On 03/15/2019 12:51 PM, Andrey Konovalov wrote: > This patch is a part of a series that extends arm64 kernel ABI to allow to > pass tagged user pointers (with the top byte set to something else other > than 0x00) as syscall arguments. > > tcp_zerocopy_receive() uses provided user pointers for vma lookups, which > can only by done with untagged pointers. > > Untag user pointers in this function. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > --- > net/ipv4/tcp.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 6baa6dc1b13b..89db3b4fc753 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -1758,6 +1758,8 @@ static int tcp_zerocopy_receive(struct sock *sk, > int inq; > int ret; > > + address = untagged_addr(address); > + > if (address & (PAGE_SIZE - 1) || address != zc->address) The second test will fail, if the top bits are changed in address but not in zc->address > return -EINVAL; > >
