From b64963a2ceeb7529310b6cf253a1e540784422f4 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Sat, 2 May 2026 19:53:21 +0200 Subject: [PATCH] batman-adv: tt: fix negative tt_buff_len batadv_orig_node::tt_buff_len was declared as s16, but the field is never intended to hold a negative value. When a value greater than 32767 is assigned, it wraps to a negative signed integer. In batadv_send_other_tt_response(), tt_buff_len is temporarily widened to s32. The incorrectly negative s16 value propagates into the s32, causing batadv_tt_prepare_tvlv_global_data() to allocate a full sized buffer but populates only a small portion of it with the collected changeset. All remaining bits are kept uninitialized. Using an u16 avoids this type confusion and ensures that no (negative) sign extension is performed in batadv_send_other_tt_response(). Cc: stable@kernel.org Fixes: a73105b8d4c7 ("batman-adv: improved client announcement mechanism") Signed-off-by: Sven Eckelmann --- net/batman-adv/types.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index b9c0b7779122..888f337a194b 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -452,7 +452,7 @@ struct batadv_orig_node { * @tt_buff_len: length of the last tt changeset this node received * from the orig node */ - s16 tt_buff_len; + u16 tt_buff_len; /** @tt_buff_lock: lock that protects tt_buff and tt_buff_len */ spinlock_t tt_buff_lock;