Quelle  test_bpftool_map.sh   Sprache: Shell

#!/bin/sh
# SPDX-License-Identifier: GPL-2.0

# Kselftest framework requirement - SKIP code is 4.
ksft_skip=4

TESTNAME="bpftool_map"
BPF_FILE="security_bpf_map.bpf.o"
BPF_ITER_FILE="bpf_iter_map_elem.bpf.o"
PROTECTED_MAP_NAME="prot_map"
NOT_PROTECTED_MAP_NAME="not_prot_map"
BPF_FS_TMP_PARENT="/tmp"
BPF_FS_PARENT=$(awk '$3 == "bpf" {print $2; exit}' /proc/mounts)
BPF_FS_PARENT=${BPF_FS_PARENT:-$BPF_FS_TMP_PARENT}
# bpftool will mount bpf file system under BPF_DIR if it is not mounted
# under BPF_FS_PARENT.
BPF_DIR="$BPF_FS_PARENT/test_$TESTNAME"
SCRIPT_DIR=$(dirname $(realpath "$0"))
BPF_FILE_PATH="$SCRIPT_DIR/$BPF_FILE"
BPF_ITER_FILE_PATH="$SCRIPT_DIR/$BPF_ITER_FILE"
BPFTOOL_PATH="bpftool"
# Assume the script is located under tools/testing/selftests/bpf/
KDIR_ROOT_DIR=$(realpath "$SCRIPT_DIR"/../../../../)

_cleanup()
{
 set +eu

 # If BPF_DIR is a mount point this will not remove the mount point itself.
 [ -d "$BPF_DIR" ] && rm -rf "$BPF_DIR" 2> /dev/null

 # Unmount if BPF filesystem was temporarily created.
 if [ "$BPF_FS_PARENT" = "$BPF_FS_TMP_PARENT" ]; then
  # A loop and recursive unmount are required as bpftool might
  # create multiple mounts. For example, a bind mount of the directory
  # to itself. The bind mount is created to change mount propagation
  # flags on an actual mount point.
  max_attempts=3
  attempt=0
  while mountpoint -q "$BPF_DIR" && [ $attempt -lt $max_attempts ]; do
   umount -R "$BPF_DIR" 2>/dev/null
   attempt=$((attempt+1))
  done

  # The directory still exists. Remove it now.
  [ -d "$BPF_DIR" ] && rm -rf "$BPF_DIR" 2>/dev/null
 fi
}

cleanup_skip()
{
 echo "selftests: $TESTNAME [SKIP]"
 _cleanup

 exit $ksft_skip
}

cleanup()
{
 if [ "$?" = 0 ]; then
  echo "selftests: $TESTNAME [PASS]"
 else
  echo "selftests: $TESTNAME [FAILED]"
 fi
 _cleanup
}

check_root_privileges() {
 if [ $(id -u) -ne 0 ]; then
  echo "Need root privileges"
  exit $ksft_skip
 fi
}

# Function to verify bpftool path.
# Parameters:
#   $1: bpftool path
verify_bpftool_path() {
 local bpftool_path="$1"
 if ! "$bpftool_path" version > /dev/null 2>&1; then
  echo "Could not run test without bpftool"
  exit $ksft_skip
 fi
}

# Function to verify BTF support.
# The test requires BTF support for fmod_ret programs.
verify_btf_support() {
 if [ ! -f /sys/kernel/btf/vmlinux ]; then
  echo "Could not run test without BTF support"
  exit $ksft_skip
 fi
}

# Function to initialize map entries with keys [0..2] and values set to 0.
# Parameters:
#  $1: Map name
#  $2: bpftool path
initialize_map_entries() {
 local map_name="$1"
 local bpftool_path="$2"

 for key in 0 1 2; do
  "$bpftool_path" map update name "$map_name" key $key 0 0 0 value 0 0 0 $key
 done
}

# Test read access to the map.
# Parameters:
#   $1: Name command (name/pinned)
#   $2: Map name
#   $3: bpftool path
#   $4: key
access_for_read() {
 local name_cmd="$1"
 local map_name="$2"
 local bpftool_path="$3"
 local key="$4"

 # Test read access to the map.
 if ! "$bpftool_path" map lookup "$name_cmd" "$map_name" key $key 1>/dev/null; then
  echo " Read access to $key in $map_name failed"
  exit 1
 fi

 # Test read access to map's BTF data.
 if ! "$bpftool_path" btf dump map "$name_cmd" "$map_name" 1>/dev/null; then
  echo " Read access to $map_name for BTF data failed"
  exit 1
 fi
}

# Test write access to the map.
# Parameters:
#   $1: Name command (name/pinned)
#   $2: Map name
#   $3: bpftool path
#   $4: key
#   $5: Whether write should succeed (true/false)
access_for_write() {
 local name_cmd="$1"
 local map_name="$2"
 local bpftool_path="$3"
 local key="$4"
 local write_should_succeed="$5"
 local value="1 1 1 1"

 if "$bpftool_path" map update "$name_cmd" "$map_name" key $key value \
   $value 2>/dev/null; then
  if [ "$write_should_succeed" = "false" ]; then
   echo " Write access to $key in $map_name succeeded but should have failed"
   exit 1
  fi
 else
  if [ "$write_should_succeed" = "true" ]; then
   echo " Write access to $key in $map_name failed but should have succeeded"
   exit 1
  fi
 fi
}

# Test entry deletion for the map.
# Parameters:
#   $1: Name command (name/pinned)
#   $2: Map name
#   $3: bpftool path
#   $4: key
#   $5: Whether write should succeed (true/false)
access_for_deletion() {
 local name_cmd="$1"
 local map_name="$2"
 local bpftool_path="$3"
 local key="$4"
 local write_should_succeed="$5"
 local value="1 1 1 1"

 # Test deletion by key for the map.
 # Before deleting, check the key exists.
 if ! "$bpftool_path" map lookup "$name_cmd" "$map_name" key $key 1>/dev/null; then
  echo " Key $key does not exist in $map_name"
  exit 1
 fi

 # Delete by key.
 if "$bpftool_path" map delete "$name_cmd" "$map_name" key $key 2>/dev/null; then
  if [ "$write_should_succeed" = "false" ]; then
   echo " Deletion for $key in $map_name succeeded but should have failed"
   exit 1
  fi
 else
  if [ "$write_should_succeed" = "true" ]; then
   echo " Deletion for $key in $map_name failed but should have succeeded"
   exit 1
  fi
 fi

 # After deleting, check the entry existence according to the expected status.
 if "$bpftool_path" map lookup "$name_cmd" "$map_name" key $key 1>/dev/null; then
  if [ "$write_should_succeed" = "true" ]; then
   echo " Key $key for $map_name was not deleted but should have been deleted"
   exit 1
  fi
 else
  if [ "$write_should_succeed" = "false" ]; then
   echo "Key $key for $map_name was deleted but should have not been deleted"
   exit 1
  fi
 fi

 # Test creation of map's deleted entry, if deletion was successful.
 # Otherwise, the entry exists.
 if "$bpftool_path" map update "$name_cmd" "$map_name" key $key value \
    $value 2>/dev/null; then
  if [ "$write_should_succeed" = "false" ]; then
   echo " Write access to $key in $map_name succeeded after deletion attempt but should have failed"
   exit 1
  fi
 else
  if [ "$write_should_succeed" = "true" ]; then
   echo " Write access to $key in $map_name failed after deletion attempt but should have succeeded"
   exit 1
  fi
 fi
}

# Test map elements iterator.
# Parameters:
#   $1: Name command (name/pinned)
#   $2: Map name
#   $3: bpftool path
#   $4: BPF_DIR
#   $5: bpf iterator object file path
iterate_map_elem() {
 local name_cmd="$1"
 local map_name="$2"
 local bpftool_path="$3"
 local bpf_dir="$4"
 local bpf_file="$5"
 local pin_path="$bpf_dir/map_iterator"

 "$bpftool_path" iter pin "$bpf_file" "$pin_path" map "$name_cmd" "$map_name"
 if [ ! -f "$pin_path" ]; then
  echo " Failed to pin iterator to $pin_path"
  exit 1
 fi

 cat "$pin_path" 1>/dev/null
 rm "$pin_path" 2>/dev/null
}

# Function to test map access with configurable write expectations
# Parameters:
#   $1: Name command (name/pinned)
#   $2: Map name
#   $3: bpftool path
#   $4: key for rw
#   $5: key to delete
#   $6: Whether write should succeed (true/false)
#   $7: BPF_DIR
#   $8: bpf iterator object file path
access_map() {
 local name_cmd="$1"
 local map_name="$2"
 local bpftool_path="$3"
 local key_for_rw="$4"
 local key_to_del="$5"
 local write_should_succeed="$6"
 local bpf_dir="$7"
 local bpf_iter_file_path="$8"

 access_for_read "$name_cmd" "$map_name" "$bpftool_path" "$key_for_rw"
 access_for_write "$name_cmd" "$map_name" "$bpftool_path" "$key_for_rw" \
  "$write_should_succeed"
 access_for_deletion "$name_cmd" "$map_name" "$bpftool_path" "$key_to_del" \
  "$write_should_succeed"
 iterate_map_elem "$name_cmd" "$map_name" "$bpftool_path" "$bpf_dir" \
  "$bpf_iter_file_path"
}

