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feat(arm): detect spectre variant 1 mitigation

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This commit is contained in:
Stéphane Lesimple 2018-04-03 15:52:25 +02:00
parent aef99d20f3
commit 056ed00baa
1 changed files with 40 additions and 8 deletions
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48
spectre-meltdown-checker.sh
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@ -1644,7 +1644,7 @@ check_variant1_linux()
fi
if [ "$opt_sysfs_only" != 1 ]; then
# no /sys interface (or offline mode), fallback to our own ways
_info_nol "* Kernel has array_index_mask_nospec: "
_info_nol "* Kernel has array_index_mask_nospec (x86): "
# vanilla: look for the Linus' mask aka array_index_mask_nospec()
# that is inlined at least in raw_copy_from_user (__get_user_X symbols)
#mov PER_CPU_VAR(current_task), %_ASM_DX
@ -1664,12 +1664,12 @@ check_variant1_linux()
perl -ne '/\x0f\x83....\x48\x19\xd2\x48\x21\xd0/ and $found++; END { exit($found) }' "$kernel"; ret=$?
if [ $ret -gt 0 ]; then
pstatus green YES "$ret occurence(s) found of 64 bits array_index_mask_nospec()"
v1_mask_nospec=1
v1_mask_nospec="64 bits array_index_mask_nospec"
else
perl -ne '/\x3b\x82..\x00\x00\x73.\x19\xd2\x21\xd0/ and $found++; END { exit($found) }' "$kernel"; ret=$?
if [ $ret -gt 0 ]; then
pstatus green YES "$ret occurence(s) found of 32 bits array_index_mask_nospec()"
v1_mask_nospec=1
v1_mask_nospec="32 bits array_index_mask_nospec"
else
pstatus yellow NO
fi
@ -1690,7 +1690,39 @@ check_variant1_linux()
pstatus yellow NO
fi
if [ "$opt_verbose" -ge 2 ] || ( [ "$v1_mask_nospec" != 1 ] && [ "$redhat_canonical_spectre" != 1 ] && [ "$redhat_canonical_spectre" != 2 ] ); then
_info_nol "* Kernel has mask_nospec64 (arm): "
#.macro mask_nospec64, idx, limit, tmp
#sub \tmp, \idx, \limit
#bic \tmp, \tmp, \idx
#and \idx, \idx, \tmp, asr #63
#csdb
#.endm
#$ aarch64-linux-gnu-objdump -d vmlinux | grep -w bic -A1 -B1 | grep -w sub -A2 | grep -w and -B2
#ffffff8008082e44: cb190353 sub x19, x26, x25
#ffffff8008082e48: 8a3a0273 bic x19, x19, x26
#ffffff8008082e4c: 8a93ff5a and x26, x26, x19, asr #63
#ffffff8008082e50: d503229f hint #0x14
# if we have v1_mask_nospec or redhat_canonical_spectre>0, don't bother disassembling the kernel, the answer is no.
if [ -n "$v1_mask_nospec" ] || [ "$redhat_canonical_spectre" -gt 0 ]; then
pstatus yellow NO
elif [ -n "$kernel_err" ]; then
pstatus yellow UNKNOWN "couldn't check ($kernel_err)"
elif ! which perl >/dev/null 2>&1; then
pstatus yellow UNKNOWN "missing 'perl' binary, please install it"
elif ! which "${opt_arch_prefix}objdump" >/dev/null 2>&1; then
pstatus yellow UNKNOWN "missing '${opt_arch_prefix}objdump' tool, please install it, usually it's in the binutils package"
else
"${opt_arch_prefix}objdump" -d "$kernel" | perl -ne 'push @r, $_; /\shint\s/ && $r[0]=~/\ssub\s+(x\d+)/ && $r[1]=~/\sbic\s+$1,\s+$1,/ && $r[2]=~/\sand\s/ && exit(9); shift @r if @r>3'; ret=$?
if [ "$ret" -eq 9 ]; then
pstatus green YES "mask_nospec64 macro is present and used"
v1_mask_nospec="arm mask_nospec64"
else
pstatus yellow NO
fi
fi
if [ "$opt_verbose" -ge 2 ] || ( [ -z "$v1_mask_nospec" ] && [ "$redhat_canonical_spectre" != 1 ] && [ "$redhat_canonical_spectre" != 2 ] ); then
# this is a slow heuristic and we don't need it if we already know the kernel is patched
# but still show it in verbose mode
_info_nol "* Checking count of LFENCE instructions following a jump in kernel... "
@ -1731,8 +1763,8 @@ check_variant1_linux()
pvulnstatus $cve OK "your CPU vendor reported your CPU model as not vulnerable"
elif [ -z "$msg" ]; then
# if msg is empty, sysfs check didn't fill it, rely on our own test
if [ "$v1_mask_nospec" = 1 ]; then
pvulnstatus $cve OK "Kernel source has been patched to mitigate the vulnerability (array_index_mask_nospec)"
if [ -n "$v1_mask_nospec" ]; then
pvulnstatus $cve OK "Kernel source has been patched to mitigate the vulnerability ($v1_mask_nospec)"
elif [ "$redhat_canonical_spectre" = 1 ] || [ "$redhat_canonical_spectre" = 2 ]; then
pvulnstatus $cve OK "Kernel source has been patched to mitigate the vulnerability (Red Hat/Ubuntu patch)"
elif [ "$v1_lfence" = 1 ]; then
@ -1743,7 +1775,7 @@ check_variant1_linux()
pvulnstatus $cve VULN "Kernel source needs to be patched to mitigate the vulnerability"
fi
else
if [ "$msg" = "Vulnerable" ] && [ "$v1_mask_nospec" = 1 ]; then
if [ "$msg" = "Vulnerable" ] && [ -n "$v1_mask_nospec" ]; then
pvulnstatus $cve OK "Kernel source has been patched to mitigate the vulnerability (silent backport of array_index_mask_nospec)"
else
[ "$msg" = "Vulnerable" ] && msg="Kernel source needs to be patched to mitigate the vulnerability"
@ -1938,7 +1970,7 @@ check_variant2_linux()
fi
_info "* Mitigation 2"
_info_nol " * Kernel has branch predictor hardening (ARM): "
_info_nol " * Kernel has branch predictor hardening (arm): "
if [ -r "$opt_config" ]; then
bp_harden_can_tell=1
bp_harden=$(grep -w 'CONFIG_HARDEN_BRANCH_PREDICTOR=y' "$opt_config")