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authorGuillaume Nault <gnault@redhat.com>2021-08-06 18:52:06 +0300
committerJakub Kicinski <kuba@kernel.org>2021-08-10 01:37:43 +0300
commit143a8526ab5fd4f8a0c4fe2a9cb28c181dc5a95f (patch)
tree9d2766c631ccc95b0ddd4103e80dbe46f1cf9e66 /drivers/net/bareudp.c
parentd6e712aa7e6a3d5a9633f4bcbe2237f3edc292bd (diff)
downloadlinux-143a8526ab5fd4f8a0c4fe2a9cb28c181dc5a95f.tar.xz
bareudp: Fix invalid read beyond skb's linear data
Data beyond the UDP header might not be part of the skb's linear data. Use skb_copy_bits() instead of direct access to skb->data+X, so that we read the correct bytes even on a fragmented skb. Fixes: 4b5f67232d95 ("net: Special handling for IP & MPLS.") Signed-off-by: Guillaume Nault <gnault@redhat.com> Link: https://lore.kernel.org/r/7741c46545c6ef02e70c80a9b32814b22d9616b3.1628264975.git.gnault@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/bareudp.c')
-rw-r--r--drivers/net/bareudp.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
index a7ee0af1af90..54e321a695ce 100644
--- a/drivers/net/bareudp.c
+++ b/drivers/net/bareudp.c
@@ -71,12 +71,18 @@ static int bareudp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
family = AF_INET6;
if (bareudp->ethertype == htons(ETH_P_IP)) {
- struct iphdr *iphdr;
+ __u8 ipversion;
- iphdr = (struct iphdr *)(skb->data + BAREUDP_BASE_HLEN);
- if (iphdr->version == 4) {
- proto = bareudp->ethertype;
- } else if (bareudp->multi_proto_mode && (iphdr->version == 6)) {
+ if (skb_copy_bits(skb, BAREUDP_BASE_HLEN, &ipversion,
+ sizeof(ipversion))) {
+ bareudp->dev->stats.rx_dropped++;
+ goto drop;
+ }
+ ipversion >>= 4;
+
+ if (ipversion == 4) {
+ proto = htons(ETH_P_IP);
+ } else if (ipversion == 6 && bareudp->multi_proto_mode) {
proto = htons(ETH_P_IPV6);
} else {
bareudp->dev->stats.rx_dropped++;