From e6522330b7414dc7f96f547045bdc5db9de0cc3e Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Thu, 8 Aug 2024 09:52:47 +0000 Subject: [PATCH] batman-adv: Don't accept TT entries for out-of-spec VIDs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 537a350d14321c8cca5efbf0a33a404fec3a9f9e upstream. The internal handling of VLAN IDs in batman-adv is only specified for following encodings: * VLAN is used - bit 15 is 1 - bit 11 - bit 0 is the VLAN ID (0-4095) - remaining bits are 0 * No VLAN is used - bit 15 is 0 - remaining bits are 0 batman-adv was only preparing new translation table entries (based on its soft interface information) using this encoding format. But the receive path was never checking if entries in the roam or TT TVLVs were also following this encoding. It was therefore possible to create more than the expected maximum of 4096 + 1 entries in the originator VLAN list. Simply by setting the "remaining bits" to "random" values in corresponding TVLV. Cc: stable@vger.kernel.org Fixes: 7ea7b4a14275 ("batman-adv: make the TT CRC logic VLAN specific") Reported-by: Linus Lüssing Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich Signed-off-by: Greg Kroah-Hartman (cherry picked from commit 4d5a2d6b7a9a1140342c5229d1a427ec37a12fd4) [Vegard: fix trivial conflicts due to missing commit 7e9a8c2ce7c5 ("batman-adv: Use parentheses in function kernel-doc").] Signed-off-by: Vegard Nossum --- net/batman-adv/originator.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c index e81b6c13356f..400253d1853b 100644 --- a/net/batman-adv/originator.c +++ b/net/batman-adv/originator.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -103,6 +104,29 @@ batadv_orig_node_vlan_get(struct batadv_orig_node *orig_node, return vlan; } +/** + * batadv_vlan_id_valid() - check if vlan id is in valid batman-adv encoding + * @vid: the VLAN identifier + * + * Return: true when either no vlan is set or if VLAN is in correct range, + * false otherwise + */ +static bool batadv_vlan_id_valid(unsigned short vid) +{ + unsigned short non_vlan = vid & ~(BATADV_VLAN_HAS_TAG | VLAN_VID_MASK); + + if (vid == 0) + return true; + + if (!(vid & BATADV_VLAN_HAS_TAG)) + return false; + + if (non_vlan) + return false; + + return true; +} + /** * batadv_orig_node_vlan_new - search and possibly create an orig_node_vlan * object @@ -121,6 +145,9 @@ batadv_orig_node_vlan_new(struct batadv_orig_node *orig_node, { struct batadv_orig_node_vlan *vlan; + if (!batadv_vlan_id_valid(vid)) + return NULL; + spin_lock_bh(&orig_node->vlan_list_lock); /* first look if an object for this vid already exists */