From patchwork Thu Feb 27 17:44:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 11409081 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 8253C13A4 for ; Thu, 27 Feb 2020 17:45:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61B01246AC for ; Thu, 27 Feb 2020 17:45:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582825507; bh=hBm1jtUcPbUO116OfaNCZ6UsniImm+mLLu76+p5Zu6c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CzcutV7rV7XCrZQvf4sgTk3odyrrimZOr4+eRtszJE5KEMHTWs8T4FvGVyIK2eKCt uWXDOyhgtNojMgTC3VtHZYW9vDTW7RCEGtg5H4NS7yMUWAJ8Q9CObX77BXW2UJlHNC 0NqgP9REGsCFh/z9BPyNdV9bmg/PLXkjuybPlBVI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730612AbgB0Roc (ORCPT ); Thu, 27 Feb 2020 12:44:32 -0500 Received: from foss.arm.com ([217.140.110.172]:55532 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730602AbgB0Rob (ORCPT ); Thu, 27 Feb 2020 12:44:31 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9FA4D1FB; Thu, 27 Feb 2020 09:44:30 -0800 (PST) Received: from localhost (unknown [10.37.6.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E27F23F73B; Thu, 27 Feb 2020 09:44:29 -0800 (PST) From: Mark Brown To: Catalin Marinas , Will Deacon Cc: Alexander Viro , Paul Elliott , Peter Zijlstra , Yu-cheng Yu , Amit Kachhap , Vincenzo Frascino , Marc Zyngier , Eugene Syromiatnikov , Szabolcs Nagy , "H . J . Lu " , Andrew Jones , Kees Cook , Arnd Bergmann , Jann Horn , Richard Henderson , =?utf-8?q?Kristina_Mart?= =?utf-8?q?=C5=A1enko?= , Thomas Gleixner , Florian Weimer , Sudakshina Das , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, Dave Martin , Mark Brown Subject: [PATCH v8 04/11] elf: Allow arch to tweak initial mmap prot flags Date: Thu, 27 Feb 2020 17:44:10 +0000 Message-Id: <20200227174417.23722-5-broonie@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200227174417.23722-1-broonie@kernel.org> References: <20200227174417.23722-1-broonie@kernel.org> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Dave Martin An arch may want to tweak the mmap prot flags for an ELFexecutable's initial mappings. For example, arm64 is going to need to add PROT_BTI for executable pages in an ELF process whose executable is marked as using Branch Target Identification (an ARMv8.5-A control flow integrity feature). So that this can be done in a generic way, add a hook arch_elf_adjust_prot() to modify the prot flags as desired: arches can select CONFIG_HAVE_ELF_PROT and implement their own backend where necessary. By default, leave the prot flags unchanged. Signed-off-by: Dave Martin Reviewed-by: Kees Cook Reviewed-by: Catalin Marinas Signed-off-by: Mark Brown --- fs/Kconfig.binfmt | 3 +++ fs/binfmt_elf.c | 18 ++++++++++++------ include/linux/elf.h | 12 ++++++++++++ 3 files changed, 27 insertions(+), 6 deletions(-) diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt index d2cfe0729a73..2358368319b8 100644 --- a/fs/Kconfig.binfmt +++ b/fs/Kconfig.binfmt @@ -36,6 +36,9 @@ config COMPAT_BINFMT_ELF config ARCH_BINFMT_ELF_STATE bool +config ARCH_HAVE_ELF_PROT + bool + config ARCH_USE_GNU_PROPERTY bool diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 1fb67e506b68..cceb29d6ef1d 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -544,7 +544,8 @@ static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp, #endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */ -static inline int make_prot(u32 p_flags) +static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state, + bool has_interp, bool is_interp) { int prot = 0; @@ -554,7 +555,8 @@ static inline int make_prot(u32 p_flags) prot |= PROT_WRITE; if (p_flags & PF_X) prot |= PROT_EXEC; - return prot; + + return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp); } /* This is much more generalized than the library routine read function, @@ -564,7 +566,8 @@ static inline int make_prot(u32 p_flags) static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, struct file *interpreter, - unsigned long no_base, struct elf_phdr *interp_elf_phdata) + unsigned long no_base, struct elf_phdr *interp_elf_phdata, + struct arch_elf_state *arch_state) { struct elf_phdr *eppnt; unsigned long load_addr = 0; @@ -596,7 +599,8 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) { if (eppnt->p_type == PT_LOAD) { int elf_type = MAP_PRIVATE | MAP_DENYWRITE; - int elf_prot = make_prot(eppnt->p_flags); + int elf_prot = make_prot(eppnt->p_flags, arch_state, + true, true); unsigned long vaddr = 0; unsigned long k, map_addr; @@ -1041,7 +1045,8 @@ static int load_elf_binary(struct linux_binprm *bprm) } } - elf_prot = make_prot(elf_ppnt->p_flags); + elf_prot = make_prot(elf_ppnt->p_flags, &arch_state, + !!interpreter, false); elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE; @@ -1184,7 +1189,8 @@ static int load_elf_binary(struct linux_binprm *bprm) if (interpreter) { elf_entry = load_elf_interp(&loc->interp_elf_ex, interpreter, - load_bias, interp_elf_phdata); + load_bias, interp_elf_phdata, + &arch_state); if (!IS_ERR((void *)elf_entry)) { /* * load_elf_interp() returns relocation diff --git a/include/linux/elf.h b/include/linux/elf.h index db5113479f5e..5d5b0321da0b 100644 --- a/include/linux/elf.h +++ b/include/linux/elf.h @@ -87,4 +87,16 @@ extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz, bool compat, struct arch_elf_state *arch); #endif +#ifdef CONFIG_ARCH_HAVE_ELF_PROT +int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, + bool has_interp, bool is_interp); +#else +static inline int arch_elf_adjust_prot(int prot, + const struct arch_elf_state *state, + bool has_interp, bool is_interp) +{ + return prot; +} +#endif + #endif /* _LINUX_ELF_H */