summaryrefslogtreecommitdiffstats
path: root/net/ipv4/tcp_output.c
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2014-09-22 13:19:44 -0700
committerDavid S. Miller <davem@davemloft.net>2014-09-22 16:27:10 -0400
commitfcdd1cf4dd63aecf86c987d7f4ec7187be5c2fbc (patch)
tree9f74f24f8fe931ffac65805a30bf7e53de7e89b1 /net/ipv4/tcp_output.c
parent35f7aa5309c048bb70e58571942795fa9411ce6a (diff)
downloadlinux-fcdd1cf4dd63aecf86c987d7f4ec7187be5c2fbc.tar.bz2
tcp: avoid possible arithmetic overflows
icsk_rto is a 32bit field, and icsk_backoff can reach 15 by default, or more if some sysctl (eg tcp_retries2) are changed. Better use 64bit to perform icsk_rto << icsk_backoff operations As Joe Perches suggested, add a helper for this. Yuchung spotted the tcp_v4_err() case. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_output.c')
-rw-r--r--net/ipv4/tcp_output.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 7f1280dcad57..8c61a7c0c889 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3279,6 +3279,7 @@ void tcp_send_probe0(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
+ unsigned long probe_max;
int err;
err = tcp_write_wakeup(sk);
@@ -3294,9 +3295,7 @@ void tcp_send_probe0(struct sock *sk)
if (icsk->icsk_backoff < sysctl_tcp_retries2)
icsk->icsk_backoff++;
icsk->icsk_probes_out++;
- inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
- min(icsk->icsk_rto << icsk->icsk_backoff, TCP_RTO_MAX),
- TCP_RTO_MAX);
+ probe_max = TCP_RTO_MAX;
} else {
/* If packet was not sent due to local congestion,
* do not backoff and do not remember icsk_probes_out.
@@ -3306,11 +3305,11 @@ void tcp_send_probe0(struct sock *sk)
*/
if (!icsk->icsk_probes_out)
icsk->icsk_probes_out = 1;
- inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
- min(icsk->icsk_rto << icsk->icsk_backoff,
- TCP_RESOURCE_PROBE_INTERVAL),
- TCP_RTO_MAX);
+ probe_max = TCP_RESOURCE_PROBE_INTERVAL;
}
+ inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
+ inet_csk_rto_backoff(icsk, probe_max),
+ TCP_RTO_MAX);
}
int tcp_rtx_synack(struct sock *sk, struct request_sock *req)