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Diffstat (limited to 'lib/dfsan/dfsan.cc')
| -rw-r--r-- | lib/dfsan/dfsan.cc | 453 |
1 files changed, 0 insertions, 453 deletions
diff --git a/lib/dfsan/dfsan.cc b/lib/dfsan/dfsan.cc deleted file mode 100644 index d4dbebc43a78d..0000000000000 --- a/lib/dfsan/dfsan.cc +++ /dev/null @@ -1,453 +0,0 @@ -//===-- dfsan.cc ----------------------------------------------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file is a part of DataFlowSanitizer. -// -// DataFlowSanitizer runtime. This file defines the public interface to -// DataFlowSanitizer as well as the definition of certain runtime functions -// called automatically by the compiler (specifically the instrumentation pass -// in llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp). -// -// The public interface is defined in include/sanitizer/dfsan_interface.h whose -// functions are prefixed dfsan_ while the compiler interface functions are -// prefixed __dfsan_. -//===----------------------------------------------------------------------===// - -#include "sanitizer_common/sanitizer_atomic.h" -#include "sanitizer_common/sanitizer_common.h" -#include "sanitizer_common/sanitizer_file.h" -#include "sanitizer_common/sanitizer_flags.h" -#include "sanitizer_common/sanitizer_flag_parser.h" -#include "sanitizer_common/sanitizer_libc.h" - -#include "dfsan/dfsan.h" - -using namespace __dfsan; - -typedef atomic_uint16_t atomic_dfsan_label; -static const dfsan_label kInitializingLabel = -1; - -static const uptr kNumLabels = 1 << (sizeof(dfsan_label) * 8); - -static atomic_dfsan_label __dfsan_last_label; -static dfsan_label_info __dfsan_label_info[kNumLabels]; - -Flags __dfsan::flags_data; - -SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL dfsan_label __dfsan_retval_tls; -SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL dfsan_label __dfsan_arg_tls[64]; - -SANITIZER_INTERFACE_ATTRIBUTE uptr __dfsan_shadow_ptr_mask; - -// On Linux/x86_64, memory is laid out as follows: -// -// +--------------------+ 0x800000000000 (top of memory) -// | application memory | -// +--------------------+ 0x700000008000 (kAppAddr) -// | | -// | unused | -// | | -// +--------------------+ 0x200200000000 (kUnusedAddr) -// | union table | -// +--------------------+ 0x200000000000 (kUnionTableAddr) -// | shadow memory | -// +--------------------+ 0x000000010000 (kShadowAddr) -// | reserved by kernel | -// +--------------------+ 0x000000000000 -// -// To derive a shadow memory address from an application memory address, -// bits 44-46 are cleared to bring the address into the range -// [0x000000008000,0x100000000000). Then the address is shifted left by 1 to -// account for the double byte representation of shadow labels and move the -// address into the shadow memory range. See the function shadow_for below. - -// On Linux/MIPS64, memory is laid out as follows: -// -// +--------------------+ 0x10000000000 (top of memory) -// | application memory | -// +--------------------+ 0xF000008000 (kAppAddr) -// | | -// | unused | -// | | -// +--------------------+ 0x2200000000 (kUnusedAddr) -// | union table | -// +--------------------+ 0x2000000000 (kUnionTableAddr) -// | shadow memory | -// +--------------------+ 0x0000010000 (kShadowAddr) -// | reserved by kernel | -// +--------------------+ 0x0000000000 - -// On Linux/AArch64 (39-bit VMA), memory is laid out as follow: -// -// +--------------------+ 0x8000000000 (top of memory) -// | application memory | -// +--------------------+ 0x7000008000 (kAppAddr) -// | | -// | unused | -// | | -// +--------------------+ 0x1200000000 (kUnusedAddr) -// | union table | -// +--------------------+ 0x1000000000 (kUnionTableAddr) -// | shadow memory | -// +--------------------+ 0x0000010000 (kShadowAddr) -// | reserved by kernel | -// +--------------------+ 0x0000000000 - -// On Linux/AArch64 (42-bit VMA), memory is