>
> On 9/20/2021 11:03 AM, Lorenzo Bianconi wrote:
> > Limit max value for mcs and nss according to specs in order to fix the
> > following warning reported by syzbot:
> >
> > WARNING: CPU: 0 PID: 10717 at include/net/mac80211.h:989 ieee80211_rate_set_vht include/net/mac80211.h:989 [inline]
> > WARNING: CPU: 0 PID: 10717 at include/net/mac80211.h:989 ieee80211_parse_tx_radiotap+0x101e/0x12d0 net/mac80211/tx.c:2244
> > Modules linked in:
> > CPU: 0 PID: 10717 Comm: syz-executor.5 Not tainted 5.14.0-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > RIP: 0010:ieee80211_rate_set_vht include/net/mac80211.h:989 [inline]
> > RIP: 0010:ieee80211_parse_tx_radiotap+0x101e/0x12d0 net/mac80211/tx.c:2244
> > RSP: 0018:ffffc9000186f3e8 EFLAGS: 00010216
> > RAX: 0000000000000618 RBX: ffff88804ef76500 RCX: ffffc900143a5000
> > RDX: 0000000000040000 RSI: ffffffff888f478e RDI: 0000000000000003
> > RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000100
> > R10: ffffffff888f46f9 R11: 0000000000000000 R12: 00000000fffffff8
> > R13: ffff88804ef7653c R14: 0000000000000001 R15: 0000000000000004
> > FS: 00007fbf5718f700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 0000001b2de23000 CR3: 000000006a671000 CR4: 00000000001506f0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
> > Call Trace:
> > ieee80211_monitor_select_queue+0xa6/0x250 net/mac80211/iface.c:740
> > netdev_core_pick_tx+0x169/0x2e0 net/core/dev.c:4089
> > __dev_queue_xmit+0x6f9/0x3710 net/core/dev.c:4165
> > __bpf_tx_skb net/core/filter.c:2114 [inline]
> > __bpf_redirect_no_mac net/core/filter.c:2139 [inline]
> > __bpf_redirect+0x5ba/0xd20 net/core/filter.c:2162
> > ____bpf_clone_redirect net/core/filter.c:2429 [inline]
> > bpf_clone_redirect+0x2ae/0x420 net/core/filter.c:2401
> > bpf_prog_eeb6f53a69e5c6a2+0x59/0x234
> > bpf_dispatcher_nop_func include/linux/bpf.h:717 [inline]
> > __bpf_prog_run include/linux/filter.h:624 [inline]
> > bpf_prog_run include/linux/filter.h:631 [inline]
> > bpf_test_run+0x381/0xa30 net/bpf/test_run.c:119
> > bpf_prog_test_run_skb+0xb84/0x1ee0 net/bpf/test_run.c:663
> > bpf_prog_test_run kernel/bpf/syscall.c:3307 [inline]
> > __sys_bpf+0x2137/0x5df0 kernel/bpf/syscall.c:4605
> > __do_sys_bpf kernel/bpf/syscall.c:4691 [inline]
> > __se_sys_bpf kernel/bpf/syscall.c:4689 [inline]
> > __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4689
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > RIP: 0033:0x4665f9
> >
> > Reported-by: syzbot+0196ac871673f0c20f68@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Fixes: 646e76bb5daf4 ("mac80211: parse VHT info in injected frames")
> > Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> > ---
> > net/mac80211/tx.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> > index 2d1193ed3eb5..d81a9409fd0e 100644
> > --- a/net/mac80211/tx.c
> > +++ b/net/mac80211/tx.c
> > @@ -2209,7 +2209,11 @@ bool ieee80211_parse_tx_radiotap(struct sk_buff *skb,
> > }
> >
> > vht_mcs = iterator.this_arg[4] >> 4;
> > + if (vht_mcs > 9)
> > + vht_mcs = 0;
>
> Some devices can use higher mcs values so maybe we may want to allow
> higher values(?). See cfg80211_calculate_bitrate_vht() [1].
Hi Arend,
AFAIK mcs10 and mcs11 are not part of 802.11ac standard but I am fine
allowing them since they are already managed in the code.
@Johannes: Do you agree?
Regards,
Lorenzo
>
> > vht_nss = iterator.this_arg[4] & 0xF;
> > + if (!vht_nss || vht_nss > 8)
> > + vht_nss = 1;
> > break;
> >
> > /*
> >
>
> Regards,
> Arend
>
> [1] https://elixir.bootlin.com/linux/latest/source/net/wireless/util.c#L1250
>
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