kernel/linux.git/net/batman-adv, branch v6.18.41

batman-adv: tt: prevent TVLV OOB check overflow

2026-07-24T14:16:58+00:00

commit 7a581d9aaba8c82bd6177fa36b2588eea77f6e2b upstream. A TT unicast TVLV contains the number of VLANs stored in it. This number is an u16 and gets multiplied by the size of the struct batadv_tvlv_tt_vlan_data (8 bytes). The size can therefore overflow the u16 used to store the tt_vlan_len. All additional safety checks to prevent out-of-bounds access of the TVLV buffer are invalid due to this overflow. Using size_t prevents this overflow and ensures that the safety checks compare against the actual buffer requirements. Cc: stable@vger.kernel.org Fixes: 7ea7b4a14275 ("batman-adv: make the TT CRC logic VLAN specific") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: mcast: avoid OOB read of num_dests header

2026-07-24T14:16:58+00:00

commit 38eaed28e250895d56f4b7989bd65479a511c5c3 upstream. Before the access to struct batadv_tvlv_mcast_tracker's num_dests, it is attempted to check whether enough space is actually in the network header. But instead of using offsetofend() to check for the whole size (2) which must be accessible, offsetof() of is called. The latter is always returning 0. The comparison with the network header length will always return that enough data is available - even when only 1 or 0 bytes are accessible. Instead of using offsetofend(), use the more common check for the whole header. Cc: stable@vger.kernel.org Fixes: 07afe1ba288c ("batman-adv: mcast: implement multicast packet reception and forwarding") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: frag: fix primary_if leak on failed linearization

2026-07-24T14:16:58+00:00

commit 353d2c1d5492e53ae34f490a84494124dc3d3531 upstream. If the skb has a frag_list, it must be linearized before it can be split using skb_split(). But when this step failed, it must not only free the skb but also take care of the reference to the already found primary_if. Cc: stable@vger.kernel.org Reported-by: Sashiko Fixes: a063f2fba3fa ("batman-adv: Don't skb_split skbuffs with frag_list") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: clean untagged VLAN on netdev registration failure

2026-07-24T14:16:58+00:00

commit 8669a550c752d86baebc5fdc83b8ff35c4372c0e upstream. When an mesh interface is registered, it creates an untagged struct batadv_meshif_vlan on top of it via the NETDEV_REGISTER notifier. But in this process, another receiver of this notification can veto the registration. The netdev registration will be aborted because of this veto. The register_netdevice() call will try to clean up the net_device using unregister_netdevice_queue() - which only uses the .priv_destructor to free private resources. In this situation, .dellink will not be called. The cleanup of the untagged batadv_meshif_vlan must thefore be done in the destructor to avoid a leak of this object. Cc: stable@vger.kernel.org Fixes: 5d2c05b21337 ("batman-adv: add per VLAN interface attribute framework") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: frag: free unfragmentable packet

2026-07-24T14:16:58+00:00

commit 6b628425aed49a1c7a4ffc997583840fc582d32b upstream. The caller of batadv_frag_send_packet() assume that the skb provided to the function are always consumed. But the pre-check for an empty payload or the zero fragment size returned an error without any further actions. A failed pre-check must use the same error handling code as the rest of the function. Cc: stable@vger.kernel.org Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: fix VLAN priority offset

2026-07-24T14:16:58+00:00

commit fdb3be00ba4dafa313e699d6b5b90d13f22f3f25 upstream. The batadv_skb_set_priority() receives an SKB with the inner ethernet header at position "offset". When it tries to extract the IPv4 and IPv6 header, it needs to skip the ethernet header to get access to the IP header. But for VLAN header, it performs the access with the struct vlan_ethhdr. This struct contains both both the ethernet header and the VLAN header. It is therefore incorrect to skip over the whole vlan_ethhdr size to get access to the vlan_ethhdr. Cc: stable@vger.kernel.org Fixes: c54f38c9aa22 ("batman-adv: set skb priority according to content") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: tt: avoid request storms during pending request

2026-07-24T14:16:58+00:00

commit 27c7d40008231ae4140d35501b60087a9de2d2c3 upstream. batadv_send_tt_request() allocates a tt_req_node when none exists for the destination originator node. This should prevent that a multiple TT requests are send at the same time to an originator. But if allocation of the send buffer failed, this request must be cleaned up again. But indicator for such a failure is "ret == false". But the actual implementation is checking for "ret == true". The check must be inverted to not loose the information about the TT request directly after it was attempted to be sent out. This should avoid potential request storms. Cc: stable@vger.kernel.org Fixes: 335fbe0f5d25 ("batman-adv: tvlv - convert tt query packet to use tvlv unicast packets") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: dat: fix tie-break for candidate selection

2026-07-24T14:16:58+00:00

commit 98052bdaf6ac1639a63ffc10244eeeab1f62ed2b upstream. The original version of the candidate selection for DAT attempted to compare both candidate and max_orig_node to identify which has the smaller MAC address. This comparison is required as tie-break when a hash collision happened. But the used function returned 0 when the function was not equal and a non-zero value when it was equal. As result, the actually selected node was dependent on the order of entries in the orig_hash and not actually on the mac addresses. The last originator in the hash collision would always win. To have a proper ordering, it must diff the actual MAC address bytes and reject the candidate when the diff is not smaller than 0. Cc: stable@vger.kernel.org Fixes: 785ea1144182 ("batman-adv: Distributed ARP Table - create DHT helper functions") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: ensure minimal ethernet header on TX

2026-07-24T14:16:58+00:00

commit 49df66b7993c80b80c7eb9a84ba5b3410c8296a0 upstream. As documented in commit 8bd67ebb50c0 ("net: bridge: xmit: make sure we have at least eth header len bytes"), it is possible by for a local user with eBPF TC hook access to attach a tc filter which truncates the packet and redirects to an batadv interface. But the code assumes that at least ETH_HLEN bytes are available and thus might read outside of the available buffer. The batadv_interface_tx() must therefore always check itself if enough data is available for the ethernet header and don't rely on min_header_len. Cc: stable@vger.kernel.org Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Reported-by: Sashiko Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman

batman-adv: dat: ensure accessible eth_hdr proto field

2026-07-24T14:16:58+00:00

commit 26560c4a03dc4d607331600c187f59ab2df5f341 upstream. When batadv_get_vid() accesses the proto field of the ethernet header, it is not checking if the data itself is accessible. The caller is responsible for it. But in contrast to other call sites, batadv_dat_get_vid() and its caller didn't make sure this is true. This could have caused an out-of-bounds access. Cc: stable@vger.kernel.org Reported-by: Sashiko Fixes: be1db4f6615b ("batman-adv: make the Distributed ARP Table vlan aware") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman