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
 13TEST="KEXEC_FILE_LOAD"
 14. ./kexec_common_lib.sh
 15
 16trap "{ 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.
 24is_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.
 60check_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.
 76check_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 $ret
 94}
 95
 96# Return 1 for appended signature (modsig) found and 0 for not found.
 97check_for_modsig()
 98{
 99	local module_sig_string="~Module signature appended~"
100	local sig="$(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 $ret
110}
111
112kexec_file_load_test()
113{
114	local succeed_msg="kexec_file_load succeeded"
115	local failed_msg="kexec_file_load failed"
116	local key_msg="try enabling the CONFIG_INTEGRITY_PLATFORM_KEYRING"
117
118	line=$(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
188require_root_privileges
189
190# get the kernel config
191get_kconfig
192
193kconfig_enabled "CONFIG_KEXEC_FILE=y" "kexec_file_load is enabled"
194if [ $? -eq 0 ]; then
195	log_skip "kexec_file_load is not enabled"
196fi
197
198# Determine which kernel config options are enabled
199kconfig_enabled "CONFIG_IMA_APPRAISE=y" "IMA enabled"
200ima_appraise=$?
201
202kconfig_enabled "CONFIG_IMA_ARCH_POLICY=y" \
203	"architecture specific policy enabled"
204arch_policy=$?
205
206kconfig_enabled "CONFIG_INTEGRITY_PLATFORM_KEYRING=y" \
207	"platform keyring enabled"
208platform_keyring=$?
209
210kconfig_enabled "CONFIG_IMA_READ_POLICY=y" "reading IMA policy permitted"
211ima_read_policy=$?
212
213kconfig_enabled "CONFIG_KEXEC_SIG_FORCE=y" \
214	"kexec signed kernel image required"
215kexec_sig_required=$?
216
217kconfig_enabled "CONFIG_KEXEC_BZIMAGE_VERIFY_SIG=y" \
218	"PE signed kernel image required"
219pe_sig_required=$?
220
221is_ima_sig_required
222ima_sig_required=$?
223
224get_secureboot_mode
225secureboot=$?
226
227# Are there pe and ima signatures
228check_for_pesig
229pe_signed=$?
230
231check_for_imasig
232ima_signed=$?
233
234check_for_modsig
235ima_modsig=$?
236
237# Test loading the kernel image via kexec_file_load syscall
238kexec_file_load_test