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table-driven checksum

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git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@2044 ec53bebd-3082-4978-b11e-865c3cabbd6b
This commit is contained in:
Assar Westerlund
1997-07-08 23:15:33 +00:00
parent 831415cbbe
commit 7cd7046903
1 changed files with 54 additions and 27 deletions
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81
lib/krb5/checksum.c
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@@ -2,6 +2,31 @@
RCSID("$Id$");
struct checksum_type {
int type;
size_t checksumsize;
void (*checksum)(void *, size_t, void *);
};
static struct checksum_type cm[] = {
{ CKSUMTYPE_NONE, 0, krb5_NULL_checksum},
{ CKSUMTYPE_CRC32, 4, krb5_CRC_checksum},
{ CKSUMTYPE_RSA_MD4, 16, krb5_MD4_checksum},
{ CKSUMTYPE_RSA_MD5, 16, krb5_MD5_checksum}
};
static int num_ctypes = sizeof(cm) / sizeof(cm[0]);
static struct checksum_type *
find_checksum_type(int ctype)
{
struct checksum_type *c;
for(c = cm; c < cm + num_ctypes; c++)
if(ctype == c->type)
return c;
return NULL;
}
krb5_error_code
krb5_create_checksum (krb5_context context,
krb5_cksumtype type,
@@ -9,21 +34,19 @@ krb5_create_checksum (krb5_context context,
size_t len,
Checksum *result)
{
struct md4 m;
struct checksum_type *c;
if (type != CKSUMTYPE_RSA_MD4)
abort ();
c = find_checksum_type (type);
if (c == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP;
result->cksumtype = type;
result->checksum.length = c->checksumsize;
result->checksum.data = malloc(result->checksum.length);
if(result->checksum.data == NULL)
return ENOMEM;
result->cksumtype = CKSUMTYPE_RSA_MD4;
result->checksum.length = 16;
result->checksum.data = malloc(16);
if (result->checksum.data == NULL)
return ENOMEM;
md4_init(&m);
md4_update(&m, ptr, len);
md4_finito (&m, result->checksum.data);
return 0;
(*c->checksum)(ptr, len, result->checksum.data);
return 0;
}
krb5_error_code
@@ -32,19 +55,23 @@ krb5_verify_checksum (krb5_context context,
size_t len,
Checksum *cksum)
{
struct md4 m;
u_char csum[16];
void *tmp;
struct checksum_type *c;
int ret;
if (cksum->cksumtype != CKSUMTYPE_RSA_MD4)
return KRB5KRB_AP_ERR_INAPP_CKSUM;
if (cksum->checksum.length != 16)
return KRB5KRB_AP_ERR_MODIFIED;
md4_init (&m);
md4_update (&m, ptr, len);
md4_finito (&m, csum);
if (memcmp (cksum->checksum.data, csum, 16) == 0)
return 0;
else
return KRB5KRB_AP_ERR_MODIFIED;
c = find_checksum_type (cksum->cksumtype);
if (c == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP;
if (cksum->checksum.length != c->checksumsize)
return KRB5KRB_AP_ERR_MODIFIED;
tmp = malloc (c->checksumsize);
if (tmp == NULL)
return ENOMEM;
(*c->checksum)(ptr, len, tmp);
ret = memcmp (cksum->checksum.data, tmp, c->checksumsize);
free (tmp);
if (ret == 0)
return 0;
else
return KRB5KRB_AP_ERR_MODIFIED;
}