Commit | Line | Data |
---|---|---|
b37d1bfb | 1 | #!/usr/bin/perl -w |
80d65e58 DH |
2 | # |
3 | # Sign a module file using the given key. | |
4 | # | |
b37d1bfb | 5 | # Format: |
80d65e58 | 6 | # |
b37d1bfb DH |
7 | # ./scripts/sign-file [-v] <key> <x509> <module> [<dest>] |
8 | # | |
9 | # | |
10 | use strict; | |
11 | use FileHandle; | |
12 | use IPC::Open2; | |
13 | ||
14 | my $verbose = 0; | |
15 | if ($#ARGV >= 0 && $ARGV[0] eq "-v") { | |
16 | $verbose = 1; | |
17 | shift; | |
18 | } | |
19 | ||
20 | die "Format: ./scripts/sign-file [-v] <key> <x509> <module> [<dest>]\n" | |
21 | if ($#ARGV != 2 && $#ARGV != 3); | |
22 | ||
23 | my $private_key = $ARGV[0]; | |
24 | my $x509 = $ARGV[1]; | |
25 | my $module = $ARGV[2]; | |
26 | my $dest = ($#ARGV == 3) ? $ARGV[3] : $ARGV[2] . "~"; | |
27 | ||
28 | die "Can't read private key\n" unless (-r $private_key); | |
29 | die "Can't read X.509 certificate\n" unless (-r $x509); | |
30 | die "Can't read module\n" unless (-r $module); | |
31 | ||
32 | # | |
33 | # Read the kernel configuration | |
34 | # | |
35 | my %config = ( | |
36 | CONFIG_MODULE_SIG_SHA512 => 1 | |
37 | ); | |
38 | ||
39 | if (-r ".config") { | |
40 | open(FD, "<.config") || die ".config"; | |
41 | while (<FD>) { | |
42 | if ($_ =~ /^(CONFIG_.*)=[ym]/) { | |
43 | $config{$1} = 1; | |
44 | } | |
45 | } | |
46 | close(FD); | |
47 | } | |
80d65e58 | 48 | |
b37d1bfb DH |
49 | # |
50 | # Function to read the contents of a file into a variable. | |
51 | # | |
52 | sub read_file($) | |
53 | { | |
54 | my ($file) = @_; | |
55 | my $contents; | |
56 | my $len; | |
57 | ||
58 | open(FD, "<$file") || die $file; | |
59 | binmode FD; | |
60 | my @st = stat(FD); | |
61 | die $file if (!@st); | |
62 | $len = read(FD, $contents, $st[7]) || die $file; | |
63 | close(FD) || die $file; | |
64 | die "$file: Wanted length ", $st[7], ", got ", $len, "\n" | |
65 | if ($len != $st[7]); | |
66 | return $contents; | |
67 | } | |
68 | ||
69 | ############################################################################### | |
70 | # | |
71 | # First of all, we have to parse the X.509 certificate to find certain details | |
72 | # about it. | |
73 | # | |
74 | # We read the DER-encoded X509 certificate and parse it to extract the Subject | |
75 | # name and Subject Key Identifier. Theis provides the data we need to build | |
76 | # the certificate identifier. | |
77 | # | |
78 | # The signer's name part of the identifier is fabricated from the commonName, | |
79 | # the organizationName or the emailAddress components of the X.509 subject | |
80 | # name. | |
81 | # | |
82 | # The subject key ID is used to select which of that signer's certificates | |
83 | # we're intending to use to sign the module. | |
84 | # | |
85 | ############################################################################### | |
86 | my $x509_certificate = read_file($x509); | |
80d65e58 | 87 | |
b37d1bfb DH |
88 | my $UNIV = 0 << 6; |
89 | my $APPL = 1 << 6; | |
90 | my $CONT = 2 << 6; | |
91 | my $PRIV = 3 << 6; | |
80d65e58 | 92 | |
b37d1bfb | 93 | my $CONS = 0x20; |
80d65e58 | 94 | |
b37d1bfb DH |
95 | my $BOOLEAN = 0x01; |
96 | my $INTEGER = 0x02; | |
97 | my $BIT_STRING = 0x03; | |
98 | my $OCTET_STRING = 0x04; | |
99 | my $NULL = 0x05; | |
100 | my $OBJ_ID = 0x06; | |
