From: Shigeru Yoshida <syoshida@redhat.com> stable inclusion from stable-v6.6.7 commit 08e3e3da6c39e74b2789e9dfb8a2d734c7885ecd category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8SSQ4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 80d875cfc9d3711a029f234ef7d680db79e8fa4b ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- net/ipv4/ip_gre.c | 11 +++++++---- 1 file 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 && -- 2.20.1