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Add TLS hash mode

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This commit is contained in:
Werner Koch 2006-10-06 10:58:18 +00:00
parent ae390ea0a2
commit 5134fc27b3
5 changed files with 150 additions and 28 deletions
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7
agent/ChangeLog
View File

@ -1,5 +1,12 @@
2006-10-05 Werner Koch <wk@g10code.com>
* command.c (has_option_name): New.
(cmd_sethash): New --hash option.
* pksign.c (do_encode_raw_pkcs1): New.
(agent_pksign_do): Use it here for the TLS algo.
* agent.h (GCRY_MD_USER_TLS_MD5SHA1): New.
* divert-scd.c (pksign): Add case for tls-md5sha1.
* divert-scd.c (encode_md_for_card): Check that the algo is valid.
2006-10-04 Werner Koch <wk@g10code.com>

9
agent/agent.h
View File

@ -36,8 +36,15 @@
#include "../common/errors.h"
#include "membuf.h"
/* To convey some special hash algorithms we use algorithm numbers
reserved for application use. */
#ifndef GCRY_MD_USER
#define GCRY_MD_USER 1024
#endif
#define GCRY_MD_USER_TLS_MD5SHA1 (GCRY_MD_USER+1)
#define MAX_DIGEST_LEN 24
/* Maximum length of a digest. */
#define MAX_DIGEST_LEN 36
/* A large struct name "opt" to keep global flags */
struct

59
agent/command.c
View File

@ -136,6 +136,21 @@ has_option (const char *line, const char *name)
return (s && (s == line || spacep (s-1)) && (!s[n] || spacep (s+n)));
}
/* Same as has_option but does only test for the name of the option
and ignores an argument, i.e. with NAME being "--hash" it would
return true for "--hash" as well as for "--hash=foo". */
static int
has_option_name (const char *line, const char *name)
{
const char *s;
int n = strlen (name);
s = strstr (line, name);
return (s && (s == line || spacep (s-1))
&& (!s[n] || spacep (s+n) || s[n] == '='));
}
/* Skip over options. It is assumed that leading spaces have been
removed (this is the case for lines passed to a handler from
assuan). Bkanls after the options are also removed. */
@ -455,7 +470,7 @@ cmd_setkeydesc (assuan_context_t ctx, char *line)
}
/* SETHASH <algonumber> <hexstring>
/* SETHASH --hash=<name>|<algonumber> <hexstring>
The client can use this command to tell the server about the data
(which usually is a hash) to be signed. */
@ -470,12 +485,37 @@ cmd_sethash (assuan_context_t ctx, char *line)
char *endp;
int algo;
/* Parse the algo number and check it. */
algo = (int)strtoul (line, &endp, 10);
for (line = endp; *line == ' ' || *line == '\t'; line++)
;
if (!algo || gcry_md_test_algo (algo))
return set_error (GPG_ERR_UNSUPPORTED_ALGORITHM, NULL);
/* Parse the alternative hash options which may be used instead of
the algo number. */
if (has_option_name (line, "--hash"))
{
if (has_option (line, "--hash=sha1"))
algo = GCRY_MD_SHA1;
else if (has_option (line, "--hash=sha256"))
algo = GCRY_MD_SHA256;
else if (has_option (line, "--hash=rmd160"))
algo = GCRY_MD_RMD160;
else if (has_option (line, "--hash=md5"))
algo = GCRY_MD_MD5;
else if (has_option (line, "--hash=tls-md5sha1"))
algo = GCRY_MD_USER_TLS_MD5SHA1;
else
return set_error (GPG_ERR_ASS_PARAMETER, "invalid hash algorithm");
}
else
algo = 0;
line = skip_options (line);
if (!algo)
{
/* No hash option has been given: require an algo number instead */
algo = (int)strtoul (line, &endp, 10);
for (line = endp; *line == ' ' || *line == '\t'; line++)
;
if (!algo || gcry_md_test_algo (algo))
return set_error (GPG_ERR_UNSUPPORTED_ALGORITHM, NULL);
}
ctrl->digest.algo = algo;
/* Parse the hash value. */
@ -483,8 +523,11 @@ cmd_sethash (assuan_context_t ctx, char *line)
if (rc)
return rc;
n /= 2;
if (n != 16 && n != 20 && n != 24 && n != 32)
if (algo == GCRY_MD_USER_TLS_MD5SHA1 && n == 36)
;
else if (n != 16 && n != 20 && n != 24 && n != 32)
return set_error (GPG_ERR_ASS_PARAMETER, "unsupported length of hash");
if (n > MAX_DIGEST_LEN)
return set_error (GPG_ERR_ASS_PARAMETER, "hash value to long");

