Commit a6f8ee58 authored by Arjun Roy's avatar Arjun Roy Committed by Jakub Kicinski
Browse files

tcp: Specify cmsgbuf is user pointer for receive zerocopy. 



A prior change (1f466e1f) introduces separate handling for
->msg_control depending on whether the pointer is a kernel or user
pointer. However, while tcp receive zerocopy is using this field, it
is not properly annotating that the buffer in this case is a user
pointer. This can cause faults when the improper mechanism is used
within put_cmsg().

This patch simply annotates tcp receive zerocopy's use as explicitly
being a user pointer.

Fixes: 7eeba170 ("tcp: Add receive timestamp support for receive zerocopy.")
Signed-off-by: default avatarArjun Roy <arjunroy@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20210506223530.2266456-1-arjunroy.kdev@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent cbaf3f6a

net/ipv4/tcp.c

+1 −0
Original line number Diff line number Diff line
@@ -2039,6 +2039,7 @@ static void tcp_zc_finalize_rx_tstamp(struct sock *sk, 
		(__kernel_size_t)zc->msg_controllen;

	cmsg_dummy.msg_flags = in_compat_syscall()

		? MSG_CMSG_COMPAT : 0;

	cmsg_dummy.msg_control_is_user = true;

	zc->msg_flags = 0;

	if (zc->msg_control == msg_control_addr &&

	    zc->msg_controllen == cmsg_dummy.msg_controllen) {