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Remote DoS on maliciously crafted answer #293

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Remote DoS on maliciously crafted answer #293

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7d98a7c
ldns_str2rdf_dname: check for successful mallocs
Dec 10, 2025
ec313f4
buffer: don't bail out when request is bigger than buffer
Dec 15, 2025
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12 changes: 7 additions & 5 deletions ldns/buffer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -356,11 +356,13 @@ ldns_buffer_available(const ldns_buffer *buffer, size_t count)
* \param[in] data pointer to the data to write to the buffer
* \param[in] count the number of bytes of data to write
*/
INLINE void
INLINE size_t
ldns_buffer_write_at(ldns_buffer *buffer, size_t at, const void *data, size_t count)
{
assert(ldns_buffer_available_at(buffer, at, count));
memcpy(buffer->_data + at, data, count);
size_t avail = ldns_buffer_remaining_at(buffer, at);
size_t copy = count < avail ? count : avail;
memcpy(buffer->_data + at, data, copy);
return copy;
}

/**
Expand All @@ -372,8 +374,8 @@ ldns_buffer_write_at(ldns_buffer *buffer, size_t at, const void *data, size_t co
INLINE void
ldns_buffer_write(ldns_buffer *buffer, const void *data, size_t count)
{
ldns_buffer_write_at(buffer, buffer->_position, data, count);
buffer->_position += count;
size_t copied = ldns_buffer_write_at(buffer, buffer->_position, data, count);
buffer->_position += copied;
}

/**
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4 changes: 2 additions & 2 deletions str2host.c
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Original file line number Diff line number Diff line change
Expand Up @@ -392,7 +392,7 @@ ldns_str2rdf_dname(ldns_rdf **d, const char *str)
/* root label */
if (1 == len && *str == '.') {
*d = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME, 1, "\0");
return LDNS_STATUS_OK;
return *d?LDNS_STATUS_OK:LDNS_STATUS_MEM_ERR;
}

/* get on with the rest */
Expand Down Expand Up @@ -457,7 +457,7 @@ ldns_str2rdf_dname(ldns_rdf **d, const char *str)
len++;

*d = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME, len, buf);
return LDNS_STATUS_OK;
return *d?LDNS_STATUS_OK:LDNS_STATUS_MEM_ERR;
}

ldns_status
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