From: Antony Antony <antony.antony@secunet.com>
Date: Tue, 30 Apr 2024 07:09:29 +0000 (+0200)
Subject: xfrm: Add dir validation to "in" data path lookup
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=304b44f0d5a4c2f91f82f7c31538d00485fb484c;p=linux.git

xfrm: Add dir validation to "in" data path lookup

Introduces validation for the x->dir attribute within the XFRM input
data lookup path. If the configured direction does not match the
expected direction, input, increment the XfrmInStateDirError counter
and drop the packet to ensure data integrity and correct flow handling.

grep -vw 0 /proc/net/xfrm_stat
XfrmInStateDirError     	1

Signed-off-by: Antony Antony <antony.antony@secunet.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---

diff --git a/Documentation/networking/xfrm_proc.rst b/Documentation/networking/xfrm_proc.rst
index 5ac3acf4cf51c..973d1571acac5 100644
--- a/Documentation/networking/xfrm_proc.rst
+++ b/Documentation/networking/xfrm_proc.rst
@@ -73,6 +73,9 @@ XfrmAcquireError:
 XfrmFwdHdrError:
 	Forward routing of a packet is not allowed
 
+XfrmInStateDirError:
+        State direction mismatch (lookup found an output state on the input path, expected input or no direction)
+
 Outbound errors
 ~~~~~~~~~~~~~~~
 XfrmOutError:
diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index 23792b8412bd2..adf5fd78dd503 100644
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -338,6 +338,7 @@ enum
 	LINUX_MIB_XFRMOUTSTATEINVALID,		/* XfrmOutStateInvalid */
 	LINUX_MIB_XFRMACQUIREERROR,		/* XfrmAcquireError */
 	LINUX_MIB_XFRMOUTSTATEDIRERROR,		/* XfrmOutStateDirError */
+	LINUX_MIB_XFRMINSTATEDIRERROR,		/* XfrmInStateDirError */
 	__LINUX_MIB_XFRMMAX
 };
 
diff --git a/net/ipv6/xfrm6_input.c b/net/ipv6/xfrm6_input.c
index 2c6aeb090b7ab..d5bac0d76b6eb 100644
--- a/net/ipv6/xfrm6_input.c
+++ b/net/ipv6/xfrm6_input.c
@@ -266,6 +266,13 @@ int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
 		if (!x)
 			continue;
 
+		if (unlikely(x->dir && x->dir != XFRM_SA_DIR_IN)) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEDIRERROR);
+			xfrm_state_put(x);
+			x = NULL;
+			continue;
+		}
+
 		spin_lock(&x->lock);
 
 		if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) &&
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 161f535c8b949..71b42de6e3c9c 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -466,6 +466,11 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 	if (encap_type < 0 || (xo && xo->flags & XFRM_GRO)) {
 		x = xfrm_input_state(skb);
 
+		if (unlikely(x->dir && x->dir != XFRM_SA_DIR_IN)) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEDIRERROR);
+			goto drop;
+		}
+
 		if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 			if (x->km.state == XFRM_STATE_ACQ)
 				XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
@@ -571,6 +576,12 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 			goto drop;
 		}
 
+		if (unlikely(x->dir && x->dir != XFRM_SA_DIR_IN)) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEDIRERROR);
+			xfrm_state_put(x);
+			goto drop;
+		}
+
 		skb->mark = xfrm_smark_get(skb->mark, x);
 
 		sp->xvec[sp->len++] = x;
diff --git a/net/xfrm/xfrm_proc.c b/net/xfrm/xfrm_proc.c
index 98606f1078f70..eeb984be03a79 100644
--- a/net/xfrm/xfrm_proc.c
+++ b/net/xfrm/xfrm_proc.c
@@ -42,6 +42,7 @@ static const struct snmp_mib xfrm_mib_list[] = {
 	SNMP_MIB_ITEM("XfrmOutStateInvalid", LINUX_MIB_XFRMOUTSTATEINVALID),
 	SNMP_MIB_ITEM("XfrmAcquireError", LINUX_MIB_XFRMACQUIREERROR),
 	SNMP_MIB_ITEM("XfrmOutStateDirError", LINUX_MIB_XFRMOUTSTATEDIRERROR),
+	SNMP_MIB_ITEM("XfrmInStateDirError", LINUX_MIB_XFRMINSTATEDIRERROR),
 	SNMP_MIB_SENTINEL
 };