Merge branch 'jm/cache-entry-from-mem-pool'
[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 static 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 static int is_gpg_start(const char *line)
105 {
106         return starts_with(line, PGP_SIGNATURE) ||
107                 starts_with(line, PGP_MESSAGE);
108 }
109
110 size_t parse_signature(const char *buf, size_t size)
111 {
112         size_t len = 0;
113         size_t match = size;
114         while (len < size) {
115                 const char *eol;
116
117                 if (is_gpg_start(buf + len))
118                         match = len;
119
120                 eol = memchr(buf + len, '\n', size - len);
121                 len += eol ? eol - (buf + len) + 1 : size - len;
122         }
123         return match;
124 }
125
126 void set_signing_key(const char *key)
127 {
128         free(configured_signing_key);
129         configured_signing_key = xstrdup(key);
130 }
131
132 int git_gpg_config(const char *var, const char *value, void *cb)
133 {
134         if (!strcmp(var, "user.signingkey")) {
135                 if (!value)
136                         return config_error_nonbool(var);
137                 set_signing_key(value);
138                 return 0;
139         }
140
141         if (!strcmp(var, "gpg.program")) {
142                 if (!value)
143                         return config_error_nonbool(var);
144                 gpg_program = xstrdup(value);
145                 return 0;
146         }
147
148         return 0;
149 }
150
151 const char *get_signing_key(void)
152 {
153         if (configured_signing_key)
154                 return configured_signing_key;
155         return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
156 }
157
158 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
159 {
160         struct child_process gpg = CHILD_PROCESS_INIT;
161         int ret;
162         size_t i, j, bottom;
163         struct strbuf gpg_status = STRBUF_INIT;
164
165         argv_array_pushl(&gpg.args,
166                          gpg_program,
167                          "--status-fd=2",
168                          "-bsau", signing_key,
169                          NULL);
170
171         bottom = signature->len;
172
173         /*
174          * When the username signingkey is bad, program could be terminated
175          * because gpg exits without reading and then write gets SIGPIPE.
176          */
177         sigchain_push(SIGPIPE, SIG_IGN);
178         ret = pipe_command(&gpg, buffer->buf, buffer->len,
179                            signature, 1024, &gpg_status, 0);
180         sigchain_pop(SIGPIPE);
181
182         ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
183         strbuf_release(&gpg_status);
184         if (ret)
185                 return error(_("gpg failed to sign the data"));
186
187         /* Strip CR from the line endings, in case we are on Windows. */
188         for (i = j = bottom; i < signature->len; i++)
189                 if (signature->buf[i] != '\r') {
190                         if (i != j)
191                                 signature->buf[j] = signature->buf[i];
192                         j++;
193                 }
194         strbuf_setlen(signature, j);
195
196         return 0;
197 }
198
199 int verify_signed_buffer(const char *payload, size_t payload_size,
200                          const char *signature, size_t signature_size,
201                          struct strbuf *gpg_output, struct strbuf *gpg_status)
202 {
203         struct child_process gpg = CHILD_PROCESS_INIT;
204         struct tempfile *temp;
205         int ret;
206         struct strbuf buf = STRBUF_INIT;
207
208         temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
209         if (!temp)
210                 return error_errno(_("could not create temporary file"));
211         if (write_in_full(temp->fd, signature, signature_size) < 0 ||
212             close_tempfile_gently(temp) < 0) {
213                 error_errno(_("failed writing detached signature to '%s'"),
214                             temp->filename.buf);
215                 delete_tempfile(&temp);
216                 return -1;
217         }
218
219         argv_array_pushl(&gpg.args,
220                          gpg_program,
221                          "--status-fd=1",
222                          "--keyid-format=long",
223                          "--verify", temp->filename.buf, "-",
224                          NULL);
225
226         if (!gpg_status)
227                 gpg_status = &buf;
228
229         sigchain_push(SIGPIPE, SIG_IGN);
230         ret = pipe_command(&gpg, payload, payload_size,
231                            gpg_status, 0, gpg_output, 0);
232         sigchain_pop(SIGPIPE);
233
234         delete_tempfile(&temp);
235
236         ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
237         strbuf_release(&buf); /* no matter it was used or not */
238
239         return ret;
240 }