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Eric Dumazet authored
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. 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: 05255b82 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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