On Fri, Nov 04, 2016 at 05:17:54PM -0700, Darrick J. Wong wrote:
> Create some routines to help us perform targeted fuzzing of individual
> fields in various XFS structures. Specifically, we want the caller to
> drop the xfs_db iocursor on the victim field; from there, the scripts
> should discover all available fields and fuzzing verbs, and try each
> fuzz verb on every available field.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> common/fuzzy | 191 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 191 insertions(+)
>
>
> diff --git a/common/fuzzy b/common/fuzzy
> index 20f1d29..6af47f1 100644
> --- a/common/fuzzy
> +++ b/common/fuzzy
> @@ -81,3 +81,194 @@ _scratch_scrub() {
> ;;
> esac
> }
> +
> +# Filter the xfs_db print command's field debug information
> +# into field name and type.
> +__filter_xfs_db_print_fields() {
> + grep ' = ' | while read key equals value; do
> + fuzzkey="$(echo "${key}" | sed -e 's/\([a-zA-Z0-9_]*\)\[\([0-9]*\)-[0-9]*\]/\1[\2]/g')"
> + if [[ "${value}" == "["* ]]; then
> + echo "${value}" | sed -e 's/^.//g' -e 's/.$//g' -e 's/,/\n/g' | while read subfield; do
> + echo "${fuzzkey}.${subfield}"
> + done
> + else
> + echo "${fuzzkey}"
> + fi
> + done
> +}
> +
> +# Navigate to some part of the filesystem and print the field info.
> +_scratch_xfs_list_metadata_fields() {
> + if [ -n "${SCRATCH_XFS_LIST_METADATA_FIELDS}" ]; then
> + echo "${SCRATCH_XFS_LIST_METADATA_FIELDS}" | sed -e 's/ /\n/g'
> + return;
> + fi
> +
> + (for arg in "$@"; do
> + echo "${arg}"
> + done
> + echo "print") | _scratch_xfs_db | __filter_xfs_db_print_fields
> +}
> +
> +# Get a metadata field
> +_scratch_xfs_get_metadata_field() {
> + key="$1"
> + shift
> +
> + grep_key="$(echo "${key}" | tr '[]()' '....')"
> + (for arg in "$@"; do
> + echo "${arg}"
> + done
> + echo "print ${key}") | _scratch_xfs_db | grep "^${grep_key}" | \
> + sed -e 's/^.* = //g'
> +}
> +
> +# Set a metadata field
> +_scratch_xfs_set_metadata_field() {
> + key="$1"
> + value="$2"
> + shift; shift
> + (for arg in "$@"; do
> + echo "${arg}"
> + done
> + echo "write -d ${key} ${value}") | _scratch_xfs_db -x
> + echo
> +}
> +
> +# Fuzz a metadata field
> +_scratch_xfs_fuzz_metadata_field() {
> + key="$1"
> + value="$2"
> + shift; shift
> +
> + if [ "${key}" = "crc" ]; then
> + fuzz_arg="-c"
> + else
> + fuzz_arg="-d"
> + fi
> + oldval="$(_scratch_xfs_get_metadata_field "${key}" "$@")"
> + (for arg in "$@"; do
> + echo "${arg}"
> + done
> + echo "fuzz ${fuzz_arg} ${key} ${value}") | _scratch_xfs_db -x
> + echo
> + newval="$(_scratch_xfs_get_metadata_field "${key}" "$@" 2> /dev/null)"
> + if [ "${oldval}" = "${newval}" ]; then
> + echo "Field ${key} already set to ${oldval}, skipping test."
> + return 1
> + fi
> + return 0
> +}
> +
> +# Try to forcibly unmount the scratch fs
> +__scratch_xfs_fuzz_unmount()
> +{
> + while _scratch_unmount 2>/dev/null; do sleep 0.2; done
Shouldn't this be
while ! _scratch_unmount 2>/dev/null; do sleep 0.2; done
so it only sleeps and try again if umount failed?
Thanks,
Eryu
> +}
> +
> +# Restore metadata to scratch device prior to field-fuzzing.
