From: Arnaldo Carvalho de Melo <[email protected]> Date: Mon, 14 Mar 2016 09:56:35 -0300
> From: Arnaldo Carvalho de Melo <[email protected]> > > The syzkaller fuzzer hit the following use-after-free: > > Call Trace: > [<ffffffff8175ea0e>] __asan_report_load8_noabort+0x3e/0x40 > mm/kasan/report.c:295 > [<ffffffff851cc31a>] __sys_recvmmsg+0x6fa/0x7f0 net/socket.c:2261 > [< inline >] SYSC_recvmmsg net/socket.c:2281 > [<ffffffff851cc57f>] SyS_recvmmsg+0x16f/0x180 net/socket.c:2270 > [<ffffffff86332bb6>] entry_SYSCALL_64_fastpath+0x16/0x7a > arch/x86/entry/entry_64.S:185 > > And, as Dmitry rightly assessed, that is because we can drop the > reference and then touch it when the underlying recvmsg calls return > some packets and then hit an error, which will make recvmmsg to set > sock->sk->sk_err, oops, fix it. > > Reported-and-Tested-by: Dmitry Vyukov <[email protected]> > Cc: Alexander Potapenko <[email protected]> > Cc: Eric Dumazet <[email protected]> > Cc: Kostya Serebryany <[email protected]> > Cc: Sasha Levin <[email protected]> > Fixes: a2e2725541fa ("net: Introduce recvmmsg socket syscall") > http://lkml.kernel.org/r/[email protected] > Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> Applied and queued up for -stable, thanks Arnaldo!
