peter/spectre-meltdown-checker
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enh: kernel decompression: better tolerance over missing tools

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fixes #297
This commit is contained in:
Stéphane Lesimple 2019-11-23 16:28:08 +01:00
parent 5ca7fe91ff
commit 6abe1bc62b
1 changed files with 26 additions and 14 deletions
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40
spectre-meltdown-checker.sh
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@ -1070,14 +1070,14 @@ kernel_err=''
check_kernel()
{
_file="$1"
_desperate_mode="$2"
_mode="$2"
# checking the return code of readelf -h is not enough, we could get
# a damaged ELF file and validate it, check for stderr warnings too
_readelf_warnings=$("${opt_arch_prefix}readelf" -S "$_file" 2>&1 >/dev/null | tr "\n" "/"); ret=$?
_readelf_sections=$("${opt_arch_prefix}readelf" -S "$_file" 2>/dev/null | grep -c -e data -e text -e init)
_kernel_size=$(stat -c %s "$_file" 2>/dev/null || stat -f %z "$_file" 2>/dev/null || echo 10000)
_debug "check_kernel: ret=$? size=$_kernel_size sections=$_readelf_sections warnings=$_readelf_warnings"
if [ -n "$_desperate_mode" ]; then
if [ "$_mode" = desperate ]; then
if "${opt_arch_prefix}strings" "$_file" | grep -Eq '^Linux version '; then
_debug "check_kernel (desperate): ... matched!"
return 0
@ -1110,9 +1110,17 @@ try_decompress()
do
_debug "try_decompress: magic for $3 found at offset $pos"
if ! command -v "$3" >/dev/null 2>&1; then
kernel_err="missing '$3' tool, please install it, usually it's in the '$5' package"
_debug "try_decompress: $kernel_err"
return 0
if [ "$8" = 1 ]; then
# pass1: if the tool is not installed, just bail out silently
# and hope that the next decompression tool will be, and that
# it'll happen to be the proper one for this kernel
_debug "try_decompress: the '$3' tool is not installed (pass 1), try the next algo"
else
# pass2: if the tool is not installed, populate kernel_err this time
kernel_err="missing '$3' tool, please install it, usually it's in the '$5' package"
_debug "try_decompress: $kernel_err"
fi
return 1
fi
pos=${pos%%:*}
# shellcheck disable=SC2086
@ -1152,16 +1160,20 @@ extract_kernel()
fi
# That didn't work, so retry after decompression.
for mode in '' 'desperate'; do
try_decompress '\037\213\010' xy gunzip '' gunzip "$1" "$mode" && return 0
try_decompress '\3757zXZ\000' abcde unxz '' xz-utils "$1" "$mode" && return 0
try_decompress 'BZh' xy bunzip2 '' bzip2 "$1" "$mode" && return 0
try_decompress '\135\0\0\0' xxx unlzma '' xz-utils "$1" "$mode" && return 0
try_decompress '\211\114\132' xy 'lzop' '-d' lzop "$1" "$mode" && return 0
try_decompress '\002\041\114\030' xyy 'lz4' '-d -l' liblz4-tool "$1" "$mode" && return 0
try_decompress '\177ELF' xxy 'cat' '' cat "$1" "$mode" && return 0
for pass in 1 2; do
for mode in normal desperate; do
_debug "extract_kernel: pass $pass $mode mode"
try_decompress '\037\213\010' xy gunzip '' gunzip "$1" "$mode" "$pass" && return 0
try_decompress '\002\041\114\030' xyy 'lz4' '-d -l' liblz4-tool "$1" "$mode" "$pass" && return 0
try_decompress '\3757zXZ\000' abcde unxz '' xz-utils "$1" "$mode" "$pass" && return 0
try_decompress 'BZh' xy bunzip2 '' bzip2 "$1" "$mode" "$pass" && return 0
try_decompress '\135\0\0\0' xxx unlzma '' xz-utils "$1" "$mode" "$pass" && return 0
try_decompress '\211\114\132' xy 'lzop' '-d' lzop "$1" "$mode" "$pass" && return 0
try_decompress '\177ELF' xxy 'cat' '' cat "$1" "$mode" "$pass" && return 0
done
done
_verbose "Couldn't extract the kernel image, accuracy might be reduced"
kernel_err="kernel compression format is unknown or image is invalid"
_verbose "Couldn't extract the kernel image ($kernel_err), accuracy might be reduced"
return 1
}