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path: root/net/netfilter/nft_exthdr.c
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Diffstat (limited to 'net/netfilter/nft_exthdr.c')
-rw-r--r--net/netfilter/nft_exthdr.c134
1 files changed, 115 insertions, 19 deletions
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 9e927ab4df15..d1dcf5b2e92e 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -35,6 +35,14 @@ static unsigned int optlen(const u8 *opt, unsigned int offset)
return opt[offset + 1];
}
+static int nft_skb_copy_to_reg(const struct sk_buff *skb, int offset, u32 *dest, unsigned int len)
+{
+ if (len % NFT_REG32_SIZE)
+ dest[len / NFT_REG32_SIZE] = 0;
+
+ return skb_copy_bits(skb, offset, dest, len);
+}
+
static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
@@ -56,8 +64,7 @@ static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
}
offset += priv->offset;
- dest[priv->len / NFT_REG32_SIZE] = 0;
- if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
+ if (nft_skb_copy_to_reg(pkt->skb, offset, dest, priv->len) < 0)
goto err;
return;
err:
@@ -153,8 +160,7 @@ static void nft_exthdr_ipv4_eval(const struct nft_expr *expr,
}
offset += priv->offset;
- dest[priv->len / NFT_REG32_SIZE] = 0;
- if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
+ if (nft_skb_copy_to_reg(pkt->skb, offset, dest, priv->len) < 0)
goto err;
return;
err:
@@ -208,9 +214,10 @@ static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
offset = i + priv->offset;
if (priv->flags & NFT_EXTHDR_F_PRESENT) {
- *dest = 1;
+ nft_reg_store8(dest, 1);
} else {
- dest[priv->len / NFT_REG32_SIZE] = 0;
+ if (priv->len % NFT_REG32_SIZE)
+ dest[priv->len / NFT_REG32_SIZE] = 0;
memcpy(dest, opt + offset, priv->len);
}
@@ -238,7 +245,12 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
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;
@@ -253,15 +265,6 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
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) {
@@ -308,6 +311,63 @@ err:
regs->verdict.code = NFT_BREAK;
}
+static void nft_exthdr_tcp_strip_eval(const struct nft_expr *expr,
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
+{
+ u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
+ struct nft_exthdr *priv = nft_expr_priv(expr);
+ unsigned int i, tcphdr_len, optl;
+ struct tcphdr *tcph;
+ u8 *opt;
+
+ tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
+ if (!tcph)
+ goto err;
+
+ if (skb_ensure_writable(pkt->skb, nft_thoff(pkt) + tcphdr_len))
+ goto drop;
+
+ 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;
+
+ optl = optlen(opt, i);
+ if (priv->type != opt[i])
+ continue;
+
+ if (i + optl > tcphdr_len)
+ goto drop;
+
+ for (j = 0; j < optl; ++j) {
+ u16 n = TCPOPT_NOP;
+ u16 o = opt[i+j];
+
+ if ((i + j) % 2 == 0) {
+ o <<= 8;
+ n <<= 8;
+ }
+ inet_proto_csum_replace2(&tcph->check, pkt->skb, htons(o),
+ htons(n), false);
+ }
+ memset(opt + i, TCPOPT_NOP, optl);
+ return;
+ }
+
+ /* option not found, continue. This allows to do multiple
+ * option removals per rule.
+ */
+ return;
+err:
+ regs->verdict.code = NFT_BREAK;
+ return;
+drop:
+ /* can't remove, no choice but to drop */
+ regs->verdict.code = NF_DROP;
+}
+
static void nft_exthdr_sctp_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
@@ -335,9 +395,8 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr,
offset + ntohs(sch->length) > pkt->skb->len)
break;
- dest[priv->len / NFT_REG32_SIZE] = 0;
- if (skb_copy_bits(pkt->skb, offset + priv->offset,
- dest, priv->len) < 0)
+ if (nft_skb_copy_to_reg(pkt->skb, offset + priv->offset,
+ dest, priv->len) < 0)
break;
return;
}
@@ -457,6 +516,28 @@ static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx,
priv->len);
}
+static int nft_exthdr_tcp_strip_init(const struct nft_ctx *ctx,
+ const struct nft_expr *expr,
+ const struct nlattr * const tb[])
+{
+ struct nft_exthdr *priv = nft_expr_priv(expr);
+
+ if (tb[NFTA_EXTHDR_SREG] ||
+ tb[NFTA_EXTHDR_DREG] ||
+ tb[NFTA_EXTHDR_FLAGS] ||
+ tb[NFTA_EXTHDR_OFFSET] ||
+ tb[NFTA_EXTHDR_LEN])
+ return -EINVAL;
+
+ if (!tb[NFTA_EXTHDR_TYPE])
+ return -EINVAL;
+
+ priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
+ priv->op = NFT_EXTHDR_OP_TCPOPT;
+
+ return 0;
+}
+
static int nft_exthdr_ipv4_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
@@ -517,6 +598,13 @@ static int nft_exthdr_dump_set(struct sk_buff *skb, const struct nft_expr *expr)
return nft_exthdr_dump_common(skb, priv);
}
+static int nft_exthdr_dump_strip(struct sk_buff *skb, const struct nft_expr *expr)
+{
+ const struct nft_exthdr *priv = nft_expr_priv(expr);
+
+ return nft_exthdr_dump_common(skb, priv);
+}
+
static const struct nft_expr_ops nft_exthdr_ipv6_ops = {
.type = &nft_exthdr_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
@@ -549,6 +637,14 @@ static const struct nft_expr_ops nft_exthdr_tcp_set_ops = {
.dump = nft_exthdr_dump_set,
};
+static const struct nft_expr_ops nft_exthdr_tcp_strip_ops = {
+ .type = &nft_exthdr_type,
+ .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
+ .eval = nft_exthdr_tcp_strip_eval,
+ .init = nft_exthdr_tcp_strip_init,
+ .dump = nft_exthdr_dump_strip,
+};
+
static const struct nft_expr_ops nft_exthdr_sctp_ops = {
.type = &nft_exthdr_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
@@ -576,7 +672,7 @@ nft_exthdr_select_ops(const struct nft_ctx *ctx,
return &nft_exthdr_tcp_set_ops;
if (tb[NFTA_EXTHDR_DREG])
return &nft_exthdr_tcp_ops;
- break;
+ return &nft_exthdr_tcp_strip_ops;
case NFT_EXTHDR_OP_IPV6:
if (tb[NFTA_EXTHDR_DREG])
return &nft_exthdr_ipv6_ops;
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-28 17:26:38 +0000