[llvm-dev] Some feedback on Libfuzzer

[Kostya Serebryany via llvm-dev]

On Sat, Sep 12, 2015 at 2:01 PM, Greg Stark <stark at mit.edu> wrote:

> On Sat, Sep 12, 2015 at 7:48 PM, Greg Stark <stark at mit.edu> wrote:
> > I get that even if I put -fPIE in CFLAGS.
>
> Er, yeah. Even a trivial test case doesn't work:
>
>
What's the version of Linux and Clang?



> $ cat foo.c
> int main(int argc, char *argv[], char *envp[]) {
> return 1;
> }
>
> $ clang -o foo -fsanitize=memory -fPIE -pie   foo.c
>
> $ sysctl kernel.randomize_va_space
> kernel.randomize_va_space = 2
>
> $ ./foo
> FATAL: Code 0x55873d194390 is out of application range. Non-PIE build?
> FATAL: MemorySanitizer can not mmap the shadow memory.
> FATAL: Make sure to compile with -fPIE and to link with -pie.
> FATAL: Disabling ASLR is known to cause this error.
> FATAL: If running under GDB, try 'set disable-randomization off'.
> ==25950==Process memory map follows:
> 0x55873d177000-0x55873d216000 /tmp/foo
> 0x55873d415000-0x55873d419000 /tmp/foo
> 0x55873d419000-0x55873f88c000
> 0x7f276d5cf000-0x7f276d921000
> 0x7f276d921000-0x7f276dac0000 /lib/x86_64-linux-gnu/libc-2.19.so
> 0x7f276dac0000-0x7f276dcc0000 /lib/x86_64-linux-gnu/libc-2.19.so
> 0x7f276dcc0000-0x7f276dcc4000 /lib/x86_64-linux-gnu/libc-2.19.so
> 0x7f276dcc4000-0x7f276dcc6000 /lib/x86_64-linux-gnu/libc-2.19.so
> 0x7f276dcc6000-0x7f276dcca000
> 0x7f276dcca000-0x7f276dce0000 /lib/x86_64-linux-gnu/libgcc_s.so.1
> 0x7f276dce0000-0x7f276dedf000 /lib/x86_64-linux-gnu/libgcc_s.so.1
> 0x7f276dedf000-0x7f276dee0000 /lib/x86_64-linux-gnu/libgcc_s.so.1
> 0x7f276dee0000-0x7f276dee3000 /lib/x86_64-linux-gnu/libdl-2.19.so
> 0x7f276dee3000-0x7f276e0e2000 /lib/x86_64-linux-gnu/libdl-2.19.so
> 0x7f276e0e2000-0x7f276e0e3000 /lib/x86_64-linux-gnu/libdl-2.19.so
> 0x7f276e0e3000-0x7f276e0e4000 /lib/x86_64-linux-gnu/libdl-2.19.so
> 0x7f276e0e4000-0x7f276e1e4000 /lib/x86_64-linux-gnu/libm-2.19.so
> 0x7f276e1e4000-0x7f276e3e3000 /lib/x86_64-linux-gnu/libm-2.19.so
> 0x7f276e3e3000-0x7f276e3e4000 /lib/x86_64-linux-gnu/libm-2.19.so
> 0x7f276e3e4000-0x7f276e3e5000 /lib/x86_64-linux-gnu/libm-2.19.so
> 0x7f276e3e5000-0x7f276e3ec000 /lib/x86_64-linux-gnu/librt-2.19.so
> 0x7f276e3ec000-0x7f276e5eb000 /lib/x86_64-linux-gnu/librt-2.19.so
> 0x7f276e5eb000-0x7f276e5ec000 /lib/x86_64-linux-gnu/librt-2.19.so
> 0x7f276e5ec000-0x7f276e5ed000 /lib/x86_64-linux-gnu/librt-2.19.so
> 0x7f276e5ed000-0x7f276e605000 /lib/x86_64-linux-gnu/libpthread-2.19.so
> 0x7f276e605000-0x7f276e804000 /lib/x86_64-linux-gnu/libpthread-2.19.so
> 0x7f276e804000-0x7f276e805000 /lib/x86_64-linux-gnu/libpthread-2.19.so
> 0x7f276e805000-0x7f276e806000 /lib/x86_64-linux-gnu/libpthread-2.19.so
> 0x7f276e806000-0x7f276e80a000
> 0x7f276e80a000-0x7f276e82a000 /lib/x86_64-linux-gnu/ld-2.19.so
> 0x7f276ea03000-0x7f276ea08000
> 0x7f276ea1e000-0x7f276ea2a000
> 0x7f276ea2a000-0x7f276ea2b000 /lib/x86_64-linux-gnu/ld-2.19.so
> 0x7f276ea2b000-0x7f276ea2c000 /lib/x86_64-linux-gnu/ld-2.19.so
> 0x7f276ea2c000-0x7f276ea2d000
> 0x7ffd99d31000-0x7ffd99d52000 [stack]
> 0x7ffd99d73000-0x7ffd99d75000 [vvar]
> 0x7ffd99d75000-0x7ffd99d77000 [vdso]
> 0xffffffffff600000-0xffffffffff601000 [vsyscall]
> ==25950==End of process memory map.
>
>
> --
> greg
>
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