[compiler-rt] r177723 - [asan] Change the way we report the alloca frame on stack-buff-overflow.

Timur Iskhodzhanov timurrrr at google.com
Mon Mar 25 15:41:42 PDT 2013


Please mind the expectations of Windows tests too.

2013/3/22 Kostya Serebryany <kcc at google.com>:
> Author: kcc
> Date: Fri Mar 22 05:36:24 2013
> New Revision: 177723
>
> URL: http://llvm.org/viewvc/llvm-project?rev=177723&view=rev
> Log:
> [asan] Change the way we report the alloca frame on stack-buff-overflow.
>
> Before: the function name was stored by the compiler as a constant string
> and the run-time was printing it.
> Now: the PC is stored instead and the run-time prints the full symbolized frame.
> This adds a couple of instructions into every function with non-empty stack frame,
> but also reduces the binary size because we store less strings (I saw 2% size reduction).
> This change bumps the asan ABI version to v3.
>
> compiler-rt part, llvm part will follow.
>
> Example of report (now):
> ==31711==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fffa77cf1c5 at pc 0x41feb0 bp 0x7fffa77cefb0 sp 0x7fffa77cefa8
> READ of size 1 at 0x7fffa77cf1c5 thread T0
>     #0 0x41feaf in Frame0(int, char*, char*, char*) stack-oob-frames.cc:20
>     #1 0x41f7ff in Frame1(int, char*, char*) stack-oob-frames.cc:24
>     #2 0x41f477 in Frame2(int, char*) stack-oob-frames.cc:28
>     #3 0x41f194 in Frame3(int) stack-oob-frames.cc:32
>     #4 0x41eee0 in main stack-oob-frames.cc:38
>     #5 0x7f0c5566f76c (/lib/x86_64-linux-gnu/libc.so.6+0x2176c)
>     #6 0x41eb1c (/usr/local/google/kcc/llvm_cmake/a.out+0x41eb1c)
> Address 0x7fffa77cf1c5 is located in stack of thread T0 at offset 293 in frame
>     #0 0x41f87f in Frame0(int, char*, char*, char*) stack-oob-frames.cc:12  <<<<<<<<<<<<<< this is new
>   This frame has 6 object(s):
>     [32, 36) 'frame.addr'
>     [96, 104) 'a.addr'
>     [160, 168) 'b.addr'
>     [224, 232) 'c.addr'
>     [288, 292) 's'
>     [352, 360) 'd'
>
>
>
> Added:
>     compiler-rt/trunk/lib/asan/lit_tests/stack-oob-frames.cc
> Modified:
>     compiler-rt/trunk/lib/asan/asan_interface_internal.h
>     compiler-rt/trunk/lib/asan/asan_report.cc
>     compiler-rt/trunk/lib/asan/asan_thread.cc
>     compiler-rt/trunk/lib/asan/asan_thread.h
>     compiler-rt/trunk/lib/asan/lit_tests/Linux/zero-base-shadow.cc
>     compiler-rt/trunk/lib/asan/lit_tests/stack-frame-demangle.cc
>     compiler-rt/trunk/lib/asan/lit_tests/stack-overflow.cc
>     compiler-rt/trunk/lib/asan/lit_tests/use-after-scope-inlined.cc
>     compiler-rt/trunk/lib/asan/tests/asan_test.cc
>
> Modified: compiler-rt/trunk/lib/asan/asan_interface_internal.h
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_interface_internal.h?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/asan_interface_internal.h (original)
> +++ compiler-rt/trunk/lib/asan/asan_interface_internal.h Fri Mar 22 05:36:24 2013
> @@ -25,8 +25,13 @@ extern "C" {
>    // Everytime the asan ABI changes we also change the version number in this
>    // name. Objects build with incompatible asan ABI version
>    // will not link with run-time.
> -  void __asan_init_v2() SANITIZER_INTERFACE_ATTRIBUTE;
> -  #define __asan_init __asan_init_v2
> +  // Changes between ABI versions:
> +  // v1=>v2: added 'module_name' to __asan_global
> +  // v2=>v3: stack frame description (created by the compiler)
> +  //         contains the function PC as the 3-rd field (see
> +  //         DescribeAddressIfStack).
