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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 56EC0C3A5A4 for ; Fri, 30 Aug 2019 05:23:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1170F21897 for ; Fri, 30 Aug 2019 05:23:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567142631; bh=RBrbhKASCqObgzuGM1/8VbCqDXFL88kBbebOGmf2Vwg=; h=In-Reply-To:References:Cc:Subject:To:From:Date:List-ID:From; b=qReQzBEp5EoE7QBHgaHp6i8H4xyB+f8WJaBLzATq2T5BgrzdBCLIl8zWAc4oour6G PU77Ia/n1Le2sg5zZs8UqnjuIwWSqm1OzmkxBcxdmtUIV/n0HhiqV7ynN38yY4cyz3 WK6Qb7x/b25V9FpIehPneVKTvNKx++uxuN2VCGfY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727780AbfH3FXu (ORCPT ); Fri, 30 Aug 2019 01:23:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:35226 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726015AbfH3FXt (ORCPT ); Fri, 30 Aug 2019 01:23:49 -0400 Received: from kernel.org (unknown [104.132.0.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8032F2073F; Fri, 30 Aug 2019 05:23:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567142627; bh=RBrbhKASCqObgzuGM1/8VbCqDXFL88kBbebOGmf2Vwg=; h=In-Reply-To:References:Cc:Subject:To:From:Date:From; b=h3hR1HH+1zoGIUMxpS5H705YLd8zt0t5Y+s6JWKb49VuZ6khR+kv8OvcZCmbsr9yd k9LIhb+hnZJE0L345yjASGGhqkrBg2fOTdVzH/NLpOxF2G8PWVE3FG6+mDnSQC4/7f rkAa3DA2/M3hjNZPEXdEZW453+TNH4haQnDLOeIo= Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: <20190829200532.13545-2-prsriva@linux.microsoft.com> References: <20190829200532.13545-1-prsriva@linux.microsoft.com> <20190829200532.13545-2-prsriva@linux.microsoft.com> Cc: jmorris@namei.org, zohar@linux.ibm.com, bauerman@linux.ibm.com Subject: Re: [RFC][PATCH 1/1] Carry ima measurement log for arm64 via kexec_file_load To: Prakhar Srivastava , linux-arm-msm@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org From: Stephen Boyd User-Agent: alot/0.8.1 Date: Thu, 29 Aug 2019 22:23:46 -0700 Message-Id: <20190830052347.8032F2073F@mail.kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Why is linux-arm-msm list CCed on this topic? Quoting Prakhar Srivastava (2019-08-29 13:05:32) > Carry ima measurement log for arm64 via kexec_file_load. > add support to kexec_file_load to pass the ima measurement log These first two sentences look sort of odd for a commit text. >=20 > This patch adds entry for the ima measurement log in the Don't use 'this patch' in commit text. It's in the wrong voice. > dtb which is then used in the kexec'ed session to fetch the > segment and then load the ima measurement log. >=20 > Signed-off-by: Prakhar Srivastava > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 3adcec05b1f6..9e1b831e7baa 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -964,6 +964,13 @@ config KEXEC_FILE > for kernel and initramfs as opposed to list of segments as > accepted by previous system call. > =20 > +config HAVE_IMA_KEXEC > + bool "enable arch specific ima buffer pass" > + depends on KEXEC_FILE > + help > + This adds support to carry ima log to the next kernel in = case Should ima be all caps here? > + of kexec_file_load Add a full-stop? > + > config KEXEC_VERIFY_SIG > bool "Verify kernel signature during kexec_file_load() syscall" > depends on KEXEC_FILE > diff --git a/arch/arm64/include/asm/ima.h b/arch/arm64/include/asm/ima.h > new file mode 100644 > index 000000000000..2c504281028d > --- /dev/null > +++ b/arch/arm64/include/asm/ima.h > @@ -0,0 +1,31 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _ASM_ARM64_IMA_H > +#define _ASM_ARM64_IMA_H > + > +#define FDT_PROP_KEXEC_BUFFER "linux,ima-kexec-buffer" Is this documented somewhere in the DT bindings? > + > +struct kimage; > + > +int ima_get_kexec_buffer(void **addr, size_t *size); > +int ima_free_kexec_buffer(void); > + > +#ifdef CONFIG_IMA > +void remove_ima_buffer(void *fdt, int chosen_node); > +#else > +static inline void remove_ima_buffer(void *fdt, int chosen_node) {} > +#endif > + > +#ifdef CONFIG_IMA_KEXEC > +int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_a= ddr, > + size_t size); > + > +int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_n= ode); > +#else > +static inline int setup_ima_buffer(const struct