30
agent/divert-scd.c
View File

@ -318,24 +318,34 @@ divert_pksign (ctrl_t ctrl,
int rc;
char *kid;
size_t siglen;
unsigned char *sigval;
unsigned char *data;
size_t ndata;
unsigned char *sigval = NULL;
rc = ask_for_card (ctrl, shadow_info, &kid);
if (rc)
return rc;
rc = encode_md_for_card (digest, digestlen, algo,
&data, &ndata);
if (rc)
return rc;
if (algo == GCRY_MD_USER_TLS_MD5SHA1)
{
rc = agent_card_pksign (ctrl, kid, getpin_cb, ctrl,
digest, digestlen, &sigval, &siglen);
}
else
{
unsigned char *data;
size_t ndata;
rc = encode_md_for_card (digest, digestlen, algo, &data, &ndata);
if (!rc)
{
rc = agent_card_pksign (ctrl, kid, getpin_cb, ctrl,
data, ndata, &sigval, &siglen);
xfree (data);
}
}
rc = agent_card_pksign (ctrl, kid, getpin_cb, ctrl,
data, ndata, &sigval, &siglen);
if (!rc)
*r_sig = sigval;
xfree (data);
xfree (kid);
return rc;

71
agent/pksign.c
View File

@ -39,7 +39,7 @@ do_encode_md (const byte * md, size_t mdlen, int algo, gcry_sexp_t * r_hash,
gcry_sexp_t hash;
int rc;
if (! raw_value)
if (!raw_value)
{
const char *s;
char tmp[16+1];
@ -55,7 +55,7 @@ do_encode_md (const byte * md, size_t mdlen, int algo, gcry_sexp_t * r_hash,
rc = gcry_sexp_build (&hash, NULL,
"(data (flags pkcs1) (hash %s %b))",
tmp, mdlen, md);
tmp, (int)mdlen, md);
}
else
{
@ -77,6 +77,55 @@ do_encode_md (const byte * md, size_t mdlen, int algo, gcry_sexp_t * r_hash,
}
/* Special version of do_encode_md to take care of pckcs#1 padding.
For TLS-MD5SHA1 we need to do the padding ourself as Libgrypt does
not know about this special scheme. Fixme: We should have a
pkcs1-only-padding flag for Libgcrypt. */
static int
do_encode_raw_pkcs1 (const byte *md, size_t mdlen, unsigned int nbits,
gcry_sexp_t *r_hash)
{
int rc;
gcry_sexp_t hash;
unsigned char *frame;
size_t i, n, nframe;
nframe = (nbits+7) / 8;
if ( !mdlen || mdlen + 8 + 4 > nframe )
{
/* Can't encode this hash into a frame of size NFRAME. */
return gpg_error (GPG_ERR_TOO_SHORT);
}
frame = xtrymalloc (nframe);
if (!frame)
return gpg_error_from_syserror ();
/* Assemble the pkcs#1 block type 1. */
n = 0;
frame[n++] = 0;
frame[n++] = 1; /* Block type. */
i = nframe - mdlen - 3 ;
assert (i >= 8); /* At least 8 bytes of padding. */
memset (frame+n, 0xff, i );
n += i;
frame[n++] = 0;
memcpy (frame+n, md, mdlen );
n += mdlen;
assert (n == nframe);
/* Create the S-expression. */
rc = gcry_sexp_build (&hash, NULL,
"(data (flags raw) (value %b))",
(int)nframe, frame);
xfree (frame);
*r_hash = hash;
return rc;
}
/* SIGN whatever information we have accumulated in CTRL and return
the signature S-Expression. */
int
@ -133,12 +182,18 @@ agent_pksign_do (ctrl_t ctrl, const char *desc_text,
gcry_sexp_t s_hash = NULL;
/* put the hash into a sexp */
rc = do_encode_md (ctrl->digest.value,
ctrl->digest.valuelen,
ctrl->digest.algo,
&s_hash,
ctrl->digest.raw_value);
/* Put the hash into a sexp */
if (ctrl->digest.algo == GCRY_MD_USER_TLS_MD5SHA1)
rc = do_encode_raw_pkcs1 (ctrl->digest.value,
ctrl->digest.valuelen,
gcry_pk_get_nbits (s_skey),
&s_hash);
else
rc = do_encode_md (ctrl->digest.value,
ctrl->digest.valuelen,
ctrl->digest.algo,
&s_hash,
ctrl->digest.raw_value);
if (rc)
goto leave;