> +  void __asan_init_v3() SANITIZER_INTERFACE_ATTRIBUTE;
> +  #define __asan_init __asan_init_v3
>
>    // This structure describes an instrumented global variable.
>    struct __asan_global {
>
> Modified: compiler-rt/trunk/lib/asan/asan_report.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_report.cc?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/asan_report.cc (original)
> +++ compiler-rt/trunk/lib/asan/asan_report.cc Fri Mar 22 05:36:24 2013
> @@ -235,33 +235,61 @@ bool DescribeAddressIfShadow(uptr addr)
>    return false;
>  }
>
> +// Return " (thread_name) " or an empty string if the name is empty.
> +const char *ThreadNameWithParenthesis(AsanThreadContext *t, char buff[],
> +                                      uptr buff_len) {
> +  const char *name = t->name;
> +  if (name[0] == '\0') return "";
> +  buff[0] = 0;
> +  internal_strncat(buff, " (", 3);
> +  internal_strncat(buff, name, buff_len - 4);
> +  internal_strncat(buff, ")", 2);
> +  return buff;
> +}
> +
> +const char *ThreadNameWithParenthesis(u32 tid, char buff[],
> +                                      uptr buff_len) {
> +  if (tid == kInvalidTid) return "";
> +  asanThreadRegistry().CheckLocked();
> +  AsanThreadContext *t = GetThreadContextByTidLocked(tid);
> +  return ThreadNameWithParenthesis(t, buff, buff_len);
> +}
> +
>  bool DescribeAddressIfStack(uptr addr, uptr access_size) {
>    AsanThread *t = FindThreadByStackAddress(addr);
>    if (!t) return false;
>    const sptr kBufSize = 4095;
>    char buf[kBufSize];
>    uptr offset = 0;
> -  const char *frame_descr = t->GetFrameNameByAddr(addr, &offset);
> +  uptr frame_pc = 0;
> +  char tname[128];
> +  const char *frame_descr = t->GetFrameNameByAddr(addr, &offset, &frame_pc);
>    // This string is created by the compiler and has the following form:
> -  // "FunctioName n alloc_1 alloc_2 ... alloc_n"
> +  // "n alloc_1 alloc_2 ... alloc_n"
>    // where alloc_i looks like "offset size len ObjectName ".
>    CHECK(frame_descr);
> -  // Report the function name and the offset.
> -  const char *name_end = internal_strchr(frame_descr, ' ');
> -  CHECK(name_end);
> -  buf[0] = 0;
> -  internal_strncat(buf, frame_descr,
> -                   Min(kBufSize,
> -                       static_cast<sptr>(name_end - frame_descr)));
>    Decorator d;
>    Printf("%s", d.Location());
> -  Printf("Address %p is located at offset %zu "
> -             "in frame <%s> of T%d's stack:\n",
> -             (void*)addr, offset, Demangle(buf), t->tid());
> +  Printf("Address %p is located in stack of thread T%d%s "
> +         "at offset %zu in frame\n",
> +         addr, t->tid(),
> +         ThreadNameWithParenthesis(t->tid(), tname, sizeof(tname)),
> +         offset);
> +  // Now we print the frame where the alloca has happened.
> +  // We print this frame as a stack trace with one element.
> +  // The symbolizer may print more than one frame if inlining was involved.
> +  // The frame numbers may be different than those in the stack trace printed
> +  // previously. That's unfortunate, but I have no better solution,
> +  // especially given that the alloca may be from entirely different place
> +  // (e.g. use-after-scope, or different thread's stack).
> +  StackTrace alloca_stack;
> +  alloca_stack.trace[0] = frame_pc + 16;
> +  alloca_stack.size = 1;
>    Printf("%s", d.EndLocation());
> +  PrintStack(&alloca_stack);
>    // Report the number of stack objects.
>    char *p;
> -  uptr n_objects = internal_simple_strtoll(name_end, &p, 10);
> +  uptr n_objects = internal_simple_strtoll(frame_descr, &p, 10);
>    CHECK(n_objects > 0);
>    Printf("  This frame has %zu object(s):\n", n_objects);
>    // Report all objects in this frame.
