1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
#!/bin/bash
# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
# Abort on error.
set -e
# Load common constants and variables.
. "$(dirname "$0")/common.sh"
# Given a kernel boot param string which includes ...dm="dmstuff"...
# this returns the dmstuff by itself.
get_dmparams() {
echo "$1" | sed 's/^.*\ dm="\([^"]*\)".*/\1/'
}
# Given a kernel boot param string which includes ...dm="stuff"...
# this returns the param string with the dm="..." section removed.
# Useful in conjunction with get_dmparams to divide and process
# the two sections of parameters in seperate passes
kparams_remove_dm() {
echo "$1" | sed 's/dm="[^"]*"//'
}
# Given a dm param string which includes dynamic values, return the
# same string with these values replaced by a magic string placeholder.
# This same magic placeholder is used in the config file, for comparison
# purposes.
dmparams_mangle() {
local dmparams=$1
# First handle new key-value style verity parameters.
dmparams=$(echo "$dmparams" |
sed -e 's/root_hexdigest=[0-9a-fA-F]*/root_hexdigest=MAGIC_HASH/' |
sed -e 's/salt=[0-9a-fA-F]*/salt=MAGIC_SALT'/)
# If we didn't substitute the MAGIC_HASH yet, these are the old
# verity parameter format.
if [[ $dmparams != *MAGIC_HASH* ]]; then
dmparams=$(echo $dmparams | sed 's/sha1 [0-9a-fA-F]*/sha1 MAGIC_HASH/')
fi
# If we have bootcache enabled, replace its copy of the root_hexdigest
# with MAGIC_HASH. The parameter is positional.
if [[ $dmparams == *bootcache* ]]; then
dmparams=$(echo $dmparams |
sed -r 's:(bootcache (PARTUUID=)?%U(/PARTNROFF=|\+)1 [0-9]+) [0-9a-fA-F]+:\1 MAGIC_HASH:')
fi
echo $dmparams
}
# This escapes any non-alphanum character, since many such characters
# are regex metacharacters.
escape_regexmetas() {
echo "$1" | sed 's/\([^a-zA-Z0-9]\)/\\\1/g'
}
usage() {
echo "Usage $PROG image [config]"
}
main() {
# We want to catch all the discrepancies, not just the first one.
# So, any time we find one, we set testfail=1 and continue.
# When finished we will use testfail to determine our exit value.
local testfail=0
# A buffer to include useful information that we dump when things fail.
local output
# Copy of a string before it has been through sed
local pre_sed
# Where the disk image is mounted.
local loopdev
if [[ $# -ne 1 ]] && [[ $# -ne 2 ]]; then
usage
exit 1
fi
local image="$1"
# A byte that should not appear in the command line to use as a sed
# marker when doing regular expression replacements.
local M=$'\001'
# Default config location: same name/directory as this script,
# with a .config file extension, ie ensure_secure_kernelparams.config.
local configfile="$(dirname "$0")/${0/%.sh/.config}"
# Or, maybe a config was provided on the command line.
if [[ $# -eq 2 ]]; then
configfile="$2"
fi
# Either way, load test-expectations data from config.
. "$configfile" || return 1
# Set up the image on a loopback device so it's faster to access.
local loopdev
loopdev=$(loopback_partscan "${image}")
# TODO(jimhebert): Perform the kernel security tests on both the kernel
# partitions. Here, we just run it on kernel partition 4
# which is the install kernel on the recovery image.
# crosbug.com/24274
local loop_kern="${loopdev}p4"
local loop_rootfs="${loopdev}p3"
local rootfs=$(make_temp_dir)
sudo mount -o ro "${loop_rootfs}" "${rootfs}"
