Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E0372874E6; Thu, 20 Aug 2026 15:07:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787238431; cv=none; b=GCgJVTgRxwgW858JbeN5Cc8oCpI5+Fpx7WruD+897czKjY6uUuVNEO9RJAsyNZ5LKSr/gpUbCPtlPCHDWkeZtiEjFfDk8zXTsMCL4CsHey8MiuyASRiRdIvsTVwak5TYV9MhSrLUmTlOgbEG56zo8BxpuaQf7xNHZZgTbzyOVxw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787238431; c=relaxed/simple; bh=+DcamW12ycnOxDAcJUf12puvH+Qt5sQeuB0ivQt4qC8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=O8YAcxrxHOgd++1gFFR68dIG7TdUu79oqhru517AjCg74yWoh1F41lBVRwvBQK9i3HO/fO5CM9YqbJfdc//hJ3I76Pf9tbOejZb67+Fu8LtdXZkxavGf00D7k9seIIgsRdO7tN7soXMUm0IC7uhaxb1a83UD11FPeFiq41A+jWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VVSWAP9a; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="VVSWAP9a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A809A1F000E9; Thu, 20 Aug 2026 15:07:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787238430; bh=sOVEZN3lNlXWkwGa6bOuqxwBm1deJeh+Ghx1/TyzPOk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=VVSWAP9aQoBJU7ek+eSj+PNBUVZzXBgZKalXcE9PFytK96rsj7LGMSGWK1yG5Df/1 VqdO5szFDtC4OOG8F4LaP6LDCWaP7mFAC73Ne0+5vONLAcIJg2NsxDGdghfzAJ3Ool 0Q00WAEjKEok8l2Cew4pHiO5aG4VnfnA79u1os88= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Harald Freudenberger , Holger Dengler , Vasily Gorbik Subject: [PATCH 7.1 106/228] s390/zcrypt: Improve CCA CPRB length and overflow checks Date: Thu, 20 Aug 2026 16:54:08 +0200 Message-ID: <20260820145247.862835905@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145244.450574346@linuxfoundation.org> References: <20260820145244.450574346@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Harald Freudenberger commit 35ac6754ba6da45fd193f5ce3f665f7490b830d5 upstream. The xcrb_msg_to_type6cprb_msgx() function lacks proper input validation, creating security vulnerabilities: 1. Integer overflow after CEIL4 alignment: Signed int variables could overflow during 4-byte boundary alignment, causing undersized buffer allocations or incorrect bounds checking. 2. Missing minimum size validation: The CPRBX structure is copied from userspace without verifying sufficient buffer length. Undersized buffers cause uninitialized memory access when reading structure fields like cprbx.cprb_len and cprbx.domain. 3. Arithmetic overflow in sum calculations: Adding control block and data block sizes could overflow, bypassing size checks and enabling buffer overflows. Fix by using size_t for length calculations, adding U32_MAX boundary checks after alignment, validating minimum control block size before copying from userspace, and detecting sum calculation overflows. Fixes: e2c6d91eb8b1 ("s390/zcrypt: Rework domain processing within zcrypt device driver") Signed-off-by: Harald Freudenberger Reviewed-by: Holger Dengler Cc: stable@vger.kernel.org # 7.1+ Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman --- drivers/s390/crypto/zcrypt_msgtype6.c | 79 ++++++++++++--------------- 1 file changed, 36 insertions(+), 43 deletions(-) diff --git a/drivers/s390/crypto/zcrypt_msgtype6.c b/drivers/s390/crypto/zcrypt_msgtype6.c index 40f72cdf284d..3e19e79d747c 100644 --- a/drivers/s390/crypto/zcrypt_msgtype6.c +++ b/drivers/s390/crypto/zcrypt_msgtype6.c @@ -342,49 +342,39 @@ static int xcrb_msg_to_type6cprb_msgx(bool userspace, struct ap_message *ap_msg, }; } __packed * msg = ap_msg->msg; - int rcblen = CEIL4(xcrb->request_control_blk_length); - int req_sumlen, resp_sumlen; - char *req_data = ap_msg->msg + sizeof(struct type6_hdr) + rcblen; - char *function_code; + size_t req_cblen, rep_cblen, req_sumlen, rep_sumlen; + char *function_code, *req_data; - if (CEIL4(xcrb->request_control_blk_length) < - xcrb->request_control_blk_length) - return -EINVAL; /* overflow after alignment*/ - - /* length checks */ - ap_msg->len = sizeof(struct type6_hdr) + - CEIL4(xcrb->request_control_blk_length) + - xcrb->request_data_length; + /* request length and overflow checks */ + if (xcrb->request_control_blk_length < sizeof(struct CPRBX)) + return -EINVAL; + req_cblen = CEIL4((size_t)xcrb->request_control_blk_length); + if (req_cblen > U32_MAX) + return -EINVAL; + req_sumlen = req_cblen + xcrb->request_data_length; + if (req_sumlen > U32_MAX) + return -EINVAL; + ap_msg->len = sizeof(struct type6_hdr) + req_sumlen; if (ap_msg->len > ap_msg->bufsize) return -EINVAL; - - /* - * Overflow check - * sum must be greater (or equal) than the largest operand - */ - req_sumlen = CEIL4(xcrb->request_control_blk_length) + - xcrb->request_data_length; - if ((CEIL4(xcrb->request_control_blk_length) <= - xcrb->request_data_length) ? + if (req_cblen <= xcrb->request_data_length ? req_sumlen < xcrb->request_data_length : - req_sumlen < CEIL4(xcrb->request_control_blk_length)) { + req_sumlen < req_cblen) { return -EINVAL; } - if (CEIL4(xcrb->reply_control_blk_length) < - xcrb->reply_control_blk_length) - return -EINVAL; /* overflow after alignment*/ - - /* - * Overflow check - * sum must be greater (or equal) than the largest operand - */ - resp_sumlen = CEIL4(xcrb->reply_control_blk_length) + - xcrb->reply_data_length; - if ((CEIL4(xcrb->reply_control_blk_length) <= - xcrb->reply_data_length) ? - resp_sumlen < xcrb->reply_data_length : - resp_sumlen < CEIL4(xcrb->reply_control_blk_length)) { + /* reply length and overflow checks */ + if (xcrb->reply_control_blk_length < sizeof(struct CPRBX)) + return -EINVAL; + rep_cblen = CEIL4((size_t)xcrb->reply_control_blk_length); + if (rep_cblen > U32_MAX) + return -EINVAL; + rep_sumlen = rep_cblen + xcrb->reply_data_length; + if (rep_sumlen > U32_MAX) + return -EINVAL; + if (rep_cblen <= xcrb->reply_data_length ? + rep_sumlen < xcrb->reply_data_length : + rep_sumlen < rep_cblen) { return -EINVAL; } @@ -393,7 +383,7 @@ static int xcrb_msg_to_type6cprb_msgx(bool userspace, struct ap_message *ap_msg, memcpy(msg->hdr.agent_id, &xcrb->agent_ID, sizeof(xcrb->agent_ID)); msg->hdr.tocardlen1 = xcrb->request_control_blk_length; if (xcrb->request_data_length) { - msg->hdr.offset2 = msg->hdr.offset1 + rcblen; + msg->hdr.offset2 = msg->hdr.offset1 + req_cblen; msg->hdr.tocardlen2 = xcrb->request_data_length; } msg->hdr.fromcardlen1 = xcrb->reply_control_blk_length; @@ -404,8 +394,8 @@ static int xcrb_msg_to_type6cprb_msgx(bool userspace, struct ap_message *ap_msg, xcrb->request_control_blk_addr, xcrb->request_control_blk_length)) return -EFAULT; - if (msg->cprbx.cprb_len + sizeof(msg->hdr.function_code) > - xcrb->request_control_blk_length) + /* copy subfunction code into AP msg type 6 function code field */ + if (msg->cprbx.cprb_len > req_cblen - sizeof(msg->hdr.function_code)) return -EINVAL; function_code = ((unsigned char *)&msg->cprbx) + msg->cprbx.cprb_len; memcpy(msg->hdr.function_code, function_code, @@ -437,10 +427,13 @@ static int xcrb_msg_to_type6cprb_msgx(bool userspace, struct ap_message *ap_msg, } /* copy data block */ - if (xcrb->request_data_length && - z_copy_from_user(userspace, req_data, xcrb->request_data_address, - xcrb->request_data_length)) - return -EFAULT; + if (xcrb->request_data_length) { + req_data = ap_msg->msg + sizeof(struct type6_hdr) + req_cblen; + if (z_copy_from_user(userspace, req_data, + xcrb->request_data_address, + xcrb->request_data_length)) + return -EFAULT; + } return 0; } -- 2.55.0