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-rw-r--r--net/ipv6/af_inet6.c4
-rw-r--r--net/ipv6/exthdrs.c67
-rw-r--r--net/ipv6/sysctl_net_ipv6.c32
3 files changed, 91 insertions, 12 deletions
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index fe5262fd6aa5..c26f71234b9c 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -810,6 +810,10 @@ static int __net_init inet6_net_init(struct net *net)
net->ipv6.sysctl.idgen_retries = 3;
net->ipv6.sysctl.idgen_delay = 1 * HZ;
net->ipv6.sysctl.flowlabel_state_ranges = 0;
+ net->ipv6.sysctl.max_dst_opts_cnt = IP6_DEFAULT_MAX_DST_OPTS_CNT;
+ net->ipv6.sysctl.max_hbh_opts_cnt = IP6_DEFAULT_MAX_HBH_OPTS_CNT;
+ net->ipv6.sysctl.max_dst_opts_len = IP6_DEFAULT_MAX_DST_OPTS_LEN;
+ net->ipv6.sysctl.max_hbh_opts_len = IP6_DEFAULT_MAX_HBH_OPTS_LEN;
atomic_set(&net->ipv6.fib6_sernum, 1);
err = ipv6_init_mibs(net);
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 9f918a770f87..83bd75713535 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -74,8 +74,20 @@ struct tlvtype_proc {
/* An unknown option is detected, decide what to do */
-static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
+static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
+ bool disallow_unknowns)
{
+ if (disallow_unknowns) {
+ /* If unknown TLVs are disallowed by configuration
+ * then always silently drop packet. Note this also
+ * means no ICMP parameter problem is sent which
+ * could be a good property to mitigate a reflection DOS
+ * attack.
+ */
+
+ goto drop;
+ }
+
switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
case 0: /* ignore */
return true;
@@ -95,20 +107,30 @@ static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
return false;
}
+drop:
kfree_skb(skb);
return false;
}
/* Parse tlv encoded option header (hop-by-hop or destination) */
-static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
+static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
+ struct sk_buff *skb,
+ int max_count)
{
- const struct tlvtype_proc *curr;
+ int len = (skb_transport_header(skb)[1] + 1) << 3;
const unsigned char *nh = skb_network_header(skb);
int off = skb_network_header_len(skb);
- int len = (skb_transport_header(skb)[1] + 1) << 3;
+ const struct tlvtype_proc *curr;
+ bool disallow_unknowns = false;
+ int tlv_count = 0;
int padlen = 0;
+ if (unlikely(max_count < 0)) {
+ disallow_unknowns = true;
+ max_count = -max_count;
+ }
+
if (skb_transport_offset(skb) + len > skb_headlen(skb))
goto bad;
@@ -149,6 +171,11 @@ static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
default: /* Other TLV code so scan list */
if (optlen > len)
goto bad;
+
+ tlv_count++;
+ if (tlv_count > max_count)
+ goto bad;
+
for (curr = procs; curr->type >= 0; curr++) {
if (curr->type == nh[off]) {
/* type specific length/alignment
@@ -159,10 +186,10 @@ static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
break;
}
}
- if (curr->type < 0) {
- if (ip6_tlvopt_unknown(skb, off) == 0)
- return false;
- }
+ if (curr->type < 0 &&
+ !ip6_tlvopt_unknown(skb, off, disallow_unknowns))
+ return false;
+
padlen = 0;
break;
}
@@ -258,23 +285,31 @@ static int ipv6_destopt_rcv(struct sk_buff *skb)
__u16 dstbuf;
#endif
struct dst_entry *dst = skb_dst(skb);
+ struct net *net = dev_net(skb->dev);
+ int extlen;
if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
!pskb_may_pull(skb, (skb_transport_offset(skb) +
((skb_transport_header(skb)[1] + 1) << 3)))) {
__IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst),
IPSTATS_MIB_INHDRERRORS);
+fail_and_free:
kfree_skb(skb);
return -1;
}
+ extlen = (skb_transport_header(skb)[1] + 1) << 3;
+ if (extlen > net->ipv6.sysctl.max_dst_opts_len)
+ goto fail_and_free;
+
opt->lastopt = opt->dst1 = skb_network_header_len(skb);
#if IS_ENABLED(CONFIG_IPV6_MIP6)
dstbuf = opt->dst1;
#endif
- if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
- skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
+ if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
+ init_net.ipv6.sysctl.max_dst_opts_cnt)) {
+ skb->transport_header += extlen;
opt = IP6CB(skb);
#if IS_ENABLED(CONFIG_IPV6_MIP6)
opt->nhoff = dstbuf;
@@ -803,6 +838,8 @@ static const struct tlvtype_proc tlvprochopopt_lst[] = {
int ipv6_parse_hopopts(struct sk_buff *skb)
{
struct inet6_skb_parm *opt = IP6CB(skb);
+ struct net *net = dev_net(skb->dev);
+ int extlen;
/*
* skb_network_header(skb) is equal to skb->data, and
@@ -813,13 +850,19 @@ int ipv6_parse_hopopts(struct sk_buff *skb)
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
!pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
((skb_transport_header(skb)[1] + 1) << 3)))) {
+fail_and_free:
kfree_skb(skb);
return -1;
}
+ extlen = (skb_transport_header(skb)[1] + 1) << 3;
+ if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
+ goto fail_and_free;
+
opt->flags |= IP6SKB_HOPBYHOP;
- if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
- skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
+ if (ip6_parse_tlv(tlvprochopopt_lst, skb,
+ init_net.ipv6.sysctl.max_hbh_opts_cnt)) {
+ skb->transport_header += extlen;
opt = IP6CB(skb);
opt->nhoff = sizeof(struct ipv6hdr);
return 1;
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 6fbf8ae5e52c..4a2f0fd870bc 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -97,6 +97,34 @@ static struct ctl_table ipv6_table_template[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
+ {
+ .procname = "max_dst_opts_number",
+ .data = &init_net.ipv6.sysctl.max_dst_opts_cnt,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec
+ },
+ {
+ .procname = "max_hbh_opts_number",
+ .data = &init_net.ipv6.sysctl.max_hbh_opts_cnt,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec
+ },
+ {
+ .procname = "max_dst_opts_length",
+ .data = &init_net.ipv6.sysctl.max_dst_opts_len,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec
+ },
+ {
+ .procname = "max_hbh_length",
+ .data = &init_net.ipv6.sysctl.max_hbh_opts_len,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec
+ },
{ }
};
@@ -157,6 +185,10 @@ static int __net_init ipv6_sysctl_net_init(struct net *net)
ipv6_table[7].data = &net->ipv6.sysctl.flowlabel_state_ranges;
ipv6_table[8].data = &net->ipv6.sysctl.ip_nonlocal_bind;
ipv6_table[9].data = &net->ipv6.sysctl.flowlabel_reflect;
+ ipv6_table[10].data = &net->ipv6.sysctl.max_dst_opts_cnt;
+ ipv6_table[11].data = &net->ipv6.sysctl.max_hbh_opts_cnt;
+ ipv6_table[12].data = &net->ipv6.sysctl.max_dst_opts_len;
+ ipv6_table[13].data = &net->ipv6.sysctl.max_hbh_opts_len;
ipv6_route_table = ipv6_route_sysctl_init(net);
if (!ipv6_route_table)
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-21 10:18:01 +0000