101 | my $UTF8String = 0x0c; | |
102 | my $SEQUENCE = 0x10; | |
103 | my $SET = 0x11; | |
104 | my $UTCTime = 0x17; | |
105 | my $GeneralizedTime = 0x18; | |
80d65e58 | 106 | |
b37d1bfb DH |
107 | my %OIDs = ( |
108 | pack("CCC", 85, 4, 3) => "commonName", | |
109 | pack("CCC", 85, 4, 6) => "countryName", | |
110 | pack("CCC", 85, 4, 10) => "organizationName", | |
111 | pack("CCC", 85, 4, 11) => "organizationUnitName", | |
112 | pack("CCCCCCCCC", 42, 134, 72, 134, 247, 13, 1, 1, 1) => "rsaEncryption", | |
113 | pack("CCCCCCCCC", 42, 134, 72, 134, 247, 13, 1, 1, 5) => "sha1WithRSAEncryption", | |
114 | pack("CCCCCCCCC", 42, 134, 72, 134, 247, 13, 1, 9, 1) => "emailAddress", | |
115 | pack("CCC", 85, 29, 35) => "authorityKeyIdentifier", | |
116 | pack("CCC", 85, 29, 14) => "subjectKeyIdentifier", | |
117 | pack("CCC", 85, 29, 19) => "basicConstraints" | |
118 | ); | |
119 | ||
120 | ############################################################################### | |
121 | # | |
122 | # Extract an ASN.1 element from a string and return information about it. | |
123 | # | |
124 | ############################################################################### | |
125 | sub asn1_extract($$@) | |
126 | { | |
127 | my ($cursor, $expected_tag, $optional) = @_; | |
128 | ||
129 | return [ -1 ] | |
130 | if ($cursor->[1] == 0 && $optional); | |
131 | ||
132 | die $x509, ": ", $cursor->[0], ": ASN.1 data underrun (elem ", $cursor->[1], ")\n" | |
133 | if ($cursor->[1] < 2); | |
134 | ||
135 | my ($tag, $len) = unpack("CC", substr(${$cursor->[2]}, $cursor->[0], 2)); | |
136 | ||
137 | if ($expected_tag != -1 && $tag != $expected_tag) { | |
138 | return [ -1 ] | |
139 | if ($optional); | |
140 | die $x509, ": ", $cursor->[0], ": ASN.1 unexpected tag (", $tag, | |
141 | " not ", $expected_tag, ")\n"; | |
142 | } | |
143 | ||
144 | $cursor->[0] += 2; | |
145 | $cursor->[1] -= 2; | |
146 | ||
147 | die $x509, ": ", $cursor->[0], ": ASN.1 long tag\n" | |
148 | if (($tag & 0x1f) == 0x1f); | |
149 | die $x509, ": ", $cursor->[0], ": ASN.1 indefinite length\n" | |
150 | if ($len == 0x80); | |
151 | ||
152 | if ($len > 0x80) { | |
153 | my $l = $len - 0x80; | |
154 | die $x509, ": ", $cursor->[0], ": ASN.1 data underrun (len len $l)\n" | |
155 | if ($cursor->[1] < $l); | |
156 | ||
157 | if ($l == 0x1) { | |
158 | $len = unpack("C", substr(${$cursor->[2]}, $cursor->[0], 1)); | |
916492b1 | 159 | } elsif ($l == 0x2) { |
b37d1bfb | 160 | $len = unpack("n", substr(${$cursor->[2]}, $cursor->[0], 2)); |
916492b1 | 161 | } elsif ($l == 0x3) { |
b37d1bfb DH |
162 | $len = unpack("C", substr(${$cursor->[2]}, $cursor->[0], 1)) << 16; |
163 | $len = unpack("n", substr(${$cursor->[2]}, $cursor->[0] + 1, 2)); | |
916492b1 | 164 | } elsif ($l == 0x4) { |
b37d1bfb DH |
165 | $len = unpack("N", substr(${$cursor->[2]}, $cursor->[0], 4)); |
166 | } else { | |
167 | die $x509, ": ", $cursor->[0], ": ASN.1 element too long (", $l, ")\n"; | |
168 | } | |
169 | ||
170 | $cursor->[0] += $l; | |
171 | $cursor->[1] -= $l; | |
172 | } | |
173 | ||
174 | die $x509, ": ", $cursor->[0], ": ASN.1 data underrun (", $len, ")\n" | |
175 | if ($cursor->[1] < $len); | |
176 | ||
177 | my $ret = [ $tag, [ $cursor->[0], $len, $cursor->[2] ] ]; | |
178 | $cursor->[0] += $len; | |
179 | $cursor->[1] -= $len; | |
