From mboxrd@z Thu Jan 1 00:00:00 1970 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=-11.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 7159BC4BA24 for ; Thu, 27 Feb 2020 07:28:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A1CE20714 for ; Thu, 27 Feb 2020 07:28:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="JP8igOlv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728438AbgB0H2C (ORCPT ); Thu, 27 Feb 2020 02:28:02 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:46125 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726999AbgB0H2B (ORCPT ); Thu, 27 Feb 2020 02:28:01 -0500 Received: by mail-pl1-f193.google.com with SMTP id y8so763178pll.13; Wed, 26 Feb 2020 23:28:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:message-id:subject:from:to:cc:date:in-reply-to:references :user-agent:mime-version; bh=+zGRKeshGQVlukDljqkxIhhlnNK1OHi6NOTC6bZRBxo=; b=JP8igOlvXFF2xXwFwX+mRVJiEE0HmlLHlKW8JEb9cytUu7VTngW2naempp5+JdSg0/ NjVVpHCqKlKD9XRnPH04dKw7Rzx8T10ltZuOwIQU4cMSrpt56cFsG4nut+YmSFjqRzuj to0SWE+umdk+sKkiz8UdoaoAHTN3UtOxJ3pA/jfs7cYCmGvHWVaVlJ+BEsGiQGiZjTPw ITQ7CnoyhlplFgcqebyXAA4r8invMgaA1YyfHxTWQPiXw9J9k9DRiAl5jWUX/NQUqIwO WLk+hW0TNe9r8d3Lg3lPn5G/jJd+U1REbyNLmps1sX6+jn6qrt6Zd9pKt5p8UrLi7eMN 4ceA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:message-id:subject:from:to:cc:date :in-reply-to:references:user-agent:mime-version; bh=+zGRKeshGQVlukDljqkxIhhlnNK1OHi6NOTC6bZRBxo=; b=JxalxasN6xAJ0YXpl9/PxUDmQPMnDuoFP4IFzVeSwfaRI2YKwK1JznSoXtZJz+283u wOKKRE3k5MtV5nB5DuwNuTSLFpdzjt2KPYTMBOEfUDVQV7UfpBSz02h/G+UiFGdeRy+1 WoHWb2JPupOwKLCP6bTt5+Da1HLRhpL89hKxW56RAb4/hjgCa5zUwB3LHBqXOBqmt9cq YJ+Co0Qkx3qdC+foxOuE847P79YdBiykzkyliTvhxFG4ffm7aqivQIdM+QLrk1hHq1lv VGA4reIO6z8EN92LysjUVJ7Plt3RJIZS7rkB0Z0iwSu8HbSu4qEtioo/BhutiI6FOpTL 1pLQ== X-Gm-Message-State: APjAAAU13nZZujZ0VGSKfUh/XiNBT3t1/uQTI6iTSNr8I2EFJcqH44AD xX4uLfGBwSo8t0kDNCVhhOUSplYGHKA= X-Google-Smtp-Source: APXvYqy8C3dfbOK2+toq1qT1z8gRW1E2cC05j1CEnvqbG5oF1+ox2Uh17JXJtOjvITXurKlGPn5r7w== X-Received: by 2002:a17:902:8204:: with SMTP id x4mr3147029pln.225.1582788479986; Wed, 26 Feb 2020 23:27:59 -0800 (PST) Received: from xps ([103.125.232.133]) by smtp.gmail.com with ESMTPSA id r66sm6061240pfc.74.2020.02.26.23.27.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Feb 2020 23:27:59 -0800 (PST) Message-ID: Subject: Re: [PATCH v3] binfmt_misc: pass binfmt_misc flags to the interpreter From: YunQiang Su To: Laurent Vivier , linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, Alexander Viro , James Bottomley , libc-alpha@sourceware.org Date: Thu, 27 Feb 2020 15:27:43 +0800 In-Reply-To: <20200128132539.782286-1-laurent@vivier.eu> References: <20200128132539.782286-1-laurent@vivier.eu> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-zE24wshRpe0xR3T9LNGS" User-Agent: Evolution 3.34.1-4 MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-zE24wshRpe0xR3T9LNGS Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =E5=9C=A8 2020-01-28=E4=BA=8C=E7=9A=84 14:25 +0100=EF=BC=8CLaurent Vivier= =E5=86=99=E9=81=93=EF=BC=9A > It can be useful to the interpreter to