Merge branch 'nd/split-index'
[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 void signature_check_clear(struct signature_check *sigc)
11 {
12         free(sigc->payload);
13         free(sigc->gpg_output);
14         free(sigc->gpg_status);
15         free(sigc->signer);
16         free(sigc->key);
17         sigc->payload = NULL;
18         sigc->gpg_output = NULL;
19         sigc->gpg_status = NULL;
20         sigc->signer = NULL;
21         sigc->key = NULL;
22 }
23
24 void set_signing_key(const char *key)
25 {
26         free(configured_signing_key);
27         configured_signing_key = xstrdup(key);
28 }
29
30 int git_gpg_config(const char *var, const char *value, void *cb)
31 {
32         if (!strcmp(var, "user.signingkey")) {
33                 set_signing_key(value);
34         }
35         if (!strcmp(var, "gpg.program")) {
36                 if (!value)
37                         return config_error_nonbool(var);
38                 gpg_program = xstrdup(value);
39         }
40         return 0;
41 }
42
43 const char *get_signing_key(void)
44 {
45         if (configured_signing_key)
46                 return configured_signing_key;
47         return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
48 }
49
50 /*
51  * Create a detached signature for the contents of "buffer" and append
52  * it after "signature"; "buffer" and "signature" can be the same
53  * strbuf instance, which would cause the detached signature appended
54  * at the end.
55  */
56 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
57 {
58         struct child_process gpg;
59         const char *args[4];
60         ssize_t len;
61         size_t i, j, bottom;
62
63         memset(&gpg, 0, sizeof(gpg));
64         gpg.argv = args;
65         gpg.in = -1;
66         gpg.out = -1;
67         args[0] = gpg_program;
68         args[1] = "-bsau";
69         args[2] = signing_key;
70         args[3] = NULL;
71
72         if (start_command(&gpg))
73                 return error(_("could not run gpg."));
74
75         /*
76          * When the username signingkey is bad, program could be terminated
77          * because gpg exits without reading and then write gets SIGPIPE.
78          */
79         sigchain_push(SIGPIPE, SIG_IGN);
80
81         if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
82                 close(gpg.in);
83                 close(gpg.out);
84                 finish_command(&gpg);
85                 return error(_("gpg did not accept the data"));
86         }
87         close(gpg.in);
88
89         bottom = signature->len;
90         len = strbuf_read(signature, gpg.out, 1024);
91         close(gpg.out);
92
93         sigchain_pop(SIGPIPE);
94
95         if (finish_command(&gpg) || !len || len < 0)
96                 return error(_("gpg failed to sign the data"));
97
98         /* Strip CR from the line endings, in case we are on Windows. */
99         for (i = j = bottom; i < signature->len; i++)
100                 if (signature->buf[i] != '\r') {
101                         if (i != j)
102                                 signature->buf[j] = signature->buf[i];
103                         j++;
104                 }
105         strbuf_setlen(signature, j);
106
107         return 0;
108 }
109
110 /*
111  * Run "gpg" to see if the payload matches the detached signature.
112  * gpg_output, when set, receives the diagnostic output from GPG.
113  * gpg_status, when set, receives the status output from GPG.
114  */
115 int verify_signed_buffer(const char *payload, size_t payload_size,
116                          const char *signature, size_t signature_size,
117                          struct strbuf *gpg_output, struct strbuf *gpg_status)
118 {
119         struct child_process gpg;
120         const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
121         char path[PATH_MAX];
122         int fd, ret;
123         struct strbuf buf = STRBUF_INIT;
124         struct strbuf *pbuf = &buf;
125
126         args_gpg[0] = gpg_program;
127         fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
128         if (fd < 0)
129                 return error(_("could not create temporary file '%s': %s"),
130                              path, strerror(errno));
131         if (write_in_full(fd, signature, signature_size) < 0)
132                 return error(_("failed writing detached signature to '%s': %s"),
133                              path, strerror(errno));
134         close(fd);
135
136         memset(&gpg, 0, sizeof(gpg));
137         gpg.argv = args_gpg;
138         gpg.in = -1;
139         gpg.out = -1;
140         if (gpg_output)
141                 gpg.err = -1;
142         args_gpg[3] = path;
143         if (start_command(&gpg)) {
144                 unlink(path);
145                 return error(_("could not run gpg."));
146         }
147
148         write_in_full(gpg.in, payload, payload_size);
149         close(gpg.in);
150
151         if (gpg_output) {
152                 strbuf_read(gpg_output, gpg.err, 0);
153                 close(gpg.err);
154         }
155         if (gpg_status)
156                 pbuf = gpg_status;
157         strbuf_read(pbuf, gpg.out, 0);
158         close(gpg.out);
159
160         ret = finish_command(&gpg);
161
162         unlink_or_warn(path);
163
164         ret |= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
165         strbuf_release(&buf); /* no matter it was used or not */
166
167         return ret;
168 }