180 | ||
181 | return $ret; | |
182 | } | |
183 | ||
184 | ############################################################################### | |
185 | # | |
186 | # Retrieve the data referred to by a cursor | |
187 | # | |
188 | ############################################################################### | |
189 | sub asn1_retrieve($) | |
190 | { | |
191 | my ($cursor) = @_; | |
192 | my ($offset, $len, $data) = @$cursor; | |
193 | return substr($$data, $offset, $len); | |
194 | } | |
195 | ||
196 | ############################################################################### | |
197 | # | |
198 | # Roughly parse the X.509 certificate | |
199 | # | |
200 | ############################################################################### | |
201 | my $cursor = [ 0, length($x509_certificate), \$x509_certificate ]; | |
202 | ||
203 | my $cert = asn1_extract($cursor, $UNIV | $CONS | $SEQUENCE); | |
204 | my $tbs = asn1_extract($cert->[1], $UNIV | $CONS | $SEQUENCE); | |
205 | my $version = asn1_extract($tbs->[1], $CONT | $CONS | 0, 1); | |
206 | my $serial_number = asn1_extract($tbs->[1], $UNIV | $INTEGER); | |
207 | my $sig_type = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE); | |
208 | my $issuer = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE); | |
209 | my $validity = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE); | |
210 | my $subject = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE); | |
211 | my $key = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE); | |
212 | my $issuer_uid = asn1_extract($tbs->[1], $CONT | $CONS | 1, 1); | |
213 | my $subject_uid = asn1_extract($tbs->[1], $CONT | $CONS | 2, 1); | |
214 | my $extension_list = asn1_extract($tbs->[1], $CONT | $CONS | 3, 1); | |
215 | ||
216 | my $subject_key_id = (); | |
217 | my $authority_key_id = (); | |
218 | ||
219 | # | |
220 | # Parse the extension list | |
221 | # | |
222 | if ($extension_list->[0] != -1) { | |
223 | my $extensions = asn1_extract($extension_list->[1], $UNIV | $CONS | $SEQUENCE); | |
224 | ||
225 | while ($extensions->[1]->[1] > 0) { | |
226 | my $ext = asn1_extract($extensions->[1], $UNIV | $CONS | $SEQUENCE); | |
227 | my $x_oid = asn1_extract($ext->[1], $UNIV | $OBJ_ID); | |
228 | my $x_crit = asn1_extract($ext->[1], $UNIV | $BOOLEAN, 1); | |
229 | my $x_val = asn1_extract($ext->[1], $UNIV | $OCTET_STRING); | |
230 | ||
231 | my $raw_oid = asn1_retrieve($x_oid->[1]); | |
232 | next if (!exists($OIDs{$raw_oid})); | |
233 | my $x_type = $OIDs{$raw_oid}; | |
234 | ||
235 | my $raw_value = asn1_retrieve($x_val->[1]); | |
236 | ||
237 | if ($x_type eq "subjectKeyIdentifier") { | |
238 | my $vcursor = [ 0, length($raw_value), \$raw_value ]; | |
239 | ||
240 | $subject_key_id = asn1_extract($vcursor, $UNIV | $OCTET_STRING); | |
241 | } | |
242 | } | |
243 | } | |
244 | ||
245 | ############################################################################### | |
246 | # | |
247 | # Determine what we're going to use as the signer's name. In order of | |
248 | # preference, take one of: commonName, organizationName or emailAddress. | |
249 | # | |
250 | ############################################################################### | |
251 | my $org = ""; | |
252 | my $cn = ""; | |
253 | my $email = ""; | |
254 | ||
