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>
--
v2: fix some errors found by Eryu Guan.
---
common/fuzzy | 189 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 189 insertions(+)
diff --git a/common/fuzzy b/common/fuzzy
index 1cc1d5e..2edcd9f 100644
--- a/common/fuzzy
+++ b/common/fuzzy
@@ -81,3 +81,192 @@ _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 ${oldval}, skipping test."
+ return 1
+ fi
+ return 0
+}
+
+# Try to forcibly unmount the scratch fs
+__scratch_xfs_fuzz_unmount()
+{
+ while ! _scratch_unmount 2>/dev/null; do sleep 0.2; done
+}
+
+# Restore metadata to scratch device prior to field-fuzzing.
+__scratch_xfs_fuzz_mdrestore()
+{
+ test -e "${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} = ${fuzzverb}.")
+}
+
+# Make sure we have all the pieces we need for field fuzzing
+_require_scratch_xfs_fuzz_fields()
+{
+ _require_scratch
+ _require_scrub
+ _require_populate_commands
+ _scratch_mkfs_xfs >/dev/null 2>&1
+ _require_xfs_db_command "fuzz"
+}
+
+# Grab the list of available fuzzing verbs
+_scratch_xfs_list_fuzz_verbs() {
+ if [ -n "${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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