================================================================== BUG: KASAN: use-after-free in l3mdev_master_ifindex_rcu+0x132/0x150 net/l3mdev/l3mdev.c:24 Read of size 4 at addr ffff88805557c21c by task syz-executor.2/15451 CPU: 1 PID: 15451 Comm: syz-executor.2 Not tainted 5.6.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:134 l3mdev_master_ifindex_rcu+0x132/0x150 net/l3mdev/l3mdev.c:24 ipv6_dev_get_saddr+0x7b8/0xc50 net/ipv6/addrconf.c:1817 ip6_route_get_saddr include/net/ip6_route.h:144 [inline] ip6_dst_lookup_tail+0x1218/0x1f20 net/ipv6/ip6_output.c:1030 ip6_dst_lookup_flow+0x8c/0x1d0 net/ipv6/ip6_output.c:1153 sctp_v6_get_dst+0x7e9/0x1d70 net/sctp/ipv6.c:278 sctp_transport_route+0x12d/0x360 net/sctp/transport.c:297 sctp_assoc_add_peer+0x5a8/0x1040 net/sctp/associola.c:659 sctp_process_param net/sctp/sm_make_chunk.c:2523 [inline] sctp_process_init+0x23eb/0x2a50 net/sctp/sm_make_chunk.c:2344 sctp_sf_do_unexpected_init net/sctp/sm_statefuns.c:1541 [inline] sctp_sf_do_unexpected_init.isra.0+0x7cd/0x1350 net/sctp/sm_statefuns.c:1441 sctp_sf_do_5_2_1_siminit+0x35/0x40 net/sctp/sm_statefuns.c:1670 sctp_do_sm+0x121/0x5330 net/sctp/sm_sideeffect.c:1153 sctp_assoc_bh_rcv+0x386/0x6d0 net/sctp/associola.c:1044 sctp_inq_push+0x1e4/0x280 net/sctp/inqueue.c:80 sctp_backlog_rcv+0x222/0x1420 net/sctp/input.c:344 sk_backlog_rcv include/net/sock.h:938 [inline] __release_sock+0x129/0x390 net/core/sock.c:2437 release_sock+0x59/0x1c0 net/core/sock.c:2953 sctp_wait_for_connect+0x33c/0x580 net/sctp/socket.c:9280 __sctp_connect+0xa35/0xcd0 net/sctp/socket.c:1225 sctp_connect net/sctp/socket.c:4893 [inline] sctp_inet_connect+0x14d/0x1c0 net/sctp/socket.c:4908 __sys_connect_file+0x161/0x1c0 net/socket.c:1857 __sys_connect+0x174/0x1b0 net/socket.c:1874 __do_sys_connect net/socket.c:1885 [inline] __se_sys_connect net/socket.c:1882 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:1882 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c6c9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb125842c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007fb1258436d4 RCX: 000000000045c6c9 RDX: 000000000000001c RSI: 0000000020000080 RDI: 0000000000000004 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000007e R14: 00000000004c2ffe R15: 000000000076bf2c Allocated by task 15278: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:515 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x163/0x770 mm/slab.c:3665 kmalloc include/linux/slab.h:560 [inline] tomoyo_realpath_from_path+0xc5/0x660 security/tomoyo/realpath.c:252 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822 tomoyo_inode_getattr+0x1d/0x30 security/tomoyo/tomoyo.c:129 security_inode_getattr+0xf2/0x150 security/security.c:1254 vfs_getattr+0x25/0x70 fs/stat.c:117 vfs_statx_fd+0x71/0xc0 fs/stat.c:147 vfs_fstat include/linux/fs.h:3287 [inline] __do_sys_newfstat+0x9b/0x120 fs/stat.c:388 __se_sys_newfstat fs/stat.c:385 [inline] __x64_sys_newfstat+0x54/0x80 fs/stat.c:385 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 15278: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 tomoyo_realpath_from_path+0x1a7/0x660 security/tomoyo/realpath.c:289 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822 tomoyo_inode_getattr+0x1d/0x30 security/tomoyo/tomoyo.c:129 security_inode_getattr+0xf2/0x150 security/security.c:1254 vfs_getattr+0x25/0x70 fs/stat.c:117 vfs_statx_fd+0x71/0xc0 fs/stat.c:147 vfs_fstat include/linux/fs.h:3287 [inline] __do_sys_newfstat+0x9b/0x120 fs/stat.c:388 __se_sys_newfstat fs/stat.c:385 [inline] __x64_sys_newfstat+0x54/0x80 fs/stat.c:385 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88805557c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 540 bytes inside of 4096-byte region [ffff88805557c000, ffff88805557d000) The buggy address belongs to the page: page:ffffea0001555f00 refcount:1 mapcount:0 mapping:ffff8880aa402000 index:0x0 compound_mapcount: 0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea0001325108 ffffea0001175388 ffff8880aa402000 raw: 0000000000000000 ffff88805557c000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88805557c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805557c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88805557c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805557c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805557c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================