Messages in this thread | | | From | Alexander Potapenko <> | Date | Wed, 27 Sep 2017 14:58:07 +0200 | Subject | Re: [PATCH v2] tun: bail out from tun_get_user() if the skb is empty |
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On Wed, Sep 27, 2017 at 2:45 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > On Wed, 2017-09-27 at 05:42 -0700, Eric Dumazet wrote: > >> Or something cleaner to avoid copy/paste and focus on proper >> skb->data[0] access and meaning. By the way I'm wondering if this is the only place where skb->data is being accessed. Isn't eth_type_trans() under IFF_TAP also touching it? Then we need to check the size earlier. >> Thanks. >> >> diff --git a/drivers/net/tun.c b/drivers/net/tun.c >> index 3c9985f299503ea65dad7eb3b47e2ab3bef87800..8ddb840687c1bdb24e4182612abc9e362624c3e9 100644 >> --- a/drivers/net/tun.c >> +++ b/drivers/net/tun.c >> @@ -1496,11 +1496,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, >> switch (tun->flags & TUN_TYPE_MASK) { >> case IFF_TUN: >> if (tun->flags & IFF_NO_PI) { >> - switch (skb->data[0] & 0xf0) { >> - case 0x40: >> + u8 ip_proto = skb->len ? (skb->data[0] >> 4) : 0; > > And name this variable ip_version ;) > > >
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