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author | 2020-12-11 12:20:40 +0100 | |
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committer | 2020-12-14 17:14:40 -0500 | |
commit | 861b2a24bc49f8ad801df5035347d7073eaafee5 (patch) | |
tree | bc2d02b925fb25ae207d3f41c593be735eddf906 | |
parent | [InstCombine] canonicalizeSaturatedAdd(): last fold is only valid for strict ... (diff) | |
download | llvm-project-861b2a24bc49f8ad801df5035347d7073eaafee5.tar.gz llvm-project-861b2a24bc49f8ad801df5035347d7073eaafee5.tar.bz2 llvm-project-861b2a24bc49f8ad801df5035347d7073eaafee5.zip |
[KernelAddressSanitizer] Fix globals exclusion for indirect aliases
GlobalAlias::getAliasee() may not always point directly to a
GlobalVariable. In such cases, try to find the canonical GlobalVariable
that the alias refers to.
Link: https://github.com/ClangBuiltLinux/linux/issues/1208
Reviewed By: dvyukov, nickdesaulniers
Differential Revision: https://reviews.llvm.org/D92846
(cherry picked from commit c28b18af19621e6b5cca257ef7139ba93833df0c)
-rw-r--r-- | clang/test/CodeGen/asan-globals-alias.cpp | 33 | ||||
-rw-r--r-- | llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp | 20 |
2 files changed, 39 insertions, 14 deletions
diff --git a/clang/test/CodeGen/asan-globals-alias.cpp b/clang/test/CodeGen/asan-globals-alias.cpp index faf160ac79c9..c859d2f2b44a 100644 --- a/clang/test/CodeGen/asan-globals-alias.cpp +++ b/clang/test/CodeGen/asan-globals-alias.cpp @@ -1,17 +1,42 @@ // RUN: %clang_cc1 -triple x86_64-linux -fsanitize=address -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,ASAN +// RUN: %clang_cc1 -triple x86_64-linux -O2 -fsanitize=address -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,ASAN // RUN: %clang_cc1 -triple x86_64-linux -fsanitize=kernel-address -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,KASAN +// RUN: %clang_cc1 -triple x86_64-linux -O2 -fsanitize=kernel-address -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,KASAN // // Not all platforms support aliases - test for Linux only. -int global; // to generate ctor for at least 1 global -int aliased_global; // KASAN - ignore globals prefixed by aliases with __-prefix (below) -extern int __attribute__((alias("aliased_global"))) __global_alias; // KASAN - aliased_global ignored +int global; // generate ctor for at least 1 global +int aliased_global; // KASAN ignored +extern int __attribute__((alias("aliased_global"))) __global_alias; + +// Recursive alias: +int aliased_global_2; // KASAN ignored +extern int __attribute__((alias("aliased_global_2"))) global_alias_2; +extern int __attribute__((alias("global_alias_2"))) __global_alias_2_alias; + +// Potential indirect alias: +struct input_device_id { + unsigned long keybit[24]; + unsigned long driver_info; +}; +struct input_device_id joydev_ids[] = { { {1}, 1234 } }; // KASAN ignored +extern struct input_device_id __attribute__((alias("joydev_ids"))) __mod_joydev_ids_device_table; // ASAN: @aliased_global{{.*}} global { i32, [60 x i8] }{{.*}}, align 32 +// ASAN: @aliased_global_2{{.*}} global { i32, [60 x i8] }{{.*}}, align 32 +// ASAN: @joydev_ids{{.*}} global { {{.*}}[56 x i8] zeroinitializer }, align 32 // KASAN: @aliased_global{{.*}} global i32 +// KASAN: @aliased_global_2{{.*}} global i32 +// KASAN: @joydev_ids{{.*}} global [1 x {{.*}}i64 1234 }], align 16 + +// Check the aliases exist: +// CHECK: @__global_alias = alias +// CHECK: @global_alias_2 = alias +// CHECK: @__global_alias_2_alias = alias +// CHECK: @__mod_joydev_ids_device_table = alias // CHECK-LABEL: define internal void @asan.module_ctor -// ASAN: call void @__asan_register_globals({{.*}}, i{{32|64}} 2) +// ASAN: call void @__asan_register_globals({{.*}}, i{{32|64}} 4) // KASAN: call void @__asan_register_globals({{.*}}, i{{32|64}} 1) // CHECK-NEXT: ret void diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp index ee09a4d9db7e..1557fad4d372 100644 --- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp +++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp @@ -792,7 +792,7 @@ private: StringRef InternalSuffix); Instruction *CreateAsanModuleDtor(Module &M); - bool canInstrumentAliasedGlobal(const GlobalAlias &GA) const; + const GlobalVariable *getExcludedAliasedGlobal(const GlobalAlias &GA) const; bool shouldInstrumentGlobal(GlobalVariable *G) const; bool ShouldUseMachOGlobalsSection() const; StringRef getGlobalMetadataSection() const; @@ -1784,20 +1784,22 @@ void ModuleAddressSanitizer::createInitializerPoisonCalls( } } -bool ModuleAddressSanitizer::canInstrumentAliasedGlobal( - const GlobalAlias &GA) const { +const GlobalVariable * +ModuleAddressSanitizer::getExcludedAliasedGlobal(const GlobalAlias &GA) const { // In case this function should be expanded to include rules that do not just // apply when CompileKernel is true, either guard all existing rules with an // 'if (CompileKernel) { ... }' or be absolutely sure that all these rules // should also apply to user space. assert(CompileKernel && "Only expecting to be called when compiling kernel"); + const Constant *C = GA.getAliasee(); + // When compiling the kernel, globals that are aliased by symbols prefixed // by "__" are special and cannot be padded with a redzone. if (GA.getName().startswith("__")) - return false; + return dyn_cast<GlobalVariable>(C->stripPointerCastsAndAliases()); - return true; + return nullptr; } bool ModuleAddressSanitizer::shouldInstrumentGlobal(GlobalVariable *G) const { @@ -2256,14 +2258,12 @@ bool ModuleAddressSanitizer::InstrumentGlobals(IRBuilder<> &IRB, Module &M, *CtorComdat = false; // Build set of globals that are aliased by some GA, where - // canInstrumentAliasedGlobal(GA) returns false. + // getExcludedAliasedGlobal(GA) returns the relevant GlobalVariable. SmallPtrSet<const GlobalVariable *, 16> AliasedGlobalExclusions; if (CompileKernel) { for (auto &GA : M.aliases()) { - if (const auto *GV = dyn_cast<GlobalVariable>(GA.getAliasee())) { - if (!canInstrumentAliasedGlobal(GA)) - AliasedGlobalExclusions.insert(GV); - } + if (const GlobalVariable *GV = getExcludedAliasedGlobal(GA)) + AliasedGlobalExclusions.insert(GV); } } |