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netfilter: nft_exthdr: break evaluation if setting TCP option fails

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Break rule evaluation on malformed TCP options.

Fixes: 99d1712bc4 ("netfilter: exthdr: tcp option set support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2021-11-30 11:34:04 +01:00
parent 0de53b0ffb
commit 962e5a4035
1 changed files with 7 additions and 4 deletions

11
net/netfilter/nft_exthdr.c
View File

@ -236,7 +236,7 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
if (!tcph)
return;
goto err;
opt = (u8 *)tcph;
for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
@ -251,16 +251,16 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
continue;
if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
return;
goto err;
if (skb_ensure_writable(pkt->skb,
nft_thoff(pkt) + i + priv->len))
return;
goto err;
tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff,
&tcphdr_len);
if (!tcph)
return;
goto err;
offset = i + priv->offset;
@ -303,6 +303,9 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
return;
}
return;
err:
regs->verdict.code = NFT_BREAK;
}
static void nft_exthdr_sctp_eval(const struct nft_expr *expr,