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 [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 389D93858D20 for ; Tue, 29 Aug 2023 19:30:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 389D93858D20 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=1693337422; 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=LiN805Itx5EUt37CWAhxQDtOEqmTUkQVW3HiejR9WAU=; b=Z6GWVbNOx9c0x1B94k45yoNlboF42ktwp8Vnt9R2NXgiVRu4kWHoW2zu+vOJilAmLumh4a sVLEgHox94XKlkP47gV/YnCkxU3SxvFvacCp606xgZytSWP38KI14kA3t/XI2d7464USU1 5LDZMSbCzXv6V0smXiw7nEJabK8xrAc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-417-ljIuDVuyOSmlf6la6LABog-1; Tue, 29 Aug 2023 15:30:21 -0400 X-MC-Unique: ljIuDVuyOSmlf6la6LABog-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 442AF8022E4 for ; Tue, 29 Aug 2023 19:30:21 +0000 (UTC) Received: from oak (unknown [10.22.33.147]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2E2A41121318 for ; Tue, 29 Aug 2023 19:30:21 +0000 (UTC) Date: Tue, 29 Aug 2023 15:30:19 -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: <20230829193019.GD3849957@oak> References: <20230626131621.763381-1-josimmon@redhat.com> MIME-Version: 1.0 In-Reply-To: <20230626131621.763381-1-josimmon@redhat.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 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=-11.8 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_H4,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. 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 >