KASAN: use-after-free Read in iotlb_access

Title	Replies (including bot)	Last reply
[PATCH 4.14 00/29] 4.14.66-stable review	33 (33)	2018/08/21 19:49
[PATCH 4.17 00/42] 4.17.18-stable review	46 (46)	2018/08/21 19:44
[PATCH net] vhost: reset metadata cache when initializing new IOTLB	2 (2)	2018/08/08 16:45
KASAN: use-after-free Read in iotlb_access_ok	1 (2)	2018/08/08 02:52

================================================================== BUG: KASAN: use-after-free in vhost_vq_meta_fetch drivers/vhost/vhost.c:702 [inline] BUG: KASAN: use-after-free in iotlb_access_ok+0x5c9/0x600 drivers/vhost/vhost.c:1177 Read of size 8 at addr ffff880197df2fc0 by task vhost-8938/8941 CPU: 0 PID: 8941 Comm: vhost-8938 Not tainted 4.18.0-rc7+ #174 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+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 vhost_vq_meta_fetch drivers/vhost/vhost.c:702 [inline] iotlb_access_ok+0x5c9/0x600 drivers/vhost/vhost.c:1177 vq_iotlb_prefetch+0x10e/0x230 drivers/vhost/vhost.c:1214 handle_rx+0x247/0x1f80 drivers/vhost/net.c:799 handle_rx_net+0x19/0x20 drivers/vhost/net.c:934 vhost_worker+0x283/0x490 drivers/vhost/vhost.c:360 kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Allocated by task 8938: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 kmalloc include/linux/slab.h:513 [inline] vhost_new_umem_range+0xcb/0x7c0 drivers/vhost/vhost.c:911 vhost_process_iotlb_msg drivers/vhost/vhost.c:1000 [inline] vhost_chr_write_iter+0xe53/0x1a00 drivers/vhost/vhost.c:1043 vhost_net_chr_write_iter+0x59/0x70 drivers/vhost/net.c:1399 call_write_iter include/linux/fs.h:1793 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x6c6/0x9f0 fs/read_write.c:487 vfs_write+0x1f8/0x560 fs/read_write.c:549 ksys_write+0x101/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8950: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 vhost_umem_free+0x944/0x14d0 drivers/vhost/vhost.c:576 vhost_umem_clean+0x83/0xf0 drivers/vhost/vhost.c:588 vhost_init_device_iotlb+0x1d7/0x290 drivers/vhost/vhost.c:1568 vhost_net_set_features drivers/vhost/net.c:1292 [inline] vhost_net_ioctl+0xff3/0x1a80 drivers/vhost/net.c:1357 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 __do_sys_ioctl fs/ioctl.c:708 [inline] __se_sys_ioctl fs/ioctl.c:706 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff880197df2f80 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 64 bytes inside of 96-byte region [ffff880197df2f80, ffff880197df2fe0) The buggy address belongs to the page: page:ffffea00065f7c80 count:1 mapcount:0 mapping:ffff8801dac004c0 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0007530148 ffffea000663b888 ffff8801dac004c0 raw: 0000000000000000 ffff880197df2000 0000000100000020 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff880197df2e80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff880197df2f00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff880197df2f80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff880197df3000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff880197df3080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================