Le ven. 5 juin 2020 à 21:49, syzbot
<syzbot+897abbbe59467cbf6...@syzkaller.appspotmail.com> a écrit :
> [ 44.1699615] panic: UBSan: Undefined Behavior in
> /syzkaller/managers/netbsd-kubsan/kernel/sys/kern/vfs_lockf.c:843:16, signed
> integer overflow: 131072 + 9223372036854771712 cannot be represented in type
> 'long int'
>
> [ 44.1931600] cpu0: Begin traceback...
> [ 44.1999503] vpanic() at netbsd:vpanic+0x287 sys/kern/subr_prf.c:290
> [ 44.2299515] isAlreadyReported() at netbsd:isAlreadyReported
> [ 44.2599494] HandleOverflow() at netbsd:HandleOverflow+0x1c9
> sys/../common/lib/libc/misc/ubsan.c:375
> [ 44.2899499] lf_advlock() at netbsd:lf_advlock+0x2124
> sys/kern/vfs_lockf.c:843
This happens in:
if (fl->l_len > 0)
end = start + fl->l_len - 1;
else {
when call to fcntl() is arranged so that 'start' ends up 0x20000 and
fl->l_len 0x7ffffffffffff000, overflowing the off_t.
I wonder, Is it important to fix cases like that?
Jaromir
