netdev - Re: [syzbot] [sctp?] KMSAN: uninit-value in sctp_sf

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Message-ID: <672024e1.050a0220.11b624.04b7.GAE@google.com>
Date: Mon, 28 Oct 2024 16:57:21 -0700
From: syzbot <syzbot+f0cbb34d39392f2746ca@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, horms@...nel.org, 
	kuba@...nel.org, linux-kernel@...r.kernel.org, linux-sctp@...r.kernel.org, 
	lucien.xin@...il.com, marcelo.leitner@...il.com, netdev@...r.kernel.org, 
	pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [sctp?] KMSAN: uninit-value in sctp_sf_ootb

syzbot has found a reproducer for the following issue on:

HEAD commit:    819837584309 Linux 6.12-rc5
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1211e940580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4d4311df74eee96f
dashboard link: https://syzkaller.appspot.com/bug?extid=f0cbb34d39392f2746ca
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11eb3230580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11f36ca7980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dfa054090a8f/disk-81983758.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/54edfdbd151e/vmlinux-81983758.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d63a317b80f9/bzImage-81983758.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f0cbb34d39392f2746ca@...kaller.appspotmail.com

syz-executor341 uses obsolete (PF_INET,SOCK_PACKET)
=====================================================
BUG: KMSAN: uninit-value in sctp_sf_ootb+0x7f5/0xce0 net/sctp/sm_statefuns.c:3712
 sctp_sf_ootb+0x7f5/0xce0 net/sctp/sm_statefuns.c:3712
 sctp_do_sm+0x181/0x93d0 net/sctp/sm_sideeffect.c:1166
 sctp_endpoint_bh_rcv+0xc38/0xf90 net/sctp/endpointola.c:407
 sctp_inq_push+0x2ef/0x380 net/sctp/inqueue.c:88
 sctp_rcv+0x3831/0x3b20 net/sctp/input.c:243
 sctp4_rcv+0x42/0x50 net/sctp/protocol.c:1159
 ip_protocol_deliver_rcu+0xb51/0x13d0 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x336/0x500 net/ipv4/ip_input.c:233
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254
 dst_input include/net/dst.h:460 [inline]
 ip_rcv_finish+0x4a2/0x520 net/ipv4/ip_input.c:449
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ip_rcv+0xcd/0x380 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core net/core/dev.c:5666 [inline]
 __netif_receive_skb+0x319/0xa00 net/core/dev.c:5779
 netif_receive_skb_internal net/core/dev.c:5865 [inline]
 netif_receive_skb+0x58/0x660 net/core/dev.c:5924
 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1550
 tun_get_user+0x5783/0x6c60 drivers/net/tun.c:2007
 tun_chr_write_iter+0x3ac/0x5d0 drivers/net/tun.c:2053
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0xb2b/0x1540 fs/read_write.c:683
 ksys_write+0x24f/0x4c0 fs/read_write.c:736
 __do_sys_write fs/read_write.c:748 [inline]
 __se_sys_write fs/read_write.c:745 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:745
 x64_sys_call+0x306a/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4091 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4186
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587
 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1322 [inline]
 alloc_skb_with_frags+0xc8/0xd00 net/core/skbuff.c:6612
 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2883
 tun_alloc_skb drivers/net/tun.c:1526 [inline]
 tun_get_user+0x20f4/0x6c60 drivers/net/tun.c:1851
 tun_chr_write_iter+0x3ac/0x5d0 drivers/net/tun.c:2053
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0xb2b/0x1540 fs/read_write.c:683
 ksys_write+0x24f/0x4c0 fs/read_write.c:736
 __do_sys_write fs/read_write.c:748 [inline]
 __se_sys_write fs/read_write.c:745 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:745
 x64_sys_call+0x306a/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5818 Comm: syz-executor341 Not tainted 6.12.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================


---
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#syz test: git://repo/address.git branch-or-commit-hash
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