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xfrm: Ensure policies always checked on XFRM-I input path

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This change adds methods in the XFRM-I input path that ensures that
policies are checked prior to processing of the subsequent decapsulated
packet, after which the relevant policies may no longer be resolvable
(due to changing src/dst/proto/etc).

Notably, raw ESP/AH packets did not perform policy checks inherently,
whereas all other encapsulated packets (UDP, TCP encapsulated) do policy
checks after calling xfrm_input handling in the respective encapsulation
layer.

Fixes: b0355dbbf1 ("Fix XFRM-I support for nested ESP tunnels")
Test: Verified with additional Android Kernel Unit tests
Test: Verified against Android CTS
Signed-off-by: Benedict Wong <benedictwong@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Benedict Wong 2023-05-10 01:30:22 +00:00 committed by Steffen Klassert
parent 1f8b6df6a9
commit a287f5b0cf
1 changed files with 50 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
net/xfrm/xfrm_interface_core.c
View File

@ -310,6 +310,52 @@ static void xfrmi_scrub_packet(struct sk_buff *skb, bool xnet)
skb->mark = 0;
}
static int xfrmi_input(struct sk_buff *skb, int nexthdr, __be32 spi,
int encap_type, unsigned short family)
{
struct sec_path *sp;
sp = skb_sec_path(skb);
if (sp && (sp->len || sp->olen) &&
!xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family))
goto discard;
XFRM_SPI_SKB_CB(skb)->family = family;
if (family == AF_INET) {
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
} else {
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
}
return xfrm_input(skb, nexthdr, spi, encap_type);
discard:
kfree_skb(skb);
return 0;
}
static int xfrmi4_rcv(struct sk_buff *skb)
{
return xfrmi_input(skb, ip_hdr(skb)->protocol, 0, 0, AF_INET);
}
static int xfrmi6_rcv(struct sk_buff *skb)
{
return xfrmi_input(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
0, 0, AF_INET6);
}
static int xfrmi4_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
{
return xfrmi_input(skb, nexthdr, spi, encap_type, AF_INET);
}
static int xfrmi6_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
{
return xfrmi_input(skb, nexthdr, spi, encap_type, AF_INET6);
}
static int xfrmi_rcv_cb(struct sk_buff *skb, int err)
{
const struct xfrm_mode *inner_mode;
@ -945,8 +991,8 @@ static struct pernet_operations xfrmi_net_ops = {
};
static struct xfrm6_protocol xfrmi_esp6_protocol __read_mostly = {
.handler = xfrm6_rcv,
.input_handler = xfrm_input,
.handler = xfrmi6_rcv,
.input_handler = xfrmi6_input,
.cb_handler = xfrmi_rcv_cb,
.err_handler = xfrmi6_err,
.priority = 10,
@ -996,8 +1042,8 @@ static struct xfrm6_tunnel xfrmi_ip6ip_handler __read_mostly = {
#endif
static struct xfrm4_protocol xfrmi_esp4_protocol __read_mostly = {
.handler = xfrm4_rcv,
.input_handler = xfrm_input,
.handler = xfrmi4_rcv,
.input_handler = xfrmi4_input,
.cb_handler = xfrmi_rcv_cb,
.err_handler = xfrmi4_err,
.priority = 10,