From mboxrd@z Thu Jan 1 00:00:00 1970 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 E9B0E421249; Mon, 17 Aug 2026 14:36:54 +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=1786977416; cv=none; b=Y1AypUBzaitsSTP46/ZToSas9gKCh6rteKrb+P3d/I+BpL58Y07+rmEsyM4mw0uQj0nTYfCITpvYqj/0G880LLt3yjhcnf4weyiT3nIB95YDGp36ZydqGJArVrJ9a5OexqbWJ6yvdCAEwn5eWwL4jWfqWt+zQfpnpeLSjNNXRxM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977416; c=relaxed/simple; bh=6QNv3Om+nXRqH8X4IaHpyrksLQvThDHvyO/qIE4+H3s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=t1kp035xAJ0NNWEicqFoiYwJDoz9xKbE80PdBO32dZSLoVU6kBn9MSBkeP/4Zo2tPz2e8hxjF2aKk0ZyEMl76Tq+tFwPIUUJiST/AYCGWtK5fz3OhzN0pnWFhl8va6vX86Dy9dQg3arBxx+V1r75R64873jjazecm0NBYW9hIqA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hKUggSMs; 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="hKUggSMs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4FDA01F000E9; Mon, 17 Aug 2026 14:36:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786977414; bh=mmXCDszZktez4rIzYwwQ72hVMgh/PyhmGrqFMuIMzW0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hKUggSMsR6jI9puigqQBI+QbaMlsFXSXHplwevdOwGmBguBK13ts1x9GoFVipzE4A HSVo7VkT4Hn947Lx7EkFTHtrjacLSKBtfTlg73o65d3QI9LigBLy4MH8S3HWgA9C4F hrgVhZMoj5/+IjKBfYZSHRdQ04SCgNW1Cg7BNMLI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Bommarito , Richard Weinberger Subject: [PATCH 5.15 322/456] um: vector: fix use-after-free in vector_mmsg_rx() Date: Mon, 17 Aug 2026 15:31:52 +0200 Message-ID: <20260817132552.280491881@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132539.792407575@linuxfoundation.org> References: <20260817132539.792407575@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Bommarito commit af421e9aed3920c7ac88c24daa48606c7112feca upstream. When vector_mmsg_rx() discards a packet whose overlay header fails verify_header(), it frees the skb and continues the loop: if (header_check < 0) { dev_kfree_skb_irq(skb); vp->estats.rx_encaps_errors++; continue; } The normal and short-packet paths fall through to the bottom of the loop body, which clears the consumed slot and advances the cursors: (*skbuff_vector) = NULL; mmsg_vector++; skbuff_vector++; The verify_header() < 0 path skips that via continue, so the freed skb is left in skbuff_vector[] and the cursors do not advance. The next iteration reads the same slot, gets the freed skb, and frees it again, producing a refcount underflow / use-after-free in the RX path. Discard the slot the same way the other paths do before continuing. Only transports whose verify_header() can return negative are affected: GRE and L2TPv3 do so on a cookie/session-id mismatch (raw/tap do not), so any peer on such a transport can trigger it without authentication. Fixes: 49da7e64f33e ("High Performance UML Vector Network Driver") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman --- arch/um/drivers/vector_kern.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/um/drivers/vector_kern.c +++ b/arch/um/drivers/vector_kern.c @@ -1007,6 +1007,9 @@ static int vector_mmsg_rx(struct vector_ */ dev_kfree_skb_irq(skb); vp->estats.rx_encaps_errors++; + (*skbuff_vector) = NULL; + mmsg_vector++; + skbuff_vector++; continue; } if (header_check > 0) {