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Diffstat (limited to 'externals/mbedtls/tests/scripts/test_zeroize.gdb')
| -rw-r--r-- | externals/mbedtls/tests/scripts/test_zeroize.gdb | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/externals/mbedtls/tests/scripts/test_zeroize.gdb b/externals/mbedtls/tests/scripts/test_zeroize.gdb new file mode 100644 index 0000000000..a7536c4064 --- /dev/null +++ b/externals/mbedtls/tests/scripts/test_zeroize.gdb @@ -0,0 +1,103 @@ +# test_zeroize.gdb +# +# Copyright The Mbed TLS Contributors +# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +# +# This file is provided under the Apache License 2.0, or the +# GNU General Public License v2.0 or later. +# +# ********** +# Apache License 2.0: +# +# Licensed under the Apache License, Version 2.0 (the "License"); you may +# not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +# +# ********** +# +# ********** +# GNU General Public License v2.0 or later: +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program; if not, write to the Free Software Foundation, Inc., +# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +# +# ********** +# +# Purpose +# +# Run a test using the debugger to check that the mbedtls_platform_zeroize() +# function in platform_util.h is not being optimized out by the compiler. To do +# so, the script loads the test program at programs/test/zeroize.c and sets a +# breakpoint at the last return statement in main(). When the breakpoint is +# hit, the debugger manually checks the contents to be zeroized and checks that +# it is actually cleared. +# +# The mbedtls_platform_zeroize() test is debugger driven because there does not +# seem to be a mechanism to reliably check whether the zeroize calls are being +# eliminated by compiler optimizations from within the compiled program. The +# problem is that a compiler would typically remove what it considers to be +# "unnecessary" assignments as part of redundant code elimination. To identify +# such code, the compilar will create some form dependency graph between +# reads and writes to variables (among other situations). It will then use this +# data structure to remove redundant code that does not have an impact on the +# program's observable behavior. In the case of mbedtls_platform_zeroize(), an +# intelligent compiler could determine that this function clears a block of +# memory that is not accessed later in the program, so removing the call to +# mbedtls_platform_zeroize() does not have an observable behavior. However, +# inserting a test after a call to mbedtls_platform_zeroize() to check whether +# the block of memory was correctly zeroed would force the compiler to not +# eliminate the mbedtls_platform_zeroize() call. If this does not occur, then +# the compiler potentially has a bug. +# +# Note: This test requires that the test program is compiled with -g3. + +set confirm off + +file ./programs/test/zeroize + +search GDB_BREAK_HERE +break $_ + +set args ./programs/test/zeroize.c +run + +set $i = 0 +set $len = sizeof(buf) +set $buf = buf + +while $i < $len + if $buf[$i++] != 0 + echo The buffer at was not zeroized\n + quit 1 + end +end + +echo The buffer was correctly zeroized\n + +continue + +if $_exitcode != 0 + echo The program did not terminate correctly\n + quit 1 +end + +quit 0 |