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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-01-30 22:21:48 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-01-31 10:26:30 -0500 |
| commit | e4823fbd229bfbba368b40cdadb8f4eeb20604cc (patch) | |
| tree | d50137ddbc56c366b47879e9602af9836d71db70 /net/ipv4/tcp_nv.c | |
| parent | 086ca23d03c0d2f4088f472386778d293e15c5f6 (diff) | |
| download | lwn-e4823fbd229bfbba368b40cdadb8f4eeb20604cc.tar.gz lwn-e4823fbd229bfbba368b40cdadb8f4eeb20604cc.zip | |
tcp_nv: fix potential integer overflow in tcpnv_acked
Add suffix ULL to constant 80000 in order to avoid a potential integer
overflow and give the compiler complete information about the proper
arithmetic to use. Notice that this constant is used in a context that
expects an expression of type u64.
The current cast to u64 effectively applies to the whole expression
as an argument of type u64 to be passed to div64_u64, but it does
not prevent it from being evaluated using 32-bit arithmetic instead
of 64-bit arithmetic.
Also, once the expression is properly evaluated using 64-bit arithmentic,
there is no need for the parentheses and the external cast to u64.
Addresses-Coverity-ID: 1357588 ("Unintentional integer overflow")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_nv.c')
| -rw-r--r-- | net/ipv4/tcp_nv.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp_nv.c b/net/ipv4/tcp_nv.c index ddbce73edae8..764298e52577 100644 --- a/net/ipv4/tcp_nv.c +++ b/net/ipv4/tcp_nv.c @@ -364,7 +364,7 @@ static void tcpnv_acked(struct sock *sk, const struct ack_sample *sample) */ cwnd_by_slope = (u32) div64_u64(((u64)ca->nv_rtt_max_rate) * ca->nv_min_rtt, - (u64)(80000 * tp->mss_cache)); + 80000ULL * tp->mss_cache); max_win = cwnd_by_slope + nv_pad; /* If cwnd > max_win, decrease cwnd |