| #include "builtin.h" |
| #include "tag.h" |
| |
| /* |
| * A signature file has a very simple fixed format: four lines |
| * of "object <sha1>" + "type <typename>" + "tag <tagname>" + |
| * "tagger <committer>", followed by a blank line, a free-form tag |
| * message and a signature block that git itself doesn't care about, |
| * but that can be verified with gpg or similar. |
| * |
| * The first four lines are guaranteed to be at least 83 bytes: |
| * "object <sha1>\n" is 48 bytes, "type tag\n" at 9 bytes is the |
| * shortest possible type-line, "tag .\n" at 6 bytes is the shortest |
| * single-character-tag line, and "tagger . <> 0 +0000\n" at 20 bytes is |
| * the shortest possible tagger-line. |
| */ |
| |
| /* |
| * We refuse to tag something we can't verify. Just because. |
| */ |
| static int verify_object(const unsigned char *sha1, const char *expected_type) |
| { |
| int ret = -1; |
| enum object_type type; |
| unsigned long size; |
| void *buffer = read_sha1_file(sha1, &type, &size); |
| const unsigned char *repl = lookup_replace_object(sha1); |
| |
| if (buffer) { |
| if (type == type_from_string(expected_type)) |
| ret = check_sha1_signature(repl, buffer, size, expected_type); |
| free(buffer); |
| } |
| return ret; |
| } |
| |
| static int verify_tag(char *buffer, unsigned long size) |
| { |
| int typelen; |
| char type[20]; |
| unsigned char sha1[20]; |
| const char *object, *type_line, *tag_line, *tagger_line, *lb, *rb; |
| size_t len; |
| |
| if (size < 84) |
| return error("wanna fool me ? you obviously got the size wrong !"); |
| |
| buffer[size] = 0; |
| |
| /* Verify object line */ |
| object = buffer; |
| if (memcmp(object, "object ", 7)) |
| return error("char%d: does not start with \"object \"", 0); |
| |
| if (get_sha1_hex(object + 7, sha1)) |
| return error("char%d: could not get SHA1 hash", 7); |
| |
| /* Verify type line */ |
| type_line = object + 48; |
| if (memcmp(type_line - 1, "\ntype ", 6)) |
| return error("char%d: could not find \"\\ntype \"", 47); |
| |
| /* Verify tag-line */ |
| tag_line = strchr(type_line, '\n'); |
| if (!tag_line) |
| return error("char%"PRIuMAX": could not find next \"\\n\"", |
| (uintmax_t) (type_line - buffer)); |
| tag_line++; |
| if (memcmp(tag_line, "tag ", 4) || tag_line[4] == '\n') |
| return error("char%"PRIuMAX": no \"tag \" found", |
| (uintmax_t) (tag_line - buffer)); |
| |
| /* Get the actual type */ |
| typelen = tag_line - type_line - strlen("type \n"); |
| if (typelen >= sizeof(type)) |
| return error("char%"PRIuMAX": type too long", |
| (uintmax_t) (type_line+5 - buffer)); |
| |
| memcpy(type, type_line+5, typelen); |
| type[typelen] = 0; |
| |
| /* Verify that the object matches */ |
| if (verify_object(sha1, type)) |
| return error("char%d: could not verify object %s", 7, sha1_to_hex(sha1)); |
| |
| /* Verify the tag-name: we don't allow control characters or spaces in it */ |
| tag_line += 4; |
| for (;;) { |
| unsigned char c = *tag_line++; |
| if (c == '\n') |
| break; |
| if (c > ' ') |
| continue; |
| return error("char%"PRIuMAX": could not verify tag name", |
| (uintmax_t) (tag_line - buffer)); |
| } |
| |
| /* Verify the tagger line */ |
| tagger_line = tag_line; |
| |
| if (memcmp(tagger_line, "tagger ", 7)) |
| return error("char%"PRIuMAX": could not find \"tagger \"", |
| (uintmax_t) (tagger_line - buffer)); |
| |
| /* |
| * Check for correct form for name and email |
| * i.e. " <" followed by "> " on _this_ line |
| * No angle brackets within the name or email address fields. |
| * No spaces within the email address field. |
| */ |
| tagger_line += 7; |
| if (!(lb = strstr(tagger_line, " <")) || !(rb = strstr(lb+2, "> ")) || |
| strpbrk(tagger_line, "<>\n") != lb+1 || |
| strpbrk(lb+2, "><\n ") != rb) |
| return error("char%"PRIuMAX": malformed tagger field", |
| (uintmax_t) (tagger_line - buffer)); |
| |
| /* Check for author name, at least one character, space is acceptable */ |
| if (lb == tagger_line) |
| return error("char%"PRIuMAX": missing tagger name", |
| (uintmax_t) (tagger_line - buffer)); |
| |
| /* timestamp, 1 or more digits followed by space */ |
| tagger_line = rb + 2; |
| if (!(len = strspn(tagger_line, "0123456789"))) |
| return error("char%"PRIuMAX": missing tag timestamp", |
| (uintmax_t) (tagger_line - buffer)); |
| tagger_line += len; |
| if (*tagger_line != ' ') |
| return error("char%"PRIuMAX": malformed tag timestamp", |
| (uintmax_t) (tagger_line - buffer)); |
| tagger_line++; |
| |
| /* timezone, 5 digits [+-]hhmm, max. 1400 */ |
| if (!((tagger_line[0] == '+' || tagger_line[0] == '-') && |
| strspn(tagger_line+1, "0123456789") == 4 && |
| tagger_line[5] == '\n' && atoi(tagger_line+1) <= 1400)) |
| return error("char%"PRIuMAX": malformed tag timezone", |
| (uintmax_t) (tagger_line - buffer)); |
| tagger_line += 6; |
| |
| /* Verify the blank line separating the header from the body */ |
| if (*tagger_line != '\n') |
| return error("char%"PRIuMAX": trailing garbage in tag header", |
| (uintmax_t) (tagger_line - buffer)); |
| |
| /* The actual stuff afterwards we don't care about.. */ |
| return 0; |
| } |
| |
| int cmd_mktag(int argc, const char **argv, const char *prefix) |
| { |
| struct strbuf buf = STRBUF_INIT; |
| unsigned char result_sha1[20]; |
| |
| if (argc != 1) |
| usage("git mktag < signaturefile"); |
| |
| if (strbuf_read(&buf, 0, 4096) < 0) { |
| die_errno("could not read from stdin"); |
| } |
| |
| /* Verify it for some basic sanity: it needs to start with |
| "object <sha1>\ntype\ntagger " */ |
| if (verify_tag(buf.buf, buf.len) < 0) |
| die("invalid tag signature file"); |
| |
| if (write_sha1_file(buf.buf, buf.len, tag_type, result_sha1) < 0) |
| die("unable to write tag file"); |
| |
| strbuf_release(&buf); |
| printf("%s\n", sha1_to_hex(result_sha1)); |
| return 0; |
| } |