This is a note to let you know that I've just added the patch titled net: Properly typecast int values to set sk_max_pacing_rate to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-properly-typecast-int-values-to-set-sk_max_pacing_rate.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sat Oct 24 11:00:25 AM CEST 2020 From: Ke Li <keli@xxxxxxxxxx> Date: Thu, 22 Oct 2020 02:41:46 -0400 Subject: net: Properly typecast int values to set sk_max_pacing_rate From: Ke Li <keli@xxxxxxxxxx> [ Upstream commit 700465fd338fe5df08a1b2e27fa16981f562547f ] 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: 76a9ebe811fb ("net: extend sk_pacing_rate to unsigned long") Signed-off-by: Ji Li <jli@xxxxxxxxxx> Signed-off-by: Ke Li <keli@xxxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Link: https://lore.kernel.org/r/20201022064146.79873-1-keli@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/core/filter.c | 3 ++- net/core/sock.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-) --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4270,7 +4270,8 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_so 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; --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1106,7 +1106,7 @@ set_rcvbuf: 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) && Patches currently in stable-queue which might be from keli@xxxxxxxxxx are queue-5.4/net-properly-typecast-int-values-to-set-sk_max_pacing_rate.patch