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Simplify verifyalg_add_rdata() with new canonicalization functions.

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This commit is contained in:
Giovanni Bajo
2012-05-02 00:31:55 +02:00
committed by Simon Kelley
parent da23c4f960
commit f119ed382e
1 changed files with 22 additions and 78 deletions
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98
src/dnssec.c
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@@ -426,64 +426,6 @@ static void verifyalg_add_data_domain(VerifyAlgCtx *alg, char* name)
}
/* Pass a DNS domain name in wire format through a hash function. Returns the
total number of bytes passed through the function or 0 in case of errors.
Updates the rdata pointer moving it further within the RR.
If alg is NULL, go in dry run mode (still correctly updates rdata and return
the correct total).
The function canonicalizes the domain name (RFC 4034, §6.2), which basically
means conversion to lower case, and uncompression. */
static int verifyalg_add_data_wire_domain(VerifyAlgCtx *alg, struct dns_header *header, size_t pktlen,
unsigned char** rdata)
{
int hops = 0, total = 0;
unsigned char label_type;
unsigned char *end = (unsigned char *)header + pktlen;
unsigned char count; unsigned char *p = *rdata;
while (1)
{
if (p >= end)
return 0;
if (!(count = *p++))
break;
label_type = count & 0xC0;
if (label_type == 0xC0)
{
if (p >= end)
return 0;
p = (unsigned char*)header + (count & 0x3F) * 256 + *p;
if (hops == 0)
*rdata = p;
if (++hops == 256)
return 0;
}
else if (label_type == 0x00)
{
if (p+count-1 >= end)
return 0;
if (alg)
{
alg->vtbl->add_data(alg, &count, 1);
/* TODO: missing conversion to lower-case and alphabet check */
alg->vtbl->add_data(alg, p, count);
}
total += count+1;
p += count;
}
else
return 0; /* unsupported label_type */
}
if (hops == 0)
*rdata = p;
if (alg)
alg->vtbl->add_data(alg, &count, 1);
return total+1;
}
/* Pass a resource record's rdata field through a verification hash function.
We must pass the record in DNS wire format, but if the record contains domain names,
@@ -491,30 +433,32 @@ static int verifyalg_add_data_wire_domain(VerifyAlgCtx *alg, struct dns_header *
static int verifyalg_add_rdata(VerifyAlgCtx *alg, int sigtype, struct dns_header *header, size_t pktlen,
unsigned char *rdata)
{
size_t len;
unsigned char *p;
int res; unsigned short rdlen;
unsigned short total;
unsigned char tmpbuf[MAXDNAME]; /* TODO: reuse part of daemon->namebuff */
RDataCForm cf1, cf2;
GETSHORT(rdlen, rdata);
p = rdata;
/* Initialize two iterations over the canonical form*/
rdata_cform_init(&cf1, header, pktlen, rdata, sigtype, tmpbuf);
cf2 = cf1;
switch (sigtype)
{
/* TODO: missing lots of RR types, see RFC4034, §6.2 */
case T_NS:
case T_CNAME:
if (!(res = verifyalg_add_data_wire_domain(NULL, header, pktlen, &p)))
/* Iteration 1: go through the canonical record and count the total octects.
This number might be different from the non-canonical rdata length
because of domain names compression. */
total = 0;
while ((p = rdata_cform_next(&cf1, &len)))
total += len;
if (rdata_cform_error(&cf1))
return 0;
if (p - rdata > rdlen)
return 0;
rdlen = htons(res);
alg->vtbl->add_data(alg, &rdlen, 2);
verifyalg_add_data_wire_domain(alg, header, pktlen, &rdata);
break;
default:
alg->vtbl->add_data(alg, rdata-2, rdlen+2);
break;
}
/* Iteration 2: process the canonical record through the hash function */
total = htons(total);
alg->vtbl->add_data(alg, &total, 2);
while ((p = rdata_cform_next(&cf2, &len)))
alg->vtbl->add_data(alg, p, len);
return 1;
}