GPG signature verification tool

The signature verification tool uses gpg to verify the detached
signature of the given file.

It also tries to obtain the signing key if it is not part of the local
key ring.

Signature verification implies the verification of the integrity and
authenticity of a given file.

Issue #748
devel
Stephan Mueller 9 years ago committed by Norman Feske
parent f07973126d
commit 9b22983e58
  1. 131
      tool/download_sigver

@ -0,0 +1,131 @@
#!/bin/bash
#
# \brief Signature verification tool
# \author Stephan Müller
# \date 2013-05-24
#
# Script to be invoked as
# $0 <file to be checked> <signature file> <source pubkeys>
#
# The source pubkey(s) is some ID that can be handled by gpg --search-keys
# or --recv-keys
# The special keyword of GNU as source pubkey implies the downloading of the GNU
# key ring.
#
# Script returns 0 on success. Any other value is a failure.
FILE=$1
SIGFILE=$2
shift;shift;
PUBKEYSRC=$@
#
# Probe if a default keyserver is configured by the user. If not, fall back to
# a predefined key server.
#
KEYSERVER=""
if ! $(cat $HOME/.gnupg/gpg.conf | grep -v '^#.*' | grep -q keyserver); then
KEYSERVER="--keyserver hkp://keys.gnupg.net"
fi
# Get a particular key
# \param key fingerprint to obtain
get_gpg_key()
{
key=$1
# check if key is present
gpg --list-key $key > /dev/null 2>&1
if [ $? -eq 0 ];then
return
fi
size=$(echo -n $key |wc -m)
if [ "$size" -eq 40 ]
then
# we have a full fingerprint
gpg $KEYSERVER --recv-keys $key
else
# we have some other ID
gpg $KEYSERVER --search-keys $key
fi
}
GNUURL="ftp://ftp.gnu.org/gnu/gnu-keyring.gpg"
get_gnu_keys()
{
sigfile=$1
sigdir=$(dirname $sigfile)
if [ ! -d "$sigdir" ]
then
echo "Directory $sigdir does not exist"
exit 1
fi
targetfile=$(basename $GNUURL)
if [ ! -f "$sigdir/$targetfile" ]
then
wget -c -P $sigdir $GNUURL
fi
}
# Get all keys handed in
# \param array of keys to be searched
get_all_keys()
{
keys=$@
for i in $keys
do
get_gpg_key $i
done
}
# Verify the file
# \param file to be verified
# \param signature file
#
# function causes script to exit:
# return 0 implies all passed
# any other return code implies failure
verify_file()
{
file=$1
sigfile=$2
gpgargs=""
targetfile=$(basename $GNUURL)
sigdir=$(dirname $sigfile)
if [ -f "$sigdir/$targetfile" ]
then
gpgargs="--keyring $sigdir/$targetfile"
fi
if [ -z "$file" -o ! -f "$file" ]
then
echo "File $file not found"
exit 1
fi
if [ -z "$sigfile" -o ! -f "$sigfile" ]
then
echo "Signature file $sigfile not found"
exit 1
fi
gpg --verify $gpgargs $sigfile $file
if [ $? -ne 0 ]
then
echo "Signature check of file $file failed"
exit 1
fi
echo "Signature check of file $file passed"
exit 0
}
if [ "$PUBKEYSRC" = "GNU" ]
then
get_gnu_keys $SIGFILE
else
get_all_keys "$PUBKEYSRC"
fi
verify_file $FILE $SIGFILE
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