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authorEric Dumazet2014-09-22 13:19:44 -0700
committerDavid S. Miller2014-09-22 16:27:10 -0400
commitfcdd1cf4dd63aecf86c987d7f4ec7187be5c2fbc (patch)
tree9f74f24f8fe931ffac65805a30bf7e53de7e89b1 /include
parent35f7aa5309c048bb70e58571942795fa9411ce6a (diff)
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 'include')
-rw-r--r--include/net/inet_connection_sock.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 5fbe6568c3cf..848e85cb5c61 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -242,6 +242,15 @@ static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
#endif
}
+static inline unsigned long
+inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
+ unsigned long max_when)
+{
+ u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
+
+ return (unsigned long)min_t(u64, when, max_when);
+}
+
struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);
struct request_sock *inet_csk_search_req(const struct sock *sk,