Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754431AbbGGFsO (ORCPT ); Tue, 7 Jul 2015 01:48:14 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:54922 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751382AbbGGFsG (ORCPT ); Tue, 7 Jul 2015 01:48:06 -0400 X-Helo: d23dlp03.au.ibm.com X-MailFrom: imunsie@au1.ibm.com X-RcptTo: linux-kernel@vger.kernel.org From: "Ian Munsie" To: mpe Cc: mikey , linux-kernel , linuxppc-dev , Matt Ochs , Ian Munsie Subject: [PATCH 2/2] cxl: Fail mmap if requested mapping is larger than assigned problem state area Date: Tue, 7 Jul 2015 15:45:46 +1000 Message-Id: <1436247946-16292-2-git-send-email-imunsie@au.ibm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436247946-16292-1-git-send-email-imunsie@au.ibm.com> References: <1436247946-16292-1-git-send-email-imunsie@au.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15070705-0013-0000-0000-0000018193F1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1859 Lines: 49 From: Ian Munsie This patch makes the mmap call fail outright if the requested region is larger than the problem state area assigned to the context so the error is reported immediately rather than waiting for an attempt to access an address out of bounds. Although we never expect users to map more than the assigned problem state area and are not aware of anyone doing this (other than for testing), this does have the potential to break users if someone has used a larger range regardless. I'm submitting it for consideration, but if this change is not considered acceptable the previous patch is sufficient to prevent access out of bounds without breaking anyone. Signed-off-by: Ian Munsie --- drivers/misc/cxl/context.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c index 6c1ce51..1287148 100644 --- a/drivers/misc/cxl/context.c +++ b/drivers/misc/cxl/context.c @@ -145,8 +145,16 @@ static const struct vm_operations_struct cxl_mmap_vmops = { */ int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) { + u64 start = vma->vm_pgoff << PAGE_SHIFT; u64 len = vma->vm_end - vma->vm_start; - len = min(len, ctx->psn_size); + + if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { + if (start + len > ctx->afu->adapter->ps_size) + return -EINVAL; + } else { + if (start + len > ctx->psn_size) + return -EINVAL; + } if (ctx->afu->current_mode != CXL_MODE_DEDICATED) { /* make sure there is a valid per process space for this AFU */ -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/