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| author | Eric Dumazet <edumazet@google.com> | 2014-09-22 13:19:44 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-09-22 16:27:10 -0400 |
| commit | fcdd1cf4dd63aecf86c987d7f4ec7187be5c2fbc (patch) | |
| tree | 9f74f24f8fe931ffac65805a30bf7e53de7e89b1 /net/ipv4/tcp_output.c | |
| parent | 35f7aa5309c048bb70e58571942795fa9411ce6a (diff) | |
| download | linux-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.c | 13 |
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) |