kernel/linux.git/net/sctp/input.c, branch v6.12.80

sctp: linearize cloned gso packets in sctp_rcv

2025-08-20T16:30:18+00:00

[ Upstream commit fd60d8a086191fe33c2d719732d2482052fa6805 ] A cloned head skb still shares these frag skbs in fraglist with the original head skb. It's not safe to access these frag skbs. syzbot reported two use-of-uninitialized-memory bugs caused by this: BUG: KMSAN: uninit-value in sctp_inq_pop+0x15b7/0x1920 net/sctp/inqueue.c:211 sctp_inq_pop+0x15b7/0x1920 net/sctp/inqueue.c:211 sctp_assoc_bh_rcv+0x1a7/0xc50 net/sctp/associola.c:998 sctp_inq_push+0x2ef/0x380 net/sctp/inqueue.c:88 sctp_backlog_rcv+0x397/0xdb0 net/sctp/input.c:331 sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1122 __release_sock+0x1da/0x330 net/core/sock.c:3106 release_sock+0x6b/0x250 net/core/sock.c:3660 sctp_wait_for_connect+0x487/0x820 net/sctp/socket.c:9360 sctp_sendmsg_to_asoc+0x1ec1/0x1f00 net/sctp/socket.c:1885 sctp_sendmsg+0x32b9/0x4a80 net/sctp/socket.c:2031 inet_sendmsg+0x25a/0x280 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:718 [inline] and BUG: KMSAN: uninit-value in sctp_assoc_bh_rcv+0x34e/0xbc0 net/sctp/associola.c:987 sctp_assoc_bh_rcv+0x34e/0xbc0 net/sctp/associola.c:987 sctp_inq_push+0x2a3/0x350 net/sctp/inqueue.c:88 sctp_backlog_rcv+0x3c7/0xda0 net/sctp/input.c:331 sk_backlog_rcv+0x142/0x420 include/net/sock.h:1148 __release_sock+0x1d3/0x330 net/core/sock.c:3213 release_sock+0x6b/0x270 net/core/sock.c:3767 sctp_wait_for_connect+0x458/0x820 net/sctp/socket.c:9367 sctp_sendmsg_to_asoc+0x223a/0x2260 net/sctp/socket.c:1886 sctp_sendmsg+0x3910/0x49f0 net/sctp/socket.c:2032 inet_sendmsg+0x269/0x2a0 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:712 [inline] This patch fixes it by linearizing cloned gso packets in sctp_rcv(). Fixes: 90017accff61 ("sctp: Add GSO support") Reported-by: syzbot+773e51afe420baaf0e2b@syzkaller.appspotmail.com Reported-by: syzbot+70a42f45e76bede082be@syzkaller.appspotmail.com Signed-off-by: Xin Long Reviewed-by: Marcelo Ricardo Leitner Link: https://patch.msgid.link/dd7dc337b99876d4132d0961f776913719f7d225.1754595611.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

sctp: Fix null-ptr-deref in reuseport_add_sock().

