Differential D19281 Diff 55664 lib/libsecureboot/pass_manifest.c

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lib/libsecureboot/pass_manifest.c

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				/*-
				* Copyright (c) 2019 Stormshield.
				* Copyright (c) 2019 Semihalf.
				*
				* Redistribution and use in source and binary forms, with or without
				* modification, are permitted provided that the following conditions
				* are met:
				* 1. Redistributions of source code must retain the above copyright
				* notice, this list of conditions and the following disclaimer.
				* 2. Redistributions in binary form must reproduce the above copyright
				* notice, this list of conditions and the following disclaimer in the
				* documentation and/or other materials provided with the distribution.
				*
				* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
				* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
				* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
				* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
				* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
				* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
				* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
				* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
				* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
				* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
				* POSSIBILITY OF SUCH DAMAGE.
				*
				* $FreeBSD$
				*/
				#include <sys/cdefs.h>
				__FBSDID("$FreeBSD$");

				#include <sys/stat.h>

				#include "libsecureboot-priv.h"
				#include <verify_file.h>

				/*
				* Values to pass to kernel by envs.
				*/
				static char manifest_path[MAXPATHLEN];
				static char manifest_prefix[MAXPATHLEN];
				static char manifest_hash[2 * br_sha256_SIZE + 2];
				static int manifest_present = 0;

				/*
				* Verify and pass manifest path and digest to kernel through envs.
				* The paths in manifest can be either absolute,
				* or "prefix", if exists will be added to the ones that are not.
				*/
				int
				pass_manifest(const char path, const char prefix)
				{
				char *content;
				struct stat st;
				unsigned char digest[br_sha256_SIZE];
				const br_hash_class *md;
				br_hash_compat_context ctx;
				int rc;

				content = NULL;
				md = &br_sha256_vtable;

				if (strnlen(path, MAXPATHLEN) == MAXPATHLEN \|\|
				strnlen(prefix, MAXPATHLEN) == MAXPATHLEN)
				return (EINVAL);

				rc = stat(path, &st);
				if (rc != 0)
				goto out;

				if (!S_ISREG(st.st_mode)) {
				rc = EINVAL;
				goto out;
				}

				rc = is_verified(&st);

				if (rc != VE_NOT_CHECKED && rc != VE_VERIFIED) {
				rc = EPERM;
				goto out;
				}

				if (rc == VE_VERIFIED)
				content = read_file(path, NULL);
				else
				content = (char *)verify_signed(path, VEF_VERBOSE);

				if (content == NULL) {
				add_verify_status(&st, VE_FINGERPRINT_WRONG);
				rc = EIO;
				goto out;
				}

				add_verify_status(&st, VE_VERIFIED);

				md->init(&ctx.vtable);
				md->update(&ctx.vtable, content, st.st_size);
				md->out(&ctx.vtable, digest);

				if (prefix == NULL)
				manifest_prefix[0] = '\0';
				else
				strcpy(manifest_prefix, prefix);

				strcpy(manifest_path, path);

				hexdigest(manifest_hash, 2 * br_sha256_SIZE + 2,
				digest, br_sha256_SIZE);
				manifest_hash[2*br_sha256_SIZE] = '\0';

				manifest_present = 1;
				rc = 0;

				out:
				if (content != NULL)
				free(content);

				return (rc);
				}

				/*
				* Set appropriate envs to inform kernel about manifest location and digest.
				* This should be called right before boot so that envs can't be replaced.
				*/
				int
				pass_manifest_export_envs()
				{
				int rc;

				/* If we have nothing to pass make sure that envs are empty. */
				if (!manifest_present) {
				unsetenv("veriexec.manifest_path");
				unsetenv("veriexec.manifest_hash");
				unsetenv("veriexec.manifest_prefix");
				return (0);
				}

				rc = setenv("veriexec.manifest_path", manifest_path, 1);
				if (rc != 0)
				return (rc);

				rc = setenv("veriexec.manifest_hash", manifest_hash, 1);
				if (rc != 0) {
				unsetenv("veriexec.manifest_path");
				return (rc);
				}

				if (manifest_prefix[0] != '\0')
				rc = setenv("veriexec.manifest_prefix", manifest_prefix, 1);

				return (rc);
				}