Use libottery for secure random numbers.

Libottery itself is hosted here:
https://github.com/nmathewson/libottery

This import is a rough adoptation of libottery to use it for secure
random numbers in rspamd when needed (and in DNS resolver specifically).
This import makes the internal chacha20 code useless, hence it is
removed now.

1 files changed, 5 insertions, 43 deletions

diff --git a/src/dns.c b/src/dns.c
index 375ec9811..3d714c240 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -29,6 +29,7 @@
 #include "main.h"
 #include "utlist.h"
 #include "uthash.h"
+#include "ottery.h"
 
 #ifdef HAVE_OPENSSL
 #include <openssl/rand.h>
@@ -36,50 +37,12 @@
 
 static void dns_retransmit_handler (gint fd, short what, void *arg);
 
-/*
- * DNS permutor utilities
- */
-
-/**
- * Init chacha20 context
- * @param p
- */
-static void
-dns_permutor_init (struct dns_permutor *p)
-{
-	/* Init random key and IV */
-	rspamd_random_bytes (p->perm_buf, PERMUTOR_KSIZE + PERMUTOR_IVSIZE);
-
-	/* Setup ctx */
-	chacha_keysetup (&p->ctx, p->perm_buf, PERMUTOR_KSIZE * 8, 0);
-	chacha_ivsetup (&p->ctx, p->perm_buf + PERMUTOR_KSIZE * 8);
-
-	chacha_encrypt_bytes (&p->ctx, p->perm_buf, p->perm_buf, sizeof (p->perm_buf));
-
-	p->pos = 0;
-}
-
-static struct dns_permutor *
-dns_permutor_new (void)
-{
-	struct dns_permutor *new;
-
-	new = g_slice_alloc0 (sizeof (struct dns_permutor));
-	dns_permutor_init (new);
-
-	return new;
-}
-
 static guint16
-dns_permutor_generate_id (struct dns_permutor *p)
+dns_permutor_generate_id (void)
 {
 	guint16 id;
-	if (p->pos + sizeof (guint16) >= sizeof (p->perm_buf)) {
-		dns_permutor_init (p);
-	}
 
-	memcpy (&id, &p->perm_buf[p->pos], sizeof (guint16));
-	p->pos += sizeof (guint16);
+	id = ottery_rand_unsigned ();
 
 	return id;
 }
@@ -280,7 +243,7 @@ make_dns_header (struct rspamd_dns_request *req)
 	/* Set DNS header values */
 	header = (struct dns_header *)req->packet;
 	memset (header, 0 , sizeof (struct dns_header));
-	header->qid = dns_permutor_generate_id (req->resolver->permutor);
+	header->qid = dns_permutor_generate_id ();
 	header->rd = 1;
 	header->qdcount = htons (1);
 	header->arcount = htons (1);
@@ -1284,7 +1247,7 @@ make_dns_request (struct rspamd_dns_resolver *resolver,
 		while (g_hash_table_lookup (req->io->requests, &req->id)) {
 			/* Check for unique id */
 			header = (struct dns_header *)req->packet;
-			header->qid = dns_permutor_generate_id (resolver->permutor);
+			header->qid = dns_permutor_generate_id ();
 			req->id = header->qid;
 			if (++r > max_id_cycles) {
 				msg_err ("cannot generate new id for server %s", serv->name);
@@ -1376,7 +1339,6 @@ dns_resolver_init (struct event_base *ev_base, struct config_file *cfg)
 	
 	new = g_slice_alloc0 (sizeof (struct rspamd_dns_resolver));
 	new->ev_base = ev_base;
-	new->permutor = dns_permutor_new ();
 	new->io_channels = g_hash_table_new (g_direct_hash, g_direct_equal);
 	new->request_timeout = cfg->dns_timeout;
 	new->max_retransmits = cfg->dns_retransmits;