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Commit | Line | Data |
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ec4465ad | 1 | #include "cache.h" |
8e440259 | 2 | #include "tag.h" |
ec4465ad LT |
3 | |
4 | /* | |
5 | * A signature file has a very simple fixed format: three lines | |
6 | * of "object <sha1>" + "type <typename>" + "tag <tagname>", | |
7 | * followed by some free-form signature that git itself doesn't | |
8 | * care about, but that can be verified with gpg or similar. | |
9 | * | |
10 | * The first three lines are guaranteed to be at least 63 bytes: | |
11 | * "object <sha1>\n" is 48 bytes, "type tag\n" at 9 bytes is the | |
12 | * shortest possible type-line, and "tag .\n" at 6 bytes is the | |
13 | * shortest single-character-tag line. | |
14 | * | |
15 | * We also artificially limit the size of the full object to 8kB. | |
16 | * Just because I'm a lazy bastard, and if you can't fit a signature | |
17 | * in that size, you're doing something wrong. | |
18 | */ | |
19 | ||
20 | // Some random size | |
21 | #define MAXSIZE (8192) | |
22 | ||
23 | /* | |
24 | * We refuse to tag something we can't verify. Just because. | |
25 | */ | |
26 | static int verify_object(unsigned char *sha1, const char *expected_type) | |
27 | { | |
28 | int ret = -1; | |
91d7b8af NP |
29 | char type[100]; |
30 | unsigned long size; | |
31 | void *buffer = read_sha1_file(sha1, type, &size); | |
ec4465ad | 32 | |
91d7b8af NP |
33 | if (buffer) { |
34 | if (!strcmp(type, expected_type)) | |
35 | ret = check_sha1_signature(sha1, buffer, size, type); | |
36 | free(buffer); | |
ec4465ad LT |
37 | } |
38 | return ret; | |
39 | } | |
40 | ||
41 | static int verify_tag(char *buffer, unsigned long size) | |
42 | { | |
43 | int typelen; | |
44 | char type[20]; | |
45 | unsigned char sha1[20]; | |
c818566d | 46 | const char *object, *type_line, *tag_line, *tagger_line; |
ec4465ad LT |
47 | |
48 | if (size < 64 || size > MAXSIZE-1) | |
49 | return -1; | |
50 | buffer[size] = 0; | |
51 | ||
52 | /* Verify object line */ | |
53 | object = buffer; | |
54 | if (memcmp(object, "object ", 7)) | |
55 | return -1; | |
56 | if (get_sha1_hex(object + 7, sha1)) | |
57 | return -1; | |
58 | ||
59 | /* Verify type line */ | |
60 | type_line = object + 48; | |
61 | if (memcmp(type_line - 1, "\ntype ", 6)) | |
62 | return -1; | |
63 | ||
64 | /* Verify tag-line */ | |
65 | tag_line = strchr(type_line, '\n'); | |
66 | if (!tag_line) | |
67 | return -1; | |
68 | tag_line++; | |
69 | if (memcmp(tag_line, "tag ", 4) || tag_line[4] == '\n') | |
70 | return -1; | |
71 | ||
72 | /* Get the actual type */ | |
73 | typelen = tag_line - type_line - strlen("type \n"); | |
74 | if (typelen >= sizeof(type)) | |
75 | return -1; | |
76 | memcpy(type, type_line+5, typelen); | |
77 | type[typelen] = 0; | |
78 | ||
79 | /* Verify that the object matches */ | |
80 | if (get_sha1_hex(object + 7, sha1)) | |
81 | return -1; | |
82 | if (verify_object(sha1, type)) | |
83 | return -1; | |
84 | ||
85 | /* Verify the tag-name: we don't allow control characters or spaces in it */ | |
86 | tag_line += 4; | |
87 | for (;;) { | |
88 | unsigned char c = *tag_line++; | |
89 | if (c == '\n') | |
90 | break; | |
91 | if (c > ' ') | |
92 | continue; | |
93 | return -1; | |
94 | } | |
95 | ||
c818566d EB |
96 | /* Verify the tagger line */ |
97 | tagger_line = tag_line; | |
98 | ||
99 | if (memcmp(tagger_line, "tagger", 6) || (tagger_line[6] == '\n')) | |
100 | return -1; | |
101 | ||
ec4465ad LT |
102 | /* The actual stuff afterwards we don't care about.. */ |
103 | return 0; | |
104 | } | |
105 | ||
106 | int main(int argc, char **argv) | |
107 | { | |
108 | unsigned long size; | |
109 | char buffer[MAXSIZE]; | |
110 | unsigned char result_sha1[20]; | |
111 | ||
112 | if (argc != 1) | |
113 | usage("cat <signaturefile> | git-mktag"); | |
114 | ||
53228a5f JH |
115 | setup_git_directory(); |
116 | ||
ec4465ad | 117 | // Read the signature |
b97e3dfa LT |
118 | size = 0; |
119 | for (;;) { | |
1c15afb9 JH |
120 | int ret = xread(0, buffer + size, MAXSIZE - size); |
121 | if (ret <= 0) | |
b97e3dfa | 122 | break; |
b97e3dfa LT |
123 | size += ret; |
124 | } | |
ec4465ad | 125 | |
c818566d | 126 | // Verify it for some basic sanity: it needs to start with "object <sha1>\ntype\ntagger " |
ec4465ad LT |
127 | if (verify_tag(buffer, size) < 0) |
128 | die("invalid tag signature file"); | |
129 | ||
8e440259 | 130 | if (write_sha1_file(buffer, size, tag_type, result_sha1) < 0) |
ec4465ad LT |
131 | die("unable to write tag file"); |
132 | printf("%s\n", sha1_to_hex(result_sha1)); | |
133 | return 0; | |
134 | } |