gpg_status[i].result;
108 /* The trust messages are not followed by key/signer information */
109 if (sigc->result != 'U') {
110 next = strchrnul(found, ' ');
111 sigc->key = xmemdupz(found, next - found);
112 /* The ERRSIG message is not followed by signer information */
113 if (*next && sigc-> result != 'E') {
114 found = next + 1;
115 next = strchrnul(found, '\n');
116 sigc->signer = xmemdupz(found, next - found);
117 }
118 }
119 }
120 }
121
122 int check_signature(const char *payload, size_t plen, const char *signature,
123 size_t slen, struct signature_check *sigc)
124 {
125 struct strbuf gpg_output = STRBUF_INIT;
126 struct strbuf gpg_status = STRBUF_INIT;
127 int status;
128
129 sigc->result = 'N';
130
131 status = verify_signed_buffer(payload, plen, signature, slen,
132 &gpg_output, &gpg_status);
133 if (status && !gpg_output.len)
134 goto out;
135 sigc->payload = xmemdupz(payload, plen);
136 sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
137 sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
138 parse_gpg_output(sigc);
139 status |= sigc->result != 'G' && sigc->result != 'U';
140
141 out:
142 strbuf_release(&gpg_status);
143 strbuf_release(&gpg_output);
144
145 return !!status;
146 }
147
148 void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
149 {
150 const char *output = flags & GPG_VERIFY_RAW ?
151 sigc->gpg_status : sigc->gpg_output;
152
153 if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
154 fputs(sigc->payload, stdout);
155
156 if (output)
157 fputs(output, stderr);
158 }
159
160 size_t parse_signature(const char *buf, size_t size)
161 {
162 size_t len = 0;
163 size_t match = size;
164 while (len < size) {
165 const char *eol;
166
167 if (get_format_by_sig(buf + len))
168 match = len;
169
170 eol = memchr(buf + len, '\n', size - len);
171 len += eol ? eol - (buf + len) + 1 : size - len;
172 }
173 return match;
174 }
175
176 void set_signing_key(const char *key)
177 {
178 free(configured_signing_key);
179 configured_signing_key = xstrdup(key);
180 }
181
182 int git_gpg_config(const char *var, const char *value, void *cb)
183 {
184 struct gpg_format *fmt = NULL;
185 char *fmtname = NULL;
186
187 if (!strcmp(var, "user.signingkey")) {
188 if (!value)
189 return config_error_nonbool(var);
190 set_signing_key(value);
191 return 0;
192 }
193
194 if (!strcmp(var, "gpg.format")) {
195 if (!value)
196 return config_error_nonbool(var);
197 fmt = get_format_by_name(value);
198 if (!fmt)
199 return error("unsupported value for %s: %s",
200 var, value);
201 use_format = fmt;
202 return 0;
203 }
204
205 if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
206 fmtname = "openpgp";
207
208 if (!strcmp(var, "gpg.x509.program"))
209 fmtname = "x509";
210
211 if (fmtname) {
212 fmt = get_format_by_name(fmtname);
213 return git_config_string(&fmt->program, var, value);
214 }
215
216 return 0;
217 }
218
219 const char *get_signing_key(void)
220 {
221 if (configured_signing_key)
222 return configured_signing_key;
223 return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
224 }
225
226 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
227 {
228 struct child_process gpg = CHILD_PROCESS_INIT;
229 int ret;
230 size_t i, j, bottom;
231 struct strbuf gpg_status = STRBUF_INIT;
232
233 argv_array_pushl(&gpg.args,
234 use_format->program,
235 "--status-fd=2",
236 "-bsau", signing_key,
237 NULL);
238
239 bottom = signature->len;
240
241 /*
242 * When the username signingkey is bad, program could be terminated
243 * because gpg exits without reading and then write gets SIGPIPE.
244 */
245 sigchain_push(SIGPIPE, SIG_IGN);
246 ret = pipe_command(&gpg, buffer->buf, buffer->len,
247 signature, 1024, &gpg_status, 0);
248 sigchain_pop(SIGPIPE);
249
250 ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
251 strbuf_release(&gpg_status);
252 if (ret)
253 return error(_("gpg failed to sign the data"));
254
255 /* Strip CR from the line endings, in case we are on Windows. */
256 for (i = j = bottom; i < signature->len; i++)
257 if (signature->buf[i] != '\r') {
258 if (i != j)
259 signature->buf[j] = signature->buf[i];
260 j++;
261 }
262 strbuf_setlen(signature, j);
263
264 return 0;
265 }
266
267 int verify_signed_buffer(const char *payload, size_t payload_size,
268 const char *signature, size_t signature_size,
269 struct strbuf *gpg_output, struct strbuf *gpg_status)
270 {
271 struct child_process gpg = CHILD_PROCESS_INIT;
272 struct gpg_format *fmt;
273 struct tempfile *temp;
274 int ret;
275 struct strbuf buf = STRBUF_INIT;
276
277 temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
278 if (!temp)
279 return error_errno(_("could not create temporary file"));
280 if (write_in_full(temp->fd, signature, signature_size) < 0 ||
281 close_tempfile_gently(temp) < 0) {
282 error_errno(_("failed writing detached signature to '%s'"),
283 temp->filename.buf);
284 delete_tempfile(&temp);
285 return -1;
286 }
287
288 fmt = get_format_by_sig(signature);
289 if (!fmt)
290 BUG("bad signature '%s'", signature);
291
292 argv_array_push(&gpg.args, fmt->program);
293 argv_array_pushv(&gpg.args, fmt->verify_args);
294 argv_array_pushl(&gpg.args,
295 "--status-fd=1",
296 "--verify", temp->filename.buf, "-",
297 NULL);
298
299 if (!gpg_status)
300 gpg_status = &buf;
301
302 sigchain_push(SIGPIPE, SIG_IGN);
303 ret = pipe_command(&gpg, payload, payload_size,
304 gpg_status, 0, gpg_output, 0);
305 sigchain_pop(SIGPIPE);
306
307 delete_tempfile(&temp);
308
309 ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
310 strbuf_release(&buf); /* no matter it was used or not */
311
312 return ret;
313 }