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//===-- asan_linux.cpp ----------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Linux-specific details.
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
SANITIZER_SOLARIS
# include <dlfcn.h>
# include <fcntl.h>
# include <limits.h>
# include <pthread.h>
# include <stdio.h>
# include <sys/mman.h>
# include <sys/resource.h>
# include <sys/syscall.h>
# include <sys/time.h>
# include <sys/types.h>
# include <unistd.h>
# include <unwind.h>
# include "asan_interceptors.h"
# include "asan_internal.h"
# include "asan_premap_shadow.h"
# include "asan_thread.h"
# include "sanitizer_common/sanitizer_flags.h"
# include "sanitizer_common/sanitizer_hash.h"
# include "sanitizer_common/sanitizer_libc.h"
# include "sanitizer_common/sanitizer_procmaps.h"
# if SANITIZER_FREEBSD
# error #include <sys/link_elf.h>
# endif
# if SANITIZER_SOLARIS
# include <link.h>
# endif
# if SANITIZER_ANDROID || SANITIZER_FREEBSD || SANITIZER_SOLARIS
# include <ucontext.h>
extern "C" void *_DYNAMIC;
# elif SANITIZER_NETBSD
# error #include <link_elf.h>
# include <ucontext.h>
extern Elf_Dyn _DYNAMIC;
# else
# include <link.h>
# include <sys/ucontext.h>
extern ElfW(Dyn) _DYNAMIC[];
# endif
typedef enum {
ASAN_RT_VERSION_UNDEFINED = 0,
ASAN_RT_VERSION_DYNAMIC,
ASAN_RT_VERSION_STATIC,
} asan_rt_version_t;
// FIXME: perhaps also store abi version here?
extern "C" {
SANITIZER_INTERFACE_ATTRIBUTE
asan_rt_version_t __asan_rt_version;
}
namespace __asan {
void InitializePlatformInterceptors() {}
void InitializePlatformExceptionHandlers() {}
bool IsSystemHeapAddress(uptr addr) { return false; }
void *AsanDoesNotSupportStaticLinkage() {
// This will fail to link with -static.
return &_DYNAMIC;
}
# if ASAN_PREMAP_SHADOW
uptr FindPremappedShadowStart(uptr shadow_size_bytes) {
uptr granularity = GetMmapGranularity();
uptr shadow_start = reinterpret_cast<uptr>(&__asan_shadow);
uptr premap_shadow_size = PremapShadowSize();
uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
// We may have mapped too much. Release extra memory.
UnmapFromTo(shadow_start + shadow_size, shadow_start + premap_shadow_size);
return shadow_start;
}
# endif
uptr FindDynamicShadowStart() {
uptr shadow_size_bytes = MemToShadowSize(kHighMemEnd);
# if ASAN_PREMAP_SHADOW
if (!PremapShadowFailed())
return FindPremappedShadowStart(shadow_size_bytes);
# endif
return MapDynamicShadow(shadow_size_bytes, ASAN_SHADOW_SCALE,
/*min_shadow_base_alignment*/ 0, kHighMemEnd);
}
void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
UNIMPLEMENTED();
}
void FlushUnneededASanShadowMemory(uptr p, uptr size) {
// Since asan's mapping is compacting, the shadow chunk may be
// not page-aligned, so we only flush the page-aligned portion.
ReleaseMemoryPagesToOS(MemToShadow(p), MemToShadow(p + size));
}
# if SANITIZER_ANDROID
// FIXME: should we do anything for Android?
void AsanCheckDynamicRTPrereqs() {}
void AsanCheckIncompatibleRT() {}
# else
static int FindFirstDSOCallback(struct dl_phdr_info *info, size_t size,
void *data) {
VReport(2, "info->dlpi_name = %s\tinfo->dlpi_addr = %p\n", info->dlpi_name,
(void *)info->dlpi_addr);
const char **name = (const char **)data;
// Ignore first entry (the main program)
if (!*name) {
*name = "";
return 0;
}
# if SANITIZER_LINUX
// Ignore vDSO. glibc versions earlier than 2.15 (and some patched
// by distributors) return an empty name for the vDSO entry, so
// detect this as well.
