random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) ================================================================== BUG: KASAN: use-after-free in tcp_connect+0x2633/0x2fa0 net/ipv4/tcp_output.c:3401 Read of size 4 at addr ffff8801b67fd6a8 by task syz-executor420/3798 CPU: 0 PID: 3798 Comm: syz-executor420 Not tainted 4.9.105-gd7e64f8 #40 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801c419f930 ffffffff81eb41a9 ffffea0006d9ff00 ffff8801b67fd6a8 0000000000000000 ffff8801b67fd6a8 ffff8801b97526d8 ffff8801c419f968 ffffffff81567e49 ffff8801b67fd6a8 0000000000000004 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_address_description+0x6c/0x234 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412 [] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 [] tcp_connect+0x2633/0x2fa0 net/ipv4/tcp_output.c:3401 [] tcp_v4_connect+0x19f0/0x1c20 net/ipv4/tcp_ipv4.c:250 [] __inet_stream_connect+0x6e0/0xbf0 net/ipv4/af_inet.c:627 [] inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:691 [] SYSC_connect+0x1b8/0x300 net/socket.c:1562 [] SyS_connect+0x24/0x30 net/socket.c:1543 [] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 3797: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:505 set_track mm/kasan/kasan.c:517 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:609 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:547 slab_post_alloc_hook mm/slab.h:417 [inline] slab_alloc_node mm/slub.c:2715 [inline] slab_alloc mm/slub.c:2723 [inline] kmem_cache_alloc+0xbe/0x290 mm/slub.c:2728 kmem_cache_alloc_node include/linux/slab.h:364 [inline] __alloc_skb+0xe6/0x600 net/core/skbuff.c:219 alloc_skb_fclone include/linux/skbuff.h:961 [inline] sk_stream_alloc_skb+0xa3/0x5d0 net/ipv4/tcp.c:828 tcp_sendmsg+0xe57/0x3040 net/ipv4/tcp.c:1230 inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770 sock_sendmsg_nosec net/socket.c:635 [inline] sock_sendmsg+0xcc/0x110 net/socket.c:645 sock_write_iter+0x223/0x3b0 net/socket.c:843 new_sync_write fs/read_write.c:496 [inline] __vfs_write+0x3e0/0x580 fs/read_write.c:509 vfs_write+0x187/0x530 fs/read_write.c:557 SYSC_write fs/read_write.c:604 [inline] SyS_write+0xd9/0x1c0 fs/read_write.c:596 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 3798: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:505 set_track mm/kasan/kasan.c:517 [inline] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:582 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2958 [inline] kmem_cache_free+0xbe/0x310 mm/slub.c:2980 kfree_skbmem+0x7c/0x100 net/core/skbuff.c:644 __kfree_skb+0x1d/0x20 net/core/skbuff.c:685 sk_wmem_free_skb include/net/sock.h:1358 [inline] tcp_write_queue_purge include/net/tcp.h:1530 [inline] tcp_connect_init net/ipv4/tcp_output.c:3241 [inline] tcp_connect+0xaaf/0x2fa0 net/ipv4/tcp_output.c:3372 tcp_v4_connect+0x19f0/0x1c20 net/ipv4/tcp_ipv4.c:250 __inet_stream_connect+0x6e0/0xbf0 net/ipv4/af_inet.c:627 inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:691 SYSC_connect+0x1b8/0x300 net/socket.c:1562 SyS_connect+0x24/0x30 net/socket.c:1543 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801b67fd680 which belongs to the cache skbuff_fclone_cache of size 456 The buggy address is located 40 bytes inside of 456-byte region [ffff8801b67fd680, ffff8801b67fd848) The buggy address belongs to the page: page:ffffea0006d9ff00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x8000000000004080(slab|head) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b67fd580: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc ffff8801b67fd600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801b67fd680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b67fd700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b67fd780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================