2024-08-02T23:25:06+00:00

syzbot reported a null-ptr-deref while accessing sk2->sk_reuseport_cb in reuseport_add_sock(). [0] The repro first creates a listener with SO_REUSEPORT. Then, it creates another listener on the same port and concurrently closes the first listener. The second listen() calls reuseport_add_sock() with the first listener as sk2, where sk2->sk_reuseport_cb is not expected to be cleared concurrently, but the close() does clear it by reuseport_detach_sock(). The problem is SCTP does not properly synchronise reuseport_alloc(), reuseport_add_sock(), and reuseport_detach_sock(). The caller of reuseport_alloc() and reuseport_{add,detach}_sock() must provide synchronisation for sockets that are classified into the same reuseport group. Otherwise, such sockets form multiple identical reuseport groups, and all groups except one would be silently dead. 1. Two sockets call listen() concurrently 2. No socket in the same group found in sctp_ep_hashtable[] 3. Two sockets call reuseport_alloc() and form two reuseport groups 4. Only one group hit first in __sctp_rcv_lookup_endpoint() receives incoming packets Also, the reported null-ptr-deref could occur. TCP/UDP guarantees that would not happen by holding the hash bucket lock. Let's apply the locking strategy to __sctp_hash_endpoint() and __sctp_unhash_endpoint(). [0]: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 1 UID: 0 PID: 10230 Comm: syz-executor119 Not tainted 6.10.0-syzkaller-12585-g301927d2d2eb #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:reuseport_add_sock+0x27e/0x5e0 net/core/sock_reuseport.c:350 Code: 00 0f b7 5d 00 bf 01 00 00 00 89 de e8 1b a4 ff f7 83 fb 01 0f 85 a3 01 00 00 e8 6d a0 ff f7 49 8d 7e 12 48 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 4b 02 00 00 41 0f b7 5e 12 49 8d 7e 14 RSP: 0018:ffffc9000b947c98 EFLAGS: 00010202 RAX: 0000000000000002 RBX: ffff8880252ddf98 RCX: ffff888079478000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000012 RBP: 0000000000000001 R08: ffffffff8993e18d R09: 1ffffffff1fef385 R10: dffffc0000000000 R11: fffffbfff1fef386 R12: ffff8880252ddac0 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f24e45b96c0(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcced5f7b8 CR3: 00000000241be000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __sctp_hash_endpoint net/sctp/input.c:762 [inline] sctp_hash_endpoint+0x52a/0x600 net/sctp/input.c:790 sctp_listen_start net/sctp/socket.c:8570 [inline] sctp_inet_listen+0x767/0xa20 net/sctp/socket.c:8625 __sys_listen_socket net/socket.c:1883 [inline] __sys_listen+0x1b7/0x230 net/socket.c:1894 __do_sys_listen net/socket.c:1902 [inline] __se_sys_listen net/socket.c:1900 [inline] __x64_sys_listen+0x5a/0x70 net/socket.c:1900 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f24e46039b9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 1a 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f24e45b9228 EFLAGS: 00000246 ORIG_RAX: 0000000000000032 RAX: ffffffffffffffda RBX: 00007f24e468e428 RCX: 00007f24e46039b9 RDX: 00007f24e46039b9 RSI: 0000000000000003 RDI: 0000000000000004 RBP: 00007f24e468e420 R08: 00007f24e45b96c0 R09: 00007f24e45b96c0 R10: 00007f24e45b96c0 R11: 0000000000000246 R12: 00007f24e468e42c R13: 00007f24e465a5dc R14: 0020000000000001 R15: 00007ffcced5f7d8 Modules linked in: Fixes: 6ba845740267 ("sctp: process sk_reuseport in sctp_get_port_local") Reported-by: syzbot+e6979a5d2f10ecb700e4@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=e6979a5d2f10ecb700e4 Tested-by: syzbot+e6979a5d2f10ecb700e4@syzkaller.appspotmail.com Signed-off-by: Kuniyuki Iwashima Acked-by: Xin Long Link: https://patch.msgid.link/20240731234624.94055-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

inet: move inet->recverr to inet->inet_flags

2023-08-16T10:09:17+00:00

IP_RECVERR socket option can now be set/get without locking the socket. This patch potentially avoid data-races around inet->recverr. Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: Simon Horman Signed-off-by: David S. Miller

sctp: delete the nested flexible array params

2023-04-21T07:19:29+00:00

This patch deletes the flexible-array params[] from the structure sctp_inithdr, sctp_addiphdr and sctp_reconf_chunk to avoid some sparse warnings: # make C=2 CF="-Wflexible-array-nested" M=./net/sctp/ net/sctp/input.c: note: in included file (through include/net/sctp/structs.h, include/net/sctp/sctp.h): ./include/linux/sctp.h:278:29: warning: nested flexible array ./include/linux/sctp.h:675:30: warning: nested flexible array This warning is reported if a structure having a flexible array member is included by other structures. Signed-off-by: Xin Long Signed-off-by: David S. Miller

net: annotate lockless accesses to sk->sk_err_soft

2023-03-17T08:25:05+00:00

This field can be read/written without lock synchronization. tcp and dccp have been handled in different patches. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

