kernel/linux.git/include/net/nexthop.h, branch v5.4.269

net: ipv4: Fix rtnexthop len when RTA_FLOW is present

2021-10-06T13:42:33+00:00

[ Upstream commit 597aa16c782496bf74c5dc3b45ff472ade6cee64 ] 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 Signed-off-by: Sasha Levin

ipv6: fix suspecious RCU usage warning

2021-03-30T12:35:25+00:00

[ Upstream commit 28259bac7f1dde06d8ba324e222bbec9d4e92f2b ] Syzbot reported the suspecious RCU usage in nexthop_fib6_nh() when called from ipv6_route_seq_show(). The reason is ipv6_route_seq_start() calls rcu_read_lock_bh(), while nexthop_fib6_nh() calls rcu_dereference_rtnl(). The fix proposed is to add a variant of nexthop_fib6_nh() to use rcu_dereference_bh_rtnl() for ipv6_route_seq_show(). The reported trace is as follows: ./include/net/nexthop.h:416 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by syz-executor.0/17895: at: seq_read+0x71/0x12a0 fs/seq_file.c:169 at: seq_file_net include/linux/seq_file_net.h:19 [inline] at: ipv6_route_seq_start+0xaf/0x300 net/ipv6/ip6_fib.c:2616 stack backtrace: CPU: 1 PID: 17895 Comm: syz-executor.0 Not tainted 4.15.0-syzkaller #0 Call Trace: [] __dump_stack lib/dump_stack.c:17 [inline] [] dump_stack+0xd8/0x147 lib/dump_stack.c:53 [] lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5745 [] nexthop_fib6_nh include/net/nexthop.h:416 [inline] [] ipv6_route_native_seq_show net/ipv6/ip6_fib.c:2488 [inline] [] ipv6_route_seq_show+0x436/0x7a0 net/ipv6/ip6_fib.c:2673 [] seq_read+0xccf/0x12a0 fs/seq_file.c:276 [] proc_reg_read+0x10c/0x1d0 fs/proc/inode.c:231 [] do_loop_readv_writev fs/read_write.c:714 [inline] [] do_loop_readv_writev fs/read_write.c:701 [inline] [] do_iter_read+0x49e/0x660 fs/read_write.c:935 [] vfs_readv+0xfb/0x170 fs/read_write.c:997 [] kernel_readv fs/splice.c:361 [inline] [] default_file_splice_read+0x487/0x9c0 fs/splice.c:416 [] do_splice_to+0x129/0x190 fs/splice.c:879 [] splice_direct_to_actor+0x256/0x890 fs/splice.c:951 [] do_splice_direct+0x1dd/0x2b0 fs/splice.c:1060 [] do_sendfile+0x597/0xce0 fs/read_write.c:1459 [] SYSC_sendfile64 fs/read_write.c:1520 [inline] [] SyS_sendfile64+0x155/0x170 fs/read_write.c:1506 [] do_syscall_64+0x1ff/0x310 arch/x86/entry/common.c:305 [] entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: f88d8ea67fbdb ("ipv6: Plumb support for nexthop object in a fib6_info") Reported-by: syzbot Signed-off-by: Wei Wang Cc: David Ahern Cc: Ido Schimmel Cc: Petr Machata Cc: Eric Dumazet Reviewed-by: Ido Schimmel Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

ipv4: nexthop version of fib_info_nh_uses_dev

2020-06-03T06:21:37+00:00

commit 1fd1c768f3624a5e66766e7b4ddb9b607cd834a5 upstream. Similar to the last path, need to fix fib_info_nh_uses_dev for external nexthops to avoid referencing multiple nh_grp structs. Move the device check in fib_info_nh_uses_dev to a helper and create a nexthop version that is called if the fib_info uses an external nexthop. Fixes: 430a049190de ("nexthop: Add support for nexthop groups") Signed-off-by: David Ahern Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

