From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 686321170E for ; Mon, 11 Sep 2023 14:27:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1461C433C7; Mon, 11 Sep 2023 14:27:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694442439; bh=w4SI68hpBfwZ6B6SZs/gIggJr1XxuhnT65Gtqx6K9ZA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2XtVBssqgqGt/iVNpdGMthn6CtefrejBcN4WW3hBtCxua+y9d/zyLLl6wgJL5J5Y1 GiBDi+52DBJ80IB9RxHJBcF7LSUyubZBu+lzbrkwNk3lSEjizONEgGodx2+nYUcNJp DD/2+6b8Ui4HATAMaJ2g/jbu32f1dnP8EBCm8Umw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Simon Horman , Dominique Martinet , Eric Van Hensbergen , Sasha Levin Subject: [PATCH 6.4 009/737] 9p: virtio: fix unlikely null pointer deref in handle_rerror Date: Mon, 11 Sep 2023 15:37:48 +0200 Message-ID: <20230911134650.579867163@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230911134650.286315610@linuxfoundation.org> References: <20230911134650.286315610@linuxfoundation.org> User-Agent: quilt/0.67 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 6.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dominique Martinet [ Upstream commit 13ade4ac5c28e8a014fa85278f5a4270b215f906 ] handle_rerror can dereference the pages pointer, but it is not necessarily set for small payloads. In practice these should be filtered out by the size check, but might as well double-check explicitly. This fixes the following scan-build warnings: net/9p/trans_virtio.c:401:24: warning: Dereference of null pointer [core.NullDereference] memcpy_from_page(to, *pages++, offs, n); ^~~~~~~~ net/9p/trans_virtio.c:406:23: warning: Dereference of null pointer (loaded from variable 'pages') [core.NullDereference] memcpy_from_page(to, *pages, offs, size); ^~~~~~ Reviewed-by: Simon Horman Signed-off-by: Dominique Martinet Signed-off-by: Eric Van Hensbergen Signed-off-by: Sasha Levin --- net/9p/trans_virtio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 3c27ffb781e3e..2c9495ccda6ba 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -384,7 +384,7 @@ static void handle_rerror(struct p9_req_t *req, int in_hdr_len, void *to = req->rc.sdata + in_hdr_len; // Fits entirely into the static data? Nothing to do. - if (req->rc.size < in_hdr_len) + if (req->rc.size < in_hdr_len || !pages) return; // Really long error message? Tough, truncate the reply. Might get -- 2.40.1