From patchwork Fri May 24 20:46:46 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fan Wu X-Patchwork-Id: 13673692 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2FABE130493; Fri, 24 May 2024 20:47:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716583626; cv=none; b=MX2tgQ7g3eg8lFBaYzMFgDKrtzw5DJuZcvZgnWJU6CJYa9JWANYvRM5ZDSr3MNBViZjAvKdXQ2wHkg1allICrcb1OolFtEiroR9XHqsp4O5tfhPio8BbItgnNsCQpiqB0uaGPJo4TU0vU3vWz5jhpPsP45VyJZ8TaZsy6Fc0LEg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716583626; c=relaxed/simple; bh=58KJqZpr7tcXAD2RtNhDSDrbIcauGmp8kRiOgMLstPQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=etqXldNEdCRDIDtScfdcZ7QwIGan6ub5im+ow9HOEnQHlLquXvGbPiWh2mwV83fweE7QfAlUlXji9sIyhjC817wF+gvTmnTMKe21XumpGhLoEnR8f+slpdnBSeyVT8AG3pN5khn8HzF80b4faQUPUGMgkrxOSRJaIczXq8JzAao= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=IVaNsk99; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="IVaNsk99" Received: by linux.microsoft.com (Postfix, from userid 1052) id 1535120BE59D; Fri, 24 May 2024 13:46:51 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1535120BE59D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1716583612; bh=JQh/ltRUW7yEppuixZLk+tmyehDU+shJD1Aw2txd0lQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IVaNsk99C4v0PYLAnZTu8jgwVPH2Ew4j4JTKKLO7uIMGtMBMc8jCGF/xM0pcSExRp lsF6MTZLeA8yx8TRKola9hSlaV9G07STJfV0IFoYUfORcayRXhRuyeT/Xi2zzhjwMm smaJAqeFNEWTFz3eJihOreDEP5COKSwZSqshdjCo= From: Fan Wu To: corbet@lwn.net, zohar@linux.ibm.com, jmorris@namei.org, serge@hallyn.com, tytso@mit.edu, ebiggers@kernel.org, axboe@kernel.dk, agk@redhat.com, snitzer@kernel.org, mpatocka@redhat.com, eparis@redhat.com, paul@paul-moore.com Cc: linux-doc@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, fsverity@lists.linux.dev, linux-block@vger.kernel.org, dm-devel@lists.linux.dev, audit@vger.kernel.org, linux-kernel@vger.kernel.org, Deven Bowers , Fan Wu Subject: [PATCH v19 17/20] scripts: add boot policy generation program Date: Fri, 24 May 2024 13:46:46 -0700 Message-Id: <1716583609-21790-18-git-send-email-wufan@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1716583609-21790-1-git-send-email-wufan@linux.microsoft.com> References: <1716583609-21790-1-git-send-email-wufan@linux.microsoft.com> Precedence: bulk X-Mailing-List: fsverity@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Deven Bowers Enables an IPE policy to be enforced from kernel start, enabling access control based on trust from kernel startup. This is accomplished by transforming an IPE policy indicated by CONFIG_IPE_BOOT_POLICY into a c-string literal that is parsed at kernel startup as an unsigned policy. Signed-off-by: Deven Bowers Signed-off-by: Fan Wu --- v2: + No Changes v3: + No Changes v4: + No Changes v5: + No Changes v6: + No Changes v7: + Move from 01/11 to 14/16 + Don't return errno directly. + Make output of script more user-friendly + Add escaping for tab and '?' + Mark argv pointer const + Invert return code check in the boot policy parsing code path. v8: + No significant changes. v9: + No changes v10: + Update the init part code for rcu changes in the eval loop patch v11: + Fix code style issues v12: + No changes v13: + No changes v14: + No changes v15: + Fix one grammar issue in Kconfig v16: + No changes v17: + Add years to license header + Fix code and documentation style issues v18: + No changes v19: + No changes --- scripts/Makefile | 1 + scripts/ipe/Makefile | 2 + scripts/ipe/polgen/.gitignore | 2 + scripts/ipe/polgen/Makefile | 5 ++ scripts/ipe/polgen/polgen.c | 145 ++++++++++++++++++++++++++++++++++ security/ipe/.gitignore | 2 + security/ipe/Kconfig | 10 +++ security/ipe/Makefile | 11 +++ security/ipe/fs.c | 8 ++ security/ipe/ipe.c | 12 +++ 10 files changed, 198 insertions(+) create mode 100644 scripts/ipe/Makefile create mode 100644 scripts/ipe/polgen/.gitignore create mode 100644 scripts/ipe/polgen/Makefile create mode 100644 scripts/ipe/polgen/polgen.c create mode 100644 security/ipe/.gitignore diff --git a/scripts/Makefile b/scripts/Makefile index fe56eeef09dd..74c6a777c5bd 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -55,6 +55,7 @@ targets += module.lds subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins subdir-$(CONFIG_MODVERSIONS) += genksyms subdir-$(CONFIG_SECURITY_SELINUX) += selinux +subdir-$(CONFIG_SECURITY_IPE) += ipe # Let clean descend into subdirs subdir- += basic dtc gdb kconfig mod diff --git a/scripts/ipe/Makefile b/scripts/ipe/Makefile new file mode 100644 index 000000000000..e87553fbb8d6 --- /dev/null +++ b/scripts/ipe/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +subdir-y := polgen diff --git a/scripts/ipe/polgen/.gitignore b/scripts/ipe/polgen/.gitignore new file mode 100644 index 000000000000..b6f05cf3dc0e --- /dev/null +++ b/scripts/ipe/polgen/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +polgen diff --git a/scripts/ipe/polgen/Makefile b/scripts/ipe/polgen/Makefile new file mode 100644 index 000000000000..c20456a2f2e9 --- /dev/null +++ b/scripts/ipe/polgen/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +hostprogs-always-y := polgen +HOST_EXTRACFLAGS += \ + -I$(srctree)/include \ + -I$(srctree)/include/uapi \ diff --git a/scripts/ipe/polgen/polgen.c b/scripts/ipe/polgen/polgen.c new file mode 100644 index 000000000000..c6283b3ff006 --- /dev/null +++ b/scripts/ipe/polgen/polgen.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include +#include +#include +#include +#include + +static void usage(const char *const name) +{ + printf("Usage: %s OutputFile (PolicyFile)\n", name); + exit(EINVAL); +} + +static int policy_to_buffer(const char *pathname, char **buffer, size_t *size) +{ + size_t fsize; + size_t read; + char *lbuf; + int rc = 0; + FILE *fd; + + fd = fopen(pathname, "r"); + if (!fd) { + rc = errno; + goto out; + } + + fseek(fd, 0, SEEK_END); + fsize = ftell(fd); + rewind(fd); + + lbuf = malloc(fsize); + if (!lbuf) { + rc = ENOMEM; + goto out_close; + } + + read = fread((void *)lbuf, sizeof(*lbuf), fsize, fd); + if (read != fsize) { + rc = -1; + goto out_free; + } + + *buffer = lbuf; + *size = fsize; + fclose(fd); + + return rc; + +out_free: + free(lbuf); +out_close: + fclose(fd); +out: + return rc; +} + +static int write_boot_policy(const char *pathname, const char *buf, size_t size) +{ + int rc = 0; + FILE *fd; + size_t i; + + fd = fopen(pathname, "w"); + if (!fd) { + rc = errno; + goto err; + } + + fprintf(fd, "/* This file is automatically generated."); + fprintf(fd, " Do not edit. */\n"); + fprintf(fd, "#include \n"); + fprintf(fd, "\nextern const char *const ipe_boot_policy;\n\n"); + fprintf(fd, "const char *const ipe_boot_policy =\n"); + + if (!buf || size == 0) { + fprintf(fd, "\tNULL;\n"); + fclose(fd); + return 0; + } + + fprintf(fd, "\t\""); + + for (i = 0; i < size; ++i) { + switch (buf[i]) { + case '"': + fprintf(fd, "\\\""); + break; + case '\'': + fprintf(fd, "'"); + break; + case '\n': + fprintf(fd, "\\n\"\n\t\""); + break; + case '\\': + fprintf(fd, "\\\\"); + break; + case '\t': + fprintf(fd, "\\t"); + break; + case '\?': + fprintf(fd, "\\?"); + break; + default: + fprintf(fd, "%c", buf[i]); + } + } + fprintf(fd, "\";\n"); + fclose(fd); + + return 0; + +err: + if (fd) + fclose(fd); + return rc; +} + +int main(int argc, const char *const argv[]) +{ + char *policy = NULL; + size_t len = 0; + int rc = 0; + + if (argc < 2) + usage(argv[0]); + + if (argc > 2) { + rc = policy_to_buffer(argv[2], &policy, &len); + if (rc != 0) + goto cleanup; + } + + rc = write_boot_policy(argv[1], policy, len); +cleanup: + if (policy) + free(policy); + if (rc != 0) + perror("An error occurred during policy conversion: "); + return rc; +} diff --git a/security/ipe/.gitignore b/security/ipe/.gitignore new file mode 100644 index 000000000000..07313d3fd74a --- /dev/null +++ b/security/ipe/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +boot-policy.c diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig index 6bc487b689e0..fccc69e66af1 100644 --- a/security/ipe/Kconfig +++ b/security/ipe/Kconfig @@ -21,6 +21,16 @@ menuconfig SECURITY_IPE If unsure, answer N. if SECURITY_IPE +config IPE_BOOT_POLICY + string "Integrity policy to apply on system startup" + help + This option specifies a filepath to an IPE policy that is compiled + into the kernel. This policy will be enforced until a policy update + is deployed via the $securityfs/ipe/policies/$policy_name/active + interface. + + If unsure, leave blank. + menu "IPE Trust Providers" config IPE_PROP_DM_VERITY diff --git a/security/ipe/Makefile b/security/ipe/Makefile index e1019bb9f0f3..84ad76556170 100644 --- a/security/ipe/Makefile +++ b/security/ipe/Makefile @@ -5,7 +5,16 @@ # Makefile for building the IPE module as part of the kernel tree. # +quiet_cmd_polgen = IPE_POL $(2) + cmd_polgen = scripts/ipe/polgen/polgen security/ipe/boot-policy.c $(2) + +targets += boot-policy.c + +$(obj)/boot-policy.c: scripts/ipe/polgen/polgen $(CONFIG_IPE_BOOT_POLICY) FORCE + $(call if_changed,polgen,$(CONFIG_IPE_BOOT_POLICY)) + obj-$(CONFIG_SECURITY_IPE) += \ + boot-policy.o \ digest.o \ eval.o \ hooks.o \ @@ -15,3 +24,5 @@ obj-$(CONFIG_SECURITY_IPE) += \ policy_fs.o \ policy_parser.o \ audit.o \ + +clean-files := boot-policy.c \ diff --git a/security/ipe/fs.c b/security/ipe/fs.c index b52fb6023904..5b6d19fb844a 100644 --- a/security/ipe/fs.c +++ b/security/ipe/fs.c @@ -190,6 +190,7 @@ static const struct file_operations enforce_fops = { static int __init ipe_init_securityfs(void) { int rc = 0; + struct ipe_policy *ap; if (!ipe_enabled) return -EOPNOTSUPP; @@ -220,6 +221,13 @@ static int __init ipe_init_securityfs(void) goto err; } + ap = rcu_access_pointer(ipe_active_policy); + if (ap) { + rc = ipe_new_policyfs_node(ap); + if (rc) + goto err; + } + np = securityfs_create_file("new_policy", 0200, root, NULL, &np_fops); if (IS_ERR(np)) { rc = PTR_ERR(np); diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c index da79f66b0010..5e993cbf3428 100644 --- a/security/ipe/ipe.c +++ b/security/ipe/ipe.c @@ -9,6 +9,7 @@ #include "hooks.h" #include "eval.h" +extern const char *const ipe_boot_policy; bool ipe_enabled; static struct lsm_blob_sizes ipe_blobs __ro_after_init = { @@ -74,9 +75,20 @@ static struct security_hook_list ipe_hooks[] __ro_after_init = { */ static int __init ipe_init(void) { + struct ipe_policy *p = NULL; + security_add_hooks(ipe_hooks, ARRAY_SIZE(ipe_hooks), &ipe_lsmid); ipe_enabled = true; + if (ipe_boot_policy) { + p = ipe_new_policy(ipe_boot_policy, strlen(ipe_boot_policy), + NULL, 0); + if (IS_ERR(p)) + return PTR_ERR(p); + + rcu_assign_pointer(ipe_active_policy, p); + } + return 0; }