From: Matthias Schiffer Date: Thu, 12 Apr 2018 22:14:56 +0200 Subject: kernel: disable accept_ra by default Our script setting accept_ra to 0 on all interfaces got lost in the transition to procd. This remained unnoticed for a long time, as was also enable forwarding on all interfaces, which prevents RA handling by default. Providing a way to ensure net.ipv6.conf.default.accept_ra is set early enough is a nicer solution than fixing up interfaces in a script (given the patch is accepted upstream). Signed-off-by: Matthias Schiffer diff --git a/target/linux/generic/config-3.18 b/target/linux/generic/config-3.18 index 4c3215b594cea9f3d001f8a9f73bbdf78e30ceff..bf13cefde0c5dc45788da9dea57aca5def9b152b 100644 --- a/target/linux/generic/config-3.18 +++ b/target/linux/generic/config-3.18 @@ -1604,6 +1604,7 @@ CONFIG_IOSCHED_NOOP=y # CONFIG_IPC_NS is not set # CONFIG_IPMI_HANDLER is not set # CONFIG_IPV6 is not set +# CONFIG_IPV6_ACCEPT_RA_DEFAULT is not set # CONFIG_IPV6_MIP6 is not set # CONFIG_IPV6_MROUTE is not set # CONFIG_IPV6_MROUTE_MULTIPLE_TABLES is not set diff --git a/target/linux/generic/config-4.4 b/target/linux/generic/config-4.4 index a8fd15d1a4a40681d80da06ad7a826966287d8d8..e2d69426370a3e50703c48fb60c5b1b3aa601ef3 100644 --- a/target/linux/generic/config-4.4 +++ b/target/linux/generic/config-4.4 @@ -1671,6 +1671,7 @@ CONFIG_IOSCHED_NOOP=y # CONFIG_IPC_NS is not set # CONFIG_IPMI_HANDLER is not set # CONFIG_IPV6 is not set +# CONFIG_IPV6_ACCEPT_RA_DEFAULT is not set # CONFIG_IPV6_ILA is not set # CONFIG_IPV6_MIP6 is not set # CONFIG_IPV6_MROUTE is not set diff --git a/target/linux/generic/patches-3.18/690-ipv6-provide-Kconfig-switch-to-disable-accept_ra-by-.patch b/target/linux/generic/patches-3.18/690-ipv6-provide-Kconfig-switch-to-disable-accept_ra-by-.patch new file mode 100644 index 0000000000000000000000000000000000000000..6067be31830f6cc788708632dba36f338eb67d39 --- /dev/null +++ b/target/linux/generic/patches-3.18/690-ipv6-provide-Kconfig-switch-to-disable-accept_ra-by-.patch @@ -0,0 +1,60 @@ +From 782710d7f18a2c9999410cb7cfc92955463897d8 Mon Sep 17 00:00:00 2001 +Message-Id: <782710d7f18a2c9999410cb7cfc92955463897d8.1523559442.git.mschiffer@universe-factory.net> +From: Matthias Schiffer +Date: Thu, 12 Apr 2018 20:08:05 +0200 +Subject: [PATCH net-next] ipv6: provide Kconfig switch to disable accept_ra by + default + +Many distributions and users prefer to handle router advertisements in +userspace; one example is OpenWrt, which includes a combined RA and DHCPv6 +client. For such configurations, accept_ra should not be enabled by +default. + +As setting net.ipv6.conf.default.accept_ra via sysctl.conf or similar +facilities may be too late to catch all interfaces and common sysctl.conf +tools do not allow setting an option for all existing interfaces, this +patch provides a Kconfig option to control the default value of +default.accept_ra. + +Using default.accept_ra is preferable to all.accept_ra for our usecase, +as disabling all.accept_ra would preclude users from explicitly enabling +accept_ra on individual interfaces. + +Signed-off-by: Matthias Schiffer +--- + net/ipv6/Kconfig | 12 ++++++++++++ + net/ipv6/addrconf.c | 2 +- + 2 files changed, 13 insertions(+), 1 deletion(-) + +--- a/net/ipv6/Kconfig ++++ b/net/ipv6/Kconfig +@@ -21,6 +21,18 @@ menuconfig IPV6 + + if IPV6 + ++config IPV6_ACCEPT_RA_DEFAULT ++ bool "IPv6: Accept router advertisements by