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https://github.com/Gericom/teak-llvm.git
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6e8526358f
Summary: In rL255491, the safestack overflow test was disabled for aarch64, since it "is currently failing on an AArch64 buildbot with a segfault, but it is currently passing on other configuration". While testing on FreeBSD on x86, I also encountered a segfault. This is because the `fct()` function actually writes before and after `buffer`, and on FreeBSD this crashes because `buffer` is usually allocated at the end of a page. That this runs correctly on Linux is probably just by accident. I propose to fix this by adding a pre and post buffer, to act as a safety zone. The pre and post buffers must be accessed in an 'unsafe' way, otherwise -fsanitize=safestack will allocate them on the safe stack, and they will not bookend `buffer` itself. Therefore, I create them large enough for `fct()`, and call it on both of them. On FreeBSD, this makes the test run as expected, without segfaulting, and I suppose this will also fix the segfault on AArch64. I do not have AArch64 testing capabilities, so if someone could try that out, I would be much obliged. Reviewers: pcc, kcc, zatrazz Subscribers: llvm-commits, aemerson, emaste Differential Revision: http://reviews.llvm.org/D15725 llvm-svn: 257106
30 lines
578 B
C
30 lines
578 B
C
// RUN: %clang_safestack %s -o %t
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// RUN: %run %t
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// RUN: %clang_nosafestack -fno-stack-protector %s -o %t
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// RUN: not %run %t
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// Test that buffer overflows on the unsafe stack do not affect variables on the
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// safe stack.
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// REQUIRES: stable-runtime
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__attribute__((noinline))
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void fct(volatile int *buffer)
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{
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memset(buffer - 1, 0, 7 * sizeof(int));
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}
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int main(int argc, char **argv)
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{
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int prebuf[7];
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int value1 = 42;
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int buffer[5];
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int value2 = 42;
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int postbuf[7];
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fct(prebuf + 1);
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fct(postbuf + 1);
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fct(buffer);
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return value1 != 42 || value2 != 42;
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}
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