linux/net, branch v5.12

Revert "net/rds: Avoid potential use after free in rds_send_remove_from_sock"

2021-04-24T16:32:35Z

This reverts commit 0c85a7e87465f2d4cbc768e245f4f45b2f299b05. The games with 'rm' are on (two separate instances) of a local variable, and make no difference. Quoting Aditya Pakki: "I was the author of the patch and it was the cause of the giant UMN revert. The patch is garbage and I was unaware of the steps involved in retracting it. I *believed* the maintainers would pull it, given it was already under Greg's list. The patch does not introduce any bugs but is pointless and is stupid. I accept my incompetence and for not requesting a revert earlier." Link: https://lwn.net/Articles/854319/ Requested-by: Aditya Pakki Cc: Santosh Shilimkar Cc: David S. Miller Cc: Al Viro Signed-off-by: Linus Torvalds

netlink: don't call ->netlink_bind with table lock held

2021-04-17T00:01:04Z

When I added support to allow generic netlink multicast groups to be restricted to subscribers with CAP_NET_ADMIN I was unaware that a genl_bind implementation already existed in the past. It was reverted due to ABBA deadlock: 1. ->netlink_bind gets called with the table lock held. 2. genetlink bind callback is invoked, it grabs the genl lock. But when a new genl subsystem is (un)registered, these two locks are taken in reverse order. One solution would be to revert again and add a comment in genl referring 1e82a62fec613, "genetlink: remove genl_bind"). This would need a second change in mptcp to not expose the raw token value anymore, e.g. by hashing the token with a secret key so userspace can still associate subflow events with the correct mptcp connection. However, Paolo Abeni reminded me to double-check why the netlink table is locked in the first place. I can't find one. netlink_bind() is already called without this lock when userspace joins a group via NETLINK_ADD_MEMBERSHIP setsockopt. Same holds for the netlink_unbind operation. Digging through the history, commit f773608026ee1 ("netlink: access nlk groups safely in netlink bind and getname") expanded the lock scope. commit 3a20773beeeeade ("net: netlink: cap max groups which will be considered in netlink_bind()") ... removed the nlk->ngroups access that the lock scope extension was all about. Reduce the lock scope again and always call ->netlink_bind without the table lock. The Fixes tag should be vs. the patch mentioned in the link below, but that one got squash-merged into the patch that came earlier in the series. Fixes: 4d54cc32112d8d ("mptcp: avoid lock_fast usage in accept path") Link: https://lore.kernel.org/mptcp/20210213000001.379332-8-mathew.j.martineau@linux.intel.com/T/#u Cc: Cong Wang Cc: Xin Long Cc: Johannes Berg Cc: Sean Tranchetti Cc: Paolo Abeni Cc: Pablo Neira Ayuso Signed-off-by: Florian Westphal Signed-off-by: David S. Miller

ethtool: pause: make sure we init driver stats

2021-04-14T20:03:06Z

The intention was for pause statistics to not be reported when driver does not have the relevant callback (only report an empty netlink nest). What happens currently we report all 0s instead. Make sure statistics are initialized to "not set" (which is -1) so the dumping code skips them. Fixes: 9a27a33027f2 ("ethtool: add standard pause stats") Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller

gro: ensure frag0 meets IP header alignment

2021-04-13T22:09:31Z

After commit 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head") Guenter Roeck reported one failure in his tests using sh architecture. After much debugging, we have been able to spot silent unaligned accesses in inet_gro_receive() The issue at hand is that upper networking stacks assume their header is word-aligned. Low level drivers are supposed to reserve NET_IP_ALIGN bytes before the Ethernet header to make that happen. This patch hardens skb_gro_reset_offset() to not allow frag0 fast-path if the fragment is not properly aligned. Some arches like x86, arm64 and powerpc do not care and define NET_IP_ALIGN as 0, this extra check will be a NOP for them. Note that if frag0 is not used, GRO will call pskb_may_pull() as many times as needed to pull network and transport headers. Fixes: 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head") Fixes: 78a478d0efd9 ("gro: Inline skb_gro_header and cache frag0 virtual address") Signed-off-by: Eric Dumazet Reported-by: Guenter Roeck Cc: Xuan Zhuo Cc: "Michael S. Tsirkin" Cc: Jason Wang Acked-by: Michael S. Tsirkin Tested-by: Guenter Roeck Signed-off-by: David S. Miller

net/sctp: fix race condition in sctp_destroy_sock

2021-04-13T21:59:46Z

If sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock held and sp->do_auto_asconf is true, then an element is removed from the auto_asconf_splist without any proper locking. This can happen in the following functions: 1. In sctp_accept, if sctp_sock_migrate fails. 2. In inet_create or inet6_create, if there is a bpf program attached to BPF_CGROUP_INET_SOCK_CREATE which denies creation of the sctp socket. The bug is fixed by acquiring addr_wq_lock in sctp_destroy_sock instead of sctp_close. This addresses CVE-2021-23133. Reported-by: Or Cohen Reviewed-by: Xin Long Fixes: 610236587600 ("bpf: Add new cgroup attach type to enable sock modifications") Signed-off-by: Or Cohen Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

