================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:406 [inline] BUG: KASAN: use-after-free in scr_memcpyw include/linux/vt_buffer.h:49 [inline] BUG: KASAN: use-after-free in vc_do_resize+0x9d8/0x1180 drivers/tty/vt/vt.c:1291 Read of size 2 at addr ffff88809e2c5e82 by task syz-executor.0/7082 CPU: 1 PID: 7082 Comm: syz-executor.0 Not tainted 5.8.0-rc7-next-20200731-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 check_memory_region_inline mm/kasan/generic.c:186 [inline] check_memory_region+0x13d/0x180 mm/kasan/generic.c:192 memcpy+0x20/0x60 mm/kasan/common.c:105 memcpy include/linux/string.h:406 [inline] scr_memcpyw include/linux/vt_buffer.h:49 [inline] vc_do_resize+0x9d8/0x1180 drivers/tty/vt/vt.c:1291 fbcon_modechanged+0x36c/0x710 drivers/video/fbdev/core/fbcon.c:2990 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:3048 fb_set_var+0xae8/0xd60 drivers/video/fbdev/core/fbmem.c:1056 do_fb_ioctl+0x33f/0x6c0 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ce79 Code: 2d 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f31baceec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000d580 RCX: 000000000045ce79 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffc0f8542af R14: 00007f31bacef9c0 R15: 000000000118bf2c Allocated by task 4808: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x1a8/0x320 mm/slab.c:3664 kmalloc include/linux/slab.h:559 [inline] kzalloc include/linux/slab.h:666 [inline] tomoyo_encode2.part.0+0xe9/0x3a0 security/tomoyo/realpath.c:45 tomoyo_encode2 security/tomoyo/realpath.c:31 [inline] tomoyo_encode+0x28/0x50 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x186/0x620 security/tomoyo/realpath.c:288 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x212/0x3f0 security/tomoyo/file.c:822 security_inode_getattr+0xcf/0x140 security/security.c:1278 vfs_getattr fs/stat.c:121 [inline] vfs_statx+0x170/0x390 fs/stat.c:206 vfs_stat include/linux/fs.h:3165 [inline] __do_sys_newstat+0x91/0x110 fs/stat.c:361 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88809e2c5e80 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 2 bytes inside of 32-byte region [ffff88809e2c5e80, ffff88809e2c5ea0) The buggy address belongs to the page: page:0000000092cae990 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809e2c5fc1 pfn:0x9e2c5 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00026668c8 ffffea00024f9c08 ffff8880aa000100 raw: ffff88809e2c5fc1 ffff88809e2c5000 000000010000003d 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809e2c5d80: 05 fc fc fc fc fc fc fc fa fb fb fb fc fc fc fc ffff88809e2c5e00: fa fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc >ffff88809e2c5e80: fb fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff88809e2c5f00: 00 01 fc fc fc fc fc fc 00 03 fc fc fc fc fc fc ffff88809e2c5f80: 00 03 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================