From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 7D5E43858D1E for ; Thu, 7 Sep 2023 12:25:53 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 7D5E43858D1E Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694089553; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=t8lGqCyQwCH0TmYXVaPLBlD+oUFY7yIc3384pcXomIg=; b=PhjQ48l8rG7nOnWjoxA38zeqi/OUXsbtNgcibzFXdCocsUEPWb/9GLmo5bXEk2wMmMHtyj ER7bvkhK0KnWY8LC57m3Bekolvv8y5buWDE5iEJR5H94MmW4oUftCsv3SpSAU+qQ0qOR31 EMgojdRhuxseAilkbMKqk8+Vate618g= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-122-QbCJ8qIbOLOm7snBjVRMsg-1; Thu, 07 Sep 2023 08:25:51 -0400 X-MC-Unique: QbCJ8qIbOLOm7snBjVRMsg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 748BB381CBFD for ; Thu, 7 Sep 2023 12:25:51 +0000 (UTC) Received: from oak (unknown [10.22.33.147]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5DCD5493112 for ; Thu, 7 Sep 2023 12:25:51 +0000 (UTC) Date: Thu, 7 Sep 2023 08:25:50 -0400 From: Joe Simmons-Talbott To: libc-alpha@sourceware.org Subject: Re: [PATCH v3] mips: dl-machine-reject-phdr: Get rid of alloca. Message-ID: <20230907122550.GL3849957@oak> References: <20230626131621.763381-1-josimmon@redhat.com> <20230829193019.GD3849957@oak> MIME-Version: 1.0 In-Reply-To: <20230829193019.GD3849957@oak> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-12.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Ping for review. On Tue, Aug 29, 2023 at 03:30:19PM -0400, Joe Simmons-Talbott via Libc-alpha wrote: > Ping. > > On Mon, Jun 26, 2023 at 09:16:21AM -0400, Joe Simmons-Talbott wrote: > > Read directly into the mips_abiflags struct rather than reading the > > entire segment and using alloca when the passed buffer is not big enough. > > > > Checked with build-many-glibcs.py on mips-linux-gnu > > --- > > Changes to v2: > > * Rather than use a scratch buffer use the mips_abiflags struct itself > > for reading since we're now just reading that much data and not the > > whole segment. > > > > sysdeps/mips/dl-machine-reject-phdr.h | 26 ++++++++++---------------- > > 1 file changed, 10 insertions(+), 16 deletions(-) > > > > diff --git a/sysdeps/mips/dl-machine-reject-phdr.h b/sysdeps/mips/dl-machine-reject-phdr.h > > index 104b590661..b784697fc1 100644 > > --- a/sysdeps/mips/dl-machine-reject-phdr.h > > +++ b/sysdeps/mips/dl-machine-reject-phdr.h > > @@ -161,7 +161,7 @@ elf_machine_reject_phdr_p (const ElfW(Phdr) *phdr, unsigned int phnum, > > Lmid_t nsid; > > int in_abi = -1; > > struct abi_req in_req; > > - Elf_MIPS_ABIFlags_v0 *mips_abiflags = NULL; > > + Elf_MIPS_ABIFlags_v0 mips_abiflags; > > bool perfect_match = false; > > #if _MIPS_SIM == _ABIO32 > > unsigned int cur_mode = -1; > > @@ -176,25 +176,19 @@ elf_machine_reject_phdr_p (const ElfW(Phdr) *phdr, unsigned int phnum, > > /* Read the attributes section. */ > > if (ph != NULL) > > { > > - ElfW(Addr) size = ph->p_filesz; > > + ElfW(Addr) size = sizeof (Elf_MIPS_ABIFlags_v0); > > > > - if (ph->p_offset + size <= len) > > - mips_abiflags = (Elf_MIPS_ABIFlags_v0 *) (buf + ph->p_offset); > > - else > > - { > > - mips_abiflags = alloca (size); > > - __lseek (fd, ph->p_offset, SEEK_SET); > > - if (__libc_read (fd, (void *) mips_abiflags, size) != size) > > - REJECT (" unable to read PT_MIPS_ABIFLAGS\n"); > > - } > > - > > - if (size < sizeof (Elf_MIPS_ABIFlags_v0)) > > + if (ph->p_filesz < size) > > REJECT (" contains malformed PT_MIPS_ABIFLAGS\n"); > > > > - if (__glibc_unlikely (mips_abiflags->flags2 != 0)) > > - REJECT (" unknown MIPS.abiflags flags2: %u\n", mips_abiflags->flags2); > > + __lseek (fd, ph->p_offset, SEEK_SET); > > + if (__libc_read (fd, (void *) &mips_abiflags, size) != size) > > + REJECT (" unable to read PT_MIPS_ABIFLAGS\n"); > > + > > + if (__glibc_unlikely (mips_abiflags.flags2 != 0)) > > + REJECT (" unknown MIPS.abiflags flags2: %u\n", mips_abiflags.flags2); > > > > - in_abi = mips_abiflags->fp_abi; > > + in_abi = mips_abiflags.fp_abi; > > } > > > > /* ANY is compatible with anything. */ > > -- > > 2.39.2 > > >