From: Eric Dumazet <eduma...@google.com> Date: Sat, 7 Jul 2018 23:00:01 -0700
> tcp_zerocopy_receive() relies on tcp_inq() to limit number of bytes > requested by user. > > syzbot found that after tcp_disconnect(), tcp_inq() was returning > a stale value (number of bytes in queue before the disconnect). > > Note that after this patch, ioctl(fd, SIOCINQ, &val) is also fixed > and returns 0, so this might be a candidate for all known linux kernels. Ok I'll queue this up for -stable. > While we are at this, we probably also should clear urg_data to > avoid other syzkaller reports after it discovers how to deal with > urgent data. > > syzkaller repro : > > socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3 > bind(3, {sa_family=AF_INET, sin_port=htons(20000), > sin_addr=inet_addr("224.0.0.1")}, 16) = 0 > connect(3, {sa_family=AF_INET, sin_port=htons(20000), > sin_addr=inet_addr("127.0.0.1")}, 16) = 0 > send(3, ..., 4096, 0) = 4096 > connect(3, {sa_family=AF_UNSPEC, sa_data="\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, > 128) = 0 > getsockopt(3, SOL_TCP, TCP_ZEROCOPY_RECEIVE, ..., [16]) = 0 // CRASH > > Fixes: 05255b823a61 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy > receive") > Signed-off-by: Eric Dumazet <eduma...@google.com> > Reported-by: syzbot <syzkal...@googlegroups.com> Applied, thanks Eric.