CVE-2023-53198

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> raw: Fix NULL deref in raw_get_next().<br /> <br /> Dae R. Jeong reported a NULL deref in raw_get_next() [0].<br /> <br /> It seems that the repro was running these sequences in parallel so<br /> that one thread was iterating on a socket that was being freed in<br /> another netns.<br /> <br /> unshare(0x40060200)<br /> r0 = syz_open_procfs(0x0, &amp;(0x7f0000002080)=&amp;#39;net/raw\x00&amp;#39;)<br /> socket$inet_icmp_raw(0x2, 0x3, 0x1)<br /> pread64(r0, &amp;(0x7f0000000000)=""/10, 0xa, 0x10000000007f)<br /> <br /> After commit 0daf07e52709 ("raw: convert raw sockets to RCU"), we<br /> use RCU and hlist_nulls_for_each_entry() to iterate over SOCK_RAW<br /> sockets. However, we should use spinlock for slow paths to avoid<br /> the NULL deref.<br /> <br /> Also, SOCK_RAW does not use SLAB_TYPESAFE_BY_RCU, and the slab object<br /> is not reused during iteration in the grace period. In fact, the<br /> lockless readers do not check the nulls marker with get_nulls_value().<br /> So, SOCK_RAW should use hlist instead of hlist_nulls.<br /> <br /> Instead of adding an unnecessary barrier by sk_nulls_for_each_rcu(),<br /> let&amp;#39;s convert hlist_nulls to hlist and use sk_for_each_rcu() for<br /> fast paths and sk_for_each() and spinlock for /proc/net/raw.<br /> <br /> [0]:<br /> general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN<br /> KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]<br /> CPU: 2 PID: 20952 Comm: syz-executor.0 Not tainted 6.2.0-g048ec869bafd-dirty #7<br /> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014<br /> RIP: 0010:read_pnet include/net/net_namespace.h:383 [inline]<br /> RIP: 0010:sock_net include/net/sock.h:649 [inline]<br /> RIP: 0010:raw_get_next net/ipv4/raw.c:974 [inline]<br /> RIP: 0010:raw_get_idx net/ipv4/raw.c:986 [inline]<br /> RIP: 0010:raw_seq_start+0x431/0x800 net/ipv4/raw.c:995<br /> Code: ef e8 33 3d 94 f7 49 8b 6d 00 4c 89 ef e8 b7 65 5f f7 49 89 ed 49 83 c5 98 0f 84 9a 00 00 00 48 83 c5 c8 48 89 e8 48 c1 e8 03 80 3c 30 00 74 08 48 89 ef e8 00 3d 94 f7 4c 8b 7d 00 48 89 ef<br /> RSP: 0018:ffffc9001154f9b0 EFLAGS: 00010206<br /> RAX: 0000000000000005 RBX: 1ffff1100302c8fd RCX: 0000000000000000<br /> RDX: 0000000000000028 RSI: ffffc9001154f988 RDI: ffffc9000f77a338<br /> RBP: 0000000000000029 R08: ffffffff8a50ffb4 R09: fffffbfff24b6bd9<br /> R10: fffffbfff24b6bd9 R11: 0000000000000000 R12: ffff88801db73b78<br /> R13: fffffffffffffff9 R14: dffffc0000000000 R15: 0000000000000030<br /> FS: 00007f843ae8e700(0000) GS:ffff888063700000(0000) knlGS:0000000000000000<br /> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br /> CR2: 000055bb9614b35f CR3: 000000003c672000 CR4: 00000000003506e0<br /> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000<br /> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400<br /> Call Trace:<br /> <br /> seq_read_iter+0x4c6/0x10f0 fs/seq_file.c:225<br /> seq_read+0x224/0x320 fs/seq_file.c:162<br /> pde_read fs/proc/inode.c:316 [inline]<br /> proc_reg_read+0x23f/0x330 fs/proc/inode.c:328<br /> vfs_read+0x31e/0xd30 fs/read_write.c:468<br /> ksys_pread64 fs/read_write.c:665 [inline]<br /> __do_sys_pread64 fs/read_write.c:675 [inline]<br /> __se_sys_pread64 fs/read_write.c:672 [inline]<br /> __x64_sys_pread64+0x1e9/0x280 fs/read_write.c:672<br /> do_syscall_x64 arch/x86/entry/common.c:51 [inline]<br /> do_syscall_64+0x4e/0xa0 arch/x86/entry/common.c:82<br /> entry_SYSCALL_64_after_hwframe+0x63/0xcd<br /> RIP: 0033:0x478d29<br /> Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 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 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48<br /> RSP: 002b:00007f843ae8dbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000011<br /> RAX: ffffffffffffffda RBX: 0000000000791408 RCX: 0000000000478d29<br /> RDX: 000000000000000a RSI: 0000000020000000 RDI: 0000000000000003<br /> RBP: 00000000f477909a R08: 0000000000000000 R09: 0000000000000000<br /> R10: 000010000000007f R11: 0000000000000246 R12: 0000000000791740<br /> R13: 0000000000791414 R14: 0000000000791408 R15: 00007ffc2eb48a50<br /> <br /> Modules linked in:<br /> ---[ end trace 0000000000000000 ]---<br /> RIP: 0010<br /> ---truncated---