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Commit 607065ba authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: avoid integer overflows in tcp_rcv_space_adjust() 



When using large tcp_rmem[2] values (I did tests with 500 MB),
I noticed overflows while computing rcvwin.

Lets fix this before the following patch.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarWei Wang <weiwan@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 02db5571

include/linux/tcp.h

+1 −1
Original line number Diff line number Diff line
@@ -344,7 +344,7 @@ struct tcp_sock { 


/* Receiver queue space */

	struct {

		int	space;

		u32	space;

		u32	seq;

		u64	time;

	} rcvq_space;

net/ipv4/tcp_input.c

+7 −5
Original line number Diff line number Diff line
@@ -576,8 +576,8 @@ static inline void tcp_rcv_rtt_measure_ts(struct sock *sk, 
void tcp_rcv_space_adjust(struct sock *sk)

{

	struct tcp_sock *tp = tcp_sk(sk);

	u32 copied;

	int time;

	int copied;



	tcp_mstamp_refresh(tp);

	time = tcp_stamp_us_delta(tp->tcp_mstamp, tp->rcvq_space.time);
@@ -600,12 +600,13 @@ void tcp_rcv_space_adjust(struct sock *sk) 


	if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&

	    !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {

		int rcvwin, rcvmem, rcvbuf;

		int rcvmem, rcvbuf;

		u64 rcvwin;



		/* minimal window to cope with packet losses, assuming

		 * steady state. Add some cushion because of small variations.

		 */

		rcvwin = (copied << 1) + 16 * tp->advmss;

		rcvwin = ((u64)copied << 1) + 16 * tp->advmss;



		/* If rate increased by 25%,

		 *	assume slow start, rcvwin = 3 * copied
@@ -625,7 +626,8 @@ void tcp_rcv_space_adjust(struct sock *sk) 
		while (tcp_win_from_space(sk, rcvmem) < tp->advmss)

			rcvmem += 128;



		rcvbuf = min(rcvwin / tp->advmss * rcvmem,

		do_div(rcvwin, tp->advmss);

		rcvbuf = min_t(u64, rcvwin * rcvmem,

			       sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);

		if (rcvbuf > sk->sk_rcvbuf) {

			sk->sk_rcvbuf = rcvbuf;