kernel/linux.git/include/net/ip_fib.h, branch v6.6.132

ipv4: Fix incorrect TOS in route get reply

2024-08-03T06:54:05+00:00

[ Upstream commit 338bb57e4c2a1c2c6fc92f9c0bd35be7587adca7 ] The TOS value that is returned to user space in the route get reply is the one with which the lookup was performed ('fl4->flowi4_tos'). This is fine when the matched route is configured with a TOS as it would not match if its TOS value did not match the one with which the lookup was performed. However, matching on TOS is only performed when the route's TOS is not zero. It is therefore possible to have the kernel incorrectly return a non-zero TOS: # ip link add name dummy1 up type dummy # ip address add 192.0.2.1/24 dev dummy1 # ip route get 192.0.2.2 tos 0xfc 192.0.2.2 tos 0x1c dev dummy1 src 192.0.2.1 uid 0 cache Fix by adding a DSCP field to the FIB result structure (inside an existing 4 bytes hole), populating it in the route lookup and using it when filling the route get reply. Output after the patch: # ip link add name dummy1 up type dummy # ip address add 192.0.2.1/24 dev dummy1 # ip route get 192.0.2.2 tos 0xfc 192.0.2.2 dev dummy1 src 192.0.2.1 uid 0 cache Fixes: 1a00fee4ffb2 ("ipv4: Remove rt_key_{src,dst,tos} from struct rtable.") Signed-off-by: Ido Schimmel Reviewed-by: David Ahern Reviewed-by: Guillaume Nault Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

ipv4/fib: send notify when delete source address routes

2023-10-03T07:00:40+00:00

After deleting an interface address in fib_del_ifaddr(), the function scans the fib_info list for stray entries and calls fib_flush() and fib_table_flush(). Then the stray entries will be deleted silently and no RTM_DELROUTE notification will be sent. This lack of notification can make routing daemons, or monitor like `ip monitor route` miss the routing changes. e.g. + ip link add dummy1 type dummy + ip link add dummy2 type dummy + ip link set dummy1 up + ip link set dummy2 up + ip addr add 192.168.5.5/24 dev dummy1 + ip route add 7.7.7.0/24 dev dummy2 src 192.168.5.5 + ip -4 route 7.7.7.0/24 dev dummy2 scope link src 192.168.5.5 192.168.5.0/24 dev dummy1 proto kernel scope link src 192.168.5.5 + ip monitor route + ip addr del 192.168.5.5/24 dev dummy1 Deleted 192.168.5.0/24 dev dummy1 proto kernel scope link src 192.168.5.5 Deleted broadcast 192.168.5.255 dev dummy1 table local proto kernel scope link src 192.168.5.5 Deleted local 192.168.5.5 dev dummy1 table local proto kernel scope host src 192.168.5.5 As Ido reminded, fib_table_flush() isn't only called when an address is deleted, but also when an interface is deleted or put down. The lack of notification in these cases is deliberate. And commit 7c6bb7d2faaf ("net/ipv6: Add knob to skip DELROUTE message on device down") introduced a sysctl to make IPv6 behave like IPv4 in this regard. So we can't send the route delete notify blindly in fib_table_flush(). To fix this issue, let's add a new flag in "struct fib_info" to track the deleted prefer source address routes, and only send notify for them. After update: + ip monitor route + ip addr del 192.168.5.5/24 dev dummy1 Deleted 192.168.5.0/24 dev dummy1 proto kernel scope link src 192.168.5.5 Deleted broadcast 192.168.5.255 dev dummy1 table local proto kernel scope link src 192.168.5.5 Deleted local 192.168.5.5 dev dummy1 table local proto kernel scope host src 192.168.5.5 Deleted 7.7.7.0/24 dev dummy2 scope link src 192.168.5.5 Suggested-by: Thomas Haller Signed-off-by: Hangbin Liu Acked-by: Nicolas Dichtel Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230922075508.848925-1-liuhangbin@gmail.com Signed-off-by: Paolo Abeni