# Pick the right set of test-expectation data to use.
local boardvar=$(get_boardvar_from_lsb_release "${rootfs}")
eval "required_kparams=(\"\${required_kparams_${boardvar}[@]}\")"
eval "required_kparams_regex=(\"\${required_kparams_regex_${boardvar}[@]}\")"
eval "optional_kparams=(\"\${optional_kparams_${boardvar}[@]}\")"
eval "optional_kparams_regex=(\"\${optional_kparams_regex_${boardvar}[@]}\")"
eval "required_dmparams=(\"\${required_dmparams_${boardvar}[@]}\")"
eval "required_dmparams_regex=(\"\${required_dmparams_regex_${boardvar}[@]}\")"
output+="required_kparams=(\n"
output+="$(printf "\t'%s'\n" "${required_kparams[@]}")\n)\n"
output+="required_kparams_regex=(\n"
output+="$(printf "\t'%s'\n" "${required_kparams_regex[@]}")\n)\n"
output+="optional_kparams=(\n"
output+="$(printf "\t'%s'\n" "${optional_kparams[@]}")\n)\n"
output+="optional_kparams_regex=(\n"
output+="$(printf "\t'%s'\n" "${optional_kparams_regex[@]}")\n)\n"
output+="required_dmparams=(\n"
output+="$(printf "\t'%s'\n" "${required_dmparams[@]}")\n)\n"
output+="required_dmparams_regex=(\n"
output+="$(printf "\t'%s'\n" "${required_dmparams_regex[@]}")\n)\n"
# Divide the dm params from the rest and process seperately.
local kparams=$(sudo dump_kernel_config "${loop_kern}")
local dmparams=$(get_dmparams "$kparams")
local kparams_nodm=$(kparams_remove_dm "$kparams")
output+="\nkparams='${kparams}'\n"
output+="\ndmparams='${dmparams}'\n"
output+="\nkparams_nodm='${kparams_nodm}'\n"
mangled_dmparams=$(dmparams_mangle "${dmparams}")
output+="\nmangled_dmparams='${mangled_dmparams}'\n"
# Special-case handling of the dm= param:
testfail=1
for expected_dmparams in "${required_dmparams[@]}"; do
# Filter out all dynamic parameters.
if [ "$mangled_dmparams" = "$expected_dmparams" ]; then
testfail=0
break
fi
done
for expected_dmparams in "${required_dmparams_regex[@]}"; do
if [[ -z $(echo "${mangled_dmparams}" | \
sed "s${M}^${expected_dmparams}\$${M}${M}") ]]; then
testfail=0
break
fi
done
if [ $testfail -eq 1 ]; then
echo "Kernel dm= parameter does not match any expected values!"
echo "Actual: $dmparams"
echo "Expected: ${required_dmparams[*]}"
echo "Expected (regex): ${required_dmparams_regex[*]}"
fi
# Ensure all other required params are present.
for param in "${required_kparams[@]}"; do
if [[ "$kparams_nodm" != *$param* ]]; then
echo "Kernel parameters missing required value: $param"
testfail=1
else
# Remove matched params as we go. If all goes well, kparams_nodm
# will be nothing left but whitespace by the end.
param=$(escape_regexmetas "$param")
kparams_nodm=$(echo " ${kparams_nodm} " |
sed "s${M} ${param} ${M} ${M}")
fi
done
# Ensure all other required regex params are present.
for param in "${required_kparams_regex[@]}"; do
pre_sed=" ${kparams_nodm} "
kparams_nodm=$(echo "${pre_sed}" | sed "s${M} ${param} ${M} ${M}")
if [[ "${pre_sed}" == "${kparams_nodm}" ]]; then
echo "Kernel parameters missing required value: ${param}"
testfail=1
fi
done
# Check-off each of the allowed-but-optional params that were present.
for param in "${optional_kparams[@]}"; do
param=$(escape_regexmetas "$param")
kparams_nodm=$(echo " ${kparams_nodm} " |
sed "s${M} ${param} ${M} ${M}")
done
# Check-off each of the allowed-but-optional params that were present.
for param in "${optional_kparams_regex[@]}"; do
kparams_nodm=$(echo " ${kparams_nodm} " |
sed "s${M} ${param} ${M} ${M}")
done
# This section enforces the default-deny for any unexpected params
# not already processed by one of the above loops.
if [[ ! -z ${kparams_nodm// /} ]]; then
echo "Unexpected kernel parameters found:"
echo " $(echo "${kparams_nodm}" | sed -r 's: +: :g')"
testfail=1
fi
if [[ ${testfail} -eq 1 ]]; then
echo "Debug output:"
printf '%b\n' "${output}"
echo "(actual error will be at the top of output)"
fi
exit $testfail
}
main $@
|
