mirror of
https://github.com/isc-projects/bind9.git
synced 2026-05-28 04:34:54 -04:00
dns_name_totext() can now resize dynamic buffers
When dns_name_totext() is called with a dynamically allocated target buffer which is too small for the name, it will resize the buffer instead of returning ISC_R_NOSPACE.
This commit is contained in:
Evan Hunt
parent
a3c703ac1c
commit
4236d6a325
1 changed files with 46 additions and 74 deletions
120
lib/dns/name.c
120
lib/dns/name.c
|
|
@ -974,15 +974,14 @@ dns_name_fromtext(dns_name_t *name, isc_buffer_t *source,
|
|||
isc_result_t
|
||||
dns_name_totext(const dns_name_t *name, unsigned int options,
|
||||
isc_buffer_t *target) {
|
||||
unsigned char *ndata;
|
||||
char *tdata;
|
||||
unsigned int nlen, tlen;
|
||||
unsigned char c;
|
||||
unsigned int trem, count;
|
||||
isc_result_t result;
|
||||
unsigned char *ndata = NULL;
|
||||
unsigned int nlen;
|
||||
unsigned int labels;
|
||||
bool saw_root = false;
|
||||
unsigned int oused;
|
||||
bool omit_final_dot = ((options & DNS_NAME_OMITFINALDOT) != 0);
|
||||
bool first = true;
|
||||
|
||||
/*
|
||||
* This function assumes the name is in proper uncompressed
|
||||
|
|
@ -996,30 +995,14 @@ dns_name_totext(const dns_name_t *name, unsigned int options,
|
|||
ndata = name->ndata;
|
||||
nlen = name->length;
|
||||
labels = dns_name_countlabels(name);
|
||||
tdata = isc_buffer_used(target);
|
||||
tlen = isc_buffer_availablelength(target);
|
||||
|
||||
trem = tlen;
|
||||
|
||||
if (labels == 0 && nlen == 0) {
|
||||
/*
|
||||
* Special handling for an empty name.
|
||||
*/
|
||||
if (trem == 0) {
|
||||
return ISC_R_NOSPACE;
|
||||
}
|
||||
|
||||
/*
|
||||
* The names of these booleans are misleading in this case.
|
||||
* This empty name is not necessarily from the root node of
|
||||
* the DNS root zone, nor is a final dot going to be included.
|
||||
* They need to be set this way, though, to keep the "@"
|
||||
* from being trounced.
|
||||
*/
|
||||
saw_root = true;
|
||||
omit_final_dot = false;
|
||||
*tdata++ = '@';
|
||||
trem--;
|
||||
omit_final_dot = true;
|
||||
CHECK(isc_buffer_reserve(target, 1));
|
||||
isc_buffer_putuint8(target, '@');
|
||||
|
||||
/*
|
||||
* Skip the while() loop.
|
||||
|
|
@ -1029,14 +1012,8 @@ dns_name_totext(const dns_name_t *name, unsigned int options,
|
|||
/*
|
||||
* Special handling for the root label.
|
||||
*/
|
||||
if (trem == 0) {
|
||||
return ISC_R_NOSPACE;
|
||||
}
|
||||
|
||||
saw_root = true;
|
||||
omit_final_dot = false;
|
||||
*tdata++ = '.';
|
||||
trem--;
|
||||
|
||||
/*
|
||||
* Skip the while() loop.