> +__scratch_xfs_fuzz_mdrestore()
> +{
> + test -e "${POPULATE_METADUMP}" || _fail "Need to set POPULATE_METADUMP"
> +
> + __scratch_xfs_fuzz_unmount
> + xfs_mdrestore "${POPULATE_METADUMP}" "${SCRATCH_DEV}"
> +}
> +
> +__fuzz_notify() {
> + echo "$@"
> + test -w /dev/ttyprintk && echo "$@" >> /dev/ttyprintk
> +}
> +
> +# Fuzz one field of some piece of metadata
> +__scratch_xfs_fuzz_field_test() {
> + field="$1"
> + fuzzverb="$2"
> + shift; shift
> +
> + # Set the new field value
> + __fuzz_notify "+ Fuzz ${field} = ${fuzzverb}"
> + echo "========================"
> + _scratch_xfs_fuzz_metadata_field "${field}" ${fuzzverb} "$@"
> + res=$?
> + test $res -ne 0 && return
> +
> + # Try to catch the error with scrub
> + echo "+ Try to catch the error"
> + _scratch_mount 2>&1
> + res=$?
> + if [ $res -eq 0 ]; then
> + _scratch_scrub -a 1 -e continue 2>&1
> + res=$?
> + test $res -eq 0 && \
> + (>&2 echo "scrub didn't fail with ${field} = ${fuzzverb}.")
> +
> + # Try modifying the filesystem!
> + __fuzz_notify "++ Try to write filesystem"
> + #_scratch_fuzz_modify 100 2>&1
> + __scratch_xfs_fuzz_unmount
> + fi
> +
> + # Repair the filesystem
> + echo "+ Fix the error"
> + _repair_scratch_fs 2>&1
> + res=$?
> + test $res -ne 0 && \
> + (>&2 echo "repair failed ($res) with ${field} = ${fuzzverb}.")
> +
> + # See if scrub finds a clean fs
> + echo "+ Make sure error is gone"
> + _scratch_mount 2>&1
> + res=$?
> + if [ $res -eq 0 ]; then
> + _scratch_scrub -e continue 2>&1
> + res=$?
> + test $res -ne 0 && \
> + (>&2 echo "re-scrub ($res) with ${field} = ${fuzzverb}.")
> +
> + # Try modifying the filesystem again!
> + __fuzz_notify "++ Try to write filesystem again"
> + _scratch_fuzz_modify 100 2>&1
> + __scratch_xfs_fuzz_unmount
> + else
> + (>&2 echo "re-mount failed ($res) with ${field} = ${fuzzverb}.")
> + fi
> +
> + # See if repair finds a clean fs
> + _scratch_xfs_repair -n 2>&1
> + res=$?
> + test $res -ne 0 && \
> + (>&2 echo "re-repair failed ($res) with ${field} = ${fuzzverb}.")
> +}
> +
> +# Make sure we have all the pieces we need for field fuzzing
> +_require_scratch_xfs_fuzz_fields()
> +{
> + _require_scratch
> + _require_scrub
> + _require_populate_commands
> + _require_command "$XFS_DB_PROG" "xfs_db"
> + _scratch_mkfs_xfs >/dev/null 2>&1
> + _scratch_xfs_db -x -c 'fuzz' 2>&1 | grep -q 'not found' && \
> + _notrun "xfs_db does not have fuzz command"
> +}
> +
> +# Grab the list of available fuzzing verbs
> +_scratch_xfs_list_fuzz_verbs() {
> + if [ -n "${SCRATCH_XFS_LIST_FUZZ_VERBS}" ]; then
> + echo "${SCRATCH_XFS_LIST_FUZZ_VERBS}" | sed -e 's/ /\n/g'
> + return;
> + fi
> + _scratch_xfs_db -x -c 'sb 0' -c 'fuzz' | grep '^Verbs:' | \
> + sed -e 's/[,.]//g' -e 's/Verbs: //g' -e 's/ /\n/g'
> +}
> +
> +# Fuzz the fields of some piece of metadata
> +_scratch_xfs_fuzz_fields() {
> + _scratch_xfs_list_metadata_fields "$@" | while read field; do
> + _scratch_xfs_list_fuzz_verbs | while read fuzzverb; do
> + __scratch_xfs_fuzz_mdrestore
> + __scratch_xfs_fuzz_field_test "${field}" "${fuzzverb}" "$@"
> + done
> + done
> +}
>
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