Hello, The following program triggers use-after-free in sixpack_close:
// autogenerated by syzkaller (http://github.com/google/syzkaller) #include <syscall.h> #include <string.h> #include <stdint.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/ioctl.h> #include <fcntl.h> int main() { int fd = open("/dev/ptmx", O_RDWR); int opt = 0x7; ioctl(fd, TIOCSETD, &opt); return 0; } ================================================================== BUG: KASAN: use-after-free in del_timer+0x116/0x130 at addr ffff88005b15f788 Write of size 8 by task a.out/6775 ============================================================================= BUG kmalloc-4096 (Not tainted): kasan: bad access detected ----------------------------------------------------------------------------- INFO: Allocated in seq_buf_alloc+0x61/0x80 age=0 cpu=3 pid=6779 [< none >] ___slab_alloc+0x489/0x4e0 mm/slub.c:2468 [< none >] __slab_alloc+0x4c/0x90 mm/slub.c:2497 [< inline >] slab_alloc_node mm/slub.c:2560 [< inline >] slab_alloc mm/slub.c:2602 [< none >] __kmalloc+0x299/0x330 mm/slub.c:3562 [< inline >] kmalloc include/linux/slab.h:463 [< none >] seq_buf_alloc+0x61/0x80 fs/seq_file.c:39 [< none >] seq_read+0x9b1/0x11d0 fs/seq_file.c:210 [< none >] __vfs_read+0x113/0x460 fs/read_write.c:432 [< none >] vfs_read+0x106/0x310 fs/read_write.c:454 [< inline >] SYSC_read fs/read_write.c:569 [< none >] SyS_read+0x111/0x220 fs/read_write.c:562 [< none >] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 INFO: Freed in kvfree+0x36/0x60 age=0 cpu=3 pid=6779 [< none >] __slab_free+0x1fc/0x320 mm/slub.c:2678 [< inline >] slab_free mm/slub.c:2833 [< none >] kfree+0x26a/0x290 mm/slub.c:3662 [< none >] kvfree+0x36/0x60 mm/util.c:324 [< inline >] seq_release fs/seq_file.c:368 [< none >] single_release+0x78/0xb0 fs/seq_file.c:605 [< none >] __fput+0x233/0x780 fs/file_table.c:208 [< none >] ____fput+0x15/0x20 fs/file_table.c:244 [< none >] task_work_run+0x16b/0x200 kernel/task_work.c:115 [< inline >] tracehook_notify_resume include/linux/tracehook.h:191 [< none >] exit_to_usermode_loop+0x180/0x1a0 arch/x86/entry/common.c:251 [< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:282 [< none >] syscall_return_slowpath+0x19f/0x210 arch/x86/entry/common.c:344 [< none >] int_ret_from_sys_call+0x25/0x9f arch/x86/entry/entry_64.S:281 INFO: Slab 0xffffea00016c5600 objects=7 used=5 fp=0xffff88005b15b588 flags=0x5fffc0000004080 INFO: Object 0xffff88005b15eb10 @offset=27408 fp=0xffff88005b15d938 CPU: 1 PID: 6775 Comm: a.out Tainted: G B 4.4.0-rc5+ #165 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 00000000ffffffff ffff88005de679d8 ffffffff82899fbd ffff88003e806a00 ffff88005b15eb10 ffff88005b158000 ffff88005de67a08 ffffffff816c56f4 ffff88003e806a00 ffffea00016c5600 ffff88005b15eb10 ffff88005de67b58 Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff82899fbd>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50 [<ffffffff816c56f4>] print_trailer+0xf4/0x150 mm/slub.c:659 [<ffffffff816cbeaf>] object_err+0x2f/0x40 mm/slub.c:689 [< inline >] print_address_description mm/kasan/report.c:138 [<ffffffff816ce86d>] kasan_report_error+0x25d/0x560 mm/kasan/report.c:251 [< inline >] kasan_report mm/kasan/report.c:274 [<ffffffff816cedae>] __asan_report_store8_noabort+0x3e/0x40 mm/kasan/report.c:300 [< inline >] timer_stats_timer_clear_start_info include/linux/timer.h:208 [<ffffffff8144f126>] del_timer+0x116/0x130 kernel/time/timer.c:1028 [<ffffffff839f0d9f>] sixpack_close+0xbf/0x140 drivers/net/hamradio/6pack.c:688 [<ffffffff82be4239>] tty_ldisc_close.isra.1+0x99/0xe0 drivers/tty/tty_ldisc.c:471 [<ffffffff82be44d2>] tty_ldisc_kill+0x42/0x190 drivers/tty/tty_ldisc.c:753 [<ffffffff82be5a77>] tty_ldisc_release+0x117/0x260 drivers/tty/tty_ldisc.c:781 [<ffffffff82bd03da>] tty_release+0xa7a/0xff0 drivers/tty/tty_io.c:1905 [<ffffffff81716103>] __fput+0x233/0x780 fs/file_table.c:208 [<ffffffff817166d5>] ____fput+0x15/0x20 fs/file_table.c:244 [<ffffffff8134679b>] task_work_run+0x16b/0x200 kernel/task_work.c:115 [< inline >] exit_task_work include/linux/task_work.h:21 [<ffffffff812f4d3b>] do_exit+0x8bb/0x2b20 kernel/exit.c:750 [<ffffffff812f7118>] do_group_exit+0x108/0x320 kernel/exit.c:880 [< inline >] SYSC_exit_group kernel/exit.c:891 [<ffffffff812f734d>] SyS_exit_group+0x1d/0x20 kernel/exit.c:889 [<ffffffff85ccc3f6>] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 ================================================================== This report is then followed by a dozen of other use-after-free reports. On commit edb42dc7bc0da0125ceacab810a553ce1f0cac8d (Dec 15). Thank you -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
