sha1_file: convert check_sha1_signature to struct object_id
[git/git.git] / builtin / mktag.c
1 #include "builtin.h"
2 #include "tag.h"
3
4 /*
5 * A signature file has a very simple fixed format: four lines
6 * of "object <sha1>" + "type <typename>" + "tag <tagname>" +
7 * "tagger <committer>", followed by a blank line, a free-form tag
8 * message and a signature block that git itself doesn't care about,
9 * but that can be verified with gpg or similar.
10 *
11 * The first four lines are guaranteed to be at least 83 bytes:
12 * "object <sha1>\n" is 48 bytes, "type tag\n" at 9 bytes is the
13 * shortest possible type-line, "tag .\n" at 6 bytes is the shortest
14 * single-character-tag line, and "tagger . <> 0 +0000\n" at 20 bytes is
15 * the shortest possible tagger-line.
16 */
17
18 /*
19 * We refuse to tag something we can't verify. Just because.
20 */
21 static int verify_object(const struct object_id *oid, const char *expected_type)
22 {
23 int ret = -1;
24 enum object_type type;
25 unsigned long size;
26 void *buffer = read_sha1_file(oid->hash, &type, &size);
27 const unsigned char *repl = lookup_replace_object(oid->hash);
28
29 if (buffer) {
30 struct object_id reploid;
31 hashcpy(reploid.hash, repl);
32
33 if (type == type_from_string(expected_type))
34 ret = check_object_signature(&reploid, buffer, size, expected_type);
35 free(buffer);
36 }
37 return ret;
38 }
39
40 static int verify_tag(char *buffer, unsigned long size)
41 {
42 int typelen;
43 char type[20];
44 struct object_id oid;
45 const char *object, *type_line, *tag_line, *tagger_line, *lb, *rb, *p;
46 size_t len;
47
48 if (size < 84)
49 return error("wanna fool me ? you obviously got the size wrong !");
50
51 buffer[size] = 0;
52
53 /* Verify object line */
54 object = buffer;
55 if (memcmp(object, "object ", 7))
56 return error("char%d: does not start with \"object \"", 0);
57
58 if (parse_oid_hex(object + 7, &oid, &p))
59 return error("char%d: could not get SHA1 hash", 7);
60
61 /* Verify type line */
62 type_line = p + 1;
63 if (memcmp(type_line - 1, "\ntype ", 6))
64 return error("char%d: could not find \"\\ntype \"", 47);
65
66 /* Verify tag-line */
67 tag_line = strchr(type_line, '\n');
68 if (!tag_line)
69 return error("char%"PRIuMAX": could not find next \"\\n\"",
70 (uintmax_t) (type_line - buffer));
71 tag_line++;
72 if (memcmp(tag_line, "tag ", 4) || tag_line[4] == '\n')
73 return error("char%"PRIuMAX": no \"tag \" found",
74 (uintmax_t) (tag_line - buffer));
75
76 /* Get the actual type */
77 typelen = tag_line - type_line - strlen("type \n");
78 if (typelen >= sizeof(type))
79 return error("char%"PRIuMAX": type too long",
80 (uintmax_t) (type_line+5 - buffer));
81
82 memcpy(type, type_line+5, typelen);
83 type[typelen] = 0;
84
85 /* Verify that the object matches */
86 if (verify_object(&oid, type))
87 return error("char%d: could not verify object %s", 7, oid_to_hex(&oid));
88
89 /* Verify the tag-name: we don't allow control characters or spaces in it */
90 tag_line += 4;
91 for (;;) {
92 unsigned char c = *tag_line++;
93 if (c == '\n')
94 break;
95 if (c > ' ')
96 continue;
97 return error("char%"PRIuMAX": could not verify tag name",
98 (uintmax_t) (tag_line - buffer));
99 }
100
101 /* Verify the tagger line */
102 tagger_line = tag_line;
103
104 if (memcmp(tagger_line, "tagger ", 7))
105 return error("char%"PRIuMAX": could not find \"tagger \"",
106 (uintmax_t) (tagger_line - buffer));
107
108 /*
109 * Check for correct form for name and email
110 * i.e. " <" followed by "> " on _this_ line
111 * No angle brackets within the name or email address fields.
112 * No spaces within the email address field.
113 */
114 tagger_line += 7;
115 if (!(lb = strstr(tagger_line, " <")) || !(rb = strstr(lb+2, "> ")) ||
116 strpbrk(tagger_line, "<>\n") != lb+1 ||
117 strpbrk(lb+2, "><\n ") != rb)
118 return error("char%"PRIuMAX": malformed tagger field",
119 (uintmax_t) (tagger_line - buffer));
120
121 /* Check for author name, at least one character, space is acceptable */
122 if (lb == tagger_line)
123 return error("char%"PRIuMAX": missing tagger name",
124 (uintmax_t) (tagger_line - buffer));
125
126 /* timestamp, 1 or more digits followed by space */
127 tagger_line = rb + 2;
128 if (!(len = strspn(tagger_line, "0123456789")))
129 return error("char%"PRIuMAX": missing tag timestamp",
130 (uintmax_t) (tagger_line - buffer));
131 tagger_line += len;
132 if (*tagger_line != ' ')
133 return error("char%"PRIuMAX": malformed tag timestamp",
134 (uintmax_t) (tagger_line - buffer));
135 tagger_line++;
136
137 /* timezone, 5 digits [+-]hhmm, max. 1400 */
138 if (!((tagger_line[0] == '+' || tagger_line[0] == '-') &&
139 strspn(tagger_line+1, "0123456789") == 4 &&
140 tagger_line[5] == '\n' && atoi(tagger_line+1) <= 1400))
141 return error("char%"PRIuMAX": malformed tag timezone",
142 (uintmax_t) (tagger_line - buffer));
143 tagger_line += 6;
144
145 /* Verify the blank line separating the header from the body */
146 if (*tagger_line != '\n')
147 return error("char%"PRIuMAX": trailing garbage in tag header",
148 (uintmax_t) (tagger_line - buffer));
149
150 /* The actual stuff afterwards we don't care about.. */
151 return 0;
152 }
153
154 int cmd_mktag(int argc, const char **argv, const char *prefix)
155 {
156 struct strbuf buf = STRBUF_INIT;
157 struct object_id result;
158
159 if (argc != 1)
160 usage("git mktag");
161
162 if (strbuf_read(&buf, 0, 4096) < 0) {
163 die_errno("could not read from stdin");
164 }
165
166 /* Verify it for some basic sanity: it needs to start with
167 "object <sha1>\ntype\ntagger " */
168 if (verify_tag(buf.buf, buf.len) < 0)
169 die("invalid tag signature file");
170
171 if (write_object_file(buf.buf, buf.len, tag_type, &result) < 0)
172 die("unable to write tag file");
173
174 strbuf_release(&buf);
175 printf("%s\n", oid_to_hex(&result));
176 return 0;
177 }