> @@ -313,26 +341,6 @@ static void DescribeAccessToHeapChunk(As
>    Printf("%s", d.EndLocation());
>  }
>
> -// Return " (thread_name) " or an empty string if the name is empty.
> -const char *ThreadNameWithParenthesis(AsanThreadContext *t, char buff[],
> -                                      uptr buff_len) {
> -  const char *name = t->name;
> -  if (name[0] == '\0') return "";
> -  buff[0] = 0;
> -  internal_strncat(buff, " (", 3);
> -  internal_strncat(buff, name, buff_len - 4);
> -  internal_strncat(buff, ")", 2);
> -  return buff;
> -}
> -
> -const char *ThreadNameWithParenthesis(u32 tid, char buff[],
> -                                      uptr buff_len) {
> -  if (tid == kInvalidTid) return "";
> -  asanThreadRegistry().CheckLocked();
> -  AsanThreadContext *t = GetThreadContextByTidLocked(tid);
> -  return ThreadNameWithParenthesis(t, buff, buff_len);
> -}
> -
>  void DescribeHeapAddress(uptr addr, uptr access_size) {
>    AsanChunkView chunk = FindHeapChunkByAddress(addr);
>    if (!chunk.IsValid()) return;
>
> Modified: compiler-rt/trunk/lib/asan/asan_thread.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_thread.cc?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/asan_thread.cc (original)
> +++ compiler-rt/trunk/lib/asan/asan_thread.cc Fri Mar 22 05:36:24 2013
> @@ -151,7 +151,8 @@ void AsanThread::ClearShadowForThreadSta
>    PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0);
>  }
>
> -const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset) {
> +const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset,
> +                                           uptr *frame_pc) {
>    uptr bottom = 0;
>    if (AddrIsInStack(addr)) {
>      bottom = stack_bottom();
> @@ -159,6 +160,7 @@ const char *AsanThread::GetFrameNameByAd
>      bottom = fake_stack().AddrIsInFakeStack(addr);
>      CHECK(bottom);
>      *offset = addr - bottom;
> +    *frame_pc = ((uptr*)bottom)[2];
>      return  (const char *)((uptr*)bottom)[1];
>    }
>    uptr aligned_addr = addr & ~(SANITIZER_WORDSIZE/8 - 1);  // align addr.
> @@ -183,6 +185,7 @@ const char *AsanThread::GetFrameNameByAd
>    uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1));
>    CHECK(ptr[0] == kCurrentStackFrameMagic);
>    *offset = addr - (uptr)ptr;
> +  *frame_pc = ptr[2];
>    return (const char*)ptr[1];
>  }
>
>
> Modified: compiler-rt/trunk/lib/asan/asan_thread.h
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_thread.h?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/asan_thread.h (original)
> +++ compiler-rt/trunk/lib/asan/asan_thread.h Fri Mar 22 05:36:24 2013
> @@ -66,7 +66,7 @@ class AsanThread {
>    AsanThreadContext *context() { return context_; }
>    void set_context(AsanThreadContext *context) { context_ = context; }
>
> -  const char *GetFrameNameByAddr(uptr addr, uptr *offset);
> +  const char *GetFrameNameByAddr(uptr addr, uptr *offset, uptr *frame_pc);
>
>    bool AddrIsInStack(uptr addr) {
>      return addr >= stack_bottom_ && addr < stack_top_;
>
> Modified: compiler-rt/trunk/lib/asan/lit_tests/Linux/zero-base-shadow.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/lit_tests/Linux/zero-base-shadow.cc?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/lit_tests/Linux/zero-base-shadow.cc (original)
> +++ compiler-rt/trunk/lib/asan/lit_tests/Linux/zero-base-shadow.cc Fri Mar 22 05:36:24 2013
> @@ -18,7 +18,8 @@ int main(int argc, char **argv) {
>    int res = x[argc * 10];  // BOOOM
>    // CHECK: {{READ of size 1 at 0x.* thread T0}}
>    // CHECK: {{    #0 0x.* in _?main .*zero-base-shadow.cc:}}[[@LINE-2]]
> -  // CHECK: {{Address 0x.* is .* frame <main>}}
> +  // CHECK: {{Address 0x.* is .* frame}}
> +  // CHECK: main
>
>    // Check that shadow for stack memory occupies lower part of address space.
