103 lines
3.6 KiB
Diff
103 lines
3.6 KiB
Diff
From f8710bdc8b29ee1176fe3bfaeabebbda1b7a79f7 Mon Sep 17 00:00:00 2001
|
|
From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
|
|
Date: Mon, 11 Nov 2024 00:56:09 +0100
|
|
Subject: [PATCH] Properly randomize query id of DNS packets
|
|
|
|
---
|
|
avahi-core/wide-area.c | 36 ++++++++++++++++++++++++++++--------
|
|
configure.ac | 3 ++-
|
|
2 files changed, 30 insertions(+), 9 deletions(-)
|
|
|
|
diff --git a/avahi-core/wide-area.c b/avahi-core/wide-area.c
|
|
index 971f5e7..00a1505 100644
|
|
--- a/avahi-core/wide-area.c
|
|
+++ b/avahi-core/wide-area.c
|
|
@@ -40,6 +40,13 @@
|
|
#include "addr-util.h"
|
|
#include "rr-util.h"
|
|
|
|
+#ifdef HAVE_SYS_RANDOM_H
|
|
+#include <sys/random.h>
|
|
+#endif
|
|
+#ifndef HAVE_GETRANDOM
|
|
+# define getrandom(d, len, flags) (-1)
|
|
+#endif
|
|
+
|
|
#define CACHE_ENTRIES_MAX 500
|
|
|
|
typedef struct AvahiWideAreaCacheEntry AvahiWideAreaCacheEntry;
|
|
@@ -84,8 +91,6 @@ struct AvahiWideAreaLookupEngine {
|
|
int fd_ipv4, fd_ipv6;
|
|
AvahiWatch *watch_ipv4, *watch_ipv6;
|
|
|
|
- uint16_t next_id;
|
|
-
|
|
/* Cache */
|
|
AVAHI_LLIST_HEAD(AvahiWideAreaCacheEntry, cache);
|
|
AvahiHashmap *cache_by_key;
|
|
@@ -201,6 +206,26 @@ static void sender_timeout_callback(AvahiTimeEvent *e, void *userdata) {
|
|
avahi_time_event_update(e, avahi_elapse_time(&tv, 1000, 0));
|
|
}
|
|
|
|
+static uint16_t get_random_uint16(void) {
|
|
+ uint16_t next_id;
|
|
+
|
|
+ if (getrandom(&next_id, sizeof(next_id), 0) == -1)
|
|
+ next_id = (uint16_t) rand();
|
|
+ return next_id;
|
|
+}
|
|
+
|
|
+static uint16_t avahi_wide_area_next_id(AvahiWideAreaLookupEngine *e) {
|
|
+ uint16_t next_id;
|
|
+
|
|
+ next_id = get_random_uint16();
|
|
+ while (find_lookup(e, next_id)) {
|
|
+ /* This ID is already used, get new. */
|
|
+ next_id = get_random_uint16();
|
|
+ }
|
|
+ return next_id;
|
|
+}
|
|
+
|
|
+
|
|
AvahiWideAreaLookup *avahi_wide_area_lookup_new(
|
|
AvahiWideAreaLookupEngine *e,
|
|
AvahiKey *key,
|
|
@@ -227,11 +252,7 @@ AvahiWideAreaLookup *avahi_wide_area_lookup_new(
|
|
/* If more than 65K wide area quries are issued simultaneously,
|
|
* this will break. This should be limited by some higher level */
|
|
|
|
- for (;; e->next_id++)
|
|
- if (!find_lookup(e, e->next_id))
|
|
- break; /* This ID is not yet used. */
|
|
-
|
|
- l->id = e->next_id++;
|
|
+ l->id = avahi_wide_area_next_id(e);
|
|
|
|
/* We keep the packet around in case we need to repeat our query */
|
|
l->packet = avahi_dns_packet_new(0);
|
|
@@ -604,7 +625,6 @@ AvahiWideAreaLookupEngine *avahi_wide_area_engine_new(AvahiServer *s) {
|
|
e->watch_ipv6 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv6, AVAHI_WATCH_IN, socket_event, e);
|
|
|
|
e->n_dns_servers = e->current_dns_server = 0;
|
|
- e->next_id = (uint16_t) rand();
|
|
|
|
/* Initialize cache */
|
|
AVAHI_LLIST_HEAD_INIT(AvahiWideAreaCacheEntry, e->cache);
|
|
diff --git a/configure.ac b/configure.ac
|
|
index a3211b8..31bce3d 100644
|
|
--- a/configure.ac
|
|
+++ b/configure.ac
|
|
@@ -367,7 +367,8 @@ AC_FUNC_SELECT_ARGTYPES
|
|
# whether libc's malloc does too. (Same for realloc.)
|
|
#AC_FUNC_MALLOC
|
|
#AC_FUNC_REALLOC
|
|
-AC_CHECK_FUNCS([gethostname memchr memmove memset mkdir select socket strchr strcspn strdup strerror strrchr strspn strstr uname setresuid setreuid setresgid setregid strcasecmp gettimeofday putenv strncasecmp strlcpy gethostbyname seteuid setegid setproctitle getprogname])
|
|
+AC_CHECK_FUNCS([gethostname memchr memmove memset mkdir select socket strchr strcspn strdup strerror strrchr strspn strstr uname setresuid setreuid setresgid setregid strcasecmp gettimeofday putenv strncasecmp strlcpy gethostbyname seteuid setegid setproctitle getprogname getrandom])
|
|
+AC_CHECK_HEADERS([sys/random.h])
|
|
|
|
AC_FUNC_CHOWN
|
|
AC_FUNC_STAT
|
|
--
|
|
2.44.0
|
|
|