leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

tcp: avoid possible arithmetic overflows

Browse Source 
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>
This commit is contained in:
Eric Dumazet
2014-09-22 13:19:44 -07:00
committed by David S. Miller
parent 35f7aa5309
commit fcdd1cf4dd
5 changed files with 23 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
net/ipv4/tcp_output.c
View File

@@ -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)