From: Max Tottenham mtottenh@akamai.com
[ Upstream commit 6c02568fd1ae53099b4ab86365c5be1ff15f586b ]
Instead of relying on skb->transport_header being set correctly, opt instead to parse the L3 header length out of the L3 headers for both IPv4/IPv6 when the Extended Layer Op for tcp/udp is used. This fixes a bug if GRO is disabled, when GRO is disabled skb->transport_header is set by __netif_receive_skb_core() to point to the L3 header, it's later fixed by the upper protocol layers, but act_pedit will receive the SKB before the fixups are completed. The existing behavior causes the following to edit the L3 header if GRO is disabled instead of the UDP header:
tc filter add dev eth0 ingress protocol ip flower ip_proto udp \ dst_ip 192.168.1.3 action pedit ex munge udp set dport 18053
Also re-introduce a rate-limited warning if we were unable to extract the header offset when using the 'ex' interface.
Fixes: 71d0ed7079df ("net/act_pedit: Support using offset relative to the conventional network headers") Signed-off-by: Max Tottenham mtottenh@akamai.com Reviewed-by: Josh Hunt johunt@akamai.com Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202305261541.N165u9TZ-lkp@intel.com/ Reviewed-by: Pedro Tammela pctammela@mojatatu.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/sched/act_pedit.c | 48 ++++++++++++++++++++++++++++++++++++++----- 1 file changed, 43 insertions(+), 5 deletions(-)
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c index 48e14cbcd8ffe..180669aa9d097 100644 --- a/net/sched/act_pedit.c +++ b/net/sched/act_pedit.c @@ -13,7 +13,10 @@ #include <linux/rtnetlink.h> #include <linux/module.h> #include <linux/init.h> +#include <linux/ip.h> +#include <linux/ipv6.h> #include <linux/slab.h> +#include <net/ipv6.h> #include <net/netlink.h> #include <net/pkt_sched.h> #include <linux/tc_act/tc_pedit.h> @@ -312,28 +315,58 @@ static bool offset_valid(struct sk_buff *skb, int offset) return true; }
-static void pedit_skb_hdr_offset(struct sk_buff *skb, +static int pedit_l4_skb_offset(struct sk_buff *skb, int *hoffset, const int header_type) +{ + const int noff = skb_network_offset(skb); + int ret = -EINVAL; + struct iphdr _iph; + + switch (skb->protocol) { + case htons(ETH_P_IP): { + const struct iphdr *iph = skb_header_pointer(skb, noff, sizeof(_iph), &_iph); + + if (!iph) + goto out; + *hoffset = noff + iph->ihl * 4; + ret = 0; + break; + } + case htons(ETH_P_IPV6): + ret = ipv6_find_hdr(skb, hoffset, header_type, NULL, NULL) == header_type ? 0 : -EINVAL; + break; + } +out: + return ret; +} + +static int pedit_skb_hdr_offset(struct sk_buff *skb, enum pedit_header_type htype, int *hoffset) { + int ret = -EINVAL; /* 'htype' is validated in the netlink parsing */ switch (htype) { case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH: - if (skb_mac_header_was_set(skb)) + if (skb_mac_header_was_set(skb)) { *hoffset = skb_mac_offset(skb); + ret = 0; + } break; case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK: case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4: case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6: *hoffset = skb_network_offset(skb); + ret = 0; break; case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP: + ret = pedit_l4_skb_offset(skb, hoffset, IPPROTO_TCP); + break; case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP: - if (skb_transport_header_was_set(skb)) - *hoffset = skb_transport_offset(skb); + ret = pedit_l4_skb_offset(skb, hoffset, IPPROTO_UDP); break; default: break; } + return ret; }
static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a, @@ -368,6 +401,7 @@ static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a, int hoffset = 0; u32 *ptr, hdata; u32 val; + int rc;
if (tkey_ex) { htype = tkey_ex->htype; @@ -376,7 +410,11 @@ static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a, tkey_ex++; }
- pedit_skb_hdr_offset(skb, htype, &hoffset); + rc = pedit_skb_hdr_offset(skb, htype, &hoffset); + if (rc) { + pr_info_ratelimited("tc action pedit unable to extract header offset for header type (0x%x)\n", htype); + goto bad; + }
if (tkey->offmask) { u8 *d, _d;