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Recommit "[libFuzzer] Disable implicit builtin knowledge about memcmp-like functions when -fsanitize=fuzzer-no-link is given." 

Summary: This patch disables implicit builtin knowledge about memcmp-like functions when compiling the program for fuzzing, i.e., when -fsanitize=fuzzer(-no-link) is given. This allows libFuzzer to always intercept memcmp-like functions as it effectively disables optimizing calls to such functions into different forms. This is done by adding a set of flags (-fno-builtin-memcmp and others) in the clang driver. Individual -fno-builtin-* flags previously used in several libFuzzer tests are now removed, as it is now done automatically in the clang driver.

The patch was once reverted in 8ef9e2bf35, as this patch was dependent on a reverted commit f78d9fceea. This reverted commit was recommitted in 831ae45e3d, so relanding this dependent patch too.

Reviewers: morehouse, hctim

Subscribers: cfe-commits, #sanitizers

Tags: #clang, #sanitizers

Differential Revision: https://reviews.llvm.org/D83987
This commit is contained in:
Dokyung Song 2020-07-16 21:24:06 +00:00
parent 7832d0f63d
commit b52b2e1c18
7 changed files with 30 additions and 9 deletions
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17
clang/lib/Driver/SanitizerArgs.cpp
View File

@ -1088,6 +1088,23 @@ void SanitizerArgs::addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
Sanitizers.has(SanitizerKind::Address))
CmdArgs.push_back("-fno-assume-sane-operator-new");
// libFuzzer wants to intercept calls to certain library functions, so the
// following -fno-builtin-* flags force the compiler to emit interposable
// libcalls to these functions. Other sanitizers effectively do the same thing
// by marking all library call sites with NoBuiltin attribute in their LLVM
// pass. (see llvm::maybeMarkSanitizerLibraryCallNoBuiltin)
if (Sanitizers.has(SanitizerKind::FuzzerNoLink)) {
CmdArgs.push_back("-fno-builtin-bcmp");
CmdArgs.push_back("-fno-builtin-memcmp");
CmdArgs.push_back("-fno-builtin-strncmp");
CmdArgs.push_back("-fno-builtin-strcmp");
CmdArgs.push_back("-fno-builtin-strncasecmp");
CmdArgs.push_back("-fno-builtin-strcasecmp");
CmdArgs.push_back("-fno-builtin-strstr");
CmdArgs.push_back("-fno-builtin-strcasestr");
CmdArgs.push_back("-fno-builtin-memmem");
}
// Require -fvisibility= flag on non-Windows when compiling if vptr CFI is
// enabled.
if (Sanitizers.hasOneOf(CFIClasses) && !TC.getTriple().isOSWindows() &&

4
compiler-rt/test/fuzzer/noasan-bcmp.test Normal file
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@ -0,0 +1,4 @@
UNSUPPORTED: darwin, freebsd, windows
RUN: %cpp_compiler -fno-sanitize=address -DMEMCMP=bcmp %S/MemcmpTest.cpp -o %t
RUN: not %run %t -seed=1 -runs=10000000 2>&1 | FileCheck %s
CHECK: BINGO

4
compiler-rt/test/fuzzer/noasan-memcmp.test
View File

@ -1,9 +1,9 @@
UNSUPPORTED: darwin, freebsd, windows
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-memcmp %S/MemcmpTest.cpp -o %t-NoAsanMemcmpTest
RUN: %cpp_compiler -fno-sanitize=address %S/MemcmpTest.cpp -o %t-NoAsanMemcmpTest
RUN: not %run %t-NoAsanMemcmpTest -seed=1 -runs=10000000 2>&1 | FileCheck %s
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-calloc -fno-builtin-memcmp %S/CustomAllocator.cpp %S/MemcmpTest.cpp -o %t-NoAsanCustomAllocatorMemcmpTest
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-calloc %S/CustomAllocator.cpp %S/MemcmpTest.cpp -o %t-NoAsanCustomAllocatorMemcmpTest
RUN: not %run %t-NoAsanCustomAllocatorMemcmpTest -seed=1 -runs=10000000 2>&1 | FileCheck %s
CHECK: BINGO

