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Tue, 8 Sep 2026 13:18:17 +0000 (GMT) Received: from funtu2.ibm.com (unknown [9.111.138.252]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 8 Sep 2026 13:18:17 +0000 (GMT) From: Harald Freudenberger To: dengler@linux.ibm.com, fcallies@linux.ibm.com, ifranzki@linux.ibm.com Cc: freude@linux.ibm.com, linux-s390@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev Subject: [PATCH v2 1/1] s390/zcrypt: Fix and improve zcrypt reply message verification checks Date: Tue, 8 Sep 2026 15:18:16 +0200 Message-ID: <20260908131817.17644-2-freude@linux.ibm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260908131817.17644-1-freude@linux.ibm.com> References: <20260908131817.17644-1-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-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 5S9rqOXVxilFYz6DlZ3bjFVvX0SY-ih6 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTA4MDE0MCBTYWx0ZWRfX6o7Rnk6A781M a1Y6Z1T5HW09kuxASi/YG5VE9+acqviX4U2BeGmWi6DAqqtBiVAsPqlEocNP4Ytx52Yk37zyeC0 EklYyxOH5o6tQPTrbOCLsNPgU3Rd/ew= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTA4MDE0MCBTYWx0ZWRfX6hLZtR4bHSV3 EhSy7LBFkBsh1Se+omfqREvxf2h+anKX9pWKqlKYj5i6l6nyZR94DC014kaS9HWB6k/M5OIakH9 tLxaxlXTD5XVAtTbos5lqAk4JuiDUNPIRWHHUeLUrxwtSEmzk3cp+0WjM21W9rHM4HiZJDqeAkn SxpZfbpPw3+G/gWrUymk+DgfDQgbwnu49PwOJcaUQL89IY+zIWAF2bxMXbMXm2x7ircqfbpaC8r VsPXhgSeCe2cxafroLcGbNKAg8iMw2hLk55z4lPKsyaAJWSO2hy67Pi5OGh0MD0wB+1SfJqr606 qtyzH8rzOL9+xWhu6T9TH02uex0PxRjO+yU0DALYM64UjQi+ME2mneMYZ2h17GkVrEzaaxDdRx4 /hqcOOXb9od/DwOyjzvnkrJwCH3gKleo64ct03JlXmJ/GPI1t6l1e/3Ge+D342ChxOO/BNBBOvM n1mps8cYZgGstXArWMQ== X-Authority-Analysis: v=2.4 cv=JaKMa0KV c=1 sm=1 tr=0 ts=6aa00b1f cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=OnDvl9nT2VvQF00v-d4A:9 X-Proofpoint-GUID: 5S9rqOXVxilFYz6DlZ3bjFVvX0SY-ih6 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-08_02,2026-09-08_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 spamscore=0 phishscore=0 impostorscore=0 lowpriorityscore=0 adultscore=0 bulkscore=0 priorityscore=1501 suspectscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609080140 Add or improve checks related to buffer sizes and reply sizes to the handling of replies from the crypto cards for CCA, EP11 (AP message type 6) and ICA (AP type 50) messages. The verification code related to reply field length was not designed well and thus firmware deficiencies could lead to unexpected behavior in the zcrypt device driver. Thus improve the code to more closely inspect especially length fields at message replies. Add length validation before accessing reply message structures in zcrypt_msgtype6_receive(), zcrypt_msgtype6_receive_ep11(), and zcrypt_msgtype50_receive() to prevent out-of-bounds reads and potential kernel memory disclosure. Also rework these three functions to validate reply lengths more carefully before copying data back into the request buffer. Use size_t for length calculations, reject inconsistent reply sizes, and add defensive handling for short invalid replies. For XCRB replies, validate both reply segments and derive the effective message length from the covered range instead of trusting only the second segment. Fixes: 3b6245fd303f ("s390/zcrypt: Separate msgtype implementation from card modules.") Signed-off-by: Harald Freudenberger Cc: stable@vger.kernel.org --- drivers/s390/crypto/zcrypt_msgtype50.c | 40 +++++-- drivers/s390/crypto/zcrypt_msgtype6.c | 160 +++++++++++++++++-------- 2 files changed, 136 insertions(+), 64 deletions(-) diff --git a/drivers/s390/crypto/zcrypt_msgtype50.c b/drivers/s390/crypto/zcrypt_msgtype50.c index d6fc2d8e7fad..80c447ea2d83 100644 --- a/drivers/s390/crypto/zcrypt_msgtype50.c +++ b/drivers/s390/crypto/zcrypt_msgtype50.c @@ -416,26 +416,40 @@ static void zcrypt_msgtype50_receive(struct ap_queue *aq, .reply_code = REP82_ERROR_MACHINE_FAILURE, }; struct type80_hdr *t80h; - int len; + size_t len; /* Copy the reply message to the request message buffer. */ if (!reply) goto out; /* ap_msg->rc indicates the error */ + t80h = reply->msg; - if (t80h->type == TYPE80_RSP_CODE) { - len = t80h->len; - if (len > reply->bufsize || len > msg->bufsize || - len != reply->len) { - pr_debug("len mismatch => EMSGSIZE\n"); - msg->rc = -EMSGSIZE; - goto out; - } - memcpy(msg->msg, reply->msg, len); - msg->len = len; - } else { - memcpy(msg->msg, reply->msg, sizeof(error_reply)); + + if (reply->len < sizeof(*t80h) || + t80h->type != TYPE80_RSP_CODE) { + if (reply->len < sizeof(error_reply)) + memcpy(msg->msg, &error_reply, sizeof(error_reply)); + else + memcpy(msg->msg, reply->msg, sizeof(error_reply)); msg->len = sizeof(error_reply); + goto out; + } + + len = t80h->len; + if (len != reply->len) { + msg->rc = -EMSGSIZE; + pr_debug("len %zu rpl.len %zu mismatch, msg.rc=%d\n", + len, reply->len, msg->rc); + goto out; } + if (len > reply->bufsize || len > msg->bufsize) { + msg->rc = -EMSGSIZE; + pr_debug("len %zu exceeds buf %zu/%zu, msg.rc=%d\n", + len, reply->bufsize, msg->bufsize, msg->rc); + goto out; + } + memcpy(msg->msg, reply->msg, len); + msg->len = len; + out: complete(&msg->response.work); } diff --git a/drivers/s390/crypto/zcrypt_msgtype6.c b/drivers/s390/crypto/zcrypt_msgtype6.c index 3df1d676de5d..b53801b0a971 100644 --- a/drivers/s390/crypto/zcrypt_msgtype6.c +++ b/drivers/s390/crypto/zcrypt_msgtype6.c @@ -766,6 +766,13 @@ static int convert_type86_rng(struct zcrypt_queue *zq, if (msg->cprbx.ccp_rtcode != 0 || msg->cprbx.ccp_rscode != 0) return -EINVAL; + /* + * Note that offset2 and count2 have already been checked in + * zcrypt_msgtype6_receive(). So only check for not exceeding + * the hard coded rng buffer size. + */ + if (msg->fmt2.count2 > ZCRYPT_RNG_BUFFER_SIZE) + return -EMSGSIZE; memcpy(buffer, data + msg->fmt2.offset2, msg->fmt2.count2); return msg->fmt2.count2; } @@ -928,48 +935,80 @@ static void zcrypt_msgtype6_receive(struct ap_queue *aq, }; struct ap_response_type *resp_type = &msg->response; struct type86x_reply *t86r; - int len; + size_t minlen, len; /* Copy the reply message to the request message buffer. */ if (!reply) goto out; /* ap_msg->rc indicates the error */ + t86r = reply->msg; - if (t86r->hdr.type == TYPE86_RSP_CODE && - t86r->cprbx.cprb_ver_id == 0x02) { - switch (resp_type->type) { - case CEXXC_RESPONSE_TYPE_ICA: - len = sizeof(struct type86x_reply) + t86r->length; - if (len > reply->bufsize || len > msg->bufsize || - len != reply->len) { - pr_debug("len mismatch => EMSGSIZE\n"); - msg->rc = -EMSGSIZE; - goto out; - } - memcpy(msg->msg, reply->msg, len); - msg->len = len; - break; - case CEXXC_RESPONSE_TYPE_XCRB: - if (t86r->fmt2.count2) - len = t86r->fmt2.offset2 + t86r->fmt2.count2; - else - len = t86r->fmt2.offset1 + t86r->fmt2.count1; - if (len > reply->bufsize || len > msg->bufsize || - len != reply->len) { - pr_debug("len mismatch => EMSGSIZE\n"); + minlen = sizeof(t86r->hdr) + sizeof(t86r->fmt2) + + offsetof(struct CPRBX, cprb_ver_id) + + sizeof(t86r->cprbx.cprb_ver_id); + + if (reply->len < minlen || + t86r->hdr.type != TYPE86_RSP_CODE || + t86r->cprbx.cprb_ver_id != 0x02) { + if (reply->len < sizeof(error_reply)) + memcpy(msg->msg, &error_reply, sizeof(error_reply)); + else + memcpy(msg->msg, reply->msg, sizeof(error_reply)); + msg->len = sizeof(error_reply); + goto out; + } + + switch (resp_type->type) { + case CEXXC_RESPONSE_TYPE_ICA: + if (reply->len < sizeof(struct type86x_reply)) { + msg->rc = -EMSGSIZE; + pr_debug("rpl.len %zu < struct type86_reply, msg.rc=%d\n", + reply->len, msg->rc); + goto out; + } + len = sizeof(struct type86x_reply) + (size_t)t86r->length; + break; + case CEXXC_RESPONSE_TYPE_XCRB: + len = (size_t)t86r->fmt2.offset1 + (size_t)t86r->fmt2.count1; + if (len > reply->len) { + msg->rc = -EMSGSIZE; + pr_debug("offset1 %u count1 %u rpl.len %zu mismatch, msg.rc=%d\n", + t86r->fmt2.offset1, t86r->fmt2.count1, + reply->len, msg->rc); + goto out; + } + if (t86r->fmt2.count2) { + len = (size_t)t86r->fmt2.offset2 + + (size_t)t86r->fmt2.count2; + if (len > reply->len) { msg->rc = -EMSGSIZE; + pr_debug("offset2 %u count2 %u rpl.len %zu mismatch, msg.rc=%d\n", + t86r->fmt2.offset2, t86r->fmt2.count2, + reply->len, msg->rc); goto out; } - memcpy(msg->msg, reply->msg, len); - msg->len = len; - break; - default: - memcpy(msg->msg, &error_reply, sizeof(error_reply)); - msg->len = sizeof(error_reply); } - } else { - memcpy(msg->msg, reply->msg, sizeof(error_reply)); + break; + default: + memcpy(msg->msg, &error_reply, sizeof(error_reply)); msg->len = sizeof(error_reply); + goto out; } + + if (len != reply->len) { + msg->rc = -EMSGSIZE; + pr_debug("len %zu rpl.len %zu mismatch, msg.rc=%d\n", + len, reply->len, msg->rc); + goto out; + } + if (len > reply->bufsize || len > msg->bufsize) { + msg->rc = -EMSGSIZE; + pr_debug("len %zu exceeds buf %zu/%zu, msg.rc=%d\n", + len, reply->bufsize, msg->bufsize, msg->rc); + goto out; + } + memcpy(msg->msg, reply->msg, len); + msg->len = len; + out: complete(&resp_type->work); } @@ -992,34 +1031,53 @@ static void zcrypt_msgtype6_receive_ep11(struct ap_queue *aq, }; struct ap_response_type *resp_type = &msg->response; struct type86_ep11_reply *t86r; - int len; + size_t minlen, len; /* Copy the reply message to the request message buffer. */ if (!reply) goto out; /* ap_msg->rc indicates the error */ + t86r = reply->msg; - if (t86r->hdr.type == TYPE86_RSP_CODE && - t86r->cprbx.cprb_ver_id == 0x04) { - switch (resp_type->type) { - case CEXXC_RESPONSE_TYPE_EP11: - len = t86r->fmt2.offset1 + t86r->fmt2.count1; - if (len > reply->bufsize || len > msg->bufsize || - len != reply->len) { - pr_debug("len mismatch => EMSGSIZE\n"); - msg->rc = -EMSGSIZE; - goto out; - } - memcpy(msg->msg, reply->msg, len); - msg->len = len; - break; - default: + minlen = sizeof(t86r->hdr) + sizeof(t86r->fmt2) + + offsetof(struct ep11_cprb, cprb_ver_id) + + sizeof(t86r->cprbx.cprb_ver_id); + + if (reply->len < minlen || + t86r->hdr.type != TYPE86_RSP_CODE || + t86r->cprbx.cprb_ver_id != 0x04) { + if (reply->len < sizeof(error_reply)) memcpy(msg->msg, &error_reply, sizeof(error_reply)); - msg->len = sizeof(error_reply); - } - } else { - memcpy(msg->msg, reply->msg, sizeof(error_reply)); + else + memcpy(msg->msg, reply->msg, sizeof(error_reply)); msg->len = sizeof(error_reply); + goto out; } + + switch (resp_type->type) { + case CEXXC_RESPONSE_TYPE_EP11: + len = (size_t)t86r->fmt2.offset1 + (size_t)t86r->fmt2.count1; + break; + default: + memcpy(msg->msg, &error_reply, sizeof(error_reply)); + msg->len = sizeof(error_reply); + goto out; + } + + if (len != reply->len) { + msg->rc = -EMSGSIZE; + pr_debug("len %zu rpl.len %zu mismatch, msg.rc=%d\n", + len, reply->len, msg->rc); + goto out; + } + if (len > reply->bufsize || len > msg->bufsize) { + msg->rc = -EMSGSIZE; + pr_debug("len %zu exceeds buf %zu/%zu, msg.rc=%d\n", + len, reply->bufsize, msg->bufsize, msg->rc); + goto out; + } + memcpy(msg->msg, reply->msg, len); + msg->len = len; + out: complete(&resp_type->work); } -- 2.43.0