|
||||
|
|
@ -1044,17 +1021,27 @@ dns_name_totext(const dns_name_t *name, unsigned int options,
|
|||
nlen = 0;
|
||||
}
|
||||
|
||||
while (labels > 0 && nlen > 0 && trem > 0) {
|
||||
while (labels > 0 && nlen > 0) {
|
||||
unsigned int count = *ndata++;
|
||||
labels--;
|
||||
count = *ndata++;
|
||||
nlen--;
|
||||
if (count == 0) {
|
||||
saw_root = true;
|
||||
break;
|
||||
} else if (!first) {
|
||||
CHECK(isc_buffer_reserve(target, 1));
|
||||
isc_buffer_putuint8(target, '.');
|
||||
}
|
||||
first = false;
|
||||
|
||||
if (count <= DNS_NAME_LABELLEN) {
|
||||
unsigned char c;
|
||||
|
||||
INSIST(nlen >= count);
|
||||
|
||||
while (count > 0) {
|
||||
uint32_t value;
|
||||
|
||||
c = *ndata;
|
||||
switch (c) {
|
||||
/* Special modifiers in zone files. */
|
||||
|
|
@ -1071,36 +1058,33 @@ dns_name_totext(const dns_name_t *name, unsigned int options,
|
|||
case 0x2E: /* '.' */
|
||||
case 0x3B: /* ';' */
|
||||
case 0x5C: /* '\\' */
|
||||
if (trem < 2) {
|
||||
return ISC_R_NOSPACE;
|
||||
}
|
||||
*tdata++ = '\\';
|
||||
*tdata++ = c;
|
||||
value = '\\' << 8 | c;
|
||||
CHECK(isc_buffer_reserve(target, 2));
|
||||
isc_buffer_putuint16(target, value);
|
||||
ndata++;
|
||||
trem -= 2;
|
||||
nlen--;
|
||||
break;
|
||||
no_escape:
|
||||
default:
|
||||
if (c > 0x20 && c < 0x7f) {
|
||||
if (trem == 0) {
|
||||
return ISC_R_NOSPACE;
|
||||
}
|
||||
*tdata++ = c;
|
||||
CHECK(isc_buffer_reserve(target,
|
||||
1));
|
||||
isc_buffer_putuint8(target, c);
|
||||
ndata++;
|
||||
trem--;
|
||||
nlen--;
|
||||
} else {
|
||||
if (trem < 4) {
|
||||
return ISC_R_NOSPACE;
|
||||
}
|
||||
*tdata++ = 0x5c;
|
||||
*tdata++ = 0x30 +
|
||||
((c / 100) % 10);
|
||||
*tdata++ = 0x30 +
|
||||
((c / 10) % 10);
|
||||
*tdata++ = 0x30 + (c % 10);
|
||||
trem -= 4;
|
||||
value = 0x5c << 24;
|
||||
value |= (0x30 +
|
||||
((c / 100) % 10))
|
||||
<< 16;
|
||||
value |=
|
||||
(0x30 + ((c / 10) % 10))
|
||||
<< 8;
|
||||
value |= 0x30 + (c % 10);
|
||||
CHECK(isc_buffer_reserve(target,
|
||||
4));
|
||||
isc_buffer_putuint32(target,
|
||||
value);
|
||||
ndata++;
|
||||
nlen--;
|
||||
}
|
||||
|
|
@ -1111,38 +1095,26 @@ dns_name_totext(const dns_name_t *name, unsigned int options,
|
|||
FATAL_ERROR("Unexpected label type %02x", count);
|
||||
UNREACHABLE();
|
||||
}
|
||||
|
||||
/*
|
||||
* The following assumes names are absolute. If not, we
|
||||
* fix things up later. Note that this means that in some
|
||||
* cases one more byte of text buffer is required than is
|
||||
* needed in the final output.
|
||||
*/
|
||||
if (trem == 0) {
|
||||
return ISC_R_NOSPACE;
|
||||
}
|
||||
*tdata++ = '.';
|
||||
trem--;
|
||||
}
|
||||
|
||||
if (nlen != 0 && trem == 0) {
|
||||
return ISC_R_NOSPACE;
|
||||
if (saw_root && !omit_final_dot) {
|
||||
CHECK(isc_buffer_reserve(target, 1));
|
||||
isc_buffer_putuint8(target, '.');
|
||||
}
|
||||
|
||||
if (!saw_root || omit_final_dot) {
|
||||
trem++;
|
||||
tdata--;
|
||||
if (isc_buffer_availablelength(target) > 1) {
|
||||
uint8_t *p = isc_buffer_used(target);
|
||||
*p = 0;
|
||||
}
|
||||
if (trem > 0) {
|
||||
*tdata = 0;
|
||||
}
|
||||
isc_buffer_add(target, tlen - trem);
|
||||
|
||||
if (totext_filter_proc != NULL) {
|
||||
return (totext_filter_proc)(target, oused);
|
||||
}
|
||||
|
||||
return ISC_R_SUCCESS;
|
||||
|
||||
cleanup:
|
||||
return result;
|
||||
}
|
||||
|
||||
isc_result_t
|
||||
|
|
|
|||
Loading…
Reference in a new issue