Message ID | 20170608153503.74199-1-willemdebruijn.kernel@gmail.com |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
On Thu, Jun 8, 2017 at 11:35 AM, Willem de Bruijn <willemdebruijn.kernel@gmail.com> wrote: > > From: Willem de Bruijn <willemb@google.com> > > When inheriting tx_flags from one skbuff to another, always apply a > mask to avoid overwriting unrelated other bits in the field. > > The two SKBTX_SHARED_FRAG cases clears all other bits. In practice, > tx_flags are zero at this point now. But this is fragile. Timestamp > flags are set, for instance, if in tcp_gso_segment, after this clear > in skb_segment. > > The SKBTX_ANY_TSTAMP mask in __skb_tstamp_tx ensures that new > skbs do not accidentally inherit flags such as SKBTX_SHARED_FRAG. > > Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
On Thu, 2017-06-08 at 11:35 -0400, Willem de Bruijn wrote: > From: Willem de Bruijn <willemb@google.com> > > When inheriting tx_flags from one skbuff to another, always apply a > mask to avoid overwriting unrelated other bits in the field. > > The two SKBTX_SHARED_FRAG cases clears all other bits. In practice, > tx_flags are zero at this point now. But this is fragile. Timestamp > flags are set, for instance, if in tcp_gso_segment, after this clear > in skb_segment. > > The SKBTX_ANY_TSTAMP mask in __skb_tstamp_tx ensures that new > skbs do not accidentally inherit flags such as SKBTX_SHARED_FRAG. > > Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Eric Dumazet <edumazet@google.com>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 82cfc9c7a090..e508c1eae67f 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2646,7 +2646,8 @@ void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) { int pos = skb_headlen(skb); - skb_shinfo(skb1)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG; + skb_shinfo(skb1)->tx_flags |= skb_shinfo(skb)->tx_flags & + SKBTX_SHARED_FRAG; if (len < pos) /* Split line is inside header. */ skb_split_inside_header(skb, skb1, len, pos); else /* Second chunk has no header, nothing to copy. */ @@ -3261,8 +3262,8 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, skb_copy_from_linear_data_offset(head_skb, offset, skb_put(nskb, hsize), hsize); - skb_shinfo(nskb)->tx_flags = skb_shinfo(head_skb)->tx_flags & - SKBTX_SHARED_FRAG; + skb_shinfo(nskb)->tx_flags |= skb_shinfo(head_skb)->tx_flags & + SKBTX_SHARED_FRAG; while (pos < offset + len) { if (i >= nfrags) { @@ -3948,7 +3949,8 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb, return; if (tsonly) { - skb_shinfo(skb)->tx_flags = skb_shinfo(orig_skb)->tx_flags; + skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags & + SKBTX_ANY_TSTAMP; skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey; }