nexthop: Expand nexthop_is_multipath in a few places

2020-06-03T06:21:37+00:00

commit 0b5e2e39739e861fa5fc84ab27a35dbe62a15330 upstream. I got too fancy consolidating checks on multipath type. The result is that path lookups can access 2 different nh_grp structs as exposed by Nik's torture tests. Expand nexthop_is_multipath within nexthop.h to avoid multiple, nh_grp dereferences and make decisions based on the consistent struct. Only 2 places left using nexthop_is_multipath are within IPv6, both only check that the nexthop is a multipath for a branching decision which are acceptable. Fixes: 430a049190de ("nexthop: Add support for nexthop groups") Signed-off-by: David Ahern Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

nexthops: don't modify published nexthop groups

2020-06-03T06:21:37+00:00

commit 90f33bffa382598a32cc82abfeb20adc92d041b6 upstream. We must avoid modifying published nexthop groups while they might be in use, otherwise we might see NULL ptr dereferences. In order to do that we allocate 2 nexthoup group structures upon nexthop creation and swap between them when we have to delete an entry. The reason is that we can't fail nexthop group removal, so we can't handle allocation failure thus we move the extra allocation on creation where we can safely fail and return ENOMEM. Fixes: 430a049190de ("nexthop: Add support for nexthop groups") Signed-off-by: Nikolay Aleksandrov Signed-off-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: Properly update v4 routes with v6 nexthop

2019-09-05T10:35:58+00:00

When creating a v4 route that uses a v6 nexthop from a nexthop group. Allow the kernel to properly send the nexthop as v6 via the RTA_VIA attribute. Broken behavior: $ ip nexthop add via fe80::9 dev eth0 $ ip nexthop show id 1 via fe80::9 dev eth0 scope link $ ip route add 4.5.6.7/32 nhid 1 $ ip route show default via 10.0.2.2 dev eth0 4.5.6.7 nhid 1 via 254.128.0.0 dev eth0 10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15 $ Fixed behavior: $ ip nexthop add via fe80::9 dev eth0 $ ip nexthop show id 1 via fe80::9 dev eth0 scope link $ ip route add 4.5.6.7/32 nhid 1 $ ip route show default via 10.0.2.2 dev eth0 4.5.6.7 nhid 1 via inet6 fe80::9 dev eth0 10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15 $ v2, v3: Addresses code review comments from David Ahern Fixes: dcb1ecb50edf (“ipv4: Prepare for fib6_nh from a nexthop object”) Signed-off-by: Donald Sharp Reviewed-by: David Ahern Signed-off-by: David S. Miller

nexthop: Fix nexthop_num_path for blackhole nexthops

2019-08-25T21:29:10+00:00

Donald reported this sequence: ip next add id 1 blackhole ip next add id 2 blackhole ip ro add 1.1.1.1/32 nhid 1 ip ro add 1.1.1.2/32 nhid 2 would cause a crash. Backtrace is: [ 151.302790] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 151.304043] CPU: 1 PID: 277 Comm: ip Not tainted 5.3.0-rc5+ #37 [ 151.305078] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1 04/01/2014 [ 151.306526] RIP: 0010:fib_add_nexthop+0x8b/0x2aa [ 151.307343] Code: 35 f7 81 48 8d 14 01 c7 02 f1 f1 f1 f1 c7 42 04 01 f4 f4 f4 48 89 f2 48 c1 ea 03 65 48 8b 0c 25 28 00 00 00 48 89 4d d0 31 c9 <80> 3c 02 00 74 08 48 89 f7 e8 1a e8 53 ff be 08 00 00 00 4c 89 e7 [ 151.310549] RSP: 0018:ffff888116c27340 EFLAGS: 00010246 [ 151.311469] RAX: dffffc0000000000 RBX: ffff8881154ece00 RCX: 0000000000000000 [ 151.312713] RDX: 0000000000000004 RSI: 0000000000000020 RDI: ffff888115649b40 [ 151.313968] RBP: ffff888116c273d8 R08: ffffed10221e3757 R09: ffff888110f1bab8 [ 151.315212] R10: 0000000000000001 R11: ffff888110f1bab3 R12: ffff888115649b40 [ 151.316456] R13: 0000000000000020 R14: ffff888116c273b0 R15: ffff888115649b40 [ 151.317707] FS: 00007f60b4d8d800(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000 [ 151.319113] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 151.320119] CR2: 0000555671ffdc00 CR3: 00000001136ba005 CR4: 0000000000020ee0 [ 151.321367] Call Trace: [ 151.321820] ? fib_nexthop_info+0x635/0x635 [ 151.322572] fib_dump_info+0xaa4/0xde0 [ 151.323247] ? fib_create_info+0x2431/0x2431 [ 151.324008] ? napi_alloc_frag+0x2a/0x2a [ 151.324711] rtmsg_fib+0x2c4/0x3be [ 151.325339] fib_table_insert+0xe2f/0xeee ... fib_dump_info incorrectly has nhs = 0 for blackhole nexthops, so it believes the nexthop object is a multipath group (nhs != 1) and ends up down the nexthop_mpath_fill_node() path which is wrong for a blackhole. The blackhole check in nexthop_num_path is leftover from early days of the blackhole implementation which did not initialize the device. In the end the design was simpler (fewer special case checks) to set the device to loopback in nh_info, so the check in nexthop_num_path should have been removed. Fixes: 430a049190de ("nexthop: Add support for nexthop groups") Reported-by: Donald Sharp Signed-off-by: David Ahern Signed-off-by: David S. Miller

