tun: add missing verification for short frame #206
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jira VULN-9005 cve CVE-2024-41091 commit-author Dongli Zhang <dongli.zhang@oracle.com> commit 0495848 The cited commit missed to check against the validity of the frame length in the tun_xdp_one() path, which could cause a corrupted skb to be sent downstack. Even before the skb is transmitted, the tun_xdp_one-->eth_type_trans() may access the Ethernet header although it can be less than ETH_HLEN. Once transmitted, this could either cause out-of-bound access beyond the actual length, or confuse the underlayer with incorrect or inconsistent header length in the skb metadata. In the alternative path, tun_get_user() already prohibits short frame which has the length less than Ethernet header size from being transmitted for IFF_TAP. This is to drop any frame shorter than the Ethernet header size just like how tun_get_user() does. CVE: CVE-2024-41091 Inspired-by: https://lore.kernel.org/netdev/1717026141-25716-1-git-send-email-si-wei.liu@oracle.com/ Fixes: 043d222 ("tuntap: accept an array of XDP buffs through sendmsg()") Cc: stable@vger.kernel.org Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Jason Wang <jasowang@redhat.com> Link: https://patch.msgid.link/20240724170452.16837-3-dongli.zhang@oracle.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> (cherry picked from commit 0495848) Signed-off-by: Jeremy Allison <jallison@ciq.com>
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baseline_selftest.txt
patched_selftest.txt
uname -a
"Linux r8_6_lts_fips 4.18.0+ #1 SMP Wed Apr 9 00:27:11 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux"
jira VULN-9005
cve CVE-2024-41091
commit-author Dongli Zhang dongli.zhang@oracle.com commit 0495848
The cited commit missed to check against the validity of the frame length in the tun_xdp_one() path, which could cause a corrupted skb to be sent downstack. Even before the skb is transmitted, the tun_xdp_one-->eth_type_trans() may access the Ethernet header although it can be less than ETH_HLEN. Once transmitted, this could either cause out-of-bound access beyond the actual length, or confuse the underlayer with incorrect or inconsistent header length in the skb metadata.
In the alternative path, tun_get_user() already prohibits short frame which has the length less than Ethernet header size from being transmitted for IFF_TAP.
This is to drop any frame shorter than the Ethernet header size just like how tun_get_user() does.
CVE: CVE-2024-41091
Inspired-by: https://lore.kernel.org/netdev/1717026141-25716-1-git-send-email-si-wei.liu@oracle.com/ Fixes: 043d222 ("tuntap: accept an array of XDP buffs through sendmsg()")
Cc: stable@vger.kernel.org
Signed-off-by: Dongli Zhang dongli.zhang@oracle.com
Reviewed-by: Si-Wei Liu si-wei.liu@oracle.com
Reviewed-by: Willem de Bruijn willemb@google.com
Reviewed-by: Paolo Abeni pabeni@redhat.com
Reviewed-by: Jason Wang jasowang@redhat.com
Link: https://patch.msgid.link/20240724170452.16837-3-dongli.zhang@oracle.com
Signed-off-by: Jakub Kicinski kuba@kernel.org
(cherry picked from commit 0495848)