diff options
| author | Shigeru Yoshida <syoshida@redhat.com> | 2023-12-03 01:14:41 +0900 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2023-12-06 10:08:05 +0100 |
| commit | 80d875cfc9d3711a029f234ef7d680db79e8fa4b (patch) | |
| tree | 97a08fefbda89deee425d59f547b9b063075380a /net/ipv4 | |
| parent | efd563ff1a7e692408c9d44bec3d90949f7a9557 (diff) | |
ipv4: ip_gre: Avoid skb_pull() failure in ipgre_xmit()
In ipgre_xmit(), skb_pull() may fail even if pskb_inet_may_pull() returns
true. For example, applications can use PF_PACKET to create a malformed
packet with no IP header. This type of packet causes a problem such as
uninit-value access.
This patch ensures that skb_pull() can pull the required size by checking
the skb with pskb_network_may_pull() before skb_pull().
Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Suman Ghosh <sumang@marvell.com>
Link: https://lore.kernel.org/r/20231202161441.221135-1-syoshida@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/ip_gre.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 22a26d1d29a0..5169c3c72cff 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -635,15 +635,18 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb, } if (dev->header_ops) { + int pull_len = tunnel->hlen + sizeof(struct iphdr); + if (skb_cow_head(skb, 0)) goto free_skb; tnl_params = (const struct iphdr *)skb->data; - /* Pull skb since ip_tunnel_xmit() needs skb->data pointing - * to gre header. - */ - skb_pull(skb, tunnel->hlen + sizeof(struct iphdr)); + if (!pskb_network_may_pull(skb, pull_len)) + goto free_skb; + + /* ip_tunnel_xmit() needs skb->data pointing to gre header. */ + skb_pull(skb, pull_len); skb_reset_mac_header(skb); if (skb->ip_summed == CHECKSUM_PARTIAL && |