================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:377 [inline] BUG: KASAN: use-after-free in skb_put_data include/linux/skbuff.h:2130 [inline] BUG: KASAN: use-after-free in bcm_can_tx+0x3d4/0x800 net/can/bcm.c:295 Read of size 72 at addr ffff888046b27d90 by task syz-executor.1/776 CPU: 1 PID: 776 Comm: syz-executor.1 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354 kasan_report+0x8f/0xa0 mm/kasan/report.c:412 memcpy+0x20/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:377 [inline] skb_put_data include/linux/skbuff.h:2130 [inline] bcm_can_tx+0x3d4/0x800 net/can/bcm.c:295 bcm_tx_timeout_tsklet+0x1f0/0x3a0 net/can/bcm.c:414 tasklet_action_common.constprop.0+0x265/0x360 kernel/softirq.c:522 __do_softirq+0x265/0x980 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x215/0x260 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:kfree+0x123/0x210 mm/slab.c:3823 Code: 89 ea 48 89 ee 4c 89 e7 e8 da ee ff ff f6 c7 02 74 ca e8 20 74 cf ff 48 83 3d 60 4d 59 08 00 0f 84 eb 00 00 00 48 89 df 57 9d <0f> 1f 44 00 00 5b 5d 41 5c 41 5d c3 65 8b 05 ea 4b 69 7e 83 f8 07 RSP: 0018:ffff888069fbf938 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: 0000000000000286 RCX: 1ffff1100a737de2 RDX: 0000000000000000 RSI: ffff8880539beef0 RDI: 0000000000000286 RBP: ffff888046b26d40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88813bff2380 R13: ffffffff8735c713 R14: ffff88809a1a6e50 R15: ffff88809a1a6e58 bcm_remove_op+0x213/0x2c0 net/can/bcm.c:770 bcm_release+0x260/0x950 net/can/bcm.c:1561 __sock_release+0xcd/0x2a0 net/socket.c:599 sock_close+0x15/0x20 net/socket.c:1214 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xbf3/0x2be0 kernel/exit.c:870 do_group_exit+0x125/0x310 kernel/exit.c:967 get_signal+0x3f2/0x1f70 kernel/signal.c:2589 do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:799 exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x277/0x2d0 arch/x86/entry/common.c:198 retint_user+0x8/0x18 RIP: 0033:0x7f7ce9c69429 Code: Bad RIP value. RSP: 002b:00007ffe53ab3620 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000018c2a RBX: 00007f7ce9ddc018 RCX: 0000001b30120000 RDX: ffffffff83740ba8 RSI: 0000001b30129058 RDI: 0000000009f18cee RBP: 000000004560dc05 R08: ffffffff83740b8c R09: 000000004560dc09 R10: 00007ffe53ab37e0 R11: 0000000000000246 R12: 00007f7ce9dd0000 R13: 0000000000000001 R14: 0000000000005ee9 R15: ffffffff83740ba8 Allocated by task 780: __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15a/0x3c0 mm/slab.c:3736 kmalloc_array include/linux/slab.h:637 [inline] bcm_tx_setup net/can/bcm.c:957 [inline] bcm_sendmsg+0x316c/0x4150 net/can/bcm.c:1386 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xc3/0x120 net/socket.c:661 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227 __sys_sendmsg net/socket.c:2265 [inline] __do_sys_sendmsg net/socket.c:2274 [inline] __se_sys_sendmsg net/socket.c:2272 [inline] __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 776: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 bcm_remove_op+0x213/0x2c0 net/can/bcm.c:770 bcm_release+0x260/0x950 net/can/bcm.c:1561 __sock_release+0xcd/0x2a0 net/socket.c:599 sock_close+0x15/0x20 net/socket.c:1214 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xbf3/0x2be0 kernel/exit.c:870 do_group_exit+0x125/0x310 kernel/exit.c:967 get_signal+0x3f2/0x1f70 kernel/signal.c:2589 do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:799 exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x277/0x2d0 arch/x86/entry/common.c:198 retint_user+0x8/0x18 The buggy address belongs to the object at ffff888046b26d40 which belongs to the cache kmalloc-32768 of size 32768 The buggy address is located 4176 bytes inside of 32768-byte region [ffff888046b26d40, ffff888046b2ed40) The buggy address belongs to the page: page:ffffea00011ac800 count:1 mapcount:0 mapping:ffff88813bff2380 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea000145ac08 ffff88813bff1d48 ffff88813bff2380 raw: 0000000000000000 ffff888046b26d40 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888046b27c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888046b27d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888046b27d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888046b27e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888046b27e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 89 ea mov %ebp,%edx 2: 48 89 ee mov %rbp,%rsi 5: 4c 89 e7 mov %r12,%rdi 8: e8 da ee ff ff callq 0xffffeee7 d: f6 c7 02 test $0x2,%bh 10: 74 ca je 0xffffffdc 12: e8 20 74 cf ff callq 0xffcf7437 17: 48 83 3d 60 4d 59 08 cmpq $0x0,0x8594d60(%rip) # 0x8594d7f 1e: 00 1f: 0f 84 eb 00 00 00 je 0x110 25: 48 89 df mov %rbx,%rdi 28: 57 push %rdi 29: 9d popfq * 2a: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) <-- trapping instruction 2f: 5b pop %rbx 30: 5d pop %rbp 31: 41 5c pop %r12 33: 41 5d pop %r13 35: c3 retq 36: 65 8b 05 ea 4b 69 7e mov %gs:0x7e694bea(%rip),%eax # 0x7e694c27 3d: 83 f8 07 cmp $0x7,%eax