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Wed, 22 Jul 2026 18:32:04 +0000 (GMT) Received: from osiris (unknown [9.111.32.204]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 22 Jul 2026 18:32:04 +0000 (GMT) Date: Wed, 22 Jul 2026 20:32:03 +0200 From: Heiko Carstens To: Harald Freudenberger Cc: Vasily Gorbik , Alexander Gordeev , linux-s390@vger.kernel.org Subject: Re: [PATCH v2 1/1] s390/zcrypt: Close speculative mem read possibility Message-ID: <20260722183203.13538Cee-hca@linux.ibm.com> References: <20260722152025.119391-1-freude@linux.ibm.com> <20260722152025.119391-2-freude@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260722152025.119391-2-freude@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ESvWMf9Ebp_BNFz6s3rVLWyLJUEFp8BE X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzIyMDE3OSBTYWx0ZWRfXzHgg1xIEaiNp 5dUTDyYo1ZY/Wk18ITnfvMICbWz/wP6rbt1+ERxHB0VJ3Wk9OO00b4HUHZ9DL9UG6LGVdCeg+DK Yx3quQKebTjfsDnQ5RhBMDkLQCZc9wdemuChvWWo6D5LZM8L7SmL3c8RQudCPjYsuikOCbTSEhd mx/KXAlMkJfA7CX8nVkVJnaTSGfLd+Yl72wWC/L8XEoszX9cOpI1fFB3vdDVZs44oKYGCGWCkUX 5p8rlJZDom2QKoHAXHXW9OW6B7u9Esfab/ADhl7IdMBisrUxppxaw3hD/ksIrYoNtG7xAQp/IM1 /nKuMgWKESGBS08sFwlK2E9dpd/C6XGBUr79x5H2j0gClsGqXLBhQovySQt1oEHA8f8W2sGpC/i AaMItu2Zsy+36gmq0jKCCuxq7evngajD6ElkBuFKUjSD0B+GdL/7OyRkLnEHfpVNOx4GNsInEPN bEiRl0Ixx7gehY6t0hw== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzIyMDE3OSBTYWx0ZWRfX78VaNOUS+WFy Rq4Q7z+fJ4DXkEKJraIvGiJUpJWhvCSJwrRXXCtCEbZoFQsw+oz2Yl8kNF+vR8e+62FKDywzJCT eNRyS6WlaidkfOdppJkn7DR3TzxAJjE= X-Proofpoint-GUID: ESvWMf9Ebp_BNFz6s3rVLWyLJUEFp8BE X-Authority-Analysis: v=2.4 cv=SM5ykuvH c=1 sm=1 tr=0 ts=6a610ca9 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=kj9zAlcOel0A:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=IpLEZtQiE9cJNPtD5WgA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-22_05,2026-07-22_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 lowpriorityscore=0 bulkscore=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 priorityscore=1501 phishscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607220179 On Wed, Jul 22, 2026 at 05:20:25PM +0200, Harald Freudenberger wrote: > The domain value is extracted from a given CCA or EP11 ioctl struct > when a CPRB is about to be sent. Thus this is a user controlled value. > Under some special conditions (custom device node used, administrative > load) this value is used as an array index after bounds checking, but > without speculation barrier. > > Add the missing array_index_nospec() call to prevent speculative > execution where this domain value is used. > > Fixes: cfd68b33094e ("s390/zcrypt: Filter admin CPRBs on custom devices") > Reported-by: Christian Borntraeger > Signed-off-by: Harald Freudenberger > Reviewed-by: Finn Callies > Cc: stable@vger.kernel.org ... > @@ -1079,6 +1080,7 @@ static long _zcrypt_send_ep11_cprb(u32 xflags, struct ap_perms *perms, > > if (perms != &ap_perms && domain < AUTOSEL_DOM) { > if (ap_msg.flags & AP_MSG_FLAG_ADMIN) { > + domain = array_index_nospec(domain, AP_DOMAINS); This hunk doesn't make sense, and it depends on the other patch you sent: "s390/zcrypt: Fix wrong domain value verification with EP11 CPRBs". Please send them as a series of two.