net: fib: avoid warn splat in flow dissector

2023-08-31T10:33:03+00:00

New skbs allocated via nf_send_reset() have skb->dev == NULL. fib*_rules_early_flow_dissect helpers already have a 'struct net' argument but its not passed down to the flow dissector core, which will then WARN as it can't derive a net namespace to use: WARNING: CPU: 0 PID: 0 at net/core/flow_dissector.c:1016 __skb_flow_dissect+0xa91/0x1cd0 [..] ip_route_me_harder+0x143/0x330 nf_send_reset+0x17c/0x2d0 [nf_reject_ipv4] nft_reject_inet_eval+0xa9/0xf2 [nft_reject_inet] nft_do_chain+0x198/0x5d0 [nf_tables] nft_do_chain_inet+0xa4/0x110 [nf_tables] nf_hook_slow+0x41/0xc0 ip_local_deliver+0xce/0x110 .. Cc: Stanislav Fomichev Cc: David Ahern Cc: Ido Schimmel Fixes: 812fa71f0d96 ("netfilter: Dissect flow after packet mangling") Link: https://bugzilla.kernel.org/show_bug.cgi?id=217826 Signed-off-by: Florian Westphal Reviewed-by: Ido Schimmel Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230830110043.30497-1-fw@strlen.de Signed-off-by: Paolo Abeni

ipv4: Use dscp_t in struct fib_entry_notifier_info

2022-04-12T00:37:50+00:00

Use the new dscp_t type to replace the tos field of struct fib_entry_notifier_info. This ensures ECN bits are ignored and makes it compatible with the dscp field of struct fib_rt_info. This also allows sparse to flag potential incorrect uses of DSCP and ECN bits. Signed-off-by: Guillaume Nault Reviewed-by: Ido Schimmel Reviewed-by: David Ahern Signed-off-by: Jakub Kicinski

ipv4: Use dscp_t in struct fib_rt_info

2022-04-12T00:37:50+00:00

Use the new dscp_t type to replace the tos field of struct fib_rt_info. This ensures ECN bits are ignored and makes it compatible with the fa_dscp field of struct fib_alias. This also allows sparse to flag potential incorrect uses of DSCP and ECN bits. Signed-off-by: Guillaume Nault Reviewed-by: Ido Schimmel Reviewed-by: David Ahern Signed-off-by: Jakub Kicinski

ipv4: Reject routes specifying ECN bits in rtm_tos

2022-02-08T04:12:46+00:00

Use the new dscp_t type to replace the fc_tos field of fib_config, to ensure IPv4 routes aren't influenced by ECN bits when configured with non-zero rtm_tos. Before this patch, IPv4 routes specifying an rtm_tos with some of the ECN bits set were accepted. However they wouldn't work (never match) as IPv4 normally clears the ECN bits with IPTOS_RT_MASK before doing a FIB lookup (although a few buggy code paths don't). After this patch, IPv4 routes specifying an rtm_tos with any ECN bit set is rejected. Note: IPv6 routes ignore rtm_tos altogether, any rtm_tos is accepted, but treated as if it were 0. Signed-off-by: Guillaume Nault Acked-by: David Ahern Reviewed-by: Toke Høiland-Jørgensen Signed-off-by: Jakub Kicinski

inet: add net device refcount tracker to struct fib_nh_common

2021-12-08T04:44:59+00:00

Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski

ipv4: convert fib_num_tclassid_users to atomic_t

2021-12-02T11:56:04+00:00

Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh") changes to net->ipv4.fib_num_tclassid_users were protected by RTNL. After the change, this is no longer the case, as free_fib_info_rcu() runs after rcu grace period, without rtnl being held. Fixes: faa041a40b9f ("ipv4: Create cleanup helper for fib_nh") Signed-off-by: Eric Dumazet Cc: David Ahern Reviewed-by: David Ahern Signed-off-by: David S. Miller

net: ipv4: Fix rtnexthop len when RTA_FLOW is present

2021-09-24T13:07:10+00:00

Multipath RTA_FLOW is embedded in nexthop. Dump it in fib_add_nexthop() to get the length of rtnexthop correct. Fixes: b0f60193632e ("ipv4: Refactor nexthop attributes in fib_dump_info") Signed-off-by: Xiao Liang Reviewed-by: David Ahern Signed-off-by: David S. Miller

net: convert fib_treeref from int to refcount_t

2021-07-30T13:33:24+00:00

refcount_t type should be used instead of int when fib_treeref is used as a reference counter,and avoid use-after-free risks. Signed-off-by: Yajun Deng Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20210729071350.28919-1-yajun.deng@linux.dev Signed-off-by: Jakub Kicinski