sctp: add dif and sdif check in asoc and ep lookup

2022-11-18T11:42:54+00:00

This patch at first adds a pernet global l3mdev_accept to decide if it accepts the packets from a l3mdev when a SCTP socket doesn't bind to any interface. It's set to 1 to avoid any possible incompatible issue, and in next patch, a sysctl will be introduced to allow to change it. Then similar to inet/udp_sk_bound_dev_eq(), sctp_sk_bound_dev_eq() is added to check either dif or sdif is equal to sk_bound_dev_if, and to check sid is 0 or l3mdev_accept is 1 if sk_bound_dev_if is not set. This function is used to match a association or a endpoint, namely called by sctp_addrs_lookup_transport() and sctp_endpoint_is_match(). All functions that needs updating are: sctp_rcv(): asoc: __sctp_rcv_lookup() __sctp_lookup_association() -> sctp_addrs_lookup_transport() __sctp_rcv_lookup_harder() __sctp_rcv_init_lookup() __sctp_lookup_association() -> sctp_addrs_lookup_transport() __sctp_rcv_walk_lookup() __sctp_rcv_asconf_lookup() __sctp_lookup_association() -> sctp_addrs_lookup_transport() ep: __sctp_rcv_lookup_endpoint() -> sctp_endpoint_is_match() sctp_connect(): sctp_endpoint_is_peeled_off() __sctp_lookup_association() sctp_has_association() sctp_lookup_association() __sctp_lookup_association() -> sctp_addrs_lookup_transport() sctp_diag_dump_one(): sctp_transport_lookup_process() -> sctp_addrs_lookup_transport() Signed-off-by: Xin Long Signed-off-by: David S. Miller

sctp: read sk->sk_bound_dev_if once in sctp_rcv()

2022-05-16T09:31:06+00:00

sctp_rcv() reads sk->sk_bound_dev_if twice while the socket is not locked. Another cpu could change this field under us. Fixes: 0fd9a65a76e8 ("[SCTP] Support SO_BINDTODEVICE socket option on incoming packets.") Signed-off-by: Eric Dumazet Cc: Neil Horman Cc: Vlad Yasevich Cc: Marcelo Ricardo Leitner Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

sctp: move hlist_node and hashent out of sctp_ep_common

2021-12-23T11:15:30+00:00

Struct sctp_ep_common is included in both asoc and ep, but hlist_node and hashent are only needed by ep after asoc_hashtable was dropped by Commit b5eff7128366 ("sctp: drop the old assoc hashtable of sctp"). So it is better to move hlist_node and hashent from sctp_ep_common to sctp_endpoint, and it saves some space for each asoc. Signed-off-by: Xin Long Signed-off-by: David S. Miller

sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb

2021-09-24T09:36:19+00:00

We should always check if skb_header_pointer's return is NULL before using it, otherwise it may cause null-ptr-deref, as syzbot reported: KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:sctp_rcv_ootb net/sctp/input.c:705 [inline] RIP: 0010:sctp_rcv+0x1d84/0x3220 net/sctp/input.c:196 Call Trace: sctp6_rcv+0x38/0x60 net/sctp/ipv6.c:1109 ip6_protocol_deliver_rcu+0x2e9/0x1ca0 net/ipv6/ip6_input.c:422 ip6_input_finish+0x62/0x170 net/ipv6/ip6_input.c:463 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:472 dst_input include/net/dst.h:460 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x28c/0x3c0 net/ipv6/ip6_input.c:297 Fixes: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize") Reported-by: syzbot+581aff2ae6b860625116@syzkaller.appspotmail.com Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

sctp: fix return value check in __sctp_rcv_asconf_lookup

2021-07-28T08:25:18+00:00

As Ben Hutchings noticed, this check should have been inverted: the call returns true in case of success. Reported-by: Ben Hutchings Fixes: 0c5dc070ff3d ("sctp: validate from_addr_param return") Signed-off-by: Marcelo Ricardo Leitner Reviewed-by: Xin Long Signed-off-by: David S. Miller