laid out as follow: -// -// +--------------------+ 0x40000000000 (top of memory) -// | application memory | -// +--------------------+ 0x3ff00008000 (kAppAddr) -// | | -// | unused | -// | | -// +--------------------+ 0x1200000000 (kUnusedAddr) -// | union table | -// +--------------------+ 0x8000000000 (kUnionTableAddr) -// | shadow memory | -// +--------------------+ 0x0000010000 (kShadowAddr) -// | reserved by kernel | -// +--------------------+ 0x0000000000 - -// On Linux/AArch64 (48-bit VMA), memory is laid out as follow: -// -// +--------------------+ 0x1000000000000 (top of memory) -// | application memory | -// +--------------------+ 0xffff00008000 (kAppAddr) -// | unused | -// +--------------------+ 0xaaaab0000000 (top of PIE address) -// | application PIE | -// +--------------------+ 0xaaaaa0000000 (top of PIE address) -// | | -// | unused | -// | | -// +--------------------+ 0x1200000000 (kUnusedAddr) -// | union table | -// +--------------------+ 0x8000000000 (kUnionTableAddr) -// | shadow memory | -// +--------------------+ 0x0000010000 (kShadowAddr) -// | reserved by kernel | -// +--------------------+ 0x0000000000 - -typedef atomic_dfsan_label dfsan_union_table_t[kNumLabels][kNumLabels]; - -#ifdef DFSAN_RUNTIME_VMA -// Runtime detected VMA size. -int __dfsan::vmaSize; -#endif - -static uptr UnusedAddr() { - return MappingArchImpl<MAPPING_UNION_TABLE_ADDR>() - + sizeof(dfsan_union_table_t); -} - -static atomic_dfsan_label *union_table(dfsan_label l1, dfsan_label l2) { - return &(*(dfsan_union_table_t *) UnionTableAddr())[l1][l2]; -} - -// Checks we do not run out of labels. -static void dfsan_check_label(dfsan_label label) { - if (label == kInitializingLabel) { - Report("FATAL: DataFlowSanitizer: out of labels\n"); - Die(); - } -} - -// Resolves the union of two unequal labels. Nonequality is a precondition for -// this function (the instrumentation pass inlines the equality test). -extern "C" SANITIZER_INTERFACE_ATTRIBUTE -dfsan_label __dfsan_union(dfsan_label l1, dfsan_label l2) { - DCHECK_NE(l1, l2); - - if (l1 == 0) - return l2; - if (l2 == 0) - return l1; - - if (l1 > l2) - Swap(l1, l2); - - atomic_dfsan_label *table_ent = union_table(l1, l2); - // We need to deal with the case where two threads concurrently request - // a union of the same pair of labels. If the table entry is uninitialized, - // (i.e. 0) use a compare-exchange to set the entry to kInitializingLabel - // (i.e. -1) to mark that we are initializing it. - dfsan_label label = 0; - if (atomic_compare_exchange_strong(table_ent, &label, kInitializingLabel, - memory_order_acquire)) { - // Check whether l2 subsumes l1. We don't need to check whether l1 - // subsumes l2 because we are guaranteed here that l1 < l2, and (at least - // in the cases we are interested in) a label may only subsume labels - // created earlier (i.e. with a lower numerical value). - if (__dfsan_label_info[l2].l1 == l1 || - __dfsan_label_info[l2].l2 == l1) { - label = l2; - } else { - label = - atomic_fetch_add(&__dfsan_last_label, 1, memory_order_relaxed) + 1; - dfsan_check_label(label); - __dfsan_label_info[label].l1 = l1; - __dfsan_label_info[label].l2 = l2; - } - atomic_store(table_ent, label, memory_order_release); - } else if (label == kInitializingLabel) { - // Another thread is initializing the entry. Wait until it is finished. - do { - internal_sched_yield(); - label = atomic_load(table_ent, memory_order_acquire); - } while (label == kInitializingLabel); - } - return label; -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE -dfsan_label __dfsan_union_load(const dfsan_label *ls, uptr n) { - dfsan_label label = ls[0]; - for (uptr i = 1; i != n; ++i) { - dfsan_label next_label = ls[i]; - if (label != next_label) - label = __dfsan_union(label, next_label); - } - return label; -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE -void __dfsan_unimplemented(char *fname) { - if (flags().warn_unimplemented) - Report("WARNING: DataFlowSanitizer: call to uninstrumented function %s\n", - fname); -} - -// Use '-mllvm -dfsan-debug-nonzero-labels' and break on this function -// to try to figure out where labels are being introduced in a nominally -// label-free program. -extern "C" SANITIZER_INTERFACE_ATTRIBUTE void __dfsan_nonzero_label() { - if (flags().warn_nonzero_labels) - Report("WARNING: DataFlowSanitizer: saw nonzero label\n"); -} - -// Indirect call to an uninstrumented vararg function. We don't have a way of -// handling these at the moment. -extern "C" SANITIZER_INTERFACE_ATTRIBUTE void -__dfsan_vararg_wrapper(const char *fname) { - Report("FATAL: DataFlowSanitizer: unsupported indirect call to vararg " - "function %s\n", fname); - Die(); -} - -// Like __dfsan_union, but for use from the client or custom functions. Hence -// the equality comparison is done here before calling __dfsan_union. -SANITIZER_INTERFACE_ATTRIBUTE dfsan_label -dfsan_union(dfsan_label l1, dfsan_label l2) { - if (l1 == l2) - return l1; - return __dfsan_union(l1, l2); -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE -dfsan_label dfsan_create_label(const char *desc, void *userdata) { - dfsan_label label = - atomic_fetch_add(&__dfsan_last_label, 1, memory_order_relaxed) + 1; - dfsan_check_label(label); - __dfsan_label_info[label].l1 = __dfsan_label_info[label].l2 = 0; - __dfsan_label_info[label].desc = desc; - __dfsan_label_info[label].userdata = userdata; - return label; -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE -void __dfsan_set_label(dfsan_label label, void *addr, uptr size) { - for (dfsan_label *labelp = shadow_for(addr); size != 0; --size, ++labelp) { - // Don't write the label if it is already the value we need it to be. - // In a program where most addresses are not labeled, it is common that - // a page of shadow memory is entirely zeroed. The Linux copy-on-write - // implementation will share all of the zeroed pages, making a copy of a - // page when any value is written. The un-sharing will happen even if - // the value written does not change the value in memory. Avoiding the - // write when both |label| and |*labelp| are zero dramatically reduces - // the amount of real memory used by large programs. - if (label == *labelp) - continue; - - *labelp = label; - } -} - -SANITIZER_INTERFACE_ATTRIBUTE -void dfsan_set_label(dfsan_label label, void *addr, uptr size) { - __dfsan_set_label(label, addr, size); -} - -SANITIZER_INTERFACE_ATTRIBUTE -void dfsan_add_label(dfsan_label label, void *addr, uptr size) { - for (dfsan_label *labelp = shadow_for(addr); size != 0; --size, ++labelp) - if (*labelp != label) - *labelp = __dfsan_union(*labelp, label); -} - -// Unlike the other dfsan interface functions the behavior of this function -// depends on the label of one of its arguments. Hence it is implemented as a -// custom function. -extern "C" SANITIZER_INTERFACE_ATTRIBUTE dfsan_label -__dfsw_dfsan_get_label(long data, dfsan_label data_label, - dfsan_label *ret_label) { - *ret_label = 0; - return data_label; -} - -SANITIZER_INTERFACE_ATTRIBUTE dfsan_label -dfsan_read_label(const void *addr, uptr size) { - if (size == 0) - return 0; - return __dfsan_union_load(shadow_for(addr), size); -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE -const struct dfsan_label_info *dfsan_get_label_info(dfsan_label label) { - return &__dfsan_label_info[label]; -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE int -dfsan_has_label(dfsan_label label, dfsan_label elem) { - if (label == elem) - return true; - const dfsan_label_info *info = dfsan_get_label_info(label); - if (info->l1 != 0) { - return dfsan_has_label(info->l1, elem) || dfsan_has_label(info->l2, elem); - } else { - return false; - } -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE dfsan_label -dfsan_has_label_with_desc(dfsan_label label, const char *desc) { - const dfsan_label_info *info = dfsan_get_label_info(label); - if (info->l1 != 0) { - return dfsan_has_label_with_desc(info->l1, desc) || - dfsan_has_label_with_desc(info->l2, desc); - } else { - return internal_strcmp(desc, info->desc) == 0; - } -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE uptr -dfsan_get_label_count(void) { - dfsan_label max_label_allocated = - atomic_load(&__dfsan_last_label, memory_order_relaxed); - - return static_cast<uptr>(max_label_allocated); -} - -extern "C" SANITIZER_INTERFACE_ATTRIBUTE void -dfsan_dump_labels(int fd) { - dfsan_label last_label = - atomic_load(&__dfsan_last_label, memory_order_relaxed); - - for (uptr l = 1; l <= last_label; ++l) { - char buf[64]; - internal_snprintf(buf, sizeof(buf), "%u %u %u ", l, - __dfsan_label_info[l].l1, __dfsan_label_info[l].l2); - WriteToFile(fd, buf, internal_strlen(buf)); - if (__dfsan_label_info[l].l1 == 0 && __dfsan_label_info[l].desc) { - WriteToFile(fd, __dfsan_label_info[l].desc, - internal_strlen(__dfsan_label_info[l].desc)); - } - WriteToFile(fd, "\n", 1); - } -} - -void Flags::SetDefaults() { -#define DFSAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue; -#include "dfsan_flags.inc" -#undef DFSAN_FLAG -} - -static void RegisterDfsanFlags(FlagParser *parser, Flags *f) { -#define DFSAN_FLAG(Type, Name, DefaultValue, Description) \ - RegisterFlag(parser, #Name, Description, &f->Name); -#include "dfsan_flags.inc" -#undef DFSAN_FLAG -} - -static void InitializeFlags() { - SetCommonFlagsDefaults(); - flags().SetDefaults(); - - FlagParser parser; - RegisterCommonFlags(&parser); - RegisterDfsanFlags(&parser, &flags()); - parser.ParseString(GetEnv("DFSAN_OPTIONS")); - InitializeCommonFlags(); - if (Verbosity()) ReportUnrecognizedFlags(); - if (common_flags()->help) parser.PrintFlagDescriptions(); -} - -static void InitializePlatformEarly() { - AvoidCVE_2016_2143(); -#ifdef DFSAN_RUNTIME_VMA - __dfsan::vmaSize = - (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1); - if (__dfsan::vmaSize == 39 || __dfsan::vmaSize == 42 || - __dfsan::vmaSize == 48) { - __dfsan_shadow_ptr_mask = ShadowMask(); - } else { - Printf("FATAL: DataFlowSanitizer: unsupported VMA range\n"); - Printf("FATAL: Found %d - Supported 39, 42, and 48\n", __dfsan::vmaSize); - Die(); - } -#endif -} - -static void dfsan_fini() { - if (internal_strcmp(flags().dump_labels_at_exit, "") != 0) { - fd_t fd = OpenFile(flags().dump_labels_at_exit, WrOnly); - if (fd == kInvalidFd) { - Report("WARNING: DataFlowSanitizer: unable to open output file %s\n", - flags().dump_labels_at_exit); - return; - } - - Report("INFO: DataFlowSanitizer: dumping labels to %s\n", - flags().dump_labels_at_exit); - dfsan_dump_labels(fd); - CloseFile(fd); - } -} - -static void dfsan_init(int argc, char **argv, char **envp) { - InitializeFlags(); - - InitializePlatformEarly(); - - if (!MmapFixedNoReserve(ShadowAddr(), UnusedAddr() - ShadowAddr())) - Die(); - - // Protect the region of memory we don't use, to preserve the one-to-one - // mapping from application to shadow memory. But if ASLR is disabled, Linux - // will load our executable in the middle of our unused region. This mostly - // works so long as the program doesn't use too much memory. We support this - // case by disabling memory protection when ASLR is disabled. - uptr init_addr = (uptr)&dfsan_init; - if (!(init_addr >= UnusedAddr() && init_addr < AppAddr())) - MmapFixedNoAccess(UnusedAddr(), AppAddr() - UnusedAddr()); - - InitializeInterceptors(); - - // Register the fini callback to run when the program terminates successfully - // or it is killed by the runtime. - Atexit(dfsan_fini); - AddDieCallback(dfsan_fini); - - __dfsan_label_info[kInitializingLabel].desc = "<init label>"; -} - -#if SANITIZER_CAN_USE_PREINIT_ARRAY -__attribute__((section(".preinit_array"), used)) -static void (*dfsan_init_ptr)(int, char **, char **) = dfsan_init; -#endif |