>    // CHECK-64: =>0x0f{{.*}}
>
> Modified: compiler-rt/trunk/lib/asan/lit_tests/stack-frame-demangle.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/lit_tests/stack-frame-demangle.cc?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/lit_tests/stack-frame-demangle.cc (original)
> +++ compiler-rt/trunk/lib/asan/lit_tests/stack-frame-demangle.cc Fri Mar 22 05:36:24 2013
> @@ -1,7 +1,4 @@
> -// Check that ASan is able to print demangled frame name even w/o
> -// symbolization.
> -
> -// RUN: %clangxx_asan -m64 -O0 %s -o %t && %t 2>&1 | FileCheck %s
> +// RUN: %clangxx_asan -m64 -O0 %s -o %t && %t 2>&1 | %symbolize | FileCheck %s
>
>  #include <string.h>
>
> @@ -11,9 +8,10 @@ struct YYY {
>      char array[10];
>      memset(array, 0, 10);
>      return array[x];  // BOOOM
> -    // CHECK: {{ERROR: AddressSanitizer: stack-buffer-overflow}}
> -    // CHECK: {{READ of size 1 at 0x.* thread T0}}
> -    // CHECK: {{Address 0x.* is .* frame <XXX::YYY::ZZZ(.*)>}}
> +    // CHECK: ERROR: AddressSanitizer: stack-buffer-overflow
> +    // CHECK: READ of size 1 at
> +    // CHECK: is located in stack of thread T0 at offset
> +    // CHECK: XXX::YYY::ZZZ
>    }
>  };
>  }  // namespace XXX
>
> Added: compiler-rt/trunk/lib/asan/lit_tests/stack-oob-frames.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/lit_tests/stack-oob-frames.cc?rev=177723&view=auto
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/lit_tests/stack-oob-frames.cc (added)
> +++ compiler-rt/trunk/lib/asan/lit_tests/stack-oob-frames.cc Fri Mar 22 05:36:24 2013
> @@ -0,0 +1,59 @@
> +// RUN: %clangxx_asan -m64 -O1 %s -o %t
> +// RUN: %t 0 2>&1 | %symbolize | FileCheck %s --check-prefix=CHECK0
> +// RUN: %t 1 2>&1 | %symbolize | FileCheck %s --check-prefix=CHECK1
> +// RUN: %t 2 2>&1 | %symbolize | FileCheck %s --check-prefix=CHECK2
> +// RUN: %t 3 2>&1 | %symbolize | FileCheck %s --check-prefix=CHECK3
> +
> +#define NOINLINE __attribute__((noinline))
> +inline void break_optimization(void *arg) {
> +  __asm__ __volatile__("" : : "r" (arg) : "memory");
> +}
> +
> +NOINLINE static void Frame0(int frame, char *a, char *b, char *c) {
> +  char s[4] = {0};
> +  char *d = s;
> +  break_optimization(&d);
> +  switch (frame) {
> +    case 3: a[5]++; break;
> +    case 2: b[5]++; break;
> +    case 1: c[5]++; break;
> +    case 0: d[5]++; break;
> +  }
> +}
> +NOINLINE static void Frame1(int frame, char *a, char *b) {
> +  char c[4] = {0}; Frame0(frame, a, b, c);
> +  break_optimization(0);
> +}
> +NOINLINE static void Frame2(int frame, char *a) {
> +  char b[4] = {0}; Frame1(frame, a, b);
> +  break_optimization(0);
> +}
> +NOINLINE static void Frame3(int frame) {
> +  char a[4] = {0}; Frame2(frame, a);
> +  break_optimization(0);
> +}
> +
> +int main(int argc, char **argv) {
> +  if (argc != 2) return 1;
> +  Frame3(argv[1][0] - '0');
> +}
> +
> +// CHECK0: AddressSanitizer: stack-buffer-overflow
> +// CHECK0: #0{{.*}}Frame0
> +// CHECK0: #1{{.*}}Frame1
> +// CHECK0: #2{{.*}}Frame2
> +// CHECK0: #3{{.*}}Frame3
> +// CHECK0: is located in stack of thread T0 at offset
> +// CHECK0-NEXT: #0{{.*}}Frame0
> +//
