6.4-stable review patch. If anyone has any objections, please let me know.
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From: Xiao Liang shaw.leon@gmail.com
commit 28427f368f0e08d504ed06e74bc7cc79d6d06511 upstream.
Fix skb_ensure_writable() size. Don't use nft_tcp_header_pointer() to make it explicit that pointers point to the packet (not local buffer).
Fixes: 99d1712bc41c ("netfilter: exthdr: tcp option set support") Fixes: 7890cbea66e7 ("netfilter: exthdr: add support for tcp option removal") Cc: stable@vger.kernel.org Signed-off-by: Xiao Liang shaw.leon@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/netfilter/nft_exthdr.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-)
--- a/net/netfilter/nft_exthdr.c +++ b/net/netfilter/nft_exthdr.c @@ -237,7 +237,12 @@ static void nft_exthdr_tcp_set_eval(cons if (!tcph) goto err;
+ if (skb_ensure_writable(pkt->skb, nft_thoff(pkt) + tcphdr_len)) + goto err; + + tcph = (struct tcphdr *)(pkt->skb->data + nft_thoff(pkt)); opt = (u8 *)tcph; + for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) { union { __be16 v16; @@ -252,15 +257,6 @@ static void nft_exthdr_tcp_set_eval(cons if (i + optl > tcphdr_len || priv->len + priv->offset > optl) goto err;
- if (skb_ensure_writable(pkt->skb, - nft_thoff(pkt) + i + priv->len)) - goto err; - - tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, - &tcphdr_len); - if (!tcph) - goto err; - offset = i + priv->offset;
switch (priv->len) { @@ -324,9 +320,9 @@ static void nft_exthdr_tcp_strip_eval(co if (skb_ensure_writable(pkt->skb, nft_thoff(pkt) + tcphdr_len)) goto drop;
- opt = (u8 *)nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len); - if (!opt) - goto err; + tcph = (struct tcphdr *)(pkt->skb->data + nft_thoff(pkt)); + opt = (u8 *)tcph; + for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) { unsigned int j;