Documentation/git-bisect.txt: git bisect term → git bisect terms
[git] / gpg-interface.c
1 #include "cache.h"
2 #include "run-command.h"
3 #include "strbuf.h"
4 #include "gpg-interface.h"
5 #include "sigchain.h"
6
7 static char *configured_signing_key;
8 static const char *gpg_program = "gpg";
9
10 #define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
11 #define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
12
13 void signature_check_clear(struct signature_check *sigc)
14 {
15         free(sigc->payload);
16         free(sigc->gpg_output);
17         free(sigc->gpg_status);
18         free(sigc->signer);
19         free(sigc->key);
20         sigc->payload = NULL;
21         sigc->gpg_output = NULL;
22         sigc->gpg_status = NULL;
23         sigc->signer = NULL;
24         sigc->key = NULL;
25 }
26
27 static struct {
28         char result;
29         const char *check;
30 } sigcheck_gpg_status[] = {
31         { 'G', "\n[GNUPG:] GOODSIG " },
32         { 'B', "\n[GNUPG:] BADSIG " },
33         { 'U', "\n[GNUPG:] TRUST_NEVER" },
34         { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
35 };
36
37 void parse_gpg_output(struct signature_check *sigc)
38 {
39         const char *buf = sigc->gpg_status;
40         int i;
41
42         /* Iterate over all search strings */
43         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
44                 const char *found, *next;
45
46                 if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
47                         found = strstr(buf, sigcheck_gpg_status[i].check);
48                         if (!found)
49                                 continue;
50                         found += strlen(sigcheck_gpg_status[i].check);
51                 }
52                 sigc->result = sigcheck_gpg_status[i].result;
53                 /* The trust messages are not followed by key/signer information */
54                 if (sigc->result != 'U') {
55                         sigc->key = xmemdupz(found, 16);
56                         found += 17;
57                         next = strchrnul(found, '\n');
58                         sigc->signer = xmemdupz(found, next - found);
59                 }
60         }
61 }
62
63 /*
64  * Look at GPG signed content (e.g. a signed tag object), whose
65  * payload is followed by a detached signature on it.  Return the
66  * offset where the embedded detached signature begins, or the end of
67  * the data when there is no such signature.
68  */
69 size_t parse_signature(const char *buf, unsigned long size)
70 {
71         char *eol;
72         size_t len = 0;
73         while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
74                         !starts_with(buf + len, PGP_MESSAGE)) {
75                 eol = memchr(buf + len, '\n', size - len);
76                 len += eol ? eol - (buf + len) + 1 : size - len;
77         }
78         return len;
79 }
80
81 void set_signing_key(const char *key)
82 {
83         free(configured_signing_key);
84         configured_signing_key = xstrdup(key);
85 }
86
87 int git_gpg_config(const char *var, const char *value, void *cb)
88 {
89         if (!strcmp(var, "user.signingkey")) {
90                 set_signing_key(value);
91         }
92         if (!strcmp(var, "gpg.program")) {
93                 if (!value)
94                         return config_error_nonbool(var);
95                 gpg_program = xstrdup(value);
96         }
97         return 0;
98 }
99
100 const char *get_signing_key(void)
101 {
102         if (configured_signing_key)
103                 return configured_signing_key;
104         return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
105 }
106
107 /*
108  * Create a detached signature for the contents of "buffer" and append
109  * it after "signature"; "buffer" and "signature" can be the same
110  * strbuf instance, which would cause the detached signature appended
111  * at the end.
112  */
113 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
114 {
115         struct child_process gpg = CHILD_PROCESS_INIT;
116         const char *args[4];
117         ssize_t len;
118         size_t i, j, bottom;
119
120         gpg.argv = args;
121         gpg.in = -1;
122         gpg.out = -1;
123         args[0] = gpg_program;
124         args[1] = "-bsau";
125         args[2] = signing_key;
126         args[3] = NULL;
127
128         if (start_command(&gpg))
129                 return error(_("could not run gpg."));
130
131         /*
132          * When the username signingkey is bad, program could be terminated
133          * because gpg exits without reading and then write gets SIGPIPE.
134          */
135         sigchain_push(SIGPIPE, SIG_IGN);
136
137         if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
138                 close(gpg.in);
139                 close(gpg.out);
140                 finish_command(&gpg);
141                 return error(_("gpg did not accept the data"));
142         }
143         close(gpg.in);
144
145         bottom = signature->len;
146         len = strbuf_read(signature, gpg.out, 1024);
147         close(gpg.out);
148
149         sigchain_pop(SIGPIPE);
150
151         if (finish_command(&gpg) || !len || len < 0)
152                 return error(_("gpg failed to sign the data"));
153
154         /* Strip CR from the line endings, in case we are on Windows. */
155         for (i = j = bottom; i < signature->len; i++)
156                 if (signature->buf[i] != '\r') {
157                         if (i != j)
158                                 signature->buf[j] = signature->buf[i];
159                         j++;
160                 }
161         strbuf_setlen(signature, j);
162
163         return 0;
164 }
165
166 /*
167  * Run "gpg" to see if the payload matches the detached signature.
168  * gpg_output, when set, receives the diagnostic output from GPG.
169  * gpg_status, when set, receives the status output from GPG.
170  */
171 int verify_signed_buffer(const char *payload, size_t payload_size,
172                          const char *signature, size_t signature_size,
173                          struct strbuf *gpg_output, struct strbuf *gpg_status)
174 {
175         struct child_process gpg = CHILD_PROCESS_INIT;
176         const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
177         char path[PATH_MAX];
178         int fd, ret;
179         struct strbuf buf = STRBUF_INIT;
180         struct strbuf *pbuf = &buf;
181
182         args_gpg[0] = gpg_program;
183         fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
184         if (fd < 0)
185                 return error(_("could not create temporary file '%s': %s"),
186                              path, strerror(errno));
187         if (write_in_full(fd, signature, signature_size) < 0)
188                 return error(_("failed writing detached signature to '%s': %s"),
189                              path, strerror(errno));
190         close(fd);
191
192         gpg.argv = args_gpg;
193         gpg.in = -1;
194         gpg.out = -1;
195         if (gpg_output)
196                 gpg.err = -1;
197         args_gpg[3] = path;
198         if (start_command(&gpg)) {
199                 unlink(path);
200                 return error(_("could not run gpg."));
201         }
202
203         write_in_full(gpg.in, payload, payload_size);
204         close(gpg.in);
205
206         if (gpg_output) {
207                 strbuf_read(gpg_output, gpg.err, 0);
208                 close(gpg.err);
209         }
210         if (gpg_status)
211                 pbuf = gpg_status;
212         strbuf_read(pbuf, gpg.out, 0);
213         close(gpg.out);
214
215         ret = finish_command(&gpg);
216
217         unlink_or_warn(path);
218
219         ret |= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
220         strbuf_release(&buf); /* no matter it was used or not */
221
222         return ret;
223 }