From 09196118e9f5f089dc09e792f040bdc97fcc7432 Mon Sep 17 00:00:00 2001
From: Ainar Garipov <a.garipov@adguard.com>
Date: Fri, 13 Nov 2020 14:40:22 +0300
Subject: [PATCH] Pull request: dhcpd: fix possible infinite loop, set timeouts
better
Merge in DNS/adguard-home from 2301-dhcp-check to master
Closes #2301.
Squashed commit of the following:
commit bf5c31b8592f909a372fcdaebacc491d310cc3e6
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date: Fri Nov 13 14:28:54 2020 +0300
dhcpd: fix possible infinite loop, set timeouts better
---
CHANGELOG.md | 4 ++++
internal/dhcpd/check_other_dhcp.go | 12 ++++++++++--
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0e67b966..63909d43 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,3 +13,7 @@ and this project adheres to
- This changelog :-) (#2294).
- `HACKING.md`, a guide for developers.
+
+### Fixed
+
+- Infinite loop in `/dhcp/find_active_dhcp` (#2301).
diff --git a/internal/dhcpd/check_other_dhcp.go b/internal/dhcpd/check_other_dhcp.go
index 0292528c..674949aa 100644
--- a/internal/dhcpd/check_other_dhcp.go
+++ b/internal/dhcpd/check_other_dhcp.go
@@ -88,13 +88,17 @@ func CheckIfOtherDHCPServersPresentV4(ifaceName string) (bool, error) {
for {
ok, next, err := tryConn(req, c, iface)
if next {
+ if err != nil {
+ log.Debug("dhcpv4: trying a connection: %s", err)
+ }
+
continue
}
if ok {
return true, nil
}
if err != nil {
- log.Debug("%s", err)
+ return false, err
}
}
}
@@ -107,7 +111,11 @@ func tryConn(req *dhcpv4.DHCPv4, c net.PacketConn, iface *net.Interface) (ok, ne
log.Tracef("waiting %v for an answer", defaultDiscoverTime)
b := make([]byte, 1500)
- _ = c.SetReadDeadline(time.Now().Add(defaultDiscoverTime))
+ err = c.SetDeadline(time.Now().Add(defaultDiscoverTime))
+ if err != nil {
+ return false, false, fmt.Errorf("setting deadline: %w", err)
+ }
+
n, _, err := c.ReadFrom(b)
if err != nil {
if isTimeout(err) {