From patchwork Fri Jun 3 12:52:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stefan Liebler X-Patchwork-Id: 54777 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id F421D38207D7 for ; Fri, 3 Jun 2022 12:53:21 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F421D38207D7 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1654260802; bh=nAfS8lZbuH22QNQCKeXC9NU0xciwEl777XDrSMOEiDw=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:Cc:From; b=Xpe4uuTiZlliIt/YIFj5fz+AQt3bWm7/uHriB9ODBvkDH5H8X8XfQVHX47RuoMy00 pF150ZeIPI1TBa8h2jpuucwODkdwNUaYVLSIgaNpyxd9Fuxvg49qwxCAqRLzfPc582 h9uf4OJG1q+x/I3KAkZZHD273V6z1EoufvoHc6DE= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by sourceware.org (Postfix) with ESMTPS id 3929938207CD for ; Fri, 3 Jun 2022 12:53:00 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 3929938207CD Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 253AjxZR010234 for ; Fri, 3 Jun 2022 12:52:59 GMT Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3gfgu723tb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 03 Jun 2022 12:52:58 +0000 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 253CpMTr011133 for ; Fri, 3 Jun 2022 12:52:56 GMT Received: from b06avi18878370.portsmouth.uk.ibm.com (b06avi18878370.portsmouth.uk.ibm.com [9.149.26.194]) by ppma06ams.nl.ibm.com with ESMTP id 3gf40prvr4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 03 Jun 2022 12:52:56 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 253Cqsff20644258 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 3 Jun 2022 12:52:54 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 89569A404D; Fri, 3 Jun 2022 12:52:53 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 69C03A4040; Fri, 3 Jun 2022 12:52:53 +0000 (GMT) Received: from t3560004.lnxne.boe (unknown [9.152.108.100]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 3 Jun 2022 12:52:53 +0000 (GMT) To: libc-alpha@sourceware.org Subject: [PATCH] Avoid -Wstringop-overflow= warning in iconv module. Date: Fri, 3 Jun 2022 14:52:51 +0200 Message-Id: <20220603125251.3903158-1-stli@linux.ibm.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: e0x-Ugtbu0ibU1fWMQBDA1FgCNfv5Qmm X-Proofpoint-GUID: e0x-Ugtbu0ibU1fWMQBDA1FgCNfv5Qmm X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.517,FMLib:17.11.64.514 definitions=2022-06-03_04,2022-06-03_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 malwarescore=0 phishscore=0 mlxlogscore=697 suspectscore=0 spamscore=0 impostorscore=0 adultscore=0 priorityscore=1501 mlxscore=0 clxscore=1011 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2204290000 definitions=main-2206030054 X-Spam-Status: No, score=-10.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Stefan Liebler via Libc-alpha From: Stefan Liebler Reply-To: Stefan Liebler Cc: Stefan Liebler Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" On s390x when compiling with GCC 12, I get this warning: utf8-utf16-z9.c: ../iconv/loop.c: In function ‘__from_utf8_loop_etf3eh_single’: ../iconv/loop.c:445:22: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=] 445 | bytebuf[inlen++] = *inptr++; | ~~~~~~~~~~~~~~~~~^~~~~~~~~~ ../iconv/loop.c:381:17: note: at offset 4 into destination object ‘bytebuf’ of size 4 381 | unsigned char bytebuf[MAX_NEEDED_INPUT]; | ^~~~~~~ ../iconv/loop.c:445:22: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=] 445 | bytebuf[inlen++] = *inptr++; | ~~~~~~~~~~~~~~~~~^~~~~~~~~~ ../iconv/loop.c:381:17: note: at offset 5 into destination object ‘bytebuf’ of size 4 381 | unsigned char bytebuf[MAX_NEEDED_INPUT]; | ^~~~~~~ This patch tells the compiler that inend is always behind inptr which avoids the warning. Note that the SINGLE function is only used to implement the mb*towc*() or wc*tomb*() functions. Those functions use inptr and inend pointing to a variable on stack, compute the inend pointer or explicitly check the arguments which always leads to inptr < inend. Reviewed-by: Siddhesh Poyarekar --- iconv/loop.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/iconv/loop.c b/iconv/loop.c index f8727a637a..09ade3b765 100644 --- a/iconv/loop.c +++ b/iconv/loop.c @@ -435,11 +435,17 @@ SINGLE(LOOPFCT) (struct __gconv_step *step, return __GCONV_FULL_OUTPUT; /* Now add characters from the normal input buffer. */ - if (inlen >= MAX_NEEDED_INPUT) + if (inlen >= MAX_NEEDED_INPUT || inptr >= inend) /* Avoid a -Wstringop-overflow= warning when this loop is unrolled. The compiler cannot otherwise see that this is unreachable because it depends on (state->__count & 7) not - being too large after a previous conversion step. */ + being too large after a previous conversion step. + Starting with GCC 12, we also have mark the inptr >= inend + case as unreachable to omit the warning. Note that this SINGLE + function is only used to implement the mb*towc*() or wc*tomb*() + functions. Those functions use inptr and inend pointing to a + variable on stack, compute the inend pointer or explicitly check + the arguments which always leads to inptr < inend. */ __builtin_unreachable (); do bytebuf[inlen++] = *inptr++;