kimage *image, void *fdt, > + int chosen_node) > +{ > + remove_ima_buffer(fdt, chosen_node); > + return 0; > +} > +#endif /* CONFIG_IMA_KEXEC */ > +#endif /* _ASM_ARM64_IMA_H */ > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexe= c.h > index 12a561a54128..ca1f9ad5c4d4 100644 > --- a/arch/arm64/include/asm/kexec.h > +++ b/arch/arm64/include/asm/kexec.h > @@ -96,6 +96,8 @@ static inline void crash_post_resume(void) {} > struct kimage_arch { > void *dtb; > unsigned long dtb_mem; > + phys_addr_t ima_buffer_addr; > + size_t ima_buffer_size; Should this be in an ifdef? > }; > =20 > extern const struct kexec_file_ops kexec_image_ops; > @@ -107,6 +109,8 @@ extern int load_other_segments(struct kimage *image, > unsigned long kernel_load_addr, unsigned long kernel_size, > char *initrd, unsigned long initrd_len, > char *cmdline); > +extern int delete_fdt_mem_rsv(void *fdt, unsigned long start, > + unsigned long size); > #endif > =20 > #endif /* __ASSEMBLY__ */ > diff --git a/arch/arm64/kernel/ima_kexec.c b/arch/arm64/kernel/ima_kexec.c > new file mode 100644 > index 000000000000..5ae0d776ec42 > --- /dev/null > +++ b/arch/arm64/kernel/ima_kexec.c > @@ -0,0 +1,219 @@ > +/* > + * Copyright (C) 2016 IBM Corporation > + * > + * Authors: > + * Thiago Jung Bauermann > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. Please use a SPDX tag instead of this boiler plate. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static int get_addr_size_cells(int *addr_cells, int *size_cells) > +{ > + struct device_node *root; > + > + root =3D of_find_node_by_path("/"); > + if (!root) > + return -EINVAL; > + > + *addr_cells =3D of_n_addr_cells(root); > + *size_cells =3D of_n_size_cells(root); > + > + of_node_put(root); > + > + return 0; > +} > + > +static int do_get_kexec_buffer(const void *prop, int len, unsigned long = *addr, > + size_t *size) > +{ > + > + int ret, addr_cells, size_cells; > + > + ret =3D get_addr_size_cells(&addr_cells, &size_cells); > + if (ret) > + return ret; > + > + if (len < 4 * (addr_cells + size_cells)) > + return -ENOENT; > + > + *addr =3D of_read_number(prop, addr_cells); > + *size =3D of_read_number(prop + 4 * addr_cells, size_cells); > + > + return 0; > +} > + > +/** > + * ima_get_kexec_buffer - get IMA buffer from the previous kernel > + * @addr: On successful return, set to point to the buffer contents. > + * @size: On successful return, set to the buffer size. > + * > + * Return: 0 on success, negative errno on error. > + */ > +int ima_get_kexec_buffer(void **addr, size_t *size) > +{ > + int ret, len; > + unsigned long tmp_addr; > + size_t tmp_size; > + const void *prop; > + > + prop =3D of_get_property(of_chosen, FDT_PROP_KEXEC_BUFFER, &len); > + if (!prop) > + return -ENOENT; > + > + ret =3D do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size); > + if (ret) > + return ret; > + > + *addr =3D __va(tmp_addr); > + *size =3D tmp_size; > + return 0; > +} > + > +/** > + * ima_free_kexec_buffer - free memory used by the IMA buffer > + */ > +int ima_free_kexec_buffer(void) > +{ > + int ret; > + unsigned long addr; > + size_t size; > + struct property *prop; > + > + prop =3D of_find_property(of_chosen, FDT_PROP_KEXEC_BUFFER, NULL); > + if (!prop) > + return -ENOENT; > + > + ret =3D do_get_kexec_buffer(prop->value, prop->length, &addr, &si= ze); > + if (ret) > + return ret; > + > + ret =3D of_remove_property(of_chosen, prop); > + if (ret) > + return ret; > + > + return memblock_free(addr, size); > +} > + > +#ifdef CONFIG_IMA > +/** > + * remove_ima_buffer - remove the IMA buffer property and reservation fr= om @fdt > + * > + * The IMA measurement buffer is of no use to a subsequent kernel, so we= always > + * remove it from the device tree. > + */ > +void remove_ima_buffer(void *fdt, int chosen_node) > +{ > + int ret, len; > + unsigned long addr; > + size_t size; > + const void *prop; > + > + prop =3D fdt_getprop(fdt, chosen_node, FDT_PROP_KEXEC_BUFFER, &le= n); > + if (!prop) > + return; > + > + ret =3D do_get_kexec_buffer(prop, len, &addr, &size); > + fdt_delprop(fdt, chosen_node, FDT_PROP_KEXEC_BUFFER); > + if (ret) > + return; > + > + ret =3D delete_fdt_mem_rsv(fdt, addr, size); > + if (!ret) > + pr_debug("Removed old IMA buffer reservation.