mirror of
https://github.com/fergalmoran/ladybird.git
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06da50afc7
Modify the user mode runtime to insert stack canaries to find stack corruptions.
The `-fstack-protector-strong` variant was chosen because it catches more
issues than vanilla `-fstack-protector`, but doesn't have substantial
performance impact like `-fstack-protector-all`.
Details:
-fstack-protector enables stack protection for vulnerable functions that contain:
* A character array larger than 8 bytes.
* An 8-bit integer array larger than 8 bytes.
* A call to alloca() with either a variable size or a constant size bigger than 8 bytes.
-fstack-protector-strong enables stack protection for vulnerable functions that contain:
* An array of any size and type.
* A call to alloca().
* A local variable that has its address taken.
Example of it catching corrupting in the `stack-smash` test:
```
courage ~ $ ./user/Tests/LibC/stack-smash
[+] Starting the stack smash ...
Error: Stack protector failure, stack smashing detected!
Shell: Job 1 (/usr/Tests/LibC/stack-smash) Aborted
```
55 lines
2.0 KiB
C++
55 lines
2.0 KiB
C++
/*
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* Copyright (c) 2021, Brian Gianforcaro <b.gianfo@gmail.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <cstdio>
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// Note: Needs to be 'noline' so stack canary isn't optimized out.
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static void __attribute__((noinline)) smasher(char* string)
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{
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Warray-bounds"
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for (int i = 0; i < 256; i++) {
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string[i] = 'A';
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}
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#pragma GCC diagnostic pop
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}
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// Note: Needs to be 'noline' so stack canary isn't optimized out.
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static void __attribute__((noinline)) stack_to_smash()
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{
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char string[8] = {};
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smasher(string);
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}
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int main()
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{
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puts("[+] Starting the stack smash...");
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stack_to_smash();
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puts("[+] Stack smash wasn't detected!");
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return 0;
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}
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