Messages in this thread | | | Date | Wed, 27 Feb 2019 16:52:47 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH] time64: Avoid undefined behaviour in timespec64_add() |
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On Mon, 25 Feb 2019, Yao HongBo wrote: > On 2/25/2019 12:53 PM, Deepa Dinamani wrote: > > On Sun, Feb 24, 2019 at 7:13 PM Hongbo Yao <yaohongbo@huawei.com> wrote: > >> I ran into this:
> >> UBSAN: Undefined behaviour in ./include/linux/time64.h:70:2 > >> signed integer overflow: > >> 1551059291 + 9223372036854775807 cannot be represented in type 'long > >> long int' > >> CPU: 5 PID: 20064 Comm: syz-executor.2 Not tainted 4.19.24 #4 > >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > >> 1.10.2-1ubuntu1 04/01/2014 > >> Call Trace: > >> __dump_stack lib/dump_stack.c:77 [inline] > >> dump_stack+0xca/0x13e lib/dump_stack.c:113 > >> ubsan_epilogue+0xe/0x81 lib/ubsan.c:159 > >> handle_overflow+0x193/0x1e2 lib/ubsan.c:190 > >> timespec64_add include/linux/time64.h:70 [inline] > >> timekeeping_inject_offset+0x3ed/0x4e0 kernel/time/timekeeping.c:1301 > >> do_adjtimex+0x1e5/0x6c0 kernel/time/timekeeping.c:2360 > >> __do_sys_clock_adjtime+0x122/0x200 kernel/time/posix-timers.c:1086 > > > You seem to be adding INT64_MAX here. Maybe the right thing to do is > > to add a check at the syscall interface rather than here. > > Thanks for this suggestion. Looks like that is a better way. > I will try it.
Yes, the input to sys_clock_adjtime() needs to be sanity checked.
Thanks,
tglx
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