tools/testing/selftests/kexec/test_kexec_file_load.sh

   1 #!/bin/sh
   2 # SPDX-License-Identifier: GPL-2.0
   3 #
   4 # Loading a kernel image via the kexec_file_load syscall can verify either
   5 # the IMA signature stored in the security.ima xattr or the PE signature,
   6 # both signatures depending on the IMA policy, or none.
   7 #
   8 # To determine whether the kernel image is signed, this test depends
   9 # on pesign and getfattr.  This test also requires the kernel to be
  10 # built with CONFIG_IKCONFIG enabled and either CONFIG_IKCONFIG_PROC
  11 # enabled or access to the extract-ikconfig script.
  12
  13 TEST="KEXEC_FILE_LOAD"
  14 . ./kexec_common_lib.sh
  15
  16 trap "{ rm -f $IKCONFIG ; }" EXIT
  17
  18 # Some of the IMA builtin policies may require the kexec kernel image to
  19 # be signed, but these policy rules may be replaced with a custom
  20 # policy.  Only CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS persists after
  21 # loading a custom policy.  Check if it is enabled, before reading the
  22 # IMA runtime sysfs policy file.
  23 # Return 1 for IMA signature required and 0 for not required.
  24 is_ima_sig_required()
  25 {
  26         local ret=0
  27
  28         kconfig_enabled "CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS=y" \
  29                 "IMA kernel image signature required"
  30         if [ $? -eq 1 ]; then
  31                 log_info "IMA signature required"
  32                 return 1
  33         fi
  34
  35         # The architecture specific or a custom policy may require the
  36         # kexec kernel image be signed.  Policy rules are walked
  37         # sequentially.  As a result, a policy rule may be defined, but
  38         # might not necessarily be used.  This test assumes if a policy
  39         # rule is specified, that is the intent.
  40
  41         # First check for appended signature (modsig), then xattr
  42         if [ $ima_read_policy -eq 1 ]; then
  43                 check_ima_policy "appraise" "func=KEXEC_KERNEL_CHECK" \
  44                         "appraise_type=imasig|modsig"
  45                 ret=$?
  46                 if [ $ret -eq 1 ]; then
  47                         log_info "IMA or appended(modsig) signature required"
  48                 else
  49                         check_ima_policy "appraise" "func=KEXEC_KERNEL_CHECK" \
  50                                 "appraise_type=imasig"
  51                         ret=$?
  52                         [ $ret -eq 1 ] && log_info "IMA signature required";
  53                 fi
  54         fi
  55         return $ret
  56 }
  57
  58 # The kexec_file_load_test() is complicated enough, require pesign.
  59 # Return 1 for PE signature found and 0 for not found.
  60 check_for_pesig()
  61 {
  62         which pesign > /dev/null 2>&1 || log_skip "pesign not found"
  63
  64         pesign -i $KERNEL_IMAGE --show-signature | grep -q "No signatures"
  65         local ret=$?
  66         if [ $ret -eq 1 ]; then
  67                 log_info "kexec kernel image PE signed"
  68         else
  69                 log_info "kexec kernel image not PE signed"
  70         fi
  71         return $ret
  72 }
  73
  74 # The kexec_file_load_test() is complicated enough, require getfattr.
  75 # Return 1 for IMA signature found and 0 for not found.
  76 check_for_imasig()
  77 {
  78         local ret=0
  79
  80         which getfattr > /dev/null 2>&1
  81         if [ $? -eq 1 ]; then
  82                 log_skip "getfattr not found"
  83         fi
  84
  85         line=$(getfattr -n security.ima -e hex --absolute-names $KERNEL_IMAGE 2>&1)
  86         echo $line | grep -q "security.ima=0x03"
  87         if [ $? -eq 0 ]; then
  88                 ret=1
  89                 log_info "kexec kernel image IMA signed"
  90         else
  91                 log_info "kexec kernel image not IMA signed"
  92         fi
  93         return $ret
  94 }
  95
  96 # Return 1 for appended signature (modsig) found and 0 for not found.
  97 check_for_modsig()
  98 {
  99         local module_sig_string="~Module signature appended~"
 100         local sig="$(tail --bytes $((${#module_sig_string} + 1)) $KERNEL_IMAGE)"
 101         local ret=0
 102
 103         if [ "$sig" == "$module_sig_string" ]; then
 104                 ret=1
 105                 log_info "kexec kernel image modsig signed"
 106         else
 107                 log_info "kexec kernel image not modsig signed"
 108         fi
 109         return $ret
 110 }
 111
 112 kexec_file_load_test()
 113 {
 114         local succeed_msg="kexec_file_load succeeded"
 115         local failed_msg="kexec_file_load failed"
 116         local key_msg="try enabling the CONFIG_INTEGRITY_PLATFORM_KEYRING"
 117
 118         line=$(kexec --load --kexec-file-syscall $KERNEL_IMAGE 2>&1)
 119
 120         if [ $? -eq 0 ]; then
 121                 kexec --unload --kexec-file-syscall
 122
 123                 # In secureboot mode with an architecture  specific
 124                 # policy, make sure either an IMA or PE signature exists.
