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skbuff: only inherit relevant tx_flags 

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>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Willem de Bruijn 2017-06-08 11:35:03 -04:00 committed by David S. Miller
parent 50430d1fca
commit fff88030b3
1 changed files with 6 additions and 4 deletions
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10
net/core/skbuff.c
View File

@ -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 @@ normal:
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;
}