2
compiler-rt/test/fuzzer/noasan-memcmp64.test
View File

@ -1,6 +1,6 @@
UNSUPPORTED: darwin, freebsd, windows
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-memcmp %S/Memcmp64BytesTest.cpp -o %t-NoAsanMemcmp64BytesTest
RUN: %cpp_compiler -fno-sanitize=address %S/Memcmp64BytesTest.cpp -o %t-NoAsanMemcmp64BytesTest
RUN: not %run %t-NoAsanMemcmp64BytesTest -seed=1 -runs=1000000 2>&1 | FileCheck %s
CHECK: BINGO

4
compiler-rt/test/fuzzer/noasan-strcmp.test
View File

@ -1,9 +1,9 @@
UNSUPPORTED: darwin, freebsd, windows
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-strcmp %S/StrcmpTest.cpp -o %t-NoAsanStrcmpTest
RUN: %cpp_compiler -fno-sanitize=address %S/StrcmpTest.cpp -o %t-NoAsanStrcmpTest
RUN: not %run %t-NoAsanStrcmpTest -seed=1 -runs=2000000 2>&1 | FileCheck %s
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-calloc -fno-builtin-strcmp %S/CustomAllocator.cpp %S/StrcmpTest.cpp -o %t-NoAsanCustomAllocatorStrcmpTest
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-calloc %S/CustomAllocator.cpp %S/StrcmpTest.cpp -o %t-NoAsanCustomAllocatorStrcmpTest
RUN: not %run %t-NoAsanCustomAllocatorStrcmpTest -seed=1 -runs=2000000 2>&1 | FileCheck %s
CHECK: BINGO

4
compiler-rt/test/fuzzer/noasan-strncmp.test
View File

@ -1,9 +1,9 @@
UNSUPPORTED: darwin, freebsd, windows
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-strncmp %S/StrncmpTest.cpp -o %t-NoAsanStrncmpTest
RUN: %cpp_compiler -fno-sanitize=address %S/StrncmpTest.cpp -o %t-NoAsanStrncmpTest
RUN: not %run %t-NoAsanStrncmpTest -seed=2 -runs=10000000 2>&1 | FileCheck %s
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-calloc -fno-builtin-strncmp %S/CustomAllocator.cpp %S/StrncmpTest.cpp -o %t-NoAsanCustomAllocatorStrncmpTest
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-calloc %S/CustomAllocator.cpp %S/StrncmpTest.cpp -o %t-NoAsanCustomAllocatorStrncmpTest
RUN: not %run %t-NoAsanCustomAllocatorStrncmpTest -seed=2 -runs=10000000 2>&1 | FileCheck %s
CHECK: BINGO

4
compiler-rt/test/fuzzer/noasan-strstr.test
View File

@ -1,9 +1,9 @@
UNSUPPORTED: darwin, freebsd, windows
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-strstr %S/StrstrTest.cpp -o %t-NoAsanStrstrTest
RUN: %cpp_compiler -fno-sanitize=address %S/StrstrTest.cpp -o %t-NoAsanStrstrTest
RUN: not %run %t-NoAsanStrstrTest -seed=1 -runs=2000000 2>&1 | FileCheck %s
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-calloc -fno-builtin-strstr %S/CustomAllocator.cpp %S/StrstrTest.cpp -o %t-NoAsanCustomAllocatorStrstrTest
RUN: %cpp_compiler -fno-sanitize=address -fno-builtin-calloc %S/CustomAllocator.cpp %S/StrstrTest.cpp -o %t-NoAsanCustomAllocatorStrstrTest
RUN: not %run %t-NoAsanCustomAllocatorStrstrTest -seed=1 -runs=2000000 2>&1 | FileCheck %s
CHECK: BINGO