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pki: Handle hash correctly.

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Looks like only DSA in grypt needs a leading zero to mark the has as
positive. See

http://lists.gnupg.org/pipermail/gcrypt-devel/2005-February/000754.html
This commit is contained in:
Andreas Schneider
2011-08-26 23:13:57 +02:00
parent 228e2edac5
commit 79ed1bc601
4 changed files with 57 additions and 50 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
src/pki_gcrypt.c
View File

@@ -1322,19 +1322,23 @@ int pki_signature_verify(ssh_session session,
const ssh_signature sig,
const ssh_key key,
const unsigned char *hash,
size_t len)
size_t hlen)
{
unsigned char ghash[hlen + 1];
gcry_sexp_t sexp;
gcry_error_t err;
switch(key->type) {
case SSH_KEYTYPE_DSS:
if(hash[1] < 0x80) {
hash = hash + 1;
} else {
len = len + 1;
/* That is to mark the number as positive */
if(hash[0] >= 0x80) {
memcpy(ghash + 1, hash, hlen);
ghash[0] = 0;
hash = ghash;
hlen += 1;
}
err = gcry_sexp_build(&sexp, NULL, "%b", len, hash);
err = gcry_sexp_build(&sexp, NULL, "%b", hlen, hash);
if (err) {
ssh_set_error(session,
SSH_FATAL,
@@ -1359,7 +1363,7 @@ int pki_signature_verify(ssh_session session,
err = gcry_sexp_build(&sexp,
NULL,
"(data(flags pkcs1)(hash sha1 %b))",
len, hash + 1);
hlen, hash);
if (err) {
ssh_set_error(session,
SSH_FATAL,
@@ -1392,6 +1396,7 @@ int pki_signature_verify(ssh_session session,
ssh_signature pki_do_sign(const ssh_key privkey,
const unsigned char *hash,
size_t hlen) {
unsigned char ghash[hlen + 1];
ssh_signature sig;
gcry_sexp_t sexp;
gcry_error_t err;
@@ -1404,11 +1409,14 @@ ssh_signature pki_do_sign(const ssh_key privkey,
switch (privkey->type) {
case SSH_KEYTYPE_DSS:
if(hash[1] < 0x80) {
hash = hash + 1;
} else {
hlen = hlen + 1;
/* That is to mark the number as positive */
if(hash[0] >= 0x80) {
memcpy(ghash + 1, hash, hlen);
ghash[0] = 0;
hash = ghash;
hlen += 1;
}
err = gcry_sexp_build(&sexp, NULL, "%b", hlen, hash);
if (err) {
ssh_signature_free(sig);
@@ -1428,7 +1436,7 @@ ssh_signature pki_do_sign(const ssh_key privkey,
NULL,
"(data(flags pkcs1)(hash sha1 %b))",
hlen,
hash + 1);
hash);
if (err) {
ssh_signature_free(sig);
return NULL;
@@ -1452,12 +1460,13 @@ ssh_signature pki_do_sign(const ssh_key privkey,
#ifdef WITH_SERVER
ssh_signature pki_do_sign_sessionid(const ssh_key key,
const unsigned char *hash)
const unsigned char *hash,
size_t hlen)
{
unsigned char ghash[hlen + 1];
ssh_signature sig;
gcry_sexp_t sexp;
gcry_error_t err;
size_t len;
sig = ssh_signature_new();
if (sig == NULL) {
@@ -1467,17 +1476,15 @@ ssh_signature pki_do_sign_sessionid(const ssh_key key,
switch(key->type) {
case SSH_KEYTYPE_DSS:
len = SHA_DIGEST_LEN;
if(hash[1] < 0x80) {
hash = hash + 1;
} else {
len = len + 1;
/* That is to mark the number as positive */
if(hash[0] >= 0x80) {
memcpy(ghash + 1, hash, hlen);
ghash[0] = 0;
hash = ghash;
hlen += 1;
}
err = gcry_sexp_build(&sexp,
NULL,
"%b",
len,
hash);
err = gcry_sexp_build(&sexp, NULL, "%b", hlen, hash);
if (err) {
ssh_signature_free(sig);
return NULL;
@@ -1494,8 +1501,8 @@ ssh_signature pki_do_sign_sessionid(const ssh_key key,
err = gcry_sexp_build(&sexp,
NULL,
"(data(flags pkcs1)(hash sha1 %b))",
SHA_DIGEST_LEN,
hash + 1);
hlen,
hash);
if (err) {
ssh_signature_free(sig);
return NULL;