know which flags are in use. >=20 > For instance, knowing if the preserve-argv[0] is in use would > allow to skip the pathname argument. >=20 > This patch uses an unused auxiliary vector, AT_FLAGS, to add a > flag to inform interpreter if the preserve-argv[0] is enabled. CC: libc-alpha. I guess we need some review from libc people. >=20 > Signed-off-by: Laurent Vivier > --- >=20 > Notes: > This can be tested with QEMU from my branch: > =20 > https://github.com/vivier/qemu/commits/binfmt-argv0 > =20 > With something like: > =20 > # cp ..../qemu-ppc /chroot/powerpc/jessie > =20 > # qemu-binfmt-conf.sh --qemu-path / --systemd ppc --credential > yes \ > --persistent no --preserve-argv0 yes > # systemctl restart systemd-binfmt.service > # cat /proc/sys/fs/binfmt_misc/qemu-ppc > enabled > interpreter //qemu-ppc > flags: POC > offset 0 > magic 7f454c4601020100000000000000000000020014 > mask ffffffffffffff00fffffffffffffffffffeffff > # chroot /chroot/powerpc/jessie sh -c 'echo $0' > sh > =20 > # qemu-binfmt-conf.sh --qemu-path / --systemd ppc --credential > yes \ > --persistent no --preserve-argv0 no > # systemctl restart systemd-binfmt.service > # cat /proc/sys/fs/binfmt_misc/qemu-ppc > enabled > interpreter //qemu-ppc > flags: OC > offset 0 > magic 7f454c4601020100000000000000000000020014 > mask ffffffffffffff00fffffffffffffffffffeffff > # chroot /chroot/powerpc/jessie sh -c 'echo $0' > /bin/sh > =20 > v3: mix my patch with one from YunQiang Su and my comments on it > introduce a new flag in the uabi for the AT_FLAGS > v2: only pass special flags (remove Magic and Enabled flags) >=20 > fs/binfmt_elf.c | 5 ++++- > fs/binfmt_elf_fdpic.c | 5 ++++- > fs/binfmt_misc.c | 4 +++- > include/linux/binfmts.h | 4 ++++ > include/uapi/linux/binfmts.h | 4 ++++ > 5 files changed, 19 insertions(+), 3 deletions(-) >=20 > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index ecd8d2698515..ff918042ceed 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -176,6 +176,7 @@ create_elf_tables(struct linux_binprm *bprm, > struct elfhdr *exec, > unsigned char k_rand_bytes[16]; > int items; > elf_addr_t *elf_info; > + elf_addr_t flags =3D 0; > int ei_index =3D 0; > const struct cred *cred =3D current_cred(); > struct vm_area_struct *vma; > @@ -250,7 +251,9 @@ create_elf_tables(struct linux_binprm *bprm, > struct elfhdr *exec, > NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr)); > NEW_AUX_ENT(AT_PHNUM, exec->e_phnum); > NEW_AUX_ENT(AT_BASE, interp_load_addr); > - NEW_AUX_ENT(AT_FLAGS, 0); > + if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0) > + flags |=3D AT_FLAGS_PRESERVE_ARGV0; > + NEW_AUX_ENT(AT_FLAGS, flags); > NEW_AUX_ENT(AT_ENTRY, exec->e_entry); > NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred- > >uid)); > NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred- > >euid)); > diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c > index 240f66663543..abb90d82aa58 100644 > --- a/fs/binfmt_elf_fdpic.c > +++ b/fs/binfmt_elf_fdpic.c > @@ -507,6 +507,7 @@ static int create_elf_fdpic_tables(struct > linux_binprm *bprm, > char __user *u_platform, *u_base_platform, *p; > int loop; > int nr; /* reset for each csp adjustment */ > + unsigned long flags =3D 0; > =20 > #ifdef CONFIG_MMU > /* In some cases (e.g. Hyper-Threading), we want to avoid L1 > evictions > @@ -647,7 +648,9 @@ static int create_elf_fdpic_tables(struct > linux_binprm *bprm, > NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr)); > NEW_AUX_ENT(AT_PHNUM, exec_params->hdr.e_phnum); > NEW_AUX_ENT(AT_BASE, interp_params->elfhdr_addr); > - NEW_AUX_ENT(AT_FLAGS, 0); > + if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0) > + flags |=3D AT_FLAGS_PRESERVE_ARGV0; > + NEW_AUX_ENT(AT_FLAGS, flags); > NEW_AUX_ENT(AT_ENTRY, exec_params->entry_addr); > NEW_AUX_ENT(AT_UID, (elf_addr_t) from_kuid_munged(cred- > >user_ns, cred->uid)); > NEW_AUX_ENT(AT_EUID, (elf_addr_t) from_kuid_munged(cred- > >user_ns, cred->euid)); > diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c > index cdb45829354d..b9acdd26a654 100644 > --- a/fs/binfmt_misc.c > +++ b/fs/binfmt_misc.c > @@ -154,7 +154,9 @@ static int load_misc_binary(struct linux_binprm > *bprm) > if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) > goto ret; > =20 > - if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { > + if (fmt->flags & MISC_FMT_PRESERVE_ARGV0) { > + bprm->interp_flags |=3D BINPRM_FLAGS_PRESERVE_ARGV0; > + } else { > retval =3D remove_arg_zero(bprm); > if (retval) > goto ret; > diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h > index b40fc633f3be..265b80d5fd6f 100644 > --- a/include/linux/binfmts.h > +++ b/include/linux/binfmts.h > @@ -78,6 +78,10 @@ struct linux_binprm { > #define BINPRM_FLAGS_PATH_INACCESSIBLE_BIT 2 > #define BINPRM_FLAGS_PATH_INACCESSIBLE (1 << > BINPRM_FLAGS_PATH_INACCESSIBLE_BIT) > =20 > +/* if preserve the argv0 for the interpreter */ > +#define BINPRM_FLAGS_PRESERVE_ARGV0_BIT 3 > +#define BINPRM_FLAGS_PRESERVE_ARGV0 (1 << > BINPRM_FLAGS_PRESERVE_ARGV0_BIT) > + > /* Function parameter for binfmt->coredump */ > struct coredump_params { > const kernel_siginfo_t *siginfo; > diff --git a/include/uapi/linux/binfmts.h > b/include/uapi/linux/binfmts.h > index 689025d9c185..a70747416130 100644 > --- a/include/uapi/linux/binfmts.h > +++ b/include/uapi/linux/binfmts.h > @@ -18,4 +18,8 @@ struct pt_regs; > /* sizeof(linux_binprm->buf) */ > #define BINPRM_BUF_SIZE 256 > =20 > +/* if preserve the argv0 for the interpreter */ > +#define AT_FLAGS_PRESERVE_ARGV0_BIT 0 > +#define AT_FLAGS_PRESERVE_ARGV0 (1 << AT_FLAGS_PRESERVE_ARGV0_BIT) > + > #endif /* _UAPI_LINUX_BINFMTS_H */ --=-zE24wshRpe0xR3T9LNGS Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEET3MbhxKET+7/a6zdW0gHVdEZ6o4FAl5Xb28ACgkQW0gHVdEZ 6o5PCgf+IhNRA4aou8ifw13gYlx/VqRW+7x1bIxFdRzNhhpSKkCGMvzKrZdq5rUA S+9PUa+MHBGrMwO8n+izBDF9Sj9G1p/9rJp7MoYbBHceZxeXWdFrDNMQ+dXIWiJQ IN8EGIOhRco+Gzf59zZZhB9WjHRBK7R23sk9h57esS6+KQiomREc3UoeioXSmYoZ sYDt+ooTDFl2QlmJC7CKzXNk7EPIQYnzGrO1DpN1icCcSSvMNYzCfG2+AIfmyJOc Lz+GVXAWne/T6yJKFa3wzsqwkkJ0qg6792vLP9ieMkbQMjD/T/eTGPfhFHqIbQUA uQhaIxAErGmi2/1KFAVTYiEerUG9Sw== =qjWv -----END PGP SIGNATURE----- --=-zE24wshRpe0xR3T9LNGS--