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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() check_kernel()
{ {
_file="$1" _file="$1"
_desperate_mode="$2" _mode="$2"
# checking the return code of readelf -h is not enough, we could get # checking the return code of readelf -h is not enough, we could get
# a damaged ELF file and validate it, check for stderr warnings too # a damaged ELF file and validate it, check for stderr warnings too
_readelf_warnings=$("${opt_arch_prefix}readelf" -S "$_file" 2>&1 >/dev/null | tr "\n" "/"); ret=$? _readelf_warnings=$("${opt_arch_prefix}readelf" -S "$_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) _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) _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=$_readelf_warnings" _debug "check_kernel: ret=$? size=$_kernel_size sections=$_readelf_sections warnings=$_readelf_warnings"
if [ -n "$_desperate_mode" ]; then if [ "$_mode" = desperate ]; then
if "${opt_arch_prefix}strings" "$_file" | grep -Eq '^Linux version '; then if "${opt_arch_prefix}strings" "$_file" | grep -Eq '^Linux version '; then
_debug "check_kernel (desperate): ... matched!" _debug "check_kernel (desperate): ... matched!"
return 0 return 0
@@ -1110,9 +1110,17 @@ try_decompress()
do do
_debug "try_decompress: magic for $3 found at offset $pos" _debug "try_decompress: magic for $3 found at offset $pos"
if ! command -v "$3" >/dev/null 2>&1; then if ! command -v "$3" >/dev/null 2>&1; then
kernel_err="missing '$3' tool, please install it, usually it's in the '$5' package" if [ "$8" = 1 ]; then
_debug "try_decompress: $kernel_err" # pass1: if the tool is not installed, just bail out silently
return 0 # 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: $kernel_err"
fi
return 1
fi fi
pos=${pos%%:*} pos=${pos%%:*}
# shellcheck disable=SC2086 # shellcheck disable=SC2086
@@ -1152,16 +1160,20 @@ extract_kernel()
fi fi
# That didn't work, so retry after decompression. # That didn't work, so retry after decompression.
for mode in '' 'desperate'; do for pass in 1 2; do
try_decompress '\037\213\010' xy gunzip '' gunzip "$1" "$mode" && return 0 for mode in normal desperate; do
try_decompress '\3757zXZ\000' abcde unxz '' xz-utils "$1" "$mode" && return 0 _debug "extract_kernel: pass $pass $mode mode"
try_decompress 'BZh' xy bunzip2 '' bzip2 "$1" "$mode" && return 0 try_decompress '\037\213\010' xy gunzip '' gunzip "$1" "$mode" "$pass" && return 0
try_decompress '\135\0\0\0' xxx unlzma '' xz-utils "$1" "$mode" && return 0 try_decompress '\002\041\114\030' xyy 'lz4' '-d -l' liblz4-tool "$1" "$mode" "$pass" && return 0
try_decompress '\211\114\132' xy 'lzop' '-d' lzop "$1" "$mode" && return 0 try_decompress '\3757zXZ\000' abcde unxz '' xz-utils "$1" "$mode" "$pass" && return 0
try_decompress '\002\041\114\030' xyy 'lz4' '-d -l' liblz4-tool "$1" "$mode" && return 0 try_decompress 'BZh' xy bunzip2 '' bzip2 "$1" "$mode" "$pass" && return 0
try_decompress '\177ELF' xxy 'cat' '' cat "$1" "$mode" && 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" "$pass" && return 0
done
done done
_verbose "Couldn't extract the kernel image, accuracy might be reduced" kernel_err="kernel compression format is unknown or image is invalid"
_verbose "Couldn't extract the kernel image ($kernel_err), accuracy might be reduced"
return 1 return 1
} }