Message-ID: <681798b9.050a0220.11da1b.0032.GAE@google.com>
Date: Sun, 04 May 2025 09:41:29 -0700
From: syzbot <syzbot+0ea39a434b610c03f7ea@...kaller.appspotmail.com>
To: davem@...emloft.net, dsahern@...nel.org, edumazet@...gle.com, 
	horms@...nel.org, kuba@...nel.org, linux-kernel@...r.kernel.org, 
	netdev@...r.kernel.org, pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] KASAN: global-out-of-bounds Read in fib6_ifup

Hello,

syzbot found the following issue on:

HEAD commit:    2a239ffbebb5 Merge tag 'sound-6.15-rc5' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12f8d8d4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=541aa584278da96c
dashboard link: https://syzkaller.appspot.com/bug?extid=0ea39a434b610c03f7ea
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9b278a43c30b/disk-2a239ffb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6643e08be3ea/vmlinux-2a239ffb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c8acd8502009/bzImage-2a239ffb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0ea39a434b610c03f7ea@...kaller.appspotmail.com

tipc: Started in network mode
tipc: Node identity 56b07f7dae81, cluster identity 4711
tipc: Enabled bearer <eth:syzkaller0>, priority 0
syzkaller0: entered promiscuous mode
syzkaller0: entered allmulticast mode
==================================================================
BUG: KASAN: global-out-of-bounds in fib6_ifup+0x257/0x2a0 net/ipv6/route.c:4815
Read of size 8 at addr ffffffff9af9a530 by task syz.5.7046/29528

CPU: 0 UID: 0 PID: 29528 Comm: syz.5.7046 Not tainted 6.15.0-rc4-syzkaller-00291-g2a239ffbebb5 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 fib6_ifup+0x257/0x2a0 net/ipv6/route.c:4815
 fib6_clean_node+0x2a4/0x5b0 net/ipv6/ip6_fib.c:2199
 fib6_walk_continue+0x44f/0x8d0 net/ipv6/ip6_fib.c:2124
 fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2172
 fib6_clean_tree+0xd4/0x110 net/ipv6/ip6_fib.c:2252
 __fib6_clean_all+0x107/0x2d0 net/ipv6/ip6_fib.c:2268
 rt6_sync_up+0xc9/0x170 net/ipv6/route.c:4837
 addrconf_notify+0x73d/0x19e0 net/ipv6/addrconf.c:3748
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2176
 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
 call_netdevice_notifiers net/core/dev.c:2228 [inline]
 __dev_notify_flags+0x12c/0x2e0 net/core/dev.c:9405
 netif_change_flags+0x108/0x160 net/core/dev.c:9434
 dev_change_flags+0xba/0x250 net/core/dev_api.c:68
 dev_ifsioc+0x1498/0x1f70 net/core/dev_ioctl.c:565
 dev_ioctl+0x223/0x10e0 net/core/dev_ioctl.c:821
 sock_do_ioctl+0x19d/0x280 net/socket.c:1204
 sock_ioctl+0x227/0x6b0 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl fs/ioctl.c:892 [inline]
 __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc72c38e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc72d1fc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc72c5b5fa0 RCX: 00007fc72c38e969
RDX: 0000200000002280 RSI: 0000000000008914 RDI: 0000000000000004
RBP: 00007fc72c410ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc72c5b5fa0 R15: 00007ffcaefaed28
 </TASK>

The buggy address belongs to the variable:
 __key.0+0x30/0x40

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1af9a
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea00006be688 ffffea00006be688 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffffffff9af9a400: 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
 ffffffff9af9a480: 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
>ffffffff9af9a500: 00 00 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
                                     ^
 ffffffff9af9a580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f9
 ffffffff9af9a600: f9 f9 f9 f9 00 00 f9 f9 f9 f9 f9 f9 00 00 f9 f9
==================================================================


---
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