KASAN: stack-out-of-bounds Read in scm_recv

[Palash Oswal]

Hello,
I found the following issue using syzkaller with enriched corpus[1] on:
HEAD commit : 0bcc4025550403ae28d2984bddacafbca0a2f112
git tree: linux
C Reproducer : I do not have a C reproducer yet. I will update this
thread when I get one.
Kernel .config :
https://gist.github.com/oswalpalash/d9580b0bfce202b37445fa5fd426e41f

Link:
1. https://github.com/cmu-pasta/linux-kernel-enriched-corpus

Console log :
==================================================================
BUG: KASAN: stack-out-of-bounds in scm_recv.constprop.0+0x5b6/0x5c0
Read of size 8 at addr ffffc90003fcf948 by task syz-executor.2/18043

CPU: 0 PID: 18043 Comm: syz-executor.2 Not tainted
6.3.0-rc6-pasta-00035-g0bcc40255504 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xd9/0x150
 print_address_description.constprop.0+0x2c/0x3c0
 kasan_report+0x11c/0x130
 scm_recv.constprop.0+0x5b6/0x5c0
 __unix_dgram_recvmsg+0x824/0xb90
 unix_dgram_recvmsg+0xc4/0xf0
 ____sys_recvmsg+0x49c/0x5a0
 ___sys_recvmsg+0xf2/0x180
 do_recvmmsg+0x25e/0x6e0
 __x64_sys_recvmmsg+0x20f/0x260
 do_syscall_64+0x39/0xb0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f17a168eacd
Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f17a2398bf8 EFLAGS: 00000246
 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f17a17bc050 RCX: 00007f17a168eacd
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000004
RBP: 00007f17a16fcb05 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdf09e0a3f R14: 00007ffdf09e0be0 R15: 00007f17a2398d80
 </TASK>

The buggy address belongs to stack of task syz-executor.2/18043
KASAN internal error: frame info validation failed; invalid marker: 0
The buggy address belongs to the virtual mapping at
 [ffffc90003fc8000, ffffc90003fd1000) created by:
 kernel_clone+0xeb/0x890

The buggy address belongs to the physical page:
page:ffffea00042a9800 refcount:1 mapcount:0 mapping:0000000000000000
index:0x0 pfn:0x10aa60
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask
0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO), pid 31, tgid
31 (kworker/u6:1), ts 269514464150, free_ts 269297799927
 get_page_from_freelist+0x1190/0x2e20
 __alloc_pages+0x1cb/0x4a0
 alloc_pages+0x1aa/0x270
 __vmalloc_node_range+0xb1c/0x14a0
 copy_process+0x1320/0x7590
 kernel_clone+0xeb/0x890
 user_mode_thread+0xb1/0xf0
 call_usermodehelper_exec_work+0xd0/0x180
 process_one_work+0x991/0x15c0
 worker_thread+0x669/0x1090
 kthread+0x2e8/0x3a0
 ret_from_fork+0x1f/0x30
page last free stack trace:
 0x10e9caa858
 0x435023b
 0x10e9caa858
 0xffffffff0435023b
 release_pages+0xcd7/0x1380
 tlb_batch_pages_flush+0xa8/0x1a0
 release_pages+0xcd7/0x1380
 tlb_batch_pages_flush+0xa8/0x1a0
 __mmput+0x128/0x4c0
mmput+0x60/0x70
 __mmput+0x128/0x4c0
 mmput+0x60/0x70
 get_signal+0x2315/0x25b0
 arch_do_signal_or_restart+0x79/0x5c0
 get_signal+0x2315/0x25b0
 arch_do_signal_or_restart+0x79/0x5c0
 do_syscall_64+0x46/0xb0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
 do_syscall_64+0x46/0xb0
 0x8a20008b
 0xef5794dbf
 0x43f023b
 0xef5794dbf
 0xffffffff043f023b
 tlb_finish_mmu+0x1a7/0x7e0
 exit_mmap+0x2ac/0x7f0
 tlb_finish_mmu+0x1a7/0x7e0
 exit_mmap+0x2ac/0x7f0
 do_exit+0x9d7/0x2960
 do_group_exit+0xd4/0x2a0
 do_exit+0x9d7/0x2960
 do_group_exit+0xd4/0x2a0
 exit_to_user_mode_prepare+0x11f/0x240
 syscall_exit_to_user_mode+0x1d/0x50
 exit_to_user_mode_prepare+0x11f/0x240
 syscall_exit_to_user_mode+0x1d/0x50
 0x0
 0xffffffff00000000
 0x0
 0x0
 kasan_save_stack+0x22/0x40
 0x81d1e785
 kasan_save_stack+0x22/0x40