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Tue, 14 Jul 2026 23:22:12 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav06.fra02v.mail.ibm.com (Postfix) with SMTP; Tue, 14 Jul 2026 23:22:12 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 4958) id 1E6BD16260D; Wed, 15 Jul 2026 01:22:12 +0200 (CEST) From: Eric Farman To: linux-s390@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Matthew Rosato , Halil Pasic , Christian Borntraeger , Eric Farman , stable@vger.kernel.org Subject: [PATCH v1 1/6] s390/vfio_ccw: fix out of bounds check on CCW array Date: Wed, 15 Jul 2026 01:22:03 +0200 Message-ID: <20260714232208.1683788-2-farman@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260714232208.1683788-1-farman@linux.ibm.com> References: <20260714232208.1683788-1-farman@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzE0MDI0MCBTYWx0ZWRfX9fR7JOnIjWFc 57O2WLU1tiLmG/PmmeKzf0csH8aKBQcG1cNL5vOZ4OrBP4pkGlSKB79BWgDRGZpdGtS7zKm2C8J ObGMw6dqbKPyv7Q9T+lFjXO7iu1pBW8= X-Proofpoint-GUID: gEChmZ9XFlrYps8-XIgC-kkpwze5kw5b X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzE0MDI0MCBTYWx0ZWRfX5pVNQ202t3x8 tFGz1ciPrDQ3a126yJeLVCgUHau6XAnoZRQ9naGKEqN+p9ufBu4Hr22Ph0EfJl5548c0zdiC86K pXFkezGBSJEhGqVIjVpMzs/xtI+S0b0vciUPyV+jYfzZxHBZzPFg1MoQQ8ISZRviTz8n7lBx+q1 bK1lvdhZRFsQDHlFpbWYxyU6KcoqCqzV6vRMYv9FhYpwa/eFjg/My0eTGIV47JSh/Wn+aHeoy0O oLuq/WNZz7hPo5N3cifQOR1FXobkmPBQaSLv17gVdwUZnV6cR+HMnAmSQL3g/IgiMFpgqckaEdO h4/sKoayHbwLBoxJT/LI+vdCOD8LOsRGgiRw0xcGq3HdL6AMSJi4J6zWuC+tXNv786z0mJvUFTJ brQXH8TjLfwLsdZl5vMZ2X4Vq/41YNpDqfzdD29YaKaKWrfjQePFPrbeB8fsJVmDrvmwPojZwvo M4ZSxpb2sj+OtHe7Xsg== X-Proofpoint-ORIG-GUID: gEChmZ9XFlrYps8-XIgC-kkpwze5kw5b X-Authority-Analysis: v=2.4 cv=PvajqQM3 c=1 sm=1 tr=0 ts=6a56c4a9 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=Ztfy0_AA8xUuwmIluScA:9 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=2026-07-14_05,2026-07-14_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 bulkscore=0 impostorscore=0 adultscore=0 clxscore=1015 lowpriorityscore=0 spamscore=0 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607140240 The routine ccwchain_calc_length() counts the number of channel command words (CCWs) that are chained together in a single channel program, and rejects anything larger than CCWCHAIN_LEN_MAX (256) CCWs. The loop itself is "do..while (count < 257)", and while the logic in is_cpa_within_range() correctly adjusts between the 0-index array of CCWs and the count of CCWs starting at 1, this means it would look at a possible 257th CCW before ending the loop and (correctly) returning an error. Fix this by limiting the loop to 256 CCWs such that only indexes 0-255 are examined. Fixes: 0a19e61e6d4c ("vfio: ccw: introduce channel program interfaces") Cc: stable@vger.kernel.org Signed-off-by: Eric Farman --- drivers/s390/cio/vfio_ccw_cp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_c= p.c index 7561aa7d3e01..80c3d87f5482 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -393,9 +393,9 @@ static int ccwchain_calc_length(u64 iova, struct chan= nel_program *cp) break; =20 ccw++; - } while (cnt < CCWCHAIN_LEN_MAX + 1); + } while (cnt < CCWCHAIN_LEN_MAX); =20 - if (cnt =3D=3D CCWCHAIN_LEN_MAX + 1) + if (cnt >=3D CCWCHAIN_LEN_MAX) cnt =3D -EINVAL; =20 return cnt; --=20 2.53.0