From nobody Thu Apr 2 23:20:10 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C3CAECAAD3 for ; Mon, 19 Sep 2022 14:33:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229832AbiISOdH (ORCPT ); Mon, 19 Sep 2022 10:33:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60266 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230128AbiISOch (ORCPT ); Mon, 19 Sep 2022 10:32:37 -0400 Received: from mail-m974.mail.163.com (mail-m974.mail.163.com [123.126.97.4]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 77E1B2D1F0 for ; Mon, 19 Sep 2022 07:32:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=iTD2U dbZKthlMc/IsUF/zdf2RgSerD0lLPtiNsZWyPM=; b=D7VRKCHqyJY1IhBAyhWCF Oob+buHUpKLLfjGOIqkqBfHF6pF+FsgdFXELm8aSZjriRBjRJOUzYfV3s+VLHqSB jdid3tExibgvz48Jy4JjRz3s9uBYyv+lynuKR3VU6ByFVpY2IN3Vmxoelm2aTbkT VG/Szj1nxqgWOxYXH+W0ww= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by smtp4 (Coremail) with SMTP id HNxpCgAXZ_NmfShjVRpZeQ--.15551S2; Mon, 19 Sep 2022 22:32:06 +0800 (CST) From: Zheng Wang To: dimitri.sivanich@hpe.com Cc: zyytlz.wz@163.com, arnd@arndb.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, alex000young@gmail.com, security@kernel.org Subject: [PATCH] misc: sgi-gru: fix use-after-free error in gru_set_context_option, gru_fault and gru_handle_user_call_os Date: Mon, 19 Sep 2022 22:32:05 +0800 Message-Id: <20220919143205.207353-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: HNxpCgAXZ_NmfShjVRpZeQ--.15551S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxur1xGr45JFy5CFyUWw47XFb_yoW7JFWxpa 1jg348urW3XF4Y9rsrta1kXFW3Cay8XFW5Gr9rt3s5ur4FyFs8GryDtas8tr4DZrW8tr4Y yF45tFnIk3Z09aDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziFdg_UUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiQgaBU1aEC9HEIQAAs7 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In grufile.c, gru_file_unlocked_ioctl function can be called by user. If the req is GRU_SET_CONTEXT_OPTION, it will call gru_set_context_option. In gru_set_context_option, as req can be controlled by user, We can reach gru_check_context_placement function call. In gru_check_context_placement function, if the error path was steped, say gru_check_chiplet_assignment return 0, Then it will fall into gru_unload_context function. And it will finnaly call kfree gts in gts_drop function. Then gru_unlock_gts will be called in gru_set_context_option function. This is a typical Use after free. The same problem exists in gru_handle_user_call_os and gru_fault. Fix it by introduce the return value to see if gts is in good case or not. Free the gts in caller when gru_check_chiplet_assignment check failed. Reported-by: Zheng Wang Zhuorao Yang Signed-off-by: Zheng Wang --- drivers/misc/sgi-gru/grufault.c | 14 ++++++++++++-- drivers/misc/sgi-gru/grumain.c | 17 +++++++++++++---- drivers/misc/sgi-gru/grutables.h | 2 +- 3 files changed, 26 insertions(+), 7 deletions(-) diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufaul= t.c index d7ef61e602ed..2b5b049fbd38 100644 --- a/drivers/misc/sgi-gru/grufault.c +++ b/drivers/misc/sgi-gru/grufault.c @@ -656,7 +656,9 @@ int gru_handle_user_call_os(unsigned long cb) if (ucbnum >=3D gts->ts_cbr_au_count * GRU_CBR_AU_SIZE) goto exit; =20 - gru_check_context_placement(gts); + ret =3D gru_check_context_placement(gts); + if (ret) + goto err; =20 /* * CCH may contain stale data if ts_force_cch_reload is set. @@ -677,6 +679,10 @@ int gru_handle_user_call_os(unsigned long cb) exit: gru_unlock_gts(gts); return ret; +err: + gru_unlock_gts(gts); + gru_unload_context(gts, 1); + return -EINVAL; } =20 /* @@ -874,7 +880,7 @@ int gru_set_context_option(unsigned long arg) } else { gts->ts_user_blade_id =3D req.val1; gts->ts_user_chiplet_id =3D req.val0; - gru_check_context_placement(gts); + ret =3D gru_check_context_placement(gts); } break; case sco_gseg_owner: @@ -889,6 +895,10 @@ int gru_set_context_option(unsigned long arg) ret =3D -EINVAL; } gru_unlock_gts(gts); + if (ret) { + gru_unload_context(gts, 1); + ret =3D -EINVAL; + } =20 return ret; } diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c index 9afda47efbf2..79903cf7e706 100644 --- a/drivers/misc/sgi-gru/grumain.c +++ b/drivers/misc/sgi-gru/grumain.c @@ -716,9 +716,10 @@ static int gru_check_chiplet_assignment(struct gru_sta= te *gru, * chiplet. Misassignment can occur if the process migrates to a different * blade or if the user changes the selected blade/chiplet. */ -void gru_check_context_placement(struct gru_thread_state *gts) +int gru_check_context_placement(struct gru_thread_state *gts) { struct gru_state *gru; + int ret =3D 0; =20 /* * If the current task is the context owner, verify that the @@ -727,14 +728,16 @@ void gru_check_context_placement(struct gru_thread_st= ate *gts) */ gru =3D gts->ts_gru; if (!gru || gts->ts_tgid_owner !=3D current->tgid) - return; + return ret; =20 if (!gru_check_chiplet_assignment(gru, gts)) { STAT(check_context_unload); - gru_unload_context(gts, 1); + ret =3D -EINVAL; } else if (gru_retarget_intr(gts)) { STAT(check_context_retarget_intr); } + + return ret; } =20 =20 @@ -919,6 +922,7 @@ vm_fault_t gru_fault(struct vm_fault *vmf) struct gru_thread_state *gts; unsigned long paddr, vaddr; unsigned long expires; + int ret; =20 vaddr =3D vmf->address; gru_dbg(grudev, "vma %p, vaddr 0x%lx (0x%lx)\n", @@ -934,7 +938,12 @@ vm_fault_t gru_fault(struct vm_fault *vmf) mutex_lock(>s->ts_ctxlock); preempt_disable(); =20 - gru_check_context_placement(gts); + ret =3D gru_check_context_placement(gts); + if (ret) { + mutex_unlock(>s->ts_ctxlock); + gru_unload_context(gts, 1); + return ret; + } =20 if (!gts->ts_gru) { STAT(load_user_context); diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutab= les.h index 5efc869fe59a..f4a5a787685f 100644 --- a/drivers/misc/sgi-gru/grutables.h +++ b/drivers/misc/sgi-gru/grutables.h @@ -632,7 +632,7 @@ extern int gru_user_flush_tlb(unsigned long arg); extern int gru_user_unload_context(unsigned long arg); extern int gru_get_exception_detail(unsigned long arg); extern int gru_set_context_option(unsigned long address); -extern void gru_check_context_placement(struct gru_thread_state *gts); +extern int gru_check_context_placement(struct gru_thread_state *gts); extern int gru_cpu_fault_map_id(void); extern struct vm_area_struct *gru_find_vma(unsigned long vaddr); extern void gru_flush_all_tlb(struct gru_state *gru); --=20 2.25.1