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authorWillem de Bruijn <willemb@google.com>2018-12-30 17:24:36 -0500
committerDavid S. Miller <davem@davemloft.net>2019-01-01 12:05:02 -0800
commitcb9f1b783850b14cbd7f87d061d784a666dfba1f (patch)
tree652c378230eed5add180c8fec9787db540b32e97 /net/ipv6
parent8c76e77f9069f10505c08e02646c3ee11ad79038 (diff)
downloadlinux-stericsson-cb9f1b783850b14cbd7f87d061d784a666dfba1f.tar.gz
ip: validate header length on virtual device xmit
KMSAN detected read beyond end of buffer in vti and sit devices when passing truncated packets with PF_PACKET. The issue affects additional ip tunnel devices. Extend commit 76c0ddd8c3a6 ("ip6_tunnel: be careful when accessing the inner header") and commit ccfec9e5cb2d ("ip_tunnel: be careful when accessing the inner header"). Move the check to a separate helper and call at the start of each ndo_start_xmit function in net/ipv4 and net/ipv6. Minor changes: - convert dev_kfree_skb to kfree_skb on error path, as dev_kfree_skb calls consume_skb which is not for error paths. - use pskb_network_may_pull even though that is pedantic here, as the same as pskb_may_pull for devices without llheaders. - do not cache ipv6 hdrs if used only once (unsafe across pskb_may_pull, was more relevant to earlier patch) Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6_gre.c10
-rw-r--r--net/ipv6/ip6_tunnel.c10
-rw-r--r--net/ipv6/ip6_vti.c8
-rw-r--r--net/ipv6/ip6mr.c17
-rw-r--r--net/ipv6/sit.c3
5 files changed, 28 insertions, 20 deletions
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 229e55c99021..09d0826742f8 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -881,6 +881,9 @@ static netdev_tx_t ip6gre_tunnel_xmit(struct sk_buff *skb,
struct net_device_stats *stats = &t->dev->stats;
int ret;
+ if (!pskb_inet_may_pull(skb))
+ goto tx_err;
+
if (!ip6_tnl_xmit_ctl(t, &t->parms.laddr, &t->parms.raddr))
goto tx_err;
@@ -923,6 +926,9 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
int nhoff;
int thoff;
+ if (!pskb_inet_may_pull(skb))
+ goto tx_err;
+
if (!ip6_tnl_xmit_ctl(t, &t->parms.laddr, &t->parms.raddr))
goto tx_err;
@@ -995,8 +1001,6 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
goto tx_err;
}
} else {
- struct ipv6hdr *ipv6h = ipv6_hdr(skb);
-
switch (skb->protocol) {
case htons(ETH_P_IP):
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@@ -1004,7 +1008,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
&dsfield, &encap_limit);
break;
case htons(ETH_P_IPV6):
- if (ipv6_addr_equal(&t->parms.raddr, &ipv6h->saddr))
+ if (ipv6_addr_equal(&t->parms.raddr, &ipv6_hdr(skb)->saddr))
goto tx_err;
if (prepare_ip6gre_xmit_ipv6(skb, dev, &fl6,
&dsfield, &encap_limit))
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 99179b9c8384..0c6403cf8b52 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1243,10 +1243,6 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
u8 tproto;
int err;
- /* ensure we can access the full inner ip header */
- if (!pskb_may_pull(skb, sizeof(struct iphdr)))
- return -1;
-
iph = ip_hdr(skb);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@@ -1321,9 +1317,6 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
u8 tproto;
int err;
- if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
- return -1;
-
ipv6h = ipv6_hdr(skb);
tproto = READ_ONCE(t->parms.proto);
if ((tproto != IPPROTO_IPV6 && tproto != 0) ||
@@ -1405,6 +1398,9 @@ ip6_tnl_start_xmit(struct sk_buff *skb, struct net_device *dev)
struct net_device_stats *stats = &t->dev->stats;
int ret;
+ if (!pskb_inet_may_pull(skb))
+ goto tx_err;
+
switch (skb->protocol) {
case htons(ETH_P_IP):
ret = ip4ip6_tnl_xmit(skb, dev);
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 706fe42e4928..8b6eefff2f7e 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -522,18 +522,18 @@ vti6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
struct net_device_stats *stats = &t->dev->stats;
- struct ipv6hdr *ipv6h;
struct flowi fl;
int ret;
+ if (!pskb_inet_may_pull(skb))
+ goto tx_err;
+
memset(&fl, 0, sizeof(fl));
switch (skb->protocol) {
case htons(ETH_P_IPV6):
- ipv6h = ipv6_hdr(skb);
-
if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
- vti6_addr_conflict(t, ipv6h))
+ vti6_addr_conflict(t, ipv6_hdr(skb)))
goto tx_err;
xfrm_decode_session(skb, &fl, AF_INET6);
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 8276f1224f16..30337b38274b 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -51,6 +51,7 @@
#include <linux/export.h>
#include <net/ip6_checksum.h>
#include <linux/netconf.h>
+#include <net/ip_tunnels.h>
#include <linux/nospec.h>
@@ -599,13 +600,12 @@ static netdev_tx_t reg_vif_xmit(struct sk_buff *skb,
.flowi6_iif = skb->skb_iif ? : LOOPBACK_IFINDEX,
.flowi6_mark = skb->mark,
};
- int err;
- err = ip6mr_fib_lookup(net, &fl6, &mrt);
- if (err < 0) {
- kfree_skb(skb);
- return err;
- }
+ if (!pskb_inet_may_pull(skb))
+ goto tx_err;
+
+ if (ip6mr_fib_lookup(net, &fl6, &mrt) < 0)
+ goto tx_err;
read_lock(&mrt_lock);
dev->stats.tx_bytes += skb->len;
@@ -614,6 +614,11 @@ static netdev_tx_t reg_vif_xmit(struct sk_buff *skb,
read_unlock(&mrt_lock);
kfree_skb(skb);
return NETDEV_TX_OK;
+
+tx_err:
+ dev->stats.tx_errors++;
+ kfree_skb(skb);
+ return NETDEV_TX_OK;
}
static int reg_vif_get_iflink(const struct net_device *dev)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 51c9f75f34b9..1e03305c0549 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1021,6 +1021,9 @@ tx_error:
static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
struct net_device *dev)
{
+ if (!pskb_inet_may_pull(skb))
+ goto tx_err;
+
switch (skb->protocol) {
case htons(ETH_P_IP):
sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);