From patchwork Thu Jan 16 08:30:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: YunQiang Su X-Patchwork-Id: 11336363 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DABB8921 for ; Thu, 16 Jan 2020 08:30:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6363206E6 for ; Thu, 16 Jan 2020 08:30:58 +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="Fggrzmcf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731036AbgAPIav (ORCPT ); Thu, 16 Jan 2020 03:30:51 -0500 Received: from mail-pj1-f65.google.com ([209.85.216.65]:52698 "EHLO mail-pj1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726230AbgAPIav (ORCPT ); Thu, 16 Jan 2020 03:30:51 -0500 Received: by mail-pj1-f65.google.com with SMTP id a6so1202585pjh.2; Thu, 16 Jan 2020 00:30:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=PRD6aeufLSd46od9AzCBC//aqtaStUZLDGOKGtSVPRE=; b=FggrzmcfUxGIJSa3geWjNxYL4+CEFhT7P/fxy7SEYin7E8xeo3A9XygBO9kjb2n0E+ gVwbZbyE6Mvar8FK2QVTSKXxQ6j/pwH8YZH/hjhKFjIfEjJc2T4b5e42PhZRuU/4mZyc YYi6c5eIi94a3DvgGQoIEElGlCWiJ1YQdXrhVRvO+TwLFfd/9/jqWep7s/pmc3CrC+3m wV7xy1FvASlYZRH/7a/zyVP8guxAn+z3JPu2ay67O9EszexVbVmypIAgJzSZJG+6AB8n hfBZGZMqgfj9PYEso1aQ+Rzas4r6mJu+OXVG3OOmgTbd4bnsnD21bDN5KZr3UVEbD3FP W2BA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=PRD6aeufLSd46od9AzCBC//aqtaStUZLDGOKGtSVPRE=; b=RsNoa6EPFBQWXhOwIRshsXSdE+H1pqPpVGuAxB1Oi2XjikJzPa5SfcipWQ7x4RJmIR osexnV5dXH50HWf5aQ7VWPuzUAHxTTYdraFS44oLHfVZkrnESmU+iV6JOZh8+CcY6Y8f eJR4az/jvqqAixdXfohaeSTF5OqHshnqihs6uH496lYycK7+boJxqHUIheaGyfThMvSq WIOwYZtFSDgemv6/DoPdKd0rzJ4d3beNTE8TINyoaSj7Dt8jy0hLzb8ise9io+4TkLe6 0PVFH24S8p0YhXMrhvd1xO4JKuYAXEPjhQe2WQstRx+5d9tgm6jcLkRQrwtfl8vjONz+ SzGQ== X-Gm-Message-State: APjAAAUyTg2pI2u1xTfkkgHWhwt+K39P/LYlrtF8XeBxPxAQjoSDJ4Ag HLPCJ2K7JAJA9FsKEkjdmvv8PNmK6freWw== X-Google-Smtp-Source: APXvYqweeOU4USwlRuwhMJ38zJ0vYKCTyawhwg7skQD3cW4OokmktruOFDl7FFPKS4Hg3FkZEK4TYA== X-Received: by 2002:a17:90a:c78f:: with SMTP id gn15mr5534469pjb.88.1579163450116; Thu, 16 Jan 2020 00:30:50 -0800 (PST) Received: from xps.lan ([103.125.232.133]) by smtp.gmail.com with ESMTPSA id l10sm2509108pjy.5.2020.01.16.00.30.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Jan 2020 00:30:49 -0800 (PST) From: YunQiang Su To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, James.Bottomley@hansenpartnership.com, viro@zeniv.linux.org.uk, laurent@vivier.eu Cc: YunQiang Su Subject: [PATCH v3] binfmt_misc: pass info about P flag by AT_FLAGS Date: Thu, 16 Jan 2020 16:30:31 +0800 Message-Id: <20200116083031.174367-1-syq@debian.org> X-Mailer: git-send-email 2.25.0.rc1 MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: YunQiang Su Currently program invoked by binfmt_misc cannot be aware about whether P flag, aka preserve path is enabled. Some applications like qemu need to know since it has 2 use case: 1. call by hand, like: qemu-mipsel-static test.app OPTION so, qemu have to assume that P option is not enabled. 2. call by binfmt_misc. If qemu cannot know about whether P flag is enabled, distribution's have to set qemu without P flag, and binfmt_misc call qemu like: qemu-mipsel-static /absolute/path/to/test.app OPTION even test.app is not called by absoulute path, like ./relative/path/to/test.app This patch passes this information by the 0st bits of unused AT_FLAGS. Then, in qemu, we can get this info by: getauxval(AT_FLAGS) & (1<<0) v2->v3: define a new AT_FLAGS_PRESERVE_ARGV0 as (1<<0), so now we use 0st bit. v1->v2: not enable kdebug See: https://bugs.launchpad.net/qemu/+bug/1818483 Signed-off-by: YunQiang Su --- fs/binfmt_elf.c | 6 +++++- fs/binfmt_elf_fdpic.c | 6 +++++- fs/binfmt_misc.c | 2 ++ include/linux/binfmts.h | 4 ++++ 4 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index f4713ea76e82..c4efff74223f 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -178,6 +178,7 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec, unsigned char k_rand_bytes[16]; int items; elf_addr_t *elf_info; + elf_addr_t flags = 0; int ei_index; const struct cred *cred = current_cred(); struct vm_area_struct *vma; @@ -252,7 +253,10 @@ create_elf_tables(struct linux_binprm *bprm, const 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 |= AT_FLAGS_PRESERVE_ARGV0; + } + NEW_AUX_ENT(AT_FLAGS, flags); NEW_AUX_ENT(AT_ENTRY, 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..c89a4630efad 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 = 0; #ifdef CONFIG_MMU /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions @@ -647,7 +648,10 @@ 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 |= 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..cb14e9bbf00f 100644 --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -158,6 +158,8 @@ static int load_misc_binary(struct linux_binprm *bprm) retval = remove_arg_zero(bprm); if (retval) goto ret; + } else { + bprm->interp_flags |= AT_FLAGS_PRESERVE_ARGV0; } if (fmt->flags & MISC_FMT_OPEN_BINARY) { diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index b40fc633f3be..380a30a46db1 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) +/* 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) + /* Function parameter for binfmt->coredump */ struct coredump_params { const kernel_siginfo_t *siginfo;