255 | while ($subject->[1]->[1] > 0) { | |
256 | my $rdn = asn1_extract($subject->[1], $UNIV | $CONS | $SET); | |
257 | my $attr = asn1_extract($rdn->[1], $UNIV | $CONS | $SEQUENCE); | |
258 | my $n_oid = asn1_extract($attr->[1], $UNIV | $OBJ_ID); | |
259 | my $n_val = asn1_extract($attr->[1], -1); | |
260 | ||
261 | my $raw_oid = asn1_retrieve($n_oid->[1]); | |
262 | next if (!exists($OIDs{$raw_oid})); | |
263 | my $n_type = $OIDs{$raw_oid}; | |
264 | ||
265 | my $raw_value = asn1_retrieve($n_val->[1]); | |
266 | ||
267 | if ($n_type eq "organizationName") { | |
268 | $org = $raw_value; | |
269 | } elsif ($n_type eq "commonName") { | |
270 | $cn = $raw_value; | |
271 | } elsif ($n_type eq "emailAddress") { | |
272 | $email = $raw_value; | |
273 | } | |
274 | } | |
275 | ||
276 | my $signers_name = $email; | |
277 | ||
278 | if ($org && $cn) { | |
279 | # Don't use the organizationName if the commonName repeats it | |
280 | if (length($org) <= length($cn) && | |
281 | substr($cn, 0, length($org)) eq $org) { | |
282 | $signers_name = $cn; | |
283 | goto got_id_name; | |
284 | } | |
285 | ||
286 | # Or a signifcant chunk of it | |
287 | if (length($org) >= 7 && | |
288 | length($cn) >= 7 && | |
289 | substr($cn, 0, 7) eq substr($org, 0, 7)) { | |
290 | $signers_name = $cn; | |
291 | goto got_id_name; | |
292 | } | |
293 | ||
294 | $signers_name = $org . ": " . $cn; | |
295 | } elsif ($org) { | |
296 | $signers_name = $org; | |
297 | } elsif ($cn) { | |
298 | $signers_name = $cn; | |
299 | } | |
300 | ||
301 | got_id_name: | |
302 | ||
303 | die $x509, ": ", "X.509: Couldn't find the Subject Key Identifier extension\n" | |
304 | if (!$subject_key_id); | |
305 | ||
306 | my $key_identifier = asn1_retrieve($subject_key_id->[1]); | |
307 | ||
308 | ############################################################################### | |
309 | # | |
310 | # Create and attach the module signature | |
311 | # | |
312 | ############################################################################### | |
80d65e58 DH |
313 | |
314 | # | |
315 | # Signature parameters | |
316 | # | |
b37d1bfb DH |
317 | my $algo = 1; # Public-key crypto algorithm: RSA |
318 | my $hash = 0; # Digest algorithm | |
319 | my $id_type = 1; # Identifier type: X.509 | |
80d65e58 DH |
320 | |
321 | # | |
322 | # Digest the data | |
323 | # | |
b37d1bfb DH |
324 | my ($dgst, $prologue) = (); |
325 | if (exists $config{"CONFIG_MODULE_SIG_SHA1"}) { | |
326 | $prologue = pack("C*", | |
327 | 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, | |
328 | 0x2B, 0x0E, 0x03, 0x02, 0x1A, | |
329 | 0x05, 0x00, 0x04, 0x14); | |
330 | $dgst = "-sha1"; | |
331 | $hash = 2; | |
332 | } elsif (exists $config{"CONFIG_MODULE_SIG_SHA224"}) { | |
333 | $prologue = pack("C*", | |
334 | 0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, | |
335 | 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, | |
336 | 0x05, 0x00, 0x04, 0x1C); | |
337 | $dgst = "-sha224"; | |
338 | $hash = 7; | |
339 | } elsif (exists $config{"CONFIG_MODULE_SIG_SHA256"}) { | |
340 | $prologue = pack("C*", | |
341 | 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, | |
342 | 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, | |
343 | 0x05, 0x00, 0x04, 0x20); | |
344 | $dgst = "-sha256"; | |
345 | $hash = 4; | |
