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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 "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_freebsd.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_procmaps.h"
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <limits.h>
#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include <unwind.h>
#if SANITIZER_FREEBSD
#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
#include <link_elf.h>
#include <ucontext.h>
extern Elf_Dyn _DYNAMIC;
#else
#include <sys/ucontext.h>
#include <link.h>
#endif
// x86-64 FreeBSD 9.2 and older define 'ucontext_t' incorrectly in
// 32-bit mode.
#if SANITIZER_FREEBSD && (SANITIZER_WORDSIZE == 32) && \
__FreeBSD_version <= 902001 // v9.2
#define ucontext_t xucontext_t
#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; // defined in link.h
}
static void UnmapFromTo(uptr from, uptr to) {
CHECK(to >= from);
if (to == from) return;
uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from);
if (UNLIKELY(internal_iserror(res))) {
Report(
"ERROR: AddresSanitizer failed to unmap 0x%zx (%zd) bytes at address "
"%p\n",
to - from, to - from, from);
CHECK("unable to unmap" && 0);
}
}
#if ASAN_PREMAP_SHADOW
uptr FindPremappedShadowStart() {
uptr granularity = GetMmapGranularity();
uptr shadow_start = reinterpret_cast<uptr>(&__asan_shadow);
uptr premap_shadow_size = PremapShadowSize();
uptr shadow_size = RoundUpTo(kHighShadowEnd, 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() {
#if ASAN_PREMAP_SHADOW
if (!PremapShadowFailed())
return FindPremappedShadowStart();
#endif
uptr granularity = GetMmapGranularity();
uptr alignment = granularity * 8;
uptr left_padding = granularity;
uptr shadow_size = RoundUpTo(kHighShadowEnd, granularity);
uptr map_size = shadow_size + left_padding + alignment;
uptr map_start = (uptr)MmapNoAccess(map_size);
CHECK_NE(map_start, ~(uptr)0);
uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
UnmapFromTo(map_start, shadow_start - left_padding);
UnmapFromTo(shadow_start + shadow_size, map_start + map_size);
return shadow_start;
}
void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
UNIMPLEMENTED();
}
#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, info->dlpi_addr);
// Continue until the first dynamic library is found
if (!info->dlpi_name || info->dlpi_name[0] == 0)
return 0;
// Ignore vDSO
if (internal_strncmp(info->dlpi_name, "linux-", sizeof("linux-") - 1) == 0)
return 0;
#if SANITIZER_FREEBSD || SANITIZER_NETBSD
// Ignore first entry (the main program)
char **p = (char **)data;
if (!(*p)) {
*p = (char *)-1;
return 0;
}
#endif
#if SANITIZER_SOLARIS
// Ignore executable on Solaris
if (info->dlpi_addr == 0)
return 0;
#endif
*(const char **)data = 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 && !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 !SANITIZER_ANDROID
void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
ucontext_t *ucp = (ucontext_t*)context;
*stack = (uptr)ucp->uc_stack.ss_sp;
*ssize = ucp->uc_stack.ss_size;
}
#else
void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
UNIMPLEMENTED();
}
#endif
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
|