[compiler-rt] r298650 - [asan] Add an interceptor for strtok
Alex Shlyapnikov via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 23 14:39:52 PDT 2017
Author: alekseyshl
Date: Thu Mar 23 16:39:52 2017
New Revision: 298650
URL: http://llvm.org/viewvc/llvm-project?rev=298650&view=rev
Log:
[asan] Add an interceptor for strtok
Summary:
This change addresses https://github.com/google/sanitizers/issues/766. I
tested the change with make check-asan and the newly added test case.
Reviewers: ygribov, kcc, alekseyshl
Subscribers: kubamracek, llvm-commits
Patch by mrigger
Differential Revision: https://reviews.llvm.org/D30384
Added:
compiler-rt/trunk/test/asan/TestCases/strtok.c
Modified:
compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc
compiler-rt/trunk/lib/sanitizer_common/sanitizer_platform_interceptors.h
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc?rev=298650&r1=298649&r2=298650&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc Thu Mar 23 16:39:52 2017
@@ -495,6 +495,52 @@ INTERCEPTOR(char*, strcasestr, const cha
#define INIT_STRCASESTR
#endif
+#if SANITIZER_INTERCEPT_STRTOK
+
+INTERCEPTOR(char*, strtok, char *str, const char *delimiters) {
+ void *ctx;
+ COMMON_INTERCEPTOR_ENTER(ctx, strtok, str, delimiters);
+ if (!common_flags()->intercept_strtok) {
+ return REAL(strtok)(str, delimiters);
+ }
+ if (common_flags()->strict_string_checks) {
+ // If strict_string_checks is enabled, we check the whole first argument
+ // string on the first call (strtok saves this string in a static buffer
+ // for subsequent calls). We do not need to check strtok's result.
+ // As the delimiters can change, we check them every call.
+ if (str != nullptr) {
+ COMMON_INTERCEPTOR_READ_RANGE(ctx, str, REAL(strlen)(str) + 1);
+ }
+ COMMON_INTERCEPTOR_READ_RANGE(ctx, delimiters,
+ REAL(strlen)(delimiters) + 1);
+ return REAL(strtok)(str, delimiters);
+ } else {
+ // However, when strict_string_checks is disabled we cannot check the
+ // whole string on the first call. Instead, we check the result string
+ // which is guaranteed to be a NULL-terminated substring of the first
+ // argument. We also conservatively check one character of str and the
+ // delimiters.
+ if (str != nullptr) {
+ COMMON_INTERCEPTOR_READ_STRING(ctx, str, 1);
+ }
+ COMMON_INTERCEPTOR_READ_RANGE(ctx, delimiters, 1);
+ char *result = REAL(strtok)(str, delimiters);
+ if (result != nullptr) {
+ COMMON_INTERCEPTOR_READ_RANGE(ctx, result, REAL(strlen)(result) + 1);
+ } else if (str != nullptr) {
+ // No delimiter were found, it's safe to assume that the entire str was
+ // scanned.
+ COMMON_INTERCEPTOR_READ_RANGE(ctx, str, REAL(strlen)(str) + 1);
+ }
+ return result;
+ }
+}
+
+#define INIT_STRTOK COMMON_INTERCEPT_FUNCTION(strtok)
+#else
+#define INIT_STRTOK
+#endif
+
#if SANITIZER_INTERCEPT_MEMMEM
DECLARE_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_memmem, uptr called_pc,
const void *s1, SIZE_T len1, const void *s2,
@@ -6079,6 +6125,7 @@ static void InitializeCommonInterceptors
INIT_STRCHRNUL;
INIT_STRRCHR;
INIT_STRSPN;
+ INIT_STRTOK;
INIT_STRPBRK;
INIT_MEMSET;
INIT_MEMMOVE;
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc?rev=298650&r1=298649&r2=298650&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc Thu Mar 23 16:39:52 2017
@@ -193,6 +193,9 @@ COMMON_FLAG(bool, intercept_strstr, true
COMMON_FLAG(bool, intercept_strspn, true,
"If set, uses custom wrappers for strspn and strcspn function "
"to find more errors.")
+COMMON_FLAG(bool, intercept_strtok, true,
+ "If set, uses a custom wrapper for the strtok function "
+ "to find more errors.")
COMMON_FLAG(bool, intercept_strpbrk, true,
"If set, uses custom wrappers for strpbrk function "
"to find more errors.")