nexthops: Add ipv6 helper to walk all fib6_nh in a nexthop struct

2019-06-10T17:44:56+00:00

IPv6 has traditionally had a single fib6_nh per fib6_info. With nexthops we can have multiple fib6_nh associated with a fib6_info. Add a nexthop helper to invoke a callback for each fib6_nh in a 'struct nexthop'. If the callback returns non-0, the loop is stopped and the return value passed to the caller. Signed-off-by: David Ahern Signed-off-by: David S. Miller

nexthop: off by one in nexthop_mpath_select()

2019-06-09T20:37:25+00:00

The nhg->nh_entries[] array is allocated in nexthop_grp_alloc() and it has nhg->num_nh elements so this check should be >= instead of >. Fixes: 430a049190de ("nexthop: Add support for nexthop groups") Signed-off-by: Dan Carpenter Reviewed-by: David Ahern Signed-off-by: David S. Miller

ipv6: Plumb support for nexthop object in a fib6_info

2019-06-05T02:26:50+00:00

Add struct nexthop and nh_list list_head to fib6_info. nh_list is the fib6_info side of the nexthop <-> fib_info relationship. Since a fib6_info referencing a nexthop object can not have 'sibling' entries (the old way of doing multipath routes), the nh_list is a union with fib6_siblings. Add f6i_list list_head to 'struct nexthop' to track fib6_info entries using a nexthop instance. Update __remove_nexthop_fib to walk f6_list and delete fib entries using the nexthop. Add a few nexthop helpers for use when a nexthop is added to fib6_info: - nexthop_fib6_nh - return first fib6_nh in a nexthop object - fib6_info_nh_dev moved to nexthop.h and updated to use nexthop_fib6_nh if the fib6_info references a nexthop object - nexthop_path_fib6_result - similar to ipv4, select a path within a multipath nexthop object. If the nexthop is a blackhole, set fib6_result type to RTN_BLACKHOLE, and set the REJECT flag Update the fib6_info references to check for nh and take a different path as needed: - rt6_qualify_for_ecmp - if a fib entry uses a nexthop object it can NOT be coalesced with other fib entries into a multipath route - rt6_duplicate_nexthop - use nexthop_cmp if either fib6_info references a nexthop - addrconf (host routes), RA's and info entries (anything configured via ndisc) does not use nexthop objects - fib6_info_destroy_rcu - put reference to nexthop object - fib6_purge_rt - drop fib6_info from f6i_list - fib6_select_path - update to use the new nexthop_path_fib6_result when fib entry uses a nexthop object - rt6_device_match - update to catch use of nexthop object as a blackhole and set fib6_type and flags. - ip6_route_info_create - don't add space for fib6_nh if fib entry is going to reference a nexthop object, take a reference to nexthop object, disallow use of source routing - rt6_nlmsg_size - add space for RTA_NH_ID - add rt6_fill_node_nexthop to add nexthop data on a dump As with ipv4, most of the changes push existing code into the else branch of whether the fib entry uses a nexthop object. Update the nexthop code to walk f6i_list on a nexthop deleted to remove fib entries referencing it. Signed-off-by: David Ahern Signed-off-by: David S. Miller