Merge branch 'nd/ignore-might-be-precious'
[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
9 void set_signing_key(const char *key)
10 {
11         free(configured_signing_key);
12         configured_signing_key = xstrdup(key);
13 }
14
15 int git_gpg_config(const char *var, const char *value, void *cb)
16 {
17         if (!strcmp(var, "user.signingkey")) {
18                 if (!value)
19                         return config_error_nonbool(var);
20                 set_signing_key(value);
21         }
22         return 0;
23 }
24
25 const char *get_signing_key(void)
26 {
27         if (configured_signing_key)
28                 return configured_signing_key;
29         return git_committer_info(IDENT_ERROR_ON_NO_NAME|IDENT_NO_DATE);
30 }
31
32 /*
33  * Create a detached signature for the contents of "buffer" and append
34  * it after "signature"; "buffer" and "signature" can be the same
35  * strbuf instance, which would cause the detached signature appended
36  * at the end.
37  */
38 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
39 {
40         struct child_process gpg;
41         const char *args[4];
42         ssize_t len;
43         size_t i, j, bottom;
44
45         memset(&gpg, 0, sizeof(gpg));
46         gpg.argv = args;
47         gpg.in = -1;
48         gpg.out = -1;
49         args[0] = "gpg";
50         args[1] = "-bsau";
51         args[2] = signing_key;
52         args[3] = NULL;
53
54         if (start_command(&gpg))
55                 return error(_("could not run gpg."));
56
57         /*
58          * When the username signingkey is bad, program could be terminated
59          * because gpg exits without reading and then write gets SIGPIPE.
60          */
61         sigchain_push(SIGPIPE, SIG_IGN);
62
63         if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
64                 close(gpg.in);
65                 close(gpg.out);
66                 finish_command(&gpg);
67                 return error(_("gpg did not accept the data"));
68         }
69         close(gpg.in);
70
71         bottom = signature->len;
72         len = strbuf_read(signature, gpg.out, 1024);
73         close(gpg.out);
74
75         sigchain_pop(SIGPIPE);
76
77         if (finish_command(&gpg) || !len || len < 0)
78                 return error(_("gpg failed to sign the data"));
79
80         /* Strip CR from the line endings, in case we are on Windows. */
81         for (i = j = bottom; i < signature->len; i++)
82                 if (signature->buf[i] != '\r') {
83                         if (i != j)
84                                 signature->buf[j] = signature->buf[i];
85                         j++;
86                 }
87         strbuf_setlen(signature, j);
88
89         return 0;
90 }
91
92 /*
93  * Run "gpg" to see if the payload matches the detached signature.
94  * gpg_output_to tells where the output from "gpg" should go:
95  *   < 0: /dev/null
96  *   = 0: standard error of the calling process
97  *   > 0: the specified file descriptor
98  */
99 int verify_signed_buffer(const char *payload, size_t payload_size,
100                          const char *signature, size_t signature_size,
101                          struct strbuf *gpg_output)
102 {
103         struct child_process gpg;
104         const char *args_gpg[] = {"gpg", "--verify", "FILE", "-", NULL};
105         char path[PATH_MAX];
106         int fd, ret;
107
108         fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
109         if (fd < 0)
110                 return error("could not create temporary file '%s': %s",
111                              path, strerror(errno));
112         if (write_in_full(fd, signature, signature_size) < 0)
113                 return error("failed writing detached signature to '%s': %s",
114                              path, strerror(errno));
115         close(fd);
116
117         memset(&gpg, 0, sizeof(gpg));
118         gpg.argv = args_gpg;
119         gpg.in = -1;
120         if (gpg_output)
121                 gpg.err = -1;
122         args_gpg[2] = path;
123         if (start_command(&gpg)) {
124                 unlink(path);
125                 return error("could not run gpg.");
126         }
127
128         write_in_full(gpg.in, payload, payload_size);
129         close(gpg.in);
130
131         if (gpg_output)
132                 strbuf_read(gpg_output, gpg.err, 0);
133         ret = finish_command(&gpg);
134
135         unlink_or_warn(path);
136
137         return ret;
138 }