On Thu, 2018-04-19 at 21:54 +0200, Petr Vorel wrote:
> -# Function: test02
> -# Description - Verify modifying, then reading, a file causes a new
> -# measurement to be added to the IMA measurement list.
> -test02()
> +ima_check()
> {
> - # Modify test.txt
> - echo $(date) - file modified >> test.txt
> + local digest="$DEFAULT_DIGEST_OLD_FORMAT"
> + local hash expected_hash line
> +
> + # need to read file to get updated $ASCII_MEASUREMENTS
> + cat $TEST_FILE > /dev/null
> +
> + line="$(grep $TEST_FILE $ASCII_MEASUREMENTS | tail -1)"
> + [ -n "$line" ] || tst_res TFAIL "cannot find measurement for '$TEST_FILE'"
>
> - # Calculating the sha1sum of test.txt should add
> - # the new measurement to the measurement list
> - hash=$(sha1sum test.txt | sed 's/ -//')
> + [ "$DIGEST_INDEX" ] && digest="$(echo "$line" | awk '{print $(NF-'$DIGEST_INDEX')}' | cut -d ':' -f 1)"
> + hash="$(echo "$line" | awk '{print $(NF-1)}' | cut -d ':' -f 2)"
With the "ima-sig" template, with a measurement that does not contain
the signature, this works fine. There's a problem with lines
containing the signature.
Sample ima-sig template measurements with/without the signature:
line="10 ee788468d1b416a394feb9f4e5650302d9cd5574 ima-sig sha256:866c2542efd5c7528591eb3bb2861a1994a655da47732ccf28f7f4b1ce42d564 /usr/lib64/libpam.so.0.84.1"
line="10 d3afb4df5fe42485b99677f4b68a04692977b4bc ima-sig sha256:7b85508c9181670fe169935310b8c95d7c2573f0318a70cecd12868569aab891 /etc/profile.d/less.sh 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"
>
> - # Check if the new measurement exists
> - cat /sys/kernel/security/ima/ascii_runtime_measurements > measurements
> - $(grep $hash measurements > /dev/null)
> + tst_res TINFO "computing hash for $digest digest"
> + expected_hash="$(compute_hash $digest $TEST_FILE)" || \
> + { tst_res TCONF "cannot compute hash for '$digest' digest"; return; }
>
> - if [ $? -ne 0 ]; then
> - tst_resm TFAIL "Modified file not measured"
> - tst_resm TINFO "iversion not supported; or not mounted with iversion"
> + if [ "$hash" = "$expected_hash" ]; then
> + tst_res TPASS "correct hash found"
> else
> - tst_resm TPASS "Modified file measured"
> + tst_res TFAIL "hash not found"
> fi
> }
>