> +// CHECK1: AddressSanitizer: stack-buffer-overflow
> +// CHECK1: is located in stack of thread T0 at offset
> +// CHECK1-NEXT: #0{{.*}}Frame1
> +//
> +// CHECK2: AddressSanitizer: stack-buffer-overflow
> +// CHECK2: is located in stack of thread T0 at offset
> +// CHECK2-NEXT: #0{{.*}}Frame2
> +//
> +// CHECK3: AddressSanitizer: stack-buffer-overflow
> +// CHECK3: is located in stack of thread T0 at offset
> +// CHECK3-NEXT: #0{{.*}}Frame3
>
> Modified: compiler-rt/trunk/lib/asan/lit_tests/stack-overflow.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/lit_tests/stack-overflow.cc?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/lit_tests/stack-overflow.cc (original)
> +++ compiler-rt/trunk/lib/asan/lit_tests/stack-overflow.cc Fri Mar 22 05:36:24 2013
> @@ -14,6 +14,7 @@ int main(int argc, char **argv) {
>    int res = x[argc * 10];  // BOOOM
>    // CHECK: {{READ of size 1 at 0x.* thread T0}}
>    // CHECK: {{    #0 0x.* in _?main .*stack-overflow.cc:}}[[@LINE-2]]
> -  // CHECK: {{Address 0x.* is .* frame <main>}}
> +  // CHECK: {{Address 0x.* is located in stack of thread T0 at offset}}
> +  // CHECK: main
>    return res;
>  }
>
> Modified: compiler-rt/trunk/lib/asan/lit_tests/use-after-scope-inlined.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/lit_tests/use-after-scope-inlined.cc?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/lit_tests/use-after-scope-inlined.cc (original)
> +++ compiler-rt/trunk/lib/asan/lit_tests/use-after-scope-inlined.cc Fri Mar 22 05:36:24 2013
> @@ -23,7 +23,8 @@ int main(int argc, char *argv[]) {
>    // CHECK: READ of size 4 at 0x{{.*}} thread T0
>    // CHECK:   #0 0x{{.*}} in {{_?}}main
>    // CHECK:      {{.*}}use-after-scope-inlined.cc:[[@LINE-4]]
> -  // CHECK: Address 0x{{.*}} is located at offset
> -  // CHECK:      [[OFFSET:[^ ]*]] in frame <main> of T0{{.*}}:
> +  // CHECK: Address 0x{{.*}} is located in stack of thread T0 at offset
> +  // CHECK:      [[OFFSET:[^ ]*]] in frame
> +  // CHECK: main
>    // CHECK:   {{\[}}[[OFFSET]], {{.*}}) 'x.i'
>  }
>
> Modified: compiler-rt/trunk/lib/asan/tests/asan_test.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/asan_test.cc?rev=177723&r1=177722&r2=177723&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/tests/asan_test.cc (original)
> +++ compiler-rt/trunk/lib/asan/tests/asan_test.cc Fri Mar 22 05:36:24 2013
> @@ -465,6 +465,9 @@ TEST(AddressSanitizer, ManyStackObjectsT
>    EXPECT_DEATH(Ident(ZZZ)[-1] = 0, ASAN_PCRE_DOTALL "XXX.*YYY.*ZZZ");
>  }
>
> +#if 0  // This test requires online symbolizer.
> +// Moved to lit_tests/stack-oob-frames.cc.
> +// Reenable here once we have online symbolizer by default.
>  NOINLINE static void Frame0(int frame, char *a, char *b, char *c) {
>    char d[4] = {0};
>    char *D = Ident(d);
> @@ -500,6 +503,7 @@ TEST(AddressSanitizer, GuiltyStackFrame2
>  TEST(AddressSanitizer, GuiltyStackFrame3Test) {
>    EXPECT_DEATH(Frame3(3), "located .*in frame <.*Frame3");
>  }
> +#endif
>
>  NOINLINE void LongJmpFunc1(jmp_buf buf) {
>    // create three red zones for these two stack objects.
>
>
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