From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=23.88.38.48 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793368279; b=hsXxZi78ceO1w5vXStJ4g7hTIlIF6OoeP4XghP53+v0QIYgIm0Z7tb0cSvwMykkN9a6s ZfjwEr95bUrf4GM4Nl2CC9bmU1EwnJYryMQClO+UmbjIqHEJXzWGkFzhCPZ/nOvnFaFwq 0nAYI4cQyinunJG/q3w48vPwbRO3zxuzM/4tgbIFEcVhGlzDEN1HZPpHBOrVnlWSXkjWg nE29hZ8D5cvbx/drxDmMC6Sk2MkSM51znOw+VQ1IStQR+e+5LtvVDIDVwakLRzIjUhgyn HgYhyKzbY/r932XaMKhejPIPB0y6x2ISJNsORwbdbgdfikVkR/fraKarJiOBQH0oGJw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793368279; h=DMARC-Filter:Received:DKIM-Signature:From:To:Cc:Subject:Date: Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=X26JA/MFDFcPSUPChPCfILHIVeZni1u9oAU8sdS5v+w=; b=u815fBYTgFTYP13+hX/Kc3WHv+Nf8ahBvadU9dAYaZ7r80Zn38CTiHJxFhXVMEJ/YUBJ 9HnjShzs+4pt1zy9Z2PjqkciaGn5CuvoH3e2sEJSPR8/bKBS6to2L7dsHh+R26V17szns xtSZGZ6VJG7brtJv8MHKFZBP7qvfOPtHgx59IZm+h5AwpHfD5T1dbf5+gLWshxvQrE/vY Xuvjnc7M8INrEyxbIBvYptvszCsc+lIzysT06o+j1AkNbVYbv+5/OfoKq8l8v7CQmqtDx 2qFMLk2nNmJtRTsQCpCSHt1TyI353/pS8aU8vXX8y1igX3CqVXZ3OVKg44RlciYljrw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=simonwunderlich.de; spf=pass smtp.mailfrom=simonwunderlich.de; dkim=pass header.d=simonwunderlich.de header.i=@simonwunderlich.de header.a=rsa-sha256 header.s=09092022 header.b=TS7fKDiH; arc=none smtp.remote-ip=23.88.38.48 Received: from mail.simonwunderlich.de (mail.simonwunderlich.de [23.88.38.48]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with UTF8SMTPS id 3EDDF606A326; Fri, 30 Oct 2026 13:51:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 3EDDF606A326 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=simonwunderlich.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=simonwunderlich.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=simonwunderlich.de header.i=@simonwunderlich.de header.a=rsa-sha256 header.s=09092022 header.b=TS7fKDiH Received: from kero.packetmixer.de (p200300C597124Fd839580C360D3eD6F6.dip0.t-ipconnect.de [IPv6:2003:c5:9712:4fd8:3958:c36:d3e:d6f6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange secp256r1 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.simonwunderlich.de (Postfix) with UTF8SMTPSA id 2D12FFA093; Fri, 30 Oct 2026 14:51:10 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=simonwunderlich.de; s=09092022; t=1793368270; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=X26JA/MFDFcPSUPChPCfILHIVeZni1u9oAU8sdS5v+w=; b=TS7fKDiHF1ScreJ3I+cqnzV0iAfeyl0+hAM+AdpeX3RqwJnifQSXx0Z602jp7wmZHCxtL4 NUhIS7aVA+RHyNBm3WF6Eb3PmpYPWVe59R2M8q0QIJbbDFzDpgB+oxzn/NdQGEcjXWTuog PLfM9x6qtcPGxR2PEDR/pSJDCRRy0A+Ba2yw6h4HB5sTtsH58y4/aiXFJkyKtFWJ2kj2zf MppZJzS3sZEXlTaz7/fSEgz16PseGshCm1+ThRKC/doCTueH+YruSPNSKdwzzjTpINUaIW OBu6c0Hj0XYGy2n3r+tSaTRJjKjCOEhRJM9K5gRflxCmTSwyzw6l+bz4fjGC1Q== From: Simon Wunderlich To: netdev@vger.kernel.org Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , b.a.t.m.a.n@lists.open-mesh.org, Kyle Zeng , stable@vger.kernel.org, Sven Eckelmann , Simon Wunderlich Subject: [PATCH net 03/14] batman-adv: mcast: validate tracker padding before forwarding Date: Fri, 30 Oct 2026 14:50:54 +0100 Message-ID: <20261030135105.2555887-4-sw@simonwunderlich.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261030135105.2555887-1-sw@simonwunderlich.de> References: <20261030135105.2555887-1-sw@simonwunderlich.de> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Kyle Zeng A multicast tracker with an even number of destinations needs two padding bytes after its destination list. batadv_mcast_forw_packet() currently only checks that the count field and the addresses fit in the tracker TVLV. If an unpadded even tracker is compacted to an odd number of destinations, batadv_mcast_forw_shrink_update_headers() includes those missing padding bytes in the amount to remove. The subsequent memmove can then write two bytes past the old packet tail. With no tailroom, this corrupts skb_shared_info. Include the required padding in the existing tracker length check. This rejects the malformed tracker before either received or locally generated packets can reach the compactor. Fixes: 2dfe644a1ce0 ("batman-adv: mcast: shrink tracker packet after scrubbing") Cc: stable@vger.kernel.org Signed-off-by: Kyle Zeng Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/multicast_forw.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/batman-adv/multicast_forw.c b/net/batman-adv/multicast_forw.c index ac97cd8b81dc9..9ffed1f237b6b 100644 --- a/net/batman-adv/multicast_forw.c +++ b/net/batman-adv/multicast_forw.c @@ -950,8 +950,11 @@ static int batadv_mcast_forw_packet(struct batadv_priv *bat_priv, dest = (u8 *)mcast_tracker + sizeof(*mcast_tracker); - /* check if full tracker tvlv is within skb length */ + /* check if full tracker tvlv, including padding, is within skb length */ tvlv_len = sizeof(*mcast_tracker) + ETH_ALEN * num_dests; + if (!(num_dests % 2)) + tvlv_len += 2; + if (tvlv_len > skb_network_header_len(skb)) return -EINVAL; -- 2.47.3