================================================================== BUG: KASAN: use-after-free in skb_end_pointer include/linux/skbuff.h:1419 [inline] BUG: KASAN: use-after-free in kcm_sendmsg+0x1d75/0x2240 net/kcm/kcmsock.c:956 Read of size 8 at addr ffff888019a6fe88 by task syz-executor.2/25576 CPU: 1 PID: 25576 Comm: syz-executor.2 Not tainted 5.13.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:436 skb_end_pointer include/linux/skbuff.h:1419 [inline] kcm_sendmsg+0x1d75/0x2240 net/kcm/kcmsock.c:956 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007effa062a188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056c0f0 RCX: 00000000004665d9 RDX: 000000002400c000 RSI: 00000000200018c0 RDI: 0000000000000005 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c0f0 R13: 00007fff6fb027af R14: 00007effa062a300 R15: 0000000000022000 Allocated by task 25575: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:428 [inline] __kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:461 kasan_slab_alloc include/linux/kasan.h:236 [inline] slab_post_alloc_hook mm/slab.h:524 [inline] slab_alloc_node mm/slub.c:2913 [inline] kmem_cache_alloc_node+0x269/0x3e0 mm/slub.c:2949 __alloc_skb+0x20b/0x340 net/core/skbuff.c:413 alloc_skb include/linux/skbuff.h:1107 [inline] kcm_sendmsg+0xc88/0x2240 net/kcm/kcmsock.c:967 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 25578: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357 ____kasan_slab_free mm/kasan/common.c:360 [inline] ____kasan_slab_free mm/kasan/common.c:325 [inline] __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:368 kasan_slab_free include/linux/kasan.h:212 [inline] slab_free_hook mm/slub.c:1582 [inline] slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1607 slab_free mm/slub.c:3167 [inline] kmem_cache_free+0x8a/0x740 mm/slub.c:3183 kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:684 __kfree_skb net/core/skbuff.c:741 [inline] kfree_skb net/core/skbuff.c:758 [inline] kfree_skb+0x140/0x3f0 net/core/skbuff.c:752 kfree_skb_list+0x3f/0x60 net/core/skbuff.c:767 kcm_sendmsg+0xe65/0x2240 net/kcm/kcmsock.c:1070 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 sock_write_iter+0x289/0x3c0 net/socket.c:1001 call_write_iter include/linux/fs.h:2114 [inline] new_sync_write+0x426/0x650 fs/read_write.c:518 vfs_write+0x796/0xa30 fs/read_write.c:605 ksys_write+0x1ee/0x250 fs/read_write.c:658 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff888019a6fdc0 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 200 bytes inside of 232-byte region [ffff888019a6fdc0, ffff888019a6fea8) The buggy address belongs to the page: page:ffffea0000669bc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x19a6f flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea00005b5c40 0000000c00000003 ffff8881400e7dc0 raw: 0000000000000000 00000000000c000c 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 0x12a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY), pid 8461, ts 123889725468, free_ts 123052494554 prep_new_page mm/page_alloc.c:2358 [inline] get_page_from_freelist+0x1033/0x2b60 mm/page_alloc.c:3994 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5200 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272 alloc_slab_page mm/slub.c:1645 [inline] allocate_slab+0x2c5/0x4c0 mm/slub.c:1785 new_slab mm/slub.c:1848 [inline] new_slab_objects mm/slub.c:2594 [inline] ___slab_alloc+0x4a1/0x810 mm/slub.c:2757 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2797 slab_alloc_node mm/slub.c:2879 [inline] slab_alloc mm/slub.c:2921 [inline] kmem_cache_alloc+0x34b/0x3a0 mm/slub.c:2926 skb_clone+0x170/0x3c0 net/core/skbuff.c:1497 __netlink_deliver_tap_skb net/netlink/af_netlink.c:296 [inline] __netlink_deliver_tap net/netlink/af_netlink.c:321 [inline] netlink_deliver_tap+0xa14/0xba0 net/netlink/af_netlink.c:334 __netlink_sendskb net/netlink/af_netlink.c:1258 [inline] netlink_sendskb net/netlink/af_netlink.c:1267 [inline] netlink_unicast+0x697/0x7d0 net/netlink/af_netlink.c:1355 netlink_ack+0x625/0xaa0 net/netlink/af_netlink.c:2474 netlink_rcv_skb+0x33d/0x420 net/netlink/af_netlink.c:2510 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 __sys_sendto+0x21c/0x320 net/socket.c:1977 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1298 [inline] free_pcp_prepare+0x223/0x300 mm/page_alloc.c:1342 free_unref_page_prepare mm/page_alloc.c:3250 [inline] free_unref_page+0x12/0x1d0 mm/page_alloc.c:3298 unfreeze_partials+0x17c/0x1d0 mm/slub.c:2375 put_cpu_partial+0x13d/0x230 mm/slub.c:2411 qlink_free mm/kasan/quarantine.c:146 [inline] qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272 __kasan_slab_alloc+0x8e/0xa0 mm/kasan/common.c:438 kasan_slab_alloc include/linux/kasan.h:236 [inline] slab_post_alloc_hook mm/slab.h:524 [inline] slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2921 [inline] __kmalloc+0x1f7/0x330 mm/slub.c:4055 kmalloc include/linux/slab.h:561 [inline] kzalloc include/linux/slab.h:686 [inline] tomoyo_init_log+0x1376/0x1ee0 security/tomoyo/audit.c:275 tomoyo_supervisor+0x34d/0xf00 security/tomoyo/common.c:2097 tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline] tomoyo_path_number_perm+0x419/0x590 security/tomoyo/file.c:734 security_file_ioctl+0x50/0xb0 security/security.c:1539 __do_sys_ioctl fs/ioctl.c:1063 [inline] __se_sys_ioctl fs/ioctl.c:1055 [inline] __x64_sys_ioctl+0xb3/0x200 fs/ioctl.c:1055 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff888019a6fd80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff888019a6fe00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888019a6fe80: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ^ ffff888019a6ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888019a6ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================