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@google.com --- net/ipv4/tcp.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 6baa6dc1b13b..e76beb5ff1ff 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1749,7 +1749,7 @@ EXPORT_SYMBOL(tcp_mmap); static int tcp_zerocopy_receive(struct sock *sk, struct tcp_zerocopy_receive *zc) { - unsigned long address = (unsigned long)zc->address; + unsigned long address; const skb_frag_t *frags = NULL; u32 length = 0, seq, offset; struct vm_area_struct *vma; @@ -1758,7 +1758,12 @@ static int tcp_zerocopy_receive(struct sock *sk, int inq; int ret;
- if (address & (PAGE_SIZE - 1) || address != zc->address) + address = (unsigned long)untagged_addr(zc->address); + + /* The second test in this if detects if the u64->unsigned long + * conversion had any truncated bits. + */ + if (address & (PAGE_SIZE - 1) || address != untagged_addr(zc->address)) return -EINVAL;
if (sk->sk_state == TCP_LISTEN)