From patchwork Tue Apr 13 05:40:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 12199335 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-21.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80948C433B4 for ; Tue, 13 Apr 2021 05:40:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 45C51613AB for ; Tue, 13 Apr 2021 05:40:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244341AbhDMFko (ORCPT ); Tue, 13 Apr 2021 01:40:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:39836 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243886AbhDMFkl (ORCPT ); Tue, 13 Apr 2021 01:40:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id DA875613AB; Tue, 13 Apr 2021 05:40:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618292422; bh=dVfQkEO1IbU3P1W9XYPvjX7BmEpF8KIVJeuVWtWiFJ4=; h=Date:From:To:Cc:Subject:From; b=LBvAnMAXGJlN+xhWL5FeGhoY7ftkVYZI93KIAhjYaciVHg8ORSCCEBThph20cMj6J +5shrIQ7xt6fmNDs017t9BITTCrFj45bJQtSBliVd2tYTFsfvuHvuMRf4jfTB5eTKR QDsFgzwYuHsnf9q5sxgvN0R5++PmPM5OqH3XXYhFLU4Ro1ft0rHaG/UruARiJ7N4dU K7MPxodnY9oLZrWpjF9MZSBNutCCC9pAQqjY1ZwGDqqWT+d6tdm8rvnclTLr1knVS+ r1OgmNzM8DRpvu8BPVdJ6gTEOytbYp1mPTPIF1NEuKpHVdKOKJGEPQBvSuhDtTWQ93 tcaMXeyz/fDfg== Date: Tue, 13 Apr 2021 00:40:32 -0500 From: "Gustavo A. R. Silva" To: Adaptec OEM Raid Solutions , "James E.J. Bottomley" , "Martin K. Petersen" Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org, Kees Cook Subject: [PATCH v2][next] scsi: aacraid: Replace one-element array with flexible-array member Message-ID: <20210413054032.GA276102@embeddedor> MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Refactor the code according to the use of a flexible-array member in struct aac_raw_io2 instead of one-element array, and use the struct_size() and flex_array_size() helpers. Also, this helps with the ongoing efforts to enable -Warray-bounds by fixing the following warnings: drivers/scsi/aacraid/aachba.c: In function ‘aac_build_sgraw2’: drivers/scsi/aacraid/aachba.c:3970:18: warning: array subscript 1 is above array bounds of ‘struct sge_ieee1212[1]’ [-Warray-bounds] 3970 | if (rio2->sge[j].length % (i*PAGE_SIZE)) { | ~~~~~~~~~^~~ drivers/scsi/aacraid/aachba.c:3974:27: warning: array subscript 1 is above array bounds of ‘struct sge_ieee1212[1]’ [-Warray-bounds] 3974 | nseg_new += (rio2->sge[j].length / (i*PAGE_SIZE)); | ~~~~~~~~~^~~ drivers/scsi/aacraid/aachba.c:4011:28: warning: array subscript 1 is above array bounds of ‘struct sge_ieee1212[1]’ [-Warray-bounds] 4011 | for (j = 0; j < rio2->sge[i].length / (pages * PAGE_SIZE); ++j) { | ~~~~~~~~~^~~ drivers/scsi/aacraid/aachba.c:4012:24: warning: array subscript 1 is above array bounds of ‘struct sge_ieee1212[1]’ [-Warray-bounds] 4012 | addr_low = rio2->sge[i].addrLow + j * pages * PAGE_SIZE; | ~~~~~~~~~^~~ drivers/scsi/aacraid/aachba.c:4014:33: warning: array subscript 1 is above array bounds of ‘struct sge_ieee1212[1]’ [-Warray-bounds] 4014 | sge[pos].addrHigh = rio2->sge[i].addrHigh; | ~~~~~~~~~^~~ drivers/scsi/aacraid/aachba.c:4015:28: warning: array subscript 1 is above array bounds of ‘struct sge_ieee1212[1]’ [-Warray-bounds] 4015 | if (addr_low < rio2->sge[i].addrLow) | ~~~~~~~~~^~~ [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/109 Build-tested-by: kernel test robot Link: https://lore.kernel.org/lkml/60414244.ur4%2FkI+fBF1ohKZs%25lkp@intel.com/ Signed-off-by: Gustavo A. R. Silva --- Changes in v2: - Add code comment for clarification. drivers/scsi/aacraid/aachba.c | 17 +++++++++++------ drivers/scsi/aacraid/aacraid.h | 2 +- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/scsi/aacraid/aachba.c b/drivers/scsi/aacraid/aachba.c index 8e06604370c4..2816a15d5633 100644 --- a/drivers/scsi/aacraid/aachba.c +++ b/drivers/scsi/aacraid/aachba.c @@ -1235,8 +1235,8 @@ static int aac_read_raw_io(struct fib * fib, struct scsi_cmnd * cmd, u64 lba, u3 if (ret < 0) return ret; command = ContainerRawIo2; - fibsize = sizeof(struct aac_raw_io2) + - ((le32_to_cpu(readcmd2->sgeCnt)-1) * sizeof(struct sge_ieee1212)); + fibsize = struct_size(readcmd2, sge, + le32_to_cpu(readcmd2->sgeCnt)); } else { struct aac_raw_io *readcmd; readcmd = (struct aac_raw_io *) fib_data(fib); @@ -1366,8 +1366,8 @@ static int aac_write_raw_io(struct fib * fib, struct scsi_cmnd * cmd, u64 lba, u if (ret < 0) return ret; command = ContainerRawIo2; - fibsize = sizeof(struct aac_raw_io2) + - ((le32_to_cpu(writecmd2->sgeCnt)-1) * sizeof(struct sge_ieee1212)); + fibsize = struct_size(writecmd2, sge, + le32_to_cpu(writecmd2->sgeCnt)); } else { struct aac_raw_io *writecmd; writecmd = (struct aac_raw_io *) fib_data(fib); @@ -4003,7 +4003,7 @@ static int aac_convert_sgraw2(struct aac_raw_io2 *rio2, int pages, int nseg, int if (aac_convert_sgl == 0) return 0; - sge = kmalloc_array(nseg_new, sizeof(struct sge_ieee1212), GFP_ATOMIC); + sge = kmalloc_array(nseg_new, sizeof(*sge), GFP_ATOMIC); if (sge == NULL) return -ENOMEM; @@ -4020,7 +4020,12 @@ static int aac_convert_sgraw2(struct aac_raw_io2 *rio2, int pages, int nseg, int } } sge[pos] = rio2->sge[nseg-1]; - memcpy(&rio2->sge[1], &sge[1], (nseg_new-1)*sizeof(struct sge_ieee1212)); + /* + * Notice that, in this case, flex_array_size() evaluates to + * (nseg_new - 1) number of sge objects of type struct sge_ieee1212. + */ + memcpy(&rio2->sge[1], &sge[1], + flex_array_size(rio2, sge, nseg_new - 1)); kfree(sge); rio2->sgeCnt = cpu_to_le32(nseg_new); diff --git a/drivers/scsi/aacraid/aacraid.h b/drivers/scsi/aacraid/aacraid.h index e3e4ecbea726..3733df77bc65 100644 --- a/drivers/scsi/aacraid/aacraid.h +++ b/drivers/scsi/aacraid/aacraid.h @@ -1929,7 +1929,7 @@ struct aac_raw_io2 { u8 bpComplete; /* reserved for F/W use */ u8 sgeFirstIndex; /* reserved for F/W use */ u8 unused[4]; - struct sge_ieee1212 sge[1]; + struct sge_ieee1212 sge[]; }; #define CT_FLUSH_CACHE 129