if (!info->dlpi_name[0] ||
internal_strncmp(info->dlpi_name, "linux-", sizeof("linux-") - 1) == 0)
return 0;
# endif
# if SANITIZER_FREEBSD
// Ignore vDSO.
if (internal_strcmp(info->dlpi_name, "[vdso]") == 0)
return 0;
# endif
*name = info->dlpi_name;
return 1;
}
static bool IsDynamicRTName(const char *libname) {
return internal_strstr(libname, "libclang_rt.asan") ||
internal_strstr(libname, "libasan.so");
}
static void ReportIncompatibleRT() {
Report("Your application is linked against incompatible ASan runtimes.\n");
Die();
}
void AsanCheckDynamicRTPrereqs() {
if (!ASAN_DYNAMIC || !flags()->verify_asan_link_order)
return;
// Ensure that dynamic RT is the first DSO in the list
const char *first_dso_name = nullptr;
dl_iterate_phdr(FindFirstDSOCallback, &first_dso_name);
if (first_dso_name && first_dso_name[0] && !IsDynamicRTName(first_dso_name)) {
Report(
"ASan runtime does not come first in initial library list; "
"you should either link runtime to your application or "
"manually preload it with LD_PRELOAD.\n");
Die();
}
}
void AsanCheckIncompatibleRT() {
if (ASAN_DYNAMIC) {
if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
__asan_rt_version = ASAN_RT_VERSION_DYNAMIC;
} else if (__asan_rt_version != ASAN_RT_VERSION_DYNAMIC) {
ReportIncompatibleRT();
}
} else {
if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
// Ensure that dynamic runtime is not present. We should detect it
// as early as possible, otherwise ASan interceptors could bind to
// the functions in dynamic ASan runtime instead of the functions in
// system libraries, causing crashes later in ASan initialization.
MemoryMappingLayout proc_maps(/*cache_enabled*/ true);
char filename[PATH_MAX];
MemoryMappedSegment segment(filename, sizeof(filename));
while (proc_maps.Next(&segment)) {
if (IsDynamicRTName(segment.filename)) {
Report(
"Your application is linked against "
"incompatible ASan runtimes.\n");
Die();
}
}
__asan_rt_version = ASAN_RT_VERSION_STATIC;
} else if (__asan_rt_version != ASAN_RT_VERSION_STATIC) {
ReportIncompatibleRT();
}
}
}
# endif // SANITIZER_ANDROID
# if ASAN_INTERCEPT_SWAPCONTEXT
constexpr u32 kAsanContextStackFlagsMagic = 0x51260eea;
static int HashContextStack(const ucontext_t &ucp) {
MurMur2Hash64Builder hash(kAsanContextStackFlagsMagic);
hash.add(reinterpret_cast<uptr>(ucp.uc_stack.ss_sp));
hash.add(ucp.uc_stack.ss_size);
return static_cast<int>(hash.get());
}
void SignContextStack(void *context) {
ucontext_t *ucp = reinterpret_cast<ucontext_t *>(context);
ucp->uc_stack.ss_flags = HashContextStack(*ucp);
}
void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
const ucontext_t *ucp = reinterpret_cast<const ucontext_t *>(context);
if (HashContextStack(*ucp) == ucp->uc_stack.ss_flags) {
*stack = reinterpret_cast<uptr>(ucp->uc_stack.ss_sp);
*ssize = ucp->uc_stack.ss_size;
return;
}
*stack = 0;
*ssize = 0;
}
# endif // ASAN_INTERCEPT_SWAPCONTEXT
void *AsanDlSymNext(const char *sym) { return dlsym(RTLD_NEXT, sym); }
bool HandleDlopenInit() {
// Not supported on this platform.
static_assert(!SANITIZER_SUPPORTS_INIT_FOR_DLOPEN,
"Expected SANITIZER_SUPPORTS_INIT_FOR_DLOPEN to be false");
return false;
}
} // namespace __asan
#endif // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD ||
// SANITIZER_SOLARIS
|
