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authorDavid S. Miller <davem@davemloft.net>2019-04-08 16:16:47 -0700
committerDavid S. Miller <davem@davemloft.net>2019-04-08 16:16:47 -0700
commit3c5189ad70995200bb5c15b5fc9bc81a35febcf4 (patch)
tree00ed4848635bab7f9a56eabc75776e4b4b82b495
parentb75bb8a5b755d0c7bf1ac071e4df2349a7644a1e (diff)
parent2a3cabae4536edbcb21d344e7aa8be7a584d2afb (diff)
download96b-common-3c5189ad70995200bb5c15b5fc9bc81a35febcf4.tar.gz
Merge branch 'erspan-use-after-free'
Lorenzo Bianconi says: ==================== fix possible use-after-free in erspan_v{4,6} Similar to what I did in commit bb9bd814ebf0 ("ipv6: sit: reset ip header pointer in ipip6_rcv"), fix possible use-after-free in erspan_rcv and ip6erspan_rcv extracting tunnel metadata since the packet can be 'uncloned' running __iptunnel_pull_header ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/ip_gre.c15
-rw-r--r--net/ipv6/ip6_gre.c20
2 files changed, 23 insertions, 12 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index fd219f7bd3ea..4b0526441476 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -259,7 +259,6 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
struct net *net = dev_net(skb->dev);
struct metadata_dst *tun_dst = NULL;
struct erspan_base_hdr *ershdr;
- struct erspan_metadata *pkt_md;
struct ip_tunnel_net *itn;
struct ip_tunnel *tunnel;
const struct iphdr *iph;
@@ -282,9 +281,6 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
if (unlikely(!pskb_may_pull(skb, len)))
return PACKET_REJECT;
- ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
- pkt_md = (struct erspan_metadata *)(ershdr + 1);
-
if (__iptunnel_pull_header(skb,
len,
htons(ETH_P_TEB),
@@ -292,8 +288,9 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
goto drop;
if (tunnel->collect_md) {
+ struct erspan_metadata *pkt_md, *md;
struct ip_tunnel_info *info;
- struct erspan_metadata *md;
+ unsigned char *gh;
__be64 tun_id;
__be16 flags;
@@ -306,6 +303,14 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
if (!tun_dst)
return PACKET_REJECT;
+ /* skb can be uncloned in __iptunnel_pull_header, so
+ * old pkt_md is no longer valid and we need to reset
+ * it
+ */
+ gh = skb_network_header(skb) +
+ skb_network_header_len(skb);
+ pkt_md = (struct erspan_metadata *)(gh + gre_hdr_len +
+ sizeof(*ershdr));
md = ip_tunnel_info_opts(&tun_dst->u.tun_info);
md->version = ver;
md2 = &md->u.md2;
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index b32c95f02128..655e46b227f9 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -525,10 +525,10 @@ static int ip6gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
}
static int ip6erspan_rcv(struct sk_buff *skb,
- struct tnl_ptk_info *tpi)
+ struct tnl_ptk_info *tpi,
+ int gre_hdr_len)
{
struct erspan_base_hdr *ershdr;
- struct erspan_metadata *pkt_md;
const struct ipv6hdr *ipv6h;
struct erspan_md2 *md2;
struct ip6_tnl *tunnel;
@@ -547,18 +547,16 @@ static int ip6erspan_rcv(struct sk_buff *skb,
if (unlikely(!pskb_may_pull(skb, len)))
return PACKET_REJECT;
- ershdr = (struct erspan_base_hdr *)skb->data;
- pkt_md = (struct erspan_metadata *)(ershdr + 1);
-
if (__iptunnel_pull_header(skb, len,
htons(ETH_P_TEB),
false, false) < 0)
return PACKET_REJECT;
if (tunnel->parms.collect_md) {
+ struct erspan_metadata *pkt_md, *md;
struct metadata_dst *tun_dst;
struct ip_tunnel_info *info;
- struct erspan_metadata *md;
+ unsigned char *gh;
__be64 tun_id;
__be16 flags;
@@ -571,6 +569,14 @@ static int ip6erspan_rcv(struct sk_buff *skb,
if (!tun_dst)
return PACKET_REJECT;
+ /* skb can be uncloned in __iptunnel_pull_header, so
+ * old pkt_md is no longer valid and we need to reset
+ * it
+ */
+ gh = skb_network_header(skb) +
+ skb_network_header_len(skb);
+ pkt_md = (struct erspan_metadata *)(gh + gre_hdr_len +
+ sizeof(*ershdr));
info = &tun_dst->u.tun_info;
md = ip_tunnel_info_opts(info);
md->version = ver;
@@ -607,7 +613,7 @@ static int gre_rcv(struct sk_buff *skb)
if (unlikely(tpi.proto == htons(ETH_P_ERSPAN) ||
tpi.proto == htons(ETH_P_ERSPAN2))) {
- if (ip6erspan_rcv(skb, &tpi) == PACKET_RCVD)
+ if (ip6erspan_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
return 0;
goto out;
}