# Function to test map access with configurable write expectations
# Parameters:
#   $1: Map name
#   $2: bpftool path
#   $3: BPF_DIR
#   $4: Whether write should succeed (true/false)
#   $5: bpf iterator object file path
test_map_access() {
 local map_name="$1"
 local bpftool_path="$2"
 local bpf_dir="$3"
 local pin_path="$bpf_dir/${map_name}_pinned"
 local write_should_succeed="$4"
 local bpf_iter_file_path="$5"

 # Test access to the map by name.
 access_map "name" "$map_name" "$bpftool_path" "0 0 0 0" "1 0 0 0" \
  "$write_should_succeed" "$bpf_dir" "$bpf_iter_file_path"

 # Pin the map to the BPF filesystem
 "$bpftool_path" map pin name "$map_name" "$pin_path"
 if [ ! -e "$pin_path" ]; then
  echo " Failed to pin $map_name"
  exit 1
 fi

 # Test access to the pinned map.
 access_map "pinned" "$pin_path" "$bpftool_path" "0 0 0 0" "2 0 0 0" \
  "$write_should_succeed" "$bpf_dir" "$bpf_iter_file_path"
}

# Function to test map creation and map-of-maps
# Parameters:
#   $1: bpftool path
#   $2: BPF_DIR
test_map_creation_and_map_of_maps() {
 local bpftool_path="$1"
 local bpf_dir="$2"
 local outer_map_name="outer_map_tt"
 local inner_map_name="inner_map_tt"

 "$bpftool_path" map create "$bpf_dir/$inner_map_name" type array key 4 \
  value 4 entries 4 name "$inner_map_name"
 if [ ! -f "$bpf_dir/$inner_map_name" ]; then
  echo " Failed to create inner map file at $bpf_dir/$outer_map_name"
  return 1
 fi

 "$bpftool_path" map create "$bpf_dir/$outer_map_name" type hash_of_maps \
  key 4 value 4 entries 2 name "$outer_map_name" inner_map name "$inner_map_name"
 if [ ! -f "$bpf_dir/$outer_map_name" ]; then
  echo " Failed to create outer map file at $bpf_dir/$outer_map_name"
  return 1
 fi

 # Add entries to the outer map by name and by pinned path.
 "$bpftool_path" map update pinned "$bpf_dir/$outer_map_name" key 0 0 0 0 \
  value pinned "$bpf_dir/$inner_map_name"
 "$bpftool_path" map update name "$outer_map_name" key 1 0 0 0 value \
  name "$inner_map_name"

 # The outer map should be full by now.
 # The following map update command is expected to fail.
 if "$bpftool_path" map update name "$outer_map_name" key 2 0 0 0 value name \
  "$inner_map_name" 2>/dev/null; then
  echo " Update for $outer_map_name succeeded but should have failed"
  exit 1
 fi
}

# Function to test map access with the btf list command
# Parameters:
#   $1: bpftool path
test_map_access_with_btf_list() {
 local bpftool_path="$1"

 # The btf list command iterates over maps for
 # loaded BPF programs.
 if ! "$bpftool_path" btf list 1>/dev/null; then
  echo " Failed to access btf data"
  exit 1
 fi
}

set -eu

trap cleanup_skip EXIT

check_root_privileges

verify_bpftool_path "$BPFTOOL_PATH"

verify_btf_support

trap cleanup EXIT

# Load and attach the BPF programs to control maps access.
"$BPFTOOL_PATH" prog loadall "$BPF_FILE_PATH" "$BPF_DIR" autoattach

initialize_map_entries "$PROTECTED_MAP_NAME" "$BPFTOOL_PATH"
initialize_map_entries "$NOT_PROTECTED_MAP_NAME" "$BPFTOOL_PATH"

# Activate the map protection mechanism. Protection status is controlled
# by a value stored in the prot_status_map at index 0.
"$BPFTOOL_PATH" map update name prot_status_map key 0 0 0 0 value 1 0 0 0

# Test protected map (write should fail).
test_map_access "$PROTECTED_MAP_NAME" "$BPFTOOL_PATH" "$BPF_DIR" "false" \
 "$BPF_ITER_FILE_PATH"

# Test not protected map (write should succeed).
test_map_access "$NOT_PROTECTED_MAP_NAME" "$BPFTOOL_PATH" "$BPF_DIR" "true" \
 "$BPF_ITER_FILE_PATH"

test_map_creation_and_map_of_maps "$BPFTOOL_PATH" "$BPF_DIR"

test_map_access_with_btf_list "$BPFTOOL_PATH"

exit 0