1 /*- 2 * Copyright (c) 2019 Stormshield. 3 * Copyright (c) 2019 Semihalf. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 17 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 18 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 20 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 22 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 23 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 24 * POSSIBILITY OF SUCH DAMAGE. 25 */ 26 #include <sys/cdefs.h> 27 #include <sys/stat.h> 28 29 #include "libsecureboot-priv.h" 30 #include <verify_file.h> 31 32 /* 33 * Values to pass to kernel by envs. 34 */ 35 static char manifest_path[MAXPATHLEN]; 36 static char manifest_prefix[MAXPATHLEN]; 37 static char manifest_hash[2 * br_sha256_SIZE + 2]; 38 static int manifest_present = 0; 39 40 /* 41 * Verify and pass manifest path and digest to kernel through envs. 42 * The paths in manifest can be either absolute, 43 * or "prefix", if exists will be added to the ones that are not. 44 */ 45 int 46 pass_manifest(const char *path, const char *prefix) 47 { 48 char *content; 49 struct stat st; 50 unsigned char digest[br_sha256_SIZE]; 51 const br_hash_class *md; 52 br_hash_compat_context ctx; 53 int rc; 54 55 content = NULL; 56 md = &br_sha256_vtable; 57 58 if (strnlen(path, MAXPATHLEN) == MAXPATHLEN || 59 strnlen(prefix, MAXPATHLEN) == MAXPATHLEN) 60 return (EINVAL); 61 62 rc = stat(path, &st); 63 if (rc != 0) 64 goto out; 65 66 if (!S_ISREG(st.st_mode)) { 67 rc = EINVAL; 68 goto out; 69 } 70 71 rc = is_verified(&st); 72 73 if (rc != VE_NOT_CHECKED && rc != VE_VERIFIED) { 74 rc = EPERM; 75 goto out; 76 } 77 78 if (rc == VE_VERIFIED) 79 content = read_file(path, NULL); 80 else 81 content = (char *)verify_signed(path, VEF_VERBOSE); 82 83 if (content == NULL) { 84 add_verify_status(&st, VE_FINGERPRINT_WRONG); 85 rc = EIO; 86 goto out; 87 } 88 89 add_verify_status(&st, VE_VERIFIED); 90 91 md->init(&ctx.vtable); 92 md->update(&ctx.vtable, content, st.st_size); 93 md->out(&ctx.vtable, digest); 94 95 if (prefix == NULL) 96 manifest_prefix[0] = '\0'; 97 else 98 strcpy(manifest_prefix, prefix); 99 100 strcpy(manifest_path, path); 101 102 hexdigest(manifest_hash, 2 * br_sha256_SIZE + 2, 103 digest, br_sha256_SIZE); 104 manifest_hash[2*br_sha256_SIZE] = '\0'; 105 106 manifest_present = 1; 107 rc = 0; 108 109 out: 110 if (content != NULL) 111 free(content); 112 113 return (rc); 114 } 115 116 /* 117 * Set appropriate envs to inform kernel about manifest location and digest. 118 * This should be called right before boot so that envs can't be replaced. 119 */ 120 int 121 pass_manifest_export_envs() 122 { 123 int rc; 124 125 /* If we have nothing to pass make sure that envs are empty. */ 126 if (!manifest_present) { 127 unsetenv("veriexec.manifest_path"); 128 unsetenv("veriexec.manifest_hash"); 129 unsetenv("veriexec.manifest_prefix"); 130 return (0); 131 } 132 133 rc = setenv("veriexec.manifest_path", manifest_path, 1); 134 if (rc != 0) 135 return (rc); 136 137 rc = setenv("veriexec.manifest_hash", manifest_hash, 1); 138 if (rc != 0) { 139 unsetenv("veriexec.manifest_path"); 140 return (rc); 141 } 142 143 if (manifest_prefix[0] != '\0') 144 rc = setenv("veriexec.manifest_prefix", manifest_prefix, 1); 145 146 return (rc); 147 } 148 149