346 | } elsif (exists $config{"CONFIG_MODULE_SIG_SHA384"}) { | |
347 | $prologue = pack("C*", | |
348 | 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, | |
349 | 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, | |
350 | 0x05, 0x00, 0x04, 0x30); | |
351 | $dgst = "-sha384"; | |
352 | $hash = 5; | |
353 | } elsif (exists $config{"CONFIG_MODULE_SIG_SHA512"}) { | |
354 | $prologue = pack("C*", | |
355 | 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, | |
356 | 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, | |
357 | 0x05, 0x00, 0x04, 0x40); | |
358 | $dgst = "-sha512"; | |
359 | $hash = 6; | |
360 | } else { | |
361 | die "Can't determine hash algorithm"; | |
362 | } | |
363 | ||
364 | # | |
365 | # Generate the digest and read from openssl's stdout | |
366 | # | |
367 | my $digest; | |
368 | $digest = readpipe("openssl dgst $dgst -binary $module") || die "openssl dgst"; | |
80d65e58 DH |
369 | |
370 | # | |
371 | # Generate the binary signature, which will be just the integer that comprises | |
372 | # the signature with no metadata attached. | |
373 | # | |
b37d1bfb DH |
374 | my $pid; |
375 | $pid = open2(*read_from, *write_to, | |
376 | "openssl rsautl -sign -inkey $private_key -keyform PEM") || | |
377 | die "openssl rsautl"; | |
378 | binmode write_to; | |
379 | print write_to $prologue . $digest || die "pipe to openssl rsautl"; | |
380 | close(write_to) || die "pipe to openssl rsautl"; | |
381 | ||
382 | binmode read_from; | |
383 | my $signature; | |
384 | read(read_from, $signature, 4096) || die "pipe from openssl rsautl"; | |
385 | close(read_from) || die "pipe from openssl rsautl"; | |
386 | $signature = pack("n", length($signature)) . $signature, | |
e2a666d5 | 387 | |
b37d1bfb DH |
388 | waitpid($pid, 0) || die; |
389 | die "openssl rsautl died: $?" if ($? >> 8); | |
80d65e58 DH |
390 | |
391 | # | |
392 | # Build the signed binary | |
393 | # | |
b37d1bfb DH |
394 | my $unsigned_module = read_file($module); |
395 | ||
396 | my $magic_number = "~Module signature appended~\n"; | |
397 | ||
398 | my $info = pack("CCCCCxxxN", | |
399 | $algo, $hash, $id_type, | |
400 | length($signers_name), | |
401 | length($key_identifier), | |
402 | length($signature)); | |
80d65e58 | 403 | |
b37d1bfb DH |
404 | if ($verbose) { |
405 | print "Size of unsigned module: ", length($unsigned_module), "\n"; | |
b37d1bfb DH |
406 | print "Size of signer's name : ", length($signers_name), "\n"; |
407 | print "Size of key identifier : ", length($key_identifier), "\n"; | |
408 | print "Size of signature : ", length($signature), "\n"; | |
409 | print "Size of informaton : ", length($info), "\n"; | |
caabe240 | 410 | print "Size of magic number : ", length($magic_number), "\n"; |
b37d1bfb DH |
411 | print "Signer's name : '", $signers_name, "'\n"; |
412 | print "Digest : $dgst\n"; | |
413 | } | |
80d65e58 | 414 | |
b37d1bfb DH |
415 | open(FD, ">$dest") || die $dest; |
416 | binmode FD; | |
417 | print FD | |
418 | $unsigned_module, | |
b37d1bfb DH |
419 | $signers_name, |
420 | $key_identifier, | |
421 | $signature, | |
caabe240 DH |
422 | $info, |
423 | $magic_number | |
b37d1bfb DH |
424 | ; |
425 | close FD || die $dest; | |
80d65e58 | 426 | |
b37d1bfb DH |
427 | if ($#ARGV != 3) { |
428 | rename($dest, $module) || die $module; | |
429 | } |