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tcp: avoid integer overflows in tcp_rcv_space_adjust()

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commit 607065bad9931e72207b0cac365d7d4abc06bd99 upstream.

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: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Wei Wang <weiwan@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[Backport: sysctl_tcp_rmem is not Namespace-ify'd in older kernels]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric Dumazet 2017-12-10 17:55:03 -08:00 committed by Greg Kroah-Hartman
parent 9b5c9f07a7
commit 70741861fc
2 changed files with 7 additions and 5 deletions
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2
include/linux/tcp.h
View File

@ -324,7 +324,7 @@ struct tcp_sock {
/* Receiver queue space */
struct {
int space;
u32 space;
u32 seq;
u32 time;
} rcvq_space;

10
net/ipv4/tcp_input.c
View File

@ -557,8 +557,8 @@ 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;
time = tcp_time_stamp - tp->rcvq_space.time;
if (time < (tp->rcv_rtt_est.rtt >> 3) || tp->rcv_rtt_est.rtt == 0)
@ -580,12 +580,13 @@ void tcp_rcv_space_adjust(struct sock *sk)
if (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
@ -605,7 +606,8 @@ void tcp_rcv_space_adjust(struct sock *sk)
while (tcp_win_from_space(rcvmem) < tp->advmss)
rcvmem += 128;
rcvbuf = min(rcvwin / tp->advmss * rcvmem, sysctl_tcp_rmem[2]);
do_div(rcvwin, tp->advmss);
rcvbuf = min_t(u64, rcvwin * rcvmem, sysctl_tcp_rmem[2]);
if (rcvbuf > sk->sk_rcvbuf) {
sk->sk_rcvbuf = rcvbuf;