From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753336AbeD2MXR (ORCPT ); Sun, 29 Apr 2018 08:23:17 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:39999 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753054AbeD2MXQ (ORCPT ); Sun, 29 Apr 2018 08:23:16 -0400 X-Google-Smtp-Source: AB8JxZq/A8968LdvKBF3V9Q43Djais+2xa7wUufIvS0TuVcJin1cAroR5jVtr1/MpX65NazZEQbUYg== From: Etienne Carriere To: alexandre.jutras@nxp.com, linux-kernel@vger.kernel.org, jens.wiklander@linaro.org Cc: Etienne Carriere Subject: [PATCH] tee: check shm references are consistent in offset/size Date: Sun, 29 Apr 2018 14:22:29 +0200 Message-Id: <1525004549-16266-1-git-send-email-etienne.carriere@linaro.org> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This change prevents userland from referencing TEE shared memory outside the area initially allocated by its owner. Prior this change an application could not reference or access memory it did not own but it could reference memory not explicitly allocated by owner but still allocated to the owner due to the memory allocation granule. Reported-by: Alexandre Jutras Signed-off-by: Etienne Carriere --- drivers/tee/tee_core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 0124a91..dd46b75 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -238,6 +238,17 @@ static int params_from_user(struct tee_context *ctx, struct tee_param *params, if (IS_ERR(shm)) return PTR_ERR(shm); + /* + * Ensure offset + size does not overflow offset + * and does not overflow the size of the referred + * shared memory object. + */ + if ((ip.a + ip.b) < ip.a || + (ip.a + ip.b) > shm->size) { + tee_shm_put(shm); + return -EINVAL; + } + params[n].u.memref.shm_offs = ip.a; params[n].u.memref.size = ip.b; params[n].u.memref.shm = shm; -- 1.9.1