Mercurial > dropbear

annotate libtomcrypt/src/pk/asn1/der/integer/der_length_integer.c @ 623:895fbe068f2c

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Fix case where "-K 1" would cause a SSH_MSG_IGNORE packet to be sent with the wrong encryption key ("bad packet length" symptom) while key exchange was happening.
author Matt Johnston <matt@ucc.asn.au>
date Tue, 07 Jun 2011 11:55:44 +0000
parents 0cbe8f6dbf9e
children f849a5ca2efc
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
285
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
2 *
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
3 * LibTomCrypt is a library that provides various cryptographic
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
4 * algorithms in a highly modular and flexible manner.
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
5 *
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
6 * The library is free for all purposes without any express
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
7 * guarantee it works.
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
8 *
382
0cbe8f6dbf9e propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f)
Matt Johnston <matt@ucc.asn.au>
parents: 285
diff changeset
9 * Tom St Denis, [email protected], http://libtomcrypt.com
285
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
10 */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
11 #include "tomcrypt.h"
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
12
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
13 /**
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
14 @file der_length_integer.c
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
15 ASN.1 DER, get length of encoding, Tom St Denis
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
16 */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
17
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
18
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
19 #ifdef LTC_DER
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
20 /**
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
21 Gets length of DER encoding of num
382
0cbe8f6dbf9e propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f)
Matt Johnston <matt@ucc.asn.au>
parents: 285
diff changeset
22 @param num The int to get the size of
285
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
23 @param outlen [out] The length of the DER encoding for the given integer
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
24 @return CRYPT_OK if successful
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
25 */
382
0cbe8f6dbf9e propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f)
Matt Johnston <matt@ucc.asn.au>
parents: 285
diff changeset
26 int der_length_integer(void *num, unsigned long *outlen)
285
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
27 {
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
28 unsigned long z, len;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
29 int leading_zero;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
30
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
31 LTC_ARGCHK(num != NULL);
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
32 LTC_ARGCHK(outlen != NULL);
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
33
382
0cbe8f6dbf9e propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f)
Matt Johnston <matt@ucc.asn.au>
parents: 285
diff changeset
34 if (mp_cmp_d(num, 0) != LTC_MP_LT) {
285
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
35 /* positive */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
36
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
37 /* we only need a leading zero if the msb of the first byte is one */
382
0cbe8f6dbf9e propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f)
Matt Johnston <matt@ucc.asn.au>
parents: 285
diff changeset
38 if ((mp_count_bits(num) & 7) == 0 || mp_iszero(num) == LTC_MP_YES) {
285
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
39 leading_zero = 1;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
40 } else {
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
41 leading_zero = 0;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
42 }
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
43
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
44 /* size for bignum */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
45 z = len = leading_zero + mp_unsigned_bin_size(num);
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
46 } else {
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
47 /* it's negative */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
48 /* find power of 2 that is a multiple of eight and greater than count bits */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
49 leading_zero = 0;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
50 z = mp_count_bits(num);
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
51 z = z + (8 - (z & 7));
382
0cbe8f6dbf9e propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f)
Matt Johnston <matt@ucc.asn.au>
parents: 285
diff changeset
52 if (((mp_cnt_lsb(num)+1)==mp_count_bits(num)) && ((mp_count_bits(num)&7)==0)) --z;
285
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
53 len = z = z >> 3;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
54 }
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
55
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
56 /* now we need a length */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
57 if (z < 128) {
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
58 /* short form */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
59 ++len;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
60 } else {
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
61 /* long form (relies on z != 0), assumes length bytes < 128 */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
62 ++len;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
63
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
64 while (z) {
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
65 ++len;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
66 z >>= 8;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
67 }
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
68 }
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
69
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
70 /* we need a 0x02 to indicate it's INTEGER */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
71 ++len;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
72
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
73 /* return length */
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
74 *outlen = len;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
75 return CRYPT_OK;
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
76 }
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
77
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
78 #endif
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
79
1b9e69c058d2 propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
80 /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/integer/der_length_integer.c,v $ */
382
0cbe8f6dbf9e propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f)
Matt Johnston <matt@ucc.asn.au>
parents: 285
diff changeset
81 /* $Revision: 1.4 $ */
0cbe8f6dbf9e propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f)
Matt Johnston <matt@ucc.asn.au>
parents: 285
diff changeset
82 /* $Date: 2006/04/22 01:22:55 $ */