default" ++ default y ++ help ++ The kernel can internally handle IPv6 router advertisements for ++ stateless address autoconfiguration (SLAAC) and route configuration, ++ which can be configured in detail and per-interface using a number of ++ sysctl options. This option controls the default value of ++ net.ipv6.conf.default.accept_ra. ++ ++ If unsure, say Y. ++ + config IPV6_ROUTER_PREF + bool "IPv6: Router Preference (RFC 4191) support" + ---help--- +--- a/net/ipv6/addrconf.c ++++ b/net/ipv6/addrconf.c +@@ -207,7 +207,7 @@ static struct ipv6_devconf ipv6_devconf_ + .forwarding = 0, + .hop_limit = IPV6_DEFAULT_HOPLIMIT, + .mtu6 = IPV6_MIN_MTU, +- .accept_ra = 1, ++ .accept_ra = IS_ENABLED(CONFIG_IPV6_ACCEPT_RA_DEFAULT), + .accept_redirects = 1, + .autoconf = 1, + .force_mld_version = 0, diff --git a/target/linux/generic/patches-4.4/690-ipv6-provide-Kconfig-switch-to-disable-accept_ra-by-.patch b/target/linux/generic/patches-4.4/690-ipv6-provide-Kconfig-switch-to-disable-accept_ra-by-.patch new file mode 100644 index 0000000000000000000000000000000000000000..8184a27705348c609d09c39a6d90b810d28fdead --- /dev/null +++ b/target/linux/generic/patches-4.4/690-ipv6-provide-Kconfig-switch-to-disable-accept_ra-by-.patch @@ -0,0 +1,60 @@ +From 782710d7f18a2c9999410cb7cfc92955463897d8 Mon Sep 17 00:00:00 2001 +Message-Id: <782710d7f18a2c9999410cb7cfc92955463897d8.1523559442.git.mschiffer@universe-factory.net> +From: Matthias Schiffer +Date: Thu, 12 Apr 2018 20:08:05 +0200 +Subject: [PATCH net-next] ipv6: provide Kconfig switch to disable accept_ra by + default + +Many distributions and users prefer to handle router advertisements in +userspace; one example is OpenWrt, which includes a combined RA and DHCPv6 +client. For such configurations, accept_ra should not be enabled by +default. + +As setting net.ipv6.conf.default.accept_ra via sysctl.conf or similar +facilities may be too late to catch all interfaces and common sysctl.conf +tools do not allow setting an option for all existing interfaces, this +patch provides a Kconfig option to control the default value of +default.accept_ra. + +Using default.accept_ra is preferable to all.accept_ra for our usecase, +as disabling all.accept_ra would preclude users from explicitly enabling +accept_ra on individual interfaces. + +Signed-off-by: Matthias Schiffer +--- + net/ipv6/Kconfig | 12 ++++++++++++ + net/ipv6/addrconf.c | 2 +- + 2 files changed, 13 insertions(+), 1 deletion(-) + +--- a/net/ipv6/Kconfig ++++ b/net/ipv6/Kconfig +@@ -20,6 +20,18 @@ menuconfig IPV6 + + if IPV6 + ++config IPV6_ACCEPT_RA_DEFAULT ++ bool "IPv6: Accept router advertisements by default" ++ default y ++ help ++ The kernel can internally handle IPv6 router advertisements for ++ stateless address autoconfiguration (SLAAC) and route configuration, ++ which can be configured in detail and per-interface using a number of ++ sysctl options. This option controls the default value of ++ net.ipv6.conf.default.accept_ra. ++ ++ If unsure, say Y. ++ + config IPV6_ROUTER_PREF + bool "IPv6: Router Preference (RFC 4191) support" + ---help--- +--- a/net/ipv6/addrconf.c ++++ b/net/ipv6/addrconf.c +@@ -222,7 +222,7 @@ static struct ipv6_devconf ipv6_devconf_ + .forwarding = 0, + .hop_limit = IPV6_DEFAULT_HOPLIMIT, + .mtu6 = IPV6_MIN_MTU, +- .accept_ra = 1, ++ .accept_ra = IS_ENABLED(CONFIG_IPV6_ACCEPT_RA_DEFAULT), + .accept_redirects = 1, + .autoconf = 1, + .force_mld_version = 0,