This is a note to let you know that I've just added the patch titled lwtunnel: Validate RTA_ENCAP_TYPE attribute length to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: lwtunnel-validate-rta_encap_type-attribute-length.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 8bda81a4d400cf8a72e554012f0d8c45e07a3904 Mon Sep 17 00:00:00 2001 From: David Ahern <dsahern@xxxxxxxxxx> Date: Thu, 30 Dec 2021 17:36:35 -0700 Subject: lwtunnel: Validate RTA_ENCAP_TYPE attribute length From: David Ahern <dsahern@xxxxxxxxxx> commit 8bda81a4d400cf8a72e554012f0d8c45e07a3904 upstream. lwtunnel_valid_encap_type_attr is used to validate encap attributes within a multipath route. Add length validation checking to the type. lwtunnel_valid_encap_type_attr is called converting attributes to fib{6,}_config struct which means it is used before fib_get_nhs, ip6_route_multipath_add, and ip6_route_multipath_del - other locations that use rtnh_ok and then nla_get_u16 on RTA_ENCAP_TYPE attribute. Fixes: 9ed59592e3e3 ("lwtunnel: fix autoload of lwt modules") Signed-off-by: David Ahern <dsahern@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/core/lwtunnel.c | 4 ++++ net/ipv4/fib_semantics.c | 3 +++ net/ipv6/route.c | 4 ++++ 3 files changed, 11 insertions(+) --- a/net/core/lwtunnel.c +++ b/net/core/lwtunnel.c @@ -197,6 +197,10 @@ int lwtunnel_valid_encap_type_attr(struc nla_entype = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); if (nla_entype) { + if (nla_len(nla_entype) < sizeof(u16)) { + NL_SET_ERR_MSG(extack, "Invalid RTA_ENCAP_TYPE"); + return -EINVAL; + } encap_type = nla_get_u16(nla_entype); if (lwtunnel_valid_encap_type(encap_type, --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -740,6 +740,9 @@ static int fib_get_nhs(struct fib_info * } fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); + /* RTA_ENCAP_TYPE length checked in + * lwtunnel_valid_encap_type_attr + */ nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); if (nla) fib_cfg.fc_encap_type = nla_get_u16(nla); --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5287,6 +5287,10 @@ static int ip6_route_multipath_add(struc r_cfg.fc_flags |= RTF_GATEWAY; } r_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); + + /* RTA_ENCAP_TYPE length checked in + * lwtunnel_valid_encap_type_attr + */ nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); if (nla) r_cfg.fc_encap_type = nla_get_u16(nla); Patches currently in stable-queue which might be from dsahern@xxxxxxxxxx are queue-5.15/ipv4-check-attribute-length-for-rta_flow-in-multipath-route.patch queue-5.15/ipv6-check-attribute-length-for-rta_gateway-when-deleting-multipath-route.patch queue-5.15/ipv6-check-attribute-length-for-rta_gateway-in-multipath-route.patch queue-5.15/lwtunnel-validate-rta_encap_type-attribute-length.patch queue-5.15/ipv4-check-attribute-length-for-rta_gateway-in-multipath-route.patch