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net: Properly typecast int values to set sk_max_pacing_rate 

In setsockopt(SO_MAX_PACING_RATE) on 64bit systems, sk_max_pacing_rate,
after extended from 'u32' to 'unsigned long', takes unintentionally
hiked value whenever assigned from an 'int' value with MSB=1, due to
binary sign extension in promoting s32 to u64, e.g. 0x80000000 becomes
0xFFFFFFFF80000000.

Thus inflated sk_max_pacing_rate causes subsequent getsockopt to return
~0U unexpectedly. It may also result in increased pacing rate.

Fix by explicitly casting the 'int' value to 'unsigned int' before
assigning it to sk_max_pacing_rate, for zero extension to happen.

Fixes: 76a9ebe811 ("net: extend sk_pacing_rate to unsigned long")
Signed-off-by: Ji Li <jli@akamai.com>
Signed-off-by: Ke Li <keli@akamai.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20201022064146.79873-1-keli@akamai.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Ke Li 2020-10-22 02:41:46 -04:00 committed by Jakub Kicinski
parent 594850ca43
commit 700465fd33
2 changed files with 3 additions and 2 deletions
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3
net/core/filter.c
View File

@ -4733,7 +4733,8 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
cmpxchg(&sk->sk_pacing_status,
SK_PACING_NONE,
SK_PACING_NEEDED);
sk->sk_max_pacing_rate = (val == ~0U) ? ~0UL : val;
sk->sk_max_pacing_rate = (val == ~0U) ?
~0UL : (unsigned int)val;
sk->sk_pacing_rate = min(sk->sk_pacing_rate,
sk->sk_max_pacing_rate);
break;

2
net/core/sock.c
View File

@ -1163,7 +1163,7 @@ set_sndbuf:
case SO_MAX_PACING_RATE:
{
unsigned long ulval = (val == ~0U) ? ~0UL : val;
unsigned long ulval = (val == ~0U) ? ~0UL : (unsigned int)val;
if (sizeof(ulval) != sizeof(val) &&
optlen >= sizeof(ulval) &&