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_platform_interceptors.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_platform_interceptors.h?rev=298650&r1=298649&r2=298650&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_platform_interceptors.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_platform_interceptors.h Thu Mar 23 16:39:52 2017
@@ -74,6 +74,7 @@
#define SANITIZER_INTERCEPT_STRCMP 1
#define SANITIZER_INTERCEPT_STRSTR 1
#define SANITIZER_INTERCEPT_STRCASESTR SI_NOT_WINDOWS
+#define SANITIZER_INTERCEPT_STRTOK 1
#define SANITIZER_INTERCEPT_STRCHR 1
#define SANITIZER_INTERCEPT_STRCHRNUL SI_UNIX_NOT_MAC
#define SANITIZER_INTERCEPT_STRRCHR 1
Added: compiler-rt/trunk/test/asan/TestCases/strtok.c
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/strtok.c?rev=298650&view=auto
==============================================================================
--- compiler-rt/trunk/test/asan/TestCases/strtok.c (added)
+++ compiler-rt/trunk/test/asan/TestCases/strtok.c Thu Mar 23 16:39:52 2017
@@ -0,0 +1,108 @@
+// RUN: %clang_asan %s -o %t
+
+// Test overflows with strict_string_checks
+
+// RUN: %env_asan_opts=strict_string_checks=true not %run %t test1 2>&1 | \
+// RUN: FileCheck %s --check-prefix=CHECK1
+// RUN: %env_asan_opts=intercept_strtok=false%run %t test1 2>&1
+// RUN: %env_asan_opts=strict_string_checks=true not %run %t test2 2>&1 | \
+// RUN: FileCheck %s --check-prefix=CHECK2
+// RUN: %env_asan_opts=intercept_strtok=false %run %t test2 2>&1
+// RUN: %env_asan_opts=strict_string_checks=true not %run %t test3 2>&1 | \
+// RUN: FileCheck %s --check-prefix=CHECK3
+// RUN: %env_asan_opts=intercept_strtok=false %run %t test3 2>&1
+// RUN: %env_asan_opts=strict_string_checks=true %run %t test4 2>&1
+// RUN: %env_asan_opts=intercept_strtok=false %run %t test4 2>&1
+
+// Test overflows with !strict_string_checks
+// RUN: %env_asan_opts=strict_string_checks=false not %run %t test5 2>&1 | \
+// RUN: FileCheck %s --check-prefix=CHECK5
+// RUN: %env_asan_opts=intercept_strtok=false %run %t test5 2>&1
+// RUN: %env_asan_opts=strict_string_checks=false not %run %t test6 2>&1 | \
+// RUN: FileCheck %s --check-prefix=CHECK6
+// RUN: %env_asan_opts=intercept_strtok=false %run %t test6 2>&1
+
+
+#include <assert.h>
+#include <string.h>
+#include <sanitizer/asan_interface.h>
+
+// Check that we find overflows in the delimiters on the first call
+// with strict_string_checks.
+void test1() {
+ char *token;
+ char s[4] = "abc";
+ char token_delimiter[2] = "b";
+ __asan_poison_memory_region ((char *)&token_delimiter[1], 2);
+ token = strtok(s, token_delimiter);
+ // CHECK1:'token_delimiter' <== Memory access at offset {{[0-9]+}} partially overflows this variable
+ assert(strcmp(token, "a") == 0);
+}
+
+// Check that we find overflows in the delimiters on the second call (str == NULL)
+// with strict_string_checks.
+void test2() {
+ char *token;
+ char s[4] = "abc";
+ char token_delimiter[2] = "b";
+ token = strtok(s, token_delimiter);
+ assert(strcmp(token, "a") == 0);
+ __asan_poison_memory_region ((char *)&token_delimiter[1], 2);
+ token = strtok(NULL, token_delimiter);
+ // CHECK2:'token_delimiter' <== Memory access at offset {{[0-9]+}} partially overflows this variable
+ assert(strcmp(token, "c") == 0);
+}
+
+// Check that we find overflows in the string (only on the first call) with strict_string_checks.
+void test3() {
+ char *token;
+ char s[4] = "abc";
+ char token_delimiter[2] = "b";
+ __asan_poison_memory_region ((char *)&s[3], 2);
+ token = strtok(s, token_delimiter);
+ // CHECK3:'s' <== Memory access at offset {{[0-9]+}} partially overflows this variable
+ assert(token == s);
+}
+
+// Check that we do not crash when strtok returns NULL with strict_string_checks.
+void test4() {
+ char *token;
+ char s[] = "";
+ char token_delimiter[] = "a";
+ token = strtok(s, token_delimiter);
+ assert(token == NULL);
+}
+
+// Check that we find overflows in the string (only on the first call) with !strict_string_checks.
+void test5() {
+ char *token;
+ char s[4] = "abc";
+ char token_delimiter[2] = "d";
+ __asan_poison_memory_region ((char *)&s[2], 2);
+ __asan_poison_memory_region ((char *)&token_delimiter[1], 2);
+ token = strtok(s, token_delimiter);
+ // CHECK5:'s' <== Memory access at offset {{[0-9]+}} partially overflows this variable
+ assert(token == s);
+}
+
+// Check that we find overflows in the delimiters (only on the first call) with !strict_string_checks.
+void test6() {
+ char *token;
+ char s[4] = "abc";
+ char token_delimiter[1] = {'d'};
+ __asan_poison_memory_region ((char *)&token_delimiter[1], 2);
+ token = strtok(s, &token_delimiter[1]);
+ // CHECK6:'token_delimiter' <== Memory access at offset {{[0-9]+}} overflows this variable
+ assert(strcmp(token, "abc") == 0);
+}
+
+int main(int argc, char **argv) {
+ if (argc != 2) return 1;
+ if (!strcmp(argv[1], "test1")) test1();
+ if (!strcmp(argv[1], "test2")) test2();
+ if (!strcmp(argv[1], "test3")) test3();
+ if (!strcmp(argv[1], "test4")) test4();
+ if (!strcmp(argv[1], "test5")) test5();
+ if (!strcmp(argv[1], "test6")) test6();
+ return 0;
+}
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