4.9-stable review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn willemb@google.com
[ Upstream commit fff88030b3ff930ca7a3d74acfee0472f33887ea ]
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 Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/skbuff.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2615,7 +2615,8 @@ void skb_split(struct sk_buff *skb, stru { 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. */ @@ -3228,8 +3229,8 @@ 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) { @@ -3881,7 +3882,8 @@ void __skb_tstamp_tx(struct sk_buff *ori 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; }