 125                 if [ $secureboot -eq 1 ] && [ $arch_policy -eq 1 ] && \
 126                         [ $ima_signed -eq 0 ] && [ $pe_signed -eq 0 ] \
 127                           && [ $ima_modsig -eq 0 ]; then
 128                         log_fail "$succeed_msg (missing sig)"
 129                 fi
 130
 131                 if [ $kexec_sig_required -eq 1 -o $pe_sig_required -eq 1 ] \
 132                      && [ $pe_signed -eq 0 ]; then
 133                         log_fail "$succeed_msg (missing PE sig)"
 134                 fi
 135
 136                 if [ $ima_sig_required -eq 1 ] && [ $ima_signed -eq 0 ] \
 137                      && [ $ima_modsig -eq 0 ]; then
 138                         log_fail "$succeed_msg (missing IMA sig)"
 139                 fi
 140
 141                 if [ $pe_sig_required -eq 0 ] && [ $ima_appraise -eq 1 ] \
 142                     && [ $ima_sig_required -eq 0 ] && [ $ima_signed -eq 0 ] \
 143                     && [ $ima_read_policy -eq 0 ]; then
 144                         log_fail "$succeed_msg (possibly missing IMA sig)"
 145                 fi
 146
 147                 if [ $pe_sig_required -eq 0 ] && [ $ima_appraise -eq 0 ]; then
 148                         log_info "No signature verification required"
 149                 elif [ $pe_sig_required -eq 0 ] && [ $ima_appraise -eq 1 ] \
 150                     && [ $ima_sig_required -eq 0 ] && [ $ima_signed -eq 0 ] \
 151                     && [ $ima_read_policy -eq 1 ]; then
 152                         log_info "No signature verification required"
 153                 fi
 154
 155                 log_pass "$succeed_msg"
 156         fi
 157
 158         # Check the reason for the kexec_file_load failure
 159         echo $line | grep -q "Required key not available"
 160         if [ $? -eq 0 ]; then
 161                 if [ $platform_keyring -eq 0 ]; then
 162                         log_pass "$failed_msg (-ENOKEY), $key_msg"
 163                 else
 164                         log_pass "$failed_msg (-ENOKEY)"
 165                 fi
 166         fi
 167
 168         if [ $kexec_sig_required -eq 1 -o $pe_sig_required -eq 1 ] \
 169              && [ $pe_signed -eq 0 ]; then
 170                 log_pass "$failed_msg (missing PE sig)"
 171         fi
 172
 173         if [ $ima_sig_required -eq 1 ] && [ $ima_signed -eq 0 ]; then
 174                 log_pass "$failed_msg (missing IMA sig)"
 175         fi
 176
 177         if [ $pe_sig_required -eq 0 ] && [ $ima_appraise -eq 1 ] \
 178             && [ $ima_sig_required -eq 0 ] && [ $ima_read_policy -eq 0 ] \
 179             && [ $ima_signed -eq 0 ]; then
 180                 log_pass "$failed_msg (possibly missing IMA sig)"
 181         fi
 182
 183         log_pass "$failed_msg"
 184         return 0
 185 }
 186
 187 # kexec requires root privileges
 188 require_root_privileges
 189
 190 # get the kernel config
 191 get_kconfig
 192
 193 kconfig_enabled "CONFIG_KEXEC_FILE=y" "kexec_file_load is enabled"
 194 if [ $? -eq 0 ]; then
 195         log_skip "kexec_file_load is not enabled"
 196 fi
 197
 198 # Determine which kernel config options are enabled
 199 kconfig_enabled "CONFIG_IMA_APPRAISE=y" "IMA enabled"
 200 ima_appraise=$?
 201
 202 kconfig_enabled "CONFIG_IMA_ARCH_POLICY=y" \
 203         "architecture specific policy enabled"
 204 arch_policy=$?
 205
 206 kconfig_enabled "CONFIG_INTEGRITY_PLATFORM_KEYRING=y" \
 207         "platform keyring enabled"
 208 platform_keyring=$?
 209
 210 kconfig_enabled "CONFIG_IMA_READ_POLICY=y" "reading IMA policy permitted"
 211 ima_read_policy=$?
 212
 213 kconfig_enabled "CONFIG_KEXEC_SIG_FORCE=y" \
 214         "kexec signed kernel image required"
 215 kexec_sig_required=$?
 216
 217 kconfig_enabled "CONFIG_KEXEC_BZIMAGE_VERIFY_SIG=y" \
 218         "PE signed kernel image required"
 219 pe_sig_required=$?
 220
 221 is_ima_sig_required
 222 ima_sig_required=$?
 223
 224 get_secureboot_mode
 225 secureboot=$?
 226
 227 # Are there pe and ima signatures
 228 check_for_pesig
 229 pe_signed=$?
 230
 231 check_for_imasig
 232 ima_signed=$?
 233
 234 check_for_modsig
 235 ima_modsig=$?
 236
 237 # Test loading the kernel image via kexec_file_load syscall
 238 kexec_file_load_test