net: Make tcp_allowed_congestion_control readonly in non-init netns

2021-04-13T21:42:51Z

Currently, tcp_allowed_congestion_control is global and writable; writing to it in any net namespace will leak into all other net namespaces. tcp_available_congestion_control and tcp_allowed_congestion_control are the only sysctls in ipv4_net_table (the per-netns sysctl table) with a NULL data pointer; their handlers (proc_tcp_available_congestion_control and proc_allowed_congestion_control) have no other way of referencing a struct net. Thus, they operate globally. Because ipv4_net_table does not use designated initializers, there is no easy way to fix up this one "bad" table entry. However, the data pointer updating logic shouldn't be applied to NULL pointers anyway, so we instead force these entries to be read-only. These sysctls used to exist in ipv4_table (init-net only), but they were moved to the per-net ipv4_net_table, presumably without realizing that tcp_allowed_congestion_control was writable and thus introduced a leak. Because the intent of that commit was only to know (i.e. read) "which congestion algorithms are available or allowed", this read-only solution should be sufficient. The logic added in recent commit 31c4d2f160eb: ("net: Ensure net namespace isolation of sysctls") does not and cannot check for NULL data pointers, because other table entries (e.g. /proc/sys/net/netfilter/nf_log/) have .data=NULL but use other methods (.extra2) to access the struct net. Fixes: 9cb8e048e5d9 ("net/ipv4/sysctl: show tcp_{allowed, available}_congestion_control in non-initial netns") Signed-off-by: Jonathon Reinhart Signed-off-by: David S. Miller

net: ip6_tunnel: Unregister catch-all devices

2021-04-13T21:31:52Z

Similarly to the sit case, we need to remove the tunnels with no addresses that have been moved to another network namespace. Fixes: 0bd8762824e73 ("ip6tnl: add x-netns support") Signed-off-by: Hristo Venev Signed-off-by: David S. Miller

net: sit: Unregister catch-all devices

2021-04-13T21:31:52Z

A sit interface created without a local or a remote address is linked into the `sit_net::tunnels_wc` list of its original namespace. When deleting a network namespace, delete the devices that have been moved. The following script triggers a null pointer dereference if devices linked in a deleted `sit_net` remain: for i in `seq 1 30`; do ip netns add ns-test ip netns exec ns-test ip link add dev veth0 type veth peer veth1 ip netns exec ns-test ip link add dev sit$i type sit dev veth0 ip netns exec ns-test ip link set dev sit$i netns $$ ip netns del ns-test done for i in `seq 1 30`; do ip link del dev sit$i done Fixes: 5e6700b3bf98f ("sit: add support of x-netns") Signed-off-by: Hristo Venev Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf

2021-04-12T23:17:50Z

Pablo Neira Ayuso says: ==================== Netfilter fixes for net The following patchset contains Netfilter fixes for net: 1) Fix NAT IPv6 offload in the flowtable. 2) icmpv6 is printed as unknown in /proc/net/nf_conntrack. 3) Use div64_u64() in nft_limit, from Eric Dumazet. 4) Use pre_exit to unregister ebtables and arptables hooks, from Florian Westphal. 5) Fix out-of-bound memset in x_tables compat match/target, also from Florian. 6) Clone set elements expression to ensure proper initialization. ==================== Signed-off-by: David S. Miller

netfilter: nftables: clone set element expression template

2021-04-12T22:19:05Z

memcpy() breaks when using connlimit in set elements. Use nft_expr_clone() to initialize the connlimit expression list, otherwise connlimit garbage collector crashes when walking on the list head copy. [ 493.064656] Workqueue: events_power_efficient nft_rhash_gc [nf_tables] [ 493.064685] RIP: 0010:find_or_evict+0x5a/0x90 [nf_conncount] [ 493.064694] Code: 2b 43 40 83 f8 01 77 0d 48 c7 c0 f5 ff ff ff 44 39 63 3c 75 df 83 6d 18 01 48 8b 43 08 48 89 de 48 8b 13 48 8b 3d ee 2f 00 00 <48> 89 42 08 48 89 10 48 b8 00 01 00 00 00 00 ad de 48 89 03 48 83 [ 493.064699] RSP: 0018:ffffc90000417dc0 EFLAGS: 00010297 [ 493.064704] RAX: 0000000000000000 RBX: ffff888134f38410 RCX: 0000000000000000 [ 493.064708] RDX: 0000000000000000 RSI: ffff888134f38410 RDI: ffff888100060cc0 [ 493.064711] RBP: ffff88812ce594a8 R08: ffff888134f38438 R09: 00000000ebb9025c [ 493.064714] R10: ffffffff8219f838 R11: 0000000000000017 R12: 0000000000000001 [ 493.064718] R13: ffffffff82146740 R14: ffff888134f38410 R15: 0000000000000000 [ 493.064721] FS: 0000000000000000(0000) GS:ffff88840e440000(0000) knlGS:0000000000000000 [ 493.064725] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 493.064729] CR2: 0000000000000008 CR3: 00000001330aa002 CR4: 00000000001706e0 [ 493.064733] Call Trace: [ 493.064737] nf_conncount_gc_list+0x8f/0x150 [nf_conncount] [ 493.064746] nft_rhash_gc+0x106/0x390 [nf_tables] Reported-by: Laura Garcia Liebana Fixes: 409444522976 ("netfilter: nf_tables: add elements with stateful expressions") Signed-off-by: Pablo Neira Ayuso