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authorEric Dumazet <edumazet@google.com>2017-12-10 17:55:03 -0800
committerDavid S. Miller <davem@davemloft.net>2017-12-12 10:53:04 -0500
commit607065bad9931e72207b0cac365d7d4abc06bd99 (patch)
treed18808d1c3bf46dd8a899c3877257ea8c4961b61
parent02db55718d53f9d426cee504c27fb768e9ed4ffe (diff)
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: 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>
-rw-r--r--include/linux/tcp.h2
-rw-r--r--net/ipv4/tcp_input.c12
2 files changed, 8 insertions, 6 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index ca4a6361389b..4f93f0953c41 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -344,7 +344,7 @@ struct tcp_sock {
/* Receiver queue space */
struct {
- int space;
+ u32 space;
u32 seq;
u64 time;
} rcvq_space;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 746a6773c482..2900e58738cd 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -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
@@ -625,8 +626,9 @@ 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,
- sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
+ 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;