Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9808744AB9E; Tue, 21 Jul 2026 21:39:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784669990; cv=none; b=FkKD8LatBGJDRaewnrZ5AE5ZDEHfBhSp9DK+J1L+77wZLTYELkxb7vU7G5wRJz9mLBqg36rjGLs4Getg41F5pnzlYW/ckeHhnFziD9X/dq0YOBdRPRT3dSuq1N2A212Sc0kWIrIPtwA69TjUnkmXYu8ZxYxbOjMXiC8boxkKcRY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784669990; c=relaxed/simple; bh=q8oZss0tppDBNaLnWuxmoNxblEALFVETr1cBlsIIsls=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I4BfzjPytc6lBPim53AME1M8YWBgmuhVO8VUI9m/LlhNr1DvuKwUSIw62C47mRPrfwsjm46DtSPkmhOdIS6xh6XrJpjRlLk2IviRV4I+UW01gxMULHOxyS2N4MXLXdgwgwn6iaIdVRRfpbbysDorzVV7dVyFyRDERJ+AFkAPu2w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HTbcgUFF; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HTbcgUFF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 051041F000E9; Tue, 21 Jul 2026 21:39:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784669989; bh=vYDWQXYtgrYsrbG1nJbGVV3/RsnDjjd9tengez0Y8AA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HTbcgUFFDHryEGYBsOYP6f/yqnQ7lpqc8pswQ3yB78TK8beKfPf7XlqXv9xdOcoJg ewt2pwesXg6wB+QjeVlY2JvW0JR9AKgQINK7mTzYCgImfbTe4XYCcjvQ+zrFSVjmYu 9zh5mwhWD3PkD5cwRL220RkkEszUufyGJ/meJFNI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sven Eckelmann Subject: [PATCH 6.1 0764/1067] batman-adv: dat: acquire ARP hw source only after skb realloc Date: Tue, 21 Jul 2026 17:22:45 +0200 Message-ID: <20260721152441.659403042@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sven Eckelmann commit 48067b2ae4504500a7093d9e1e16b42e70330480 upstream. The pskb_may_pull() called by batadv_get_vid() could reallocate the buffer behind the skb. Variables which were pointing to the old buffer need to be reassigned to avoid an use-after-free. Cc: stable@vger.kernel.org Fixes: b61ec31c8575 ("batman-adv: Snoop DHCPACKs for DAT") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/distributed-arp-table.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/batman-adv/distributed-arp-table.c +++ b/net/batman-adv/distributed-arp-table.c @@ -1758,6 +1758,7 @@ void batadv_dat_snoop_incoming_dhcp_ack( struct ethhdr *ethhdr; __be32 ip_src, yiaddr; unsigned short vid; + int hdr_size_tmp; __be16 proto; u8 *hw_src; @@ -1774,8 +1775,10 @@ void batadv_dat_snoop_incoming_dhcp_ack( if (!batadv_dat_check_dhcp_ack(skb, proto, &ip_src, chaddr, &yiaddr)) return; + hdr_size_tmp = hdr_size; + vid = batadv_dat_get_vid(skb, &hdr_size_tmp); + ethhdr = (struct ethhdr *)(skb->data + hdr_size); hw_src = ethhdr->h_source; - vid = batadv_dat_get_vid(skb, &hdr_size); batadv_dat_entry_add(bat_priv, yiaddr, chaddr, vid); batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid);