worktree: remove extra members from struct add_opts
[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 static const char *gpg_program = "gpg";
11
12 #define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
13 #define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
14
15 void signature_check_clear(struct signature_check *sigc)
16 {
17         FREE_AND_NULL(sigc->payload);
18         FREE_AND_NULL(sigc->gpg_output);
19         FREE_AND_NULL(sigc->gpg_status);
20         FREE_AND_NULL(sigc->signer);
21         FREE_AND_NULL(sigc->key);
22 }
23
24 static struct {
25         char result;
26         const char *check;
27 } sigcheck_gpg_status[] = {
28         { 'G', "\n[GNUPG:] GOODSIG " },
29         { 'B', "\n[GNUPG:] BADSIG " },
30         { 'U', "\n[GNUPG:] TRUST_NEVER" },
31         { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
32         { 'E', "\n[GNUPG:] ERRSIG "},
33         { 'X', "\n[GNUPG:] EXPSIG "},
34         { 'Y', "\n[GNUPG:] EXPKEYSIG "},
35         { 'R', "\n[GNUPG:] REVKEYSIG "},
36 };
37
38 void parse_gpg_output(struct signature_check *sigc)
39 {
40         const char *buf = sigc->gpg_status;
41         int i;
42
43         /* Iterate over all search strings */
44         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
45                 const char *found, *next;
46
47                 if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
48                         found = strstr(buf, sigcheck_gpg_status[i].check);
49                         if (!found)
50                                 continue;
51                         found += strlen(sigcheck_gpg_status[i].check);
52                 }
53                 sigc->result = sigcheck_gpg_status[i].result;
54                 /* The trust messages are not followed by key/signer information */
55                 if (sigc->result != 'U') {
56                         sigc->key = xmemdupz(found, 16);
57                         /* The ERRSIG message is not followed by signer information */
58                         if (sigc-> result != 'E') {
59                                 found += 17;
60                                 next = strchrnul(found, '\n');
61                                 sigc->signer = xmemdupz(found, next - found);
62                         }
63                 }
64         }
65 }
66
67 int check_signature(const char *payload, size_t plen, const char *signature,
68         size_t slen, struct signature_check *sigc)
69 {
70         struct strbuf gpg_output = STRBUF_INIT;
71         struct strbuf gpg_status = STRBUF_INIT;
72         int status;
73
74         sigc->result = 'N';
75
76         status = verify_signed_buffer(payload, plen, signature, slen,
77                                       &gpg_output, &gpg_status);
78         if (status && !gpg_output.len)
79                 goto out;
80         sigc->payload = xmemdupz(payload, plen);
81         sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
82         sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
83         parse_gpg_output(sigc);
84
85  out:
86         strbuf_release(&gpg_status);
87         strbuf_release(&gpg_output);
88
89         return sigc->result != 'G' && sigc->result != 'U';
90 }
91
92 void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
93 {
94         const char *output = flags & GPG_VERIFY_RAW ?
95                 sigc->gpg_status : sigc->gpg_output;
96
97         if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
98                 fputs(sigc->payload, stdout);
99
100         if (output)
101                 fputs(output, stderr);
102 }
103
104 /*
105  * Look at GPG signed content (e.g. a signed tag object), whose
106  * payload is followed by a detached signature on it.  Return the
107  * offset where the embedded detached signature begins, or the end of
108  * the data when there is no such signature.
109  */
110 size_t parse_signature(const char *buf, unsigned long size)
111 {
112         char *eol;
113         size_t len = 0;
114         while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
115                         !starts_with(buf + len, PGP_MESSAGE)) {
116                 eol = memchr(buf + len, '\n', size - len);
117                 len += eol ? eol - (buf + len) + 1 : size - len;
118         }
119         return len;
120 }
121
122 void set_signing_key(const char *key)
123 {
124         free(configured_signing_key);
125         configured_signing_key = xstrdup(key);
126 }
127
128 int git_gpg_config(const char *var, const char *value, void *cb)
129 {
130         if (!strcmp(var, "user.signingkey")) {
131                 set_signing_key(value);
132         }
133         if (!strcmp(var, "gpg.program")) {
134                 if (!value)
135                         return config_error_nonbool(var);
136                 gpg_program = xstrdup(value);
137         }
138         return 0;
139 }
140
141 const char *get_signing_key(void)
142 {
143         if (configured_signing_key)
144                 return configured_signing_key;
145         return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
146 }
147
148 /*
149  * Create a detached signature for the contents of "buffer" and append
150  * it after "signature"; "buffer" and "signature" can be the same
151  * strbuf instance, which would cause the detached signature appended
152  * at the end.
153  */
154 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
155 {
156         struct child_process gpg = CHILD_PROCESS_INIT;
157         int ret;
158         size_t i, j, bottom;
159         struct strbuf gpg_status = STRBUF_INIT;
160
161         argv_array_pushl(&gpg.args,
162                          gpg_program,
163                          "--status-fd=2",
164                          "-bsau", signing_key,
165                          NULL);
166
167         bottom = signature->len;
168
169         /*
170          * When the username signingkey is bad, program could be terminated
171          * because gpg exits without reading and then write gets SIGPIPE.
172          */
173         sigchain_push(SIGPIPE, SIG_IGN);
174         ret = pipe_command(&gpg, buffer->buf, buffer->len,
175                            signature, 1024, &gpg_status, 0);
176         sigchain_pop(SIGPIPE);
177
178         ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
179         strbuf_release(&gpg_status);
180         if (ret)
181                 return error(_("gpg failed to sign the data"));
182
183         /* Strip CR from the line endings, in case we are on Windows. */
184         for (i = j = bottom; i < signature->len; i++)
185                 if (signature->buf[i] != '\r') {
186                         if (i != j)
187                                 signature->buf[j] = signature->buf[i];
188                         j++;
189                 }
190         strbuf_setlen(signature, j);
191
192         return 0;
193 }
194
195 /*
196  * Run "gpg" to see if the payload matches the detached signature.
197  * gpg_output, when set, receives the diagnostic output from GPG.
198  * gpg_status, when set, receives the status output from GPG.
199  */
200 int verify_signed_buffer(const char *payload, size_t payload_size,
201                          const char *signature, size_t signature_size,
202                          struct strbuf *gpg_output, struct strbuf *gpg_status)
203 {
204         struct child_process gpg = CHILD_PROCESS_INIT;
205         struct tempfile *temp;
206         int ret;
207         struct strbuf buf = STRBUF_INIT;
208
209         temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
210         if (!temp)
211                 return error_errno(_("could not create temporary file"));
212         if (write_in_full(temp->fd, signature, signature_size) < 0 ||
213             close_tempfile_gently(temp) < 0) {
214                 error_errno(_("failed writing detached signature to '%s'"),
215                             temp->filename.buf);
216                 delete_tempfile(&temp);
217                 return -1;
218         }
219
220         argv_array_pushl(&gpg.args,
221                          gpg_program,
222                          "--status-fd=1",
223                          "--keyid-format=long",
224                          "--verify", temp->filename.buf, "-",
225                          NULL);
226
227         if (!gpg_status)
228                 gpg_status = &buf;
229
230         sigchain_push(SIGPIPE, SIG_IGN);
231         ret = pipe_command(&gpg, payload, payload_size,
232                            gpg_status, 0, gpg_output, 0);
233         sigchain_pop(SIGPIPE);
234
235         delete_tempfile(&temp);
236
237         ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
238         strbuf_release(&buf); /* no matter it was used or not */
239
240         return ret;
241 }