Created
May 24, 2011 23:04
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Get entrypoints from elf files
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#!/bin/bash | |
# Get program entry points with the help of objdump and hexdump | |
# Copyleft dipswitch@ownage4u.nl 2011 | |
if [[ -z $1 ]]; then | |
echo "Usage: $0 <elf>" 1>&2; | |
exit 1; | |
fi; | |
if [[ ! -e "$1" ]]; then | |
echo "No file named '$1' found me mate!" 1>&2; | |
exit 2; | |
fi; | |
if ! file $1 | grep ELF 2>&1 > /dev/null; then | |
echo "Arrgggg this no even looks like an ELF to me, me mate!" 1>&2; | |
exit 3; | |
fi; | |
CTOR_START="0xffffffff"; | |
CTOR_END="0x00000000"; | |
ADDR_FORMAT='"0x%08x "'; | |
BYTE_COUNT=32; | |
if file $1 | grep 'ELF 64' 2>&1 > /dev/null; then | |
CTOR_START="${CTOR_START}ffffffff"; | |
CTOR_END="${CTOR_END}00000000"; | |
ADDR_FORMAT='"0x%08x%08x "'; | |
BYTE_COUNT=64; | |
fi; | |
for addr in $(hexdump -e "$ADDR_FORMAT" -n $BYTE_COUNT -s 0x`objdump -x "$1" | grep .ctors | sed -e 's/ */ /g' | cut -d' ' -f 7 | line` "$1"); do | |
if [[ $addr == $CTOR_START ]]; then | |
continue; | |
elif [[ $addr == $CTOR_END ]]; then | |
if [[ -n $FIRST ]]; then | |
echo -ne "\n" | |
fi; | |
break; | |
else | |
if [[ -z $FIRST ]]; then | |
echo ".ctors:"; | |
FIRST=1; | |
fi; | |
if [[ $BYTE_COUNT -eq 64 ]]; then | |
echo $addr | sed -e 's/\(0x\)\([0-9a-f]\{8\}\)\([0-9a-f]\{8\}\)/\1\3\2/g' | |
else | |
echo $addr; | |
fi; | |
fi; | |
done; | |
tmp=`mktemp /tmp/input.XXXX`; | |
echo "entrypoints:"; | |
if objdump -x "$1" | grep 'start address' | grep -o '0x[0-9a-f]*' > $tmp; then | |
echo ".text: "`cat ${tmp}`; | |
fi; | |
if objdump -j .text -M intel -D "$1" | grep '<_start>:' | grep -o '[0-9a-f]* ' > $tmp; then | |
echo "_start: 0x"`cat ${tmp}`; | |
fi; | |
if objdump -j .text -M intel -D "$1" | grep '<main>:' | grep -o '[0-9a-f]* ' > $tmp; then | |
echo "main: 0x"`cat ${tmp}`; | |
fi; | |
if objdump -j .text -M intel -D "$1" | grep '<.text>:' -A20 | grep '__libc_start_main' -B1 | line | grep -o '0x[0-9a-z]*' > $tmp; then | |
echo "Stripped main: "`cat ${tmp}`; | |
elif objdump -j .text -M intel -D "$1" | grep '<.text>:' -A20 | grep 'hlt' -B2 | line | grep -o '0x[0-9a-z]*' > $tmp; then | |
echo "Static stripped main: "`cat ${tmp}`; | |
fi; | |
unset FIRST | |
for addr in $(hexdump -e "$ADDR_FORMAT" -n $BYTE_COUNT -s 0x`objdump -x "$1" | grep .dtors | sed -e 's/ */ /g' | cut -d' ' -f 7 | line` "$1"); do | |
if [[ $addr == $CTOR_START ]]; then | |
continue; | |
elif [[ $addr == $CTOR_END ]]; then | |
break; | |
else | |
if [[ -z $FIRST ]]; then | |
echo -e "\n.dtors:"; | |
FIRST=1; | |
fi; | |
if [[ $BYTE_COUNT -eq 64 ]]; then | |
echo $addr | sed -e 's/\(0x\)\([0-9a-f]\{8\}\)\([0-9a-f]\{8\}\)/\1\3\2/g' | |
else | |
echo $addr; | |
fi; | |
fi; | |
done; | |
rm $tmp 2> /dev/null |
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