\n"); > +} > +#endif /* CONFIG_IMA */ > + > +#ifdef CONFIG_IMA_KEXEC > +/** > + * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buf= fer > + * > + * Architectures should use this function to pass on the IMA buffer > + * information to the next kernel. > + * > + * Return: 0 on success, negative errno on error. > + */ > +int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_a= ddr, > + size_t size) > +{ > + image->arch.ima_buffer_addr =3D load_addr; > + image->arch.ima_buffer_size =3D size; > + return 0; > +} > + > +static int write_number(void *p, u64 value, int cells) Maybe this should be an of_write_number() API exposed by the DT parsing code? > +{ > + if (cells =3D=3D 1) { > + u32 tmp; > + > + if (value > U32_MAX) > + return -EINVAL; > + > + tmp =3D cpu_to_be32(value); > + memcpy(p, &tmp, sizeof(tmp)); > + } else if (cells =3D=3D 2) { > + u64 tmp; > + > + tmp =3D cpu_to_be64(value); > + memcpy(p, &tmp, sizeof(tmp)); > + } else > + return -EINVAL; Put braces around this else please. > + return 0; > +} > + > +/** > + * setup_ima_buffer - add IMA buffer information to the fdt > + * @image: kexec image being loaded. > + * @dtb: Flattened device tree for the next kernel. > + * @chosen_node: Offset to the chosen node. Why capitalize Flattened and Offset? > + * > + * Return: 0 on success, or negative errno on error. > + */ > +int setup_ima_buffer(const struct kimage *image, void *dtb, int chosen_n= ode) > +{ > + int ret, addr_cells, size_cells, entry_size; > + u8 value[16]; > + > + remove_ima_buffer(dtb, chosen_node); > + > + ret =3D get_addr_size_cells(&addr_cells, &size_cells); > + if (ret) > + return ret; > + > + entry_size =3D 4 * (addr_cells + size_cells); > + > + if (entry_size > sizeof(value)) > + return -EINVAL; > + > + ret =3D write_number(value, image->arch.ima_buffer_addr, addr_cel= ls); > + if (ret) > + return ret; > + > + ret =3D write_number(value + 4 * addr_cells, image->arch.ima_buff= er_size, > + size_cells); > + if (ret) > + return ret; > + > + ret =3D fdt_setprop(dtb, chosen_node, FDT_PROP_KEXEC_BUFFER, valu= e, > + entry_size); > + if (ret < 0) > + return -EINVAL; > + > + ret =3D fdt_add_mem_rsv(dtb, image->segment[0].mem, > + image->segment[0].memsz); > + if (ret) > + return -EINVAL; > + > + return 0; > +} > +#endif /* CONFIG_IMA_KEXEC */ > diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/m= achine_kexec_file.c > index 58871333737a..c05ad6b74b62 100644 > --- a/arch/arm64/kernel/machine_kexec_file.c > +++ b/arch/arm64/kernel/machine_kexec_file.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > =20 > /* relevant device tree properties */ > #define FDT_PROP_INITRD_START "linux,initrd-start" > @@ -85,6 +86,11 @@ static int setup_dtb(struct kimage *image, > goto out; > } > =20 > + /* add ima_buffer */ > + ret =3D setup_ima_buffer(image, dtb, off); > + if (ret) > + goto out; > + > /* add kaslr-seed */ > ret =3D fdt_delprop(dtb, off, FDT_PROP_KASLR_SEED); > if (ret =3D=3D -FDT_ERR_NOTFOUND) > @@ -114,6 +120,39 @@ static int setup_dtb(struct kimage *image, > */ > #define DTB_EXTRA_SPACE 0x1000 > =20 > + > +/** > + * delete_fdt_mem_rsv - delete memory reservation with given address and= size > + * Can you document the arguments too? > + * Return: 0 on success, or negative errno on error. > + */ > +int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long siz= e) > +{ > + int i, ret, num_rsvs =3D fdt_num_mem_rsv(fdt); > + > + for (i =3D 0; i < num_rsvs; i++) { > + uint64_t rsv_start, rsv_size; > + > + ret =3D fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size); > + if (ret) { > + pr_err("Malformed device tree.\n"); Please drop the full-stop on this printk. > + return -EINVAL; > + } > + > + if (rsv_start =3D=3D start && rsv_size =3D=3D size) { > + ret =3D fdt_del_mem_rsv(fdt, i); > + if (ret) { > + pr_err("Error deleting device tree reserv= ation.\n"); Same comment. > + return -EINVAL; > + } > + > + return 0; > + } > + } > + > + return -ENOENT; > +} A lot of this code looks DT generic. Can it be moved out of the arch layer to drivers/of/?