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Thu, 27 Oct 2022 12:26:22 +0000 (UTC) Received: from hpe.com (unknown [16.231.227.36]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by p1lg14886.dc01.its.hpecorp.net (Postfix) with ESMTPS id C882B8052AA; Thu, 27 Oct 2022 12:26:20 +0000 (UTC) Date: Thu, 27 Oct 2022 07:26:18 -0500 From: Dimitri Sivanich To: Zheng Wang Cc: gregkh@linuxfoundation.org, zhengyejian1@huawei.com, dimitri.sivanich@hpe.com, arnd@arndb.de, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, alex000young@gmail.com, security@kernel.org, lkp@intel.com Subject: Re: [PATCH v6] misc: sgi-gru: fix use-after-free error in gru_set_context_option, gru_fault and gru_handle_user_call_os Message-ID: <20221027122618.GA27734@hpe.com> References: <20221027071453.118394-1-zyytlz.wz@163.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221027071453.118394-1-zyytlz.wz@163.com> X-Proofpoint-ORIG-GUID: NBZ7-JNpDH2ksx8orOJeXxgoOvjrRafR X-Proofpoint-GUID: NBZ7-JNpDH2ksx8orOJeXxgoOvjrRafR X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-HPE-SCL: -1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-10-27_05,2022-10-27_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 lowpriorityscore=0 phishscore=0 mlxlogscore=999 priorityscore=1501 mlxscore=0 spamscore=0 impostorscore=0 malwarescore=0 suspectscore=0 clxscore=1011 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2210170000 definitions=main-2210270068 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Acked-by: Dimitri Sivanich On Thu, Oct 27, 2022 at 03:14:53PM +0800, Zheng Wang wrote: > Gts may be freed in gru_check_chiplet_assignment. > The caller still use it after that, UAF happens. > > Fix it by introducing a return value to see if it's in error path or not. > Free the gts in caller if gru_check_chiplet_assignment check failed. > > Fixes: 55484c45dbec ("gru: allow users to specify gru chiplet 2") > Reported-by: Zheng Wang > Reported-by: kernel test robot > > Signed-off-by: Zheng Wang > --- > v6: > - remove unused var checked by kernel test robot > > v5: > - fix logical issue and remove unnecessary variable suggested by Dimitri Sivanich > > v4: > - use VM_FAULT_NOPAGE as failure code in gru_fault and -EINVAL in other functions suggested by Yejian > > v3: > - add preempt_enable and use VM_FAULT_NOPAGE as failure code suggested by Yejian > > v2: > - commit message changes suggested by Greg > > v1: https://lore.kernel.org/lkml/CAJedcCzY72jqgF-pCPtx66vXXwdPn-KMagZnqrxcpWw1NxTLaA@mail.gmail.com/ > --- > drivers/misc/sgi-gru/grufault.c | 14 ++++++++++++-- > drivers/misc/sgi-gru/grumain.c | 16 ++++++++++++---- > drivers/misc/sgi-gru/grutables.h | 2 +- > 3 files changed, 25 insertions(+), 7 deletions(-) > > diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c > index d7ef61e602ed..bdd515d33225 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 >= gts->ts_cbr_au_count * GRU_CBR_AU_SIZE) > goto exit; > > - gru_check_context_placement(gts); > + ret = gru_check_context_placement(gts); > + if (ret) > + goto err; > > /* > * 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; > } > > /* > @@ -874,7 +880,11 @@ int gru_set_context_option(unsigned long arg) > } else { > gts->ts_user_blade_id = req.val1; > gts->ts_user_chiplet_id = req.val0; > - gru_check_context_placement(gts); > + if (gru_check_context_placement(gts)) { > + gru_unlock_gts(gts); > + gru_unload_context(gts, 1); > + return -EINVAL; > + } > } > break; > case sco_gseg_owner: > diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c > index 9afda47efbf2..beba69fc3cd7 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_state *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 = 0; > > /* > * If the current task is the context owner, verify that the > @@ -727,14 +728,16 @@ void gru_check_context_placement(struct gru_thread_state *gts) > */ > gru = gts->ts_gru; > if (!gru || gts->ts_tgid_owner != current->tgid) > - return; > + return ret; > > if (!gru_check_chiplet_assignment(gru, gts)) { > STAT(check_context_unload); > - gru_unload_context(gts, 1); > + ret = -EINVAL; > } else if (gru_retarget_intr(gts)) { > STAT(check_context_retarget_intr); > } > + > + return ret; > } > > > @@ -934,7 +937,12 @@ vm_fault_t gru_fault(struct vm_fault *vmf) > mutex_lock(>s->ts_ctxlock); > preempt_disable(); > > - gru_check_context_placement(gts); > + if (gru_check_context_placement(gts)) { > + preempt_enable(); > + mutex_unlock(>s->ts_ctxlock); > + gru_unload_context(gts, 1); > + return VM_FAULT_NOPAGE; > + } > > if (!gts->ts_gru) { > STAT(load_user_context); > diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.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); > -- > 2.25.1