verify-tag: add tests
[git/git.git] / gpg-interface.c
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1#include "cache.h"
2#include "run-command.h"
3#include "strbuf.h"
4#include "gpg-interface.h"
5#include "sigchain.h"
6
7static char *configured_signing_key;
0c5e70f0 8static const char *gpg_program = "gpg";
2f47eae2 9
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10#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
11#define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
12
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13void signature_check_clear(struct signature_check *sigc)
14{
71c214c8 15 free(sigc->payload);
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16 free(sigc->gpg_output);
17 free(sigc->gpg_status);
18 free(sigc->signer);
19 free(sigc->key);
71c214c8 20 sigc->payload = NULL;
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21 sigc->gpg_output = NULL;
22 sigc->gpg_status = NULL;
23 sigc->signer = NULL;
24 sigc->key = NULL;
25}
26
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27static 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
37void 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
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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 */
69size_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
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81void set_signing_key(const char *key)
82{
83 free(configured_signing_key);
84 configured_signing_key = xstrdup(key);
85}
86
87int git_gpg_config(const char *var, const char *value, void *cb)
88{
89 if (!strcmp(var, "user.signingkey")) {
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90 set_signing_key(value);
91 }
92 if (!strcmp(var, "gpg.program")) {
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93 if (!value)
94 return config_error_nonbool(var);
0c5e70f0 95 gpg_program = xstrdup(value);
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96 }
97 return 0;
98}
99
100const char *get_signing_key(void)
101{
102 if (configured_signing_key)
103 return configured_signing_key;
f9bc573f 104 return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
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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 */
113int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
114{
d3180279 115 struct child_process gpg = CHILD_PROCESS_INIT;
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116 const char *args[4];
117 ssize_t len;
118 size_t i, j, bottom;
119
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120 gpg.argv = args;
121 gpg.in = -1;
122 gpg.out = -1;
0c5e70f0 123 args[0] = gpg_program;
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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.
e3f55e07 168 * gpg_output, when set, receives the diagnostic output from GPG.
b60b7566 169 * gpg_status, when set, receives the status output from GPG.
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170 */
171int verify_signed_buffer(const char *payload, size_t payload_size,
172 const char *signature, size_t signature_size,
9cc4ac8f 173 struct strbuf *gpg_output, struct strbuf *gpg_status)
2f47eae2 174{
d3180279 175 struct child_process gpg = CHILD_PROCESS_INIT;
b60b7566 176 const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
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177 char path[PATH_MAX];
178 int fd, ret;
b60b7566 179 struct strbuf buf = STRBUF_INIT;
9cc4ac8f 180 struct strbuf *pbuf = &buf;
2f47eae2 181
0c5e70f0 182 args_gpg[0] = gpg_program;
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183 fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
184 if (fd < 0)
4c9a4182 185 return error(_("could not create temporary file '%s': %s"),
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186 path, strerror(errno));
187 if (write_in_full(fd, signature, signature_size) < 0)
4c9a4182 188 return error(_("failed writing detached signature to '%s': %s"),
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189 path, strerror(errno));
190 close(fd);
191
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192 gpg.argv = args_gpg;
193 gpg.in = -1;
b60b7566 194 gpg.out = -1;
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195 if (gpg_output)
196 gpg.err = -1;
b60b7566 197 args_gpg[3] = path;
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198 if (start_command(&gpg)) {
199 unlink(path);
4c9a4182 200 return error(_("could not run gpg."));
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201 }
202
203 write_in_full(gpg.in, payload, payload_size);
204 close(gpg.in);
205
7dac3f83 206 if (gpg_output) {
2f47eae2 207 strbuf_read(gpg_output, gpg.err, 0);
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208 close(gpg.err);
209 }
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210 if (gpg_status)
211 pbuf = gpg_status;
212 strbuf_read(pbuf, gpg.out, 0);
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213 close(gpg.out);
214
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215 ret = finish_command(&gpg);
216
217 unlink_or_warn(path);
218
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219 ret |= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
220 strbuf_release(&buf); /* no matter it was used or not */
b60b7566 221
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222 return ret;
223}