[compiler-rt] r286708 - [asan] Fix strncmp and strncasecmp interceptors
Reid Kleckner via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 14 13:13:55 PST 2016
I like having a separate test case for each interceptor, so that if we
start failing to intercept one function, only one test fails for that
function.
On Mon, Nov 14, 2016 at 12:36 PM, Vitaly Buka <vitalybuka at google.com> wrote:
> maybe better just redefine strncasecmp to strncmp for Windows inside of
> the test to avoid code duplication?
>
> On Mon, Nov 14, 2016 at 9:47 AM Reid Kleckner <rnk at google.com> wrote:
>
>> Windows doesn't have strncasecmp. I have a hack to make the test pass,
>> but maybe it would be better to split the test into strncmp and strncasecmp
>> and XFAIL the strncasecmp one.
>>
>> On Fri, Nov 11, 2016 at 8:32 PM, Vitaly Buka via llvm-commits <
>> llvm-commits at lists.llvm.org> wrote:
>>
>> Author: vitalybuka
>> Date: Fri Nov 11 22:32:31 2016
>> New Revision: 286708
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=286708&view=rev
>> Log:
>> [asan] Fix strncmp and strncasecmp interceptors
>>
>> Summary:
>> In non-strict mode we will check memory access for both strings from
>> beginning
>> to either:
>> 1. 0-char
>> 2. size
>> 3. different chars
>>
>> In strict mode we will check from beginning to either:
>> 1. 0-char
>> 2. size
>>
>> Previously in strict mode we always checked up to the 0-char.
>>
>> Reviewers: kcc, eugenis
>>
>> Subscribers: llvm-commits, kubabrecka
>>
>> Differential Revision: https://reviews.llvm.org/D26574
>>
>> Modified:
>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_
>> common_interceptors.inc
>> compiler-rt/trunk/test/asan/TestCases/strncmp_strict.c
>>
>> 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=
>> 286708&r1=286707&r2=286708&view=diff
>> ============================================================
>> ==================
>> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
>> (original)
>> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
>> Fri Nov 11 22:32:31 2016
>> @@ -304,8 +304,14 @@ INTERCEPTOR(int, strncmp, const char *s1
>> c2 = (unsigned char)s2[i];
>> if (c1 != c2 || c1 == '\0') break;
>> }
>> - COMMON_INTERCEPTOR_READ_STRING(ctx, s1, Min(i + 1, size));
>> - COMMON_INTERCEPTOR_READ_STRING(ctx, s2, Min(i + 1, size));
>> + uptr i1 = i;
>> + uptr i2 = i;
>> + if (common_flags()->strict_string_checks) {
>> + for (; i1 < size && s1[i1]; i1++) {}
>> + for (; i2 < size && s2[i2]; i2++) {}
>> + }
>> + COMMON_INTERCEPTOR_READ_RANGE((ctx), (s1), Min(i1 + 1, size));
>> + COMMON_INTERCEPTOR_READ_RANGE((ctx), (s2), Min(i2 + 1, size));
>> int result = CharCmpX(c1, c2);
>> CALL_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_strncmp,
>> GET_CALLER_PC(), s1,
>> s2, size, result);
>> @@ -348,24 +354,30 @@ INTERCEPTOR(int, strcasecmp, const char
>> }
>>
>> DECLARE_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_strncasecmp, uptr
>> called_pc,
>> - const char *s1, const char *s2, uptr n,
>> + const char *s1, const char *s2, uptr size,
>> int result)
>>
>> -INTERCEPTOR(int, strncasecmp, const char *s1, const char *s2, SIZE_T n) {
>> +INTERCEPTOR(int, strncasecmp, const char *s1, const char *s2, SIZE_T
>> size) {
>> void *ctx;
>> - COMMON_INTERCEPTOR_ENTER(ctx, strncasecmp, s1, s2, n);
>> + COMMON_INTERCEPTOR_ENTER(ctx, strncasecmp, s1, s2, size);
>> unsigned char c1 = 0, c2 = 0;
>> uptr i;
>> - for (i = 0; i < n; i++) {
>> + for (i = 0; i < size; i++) {
>> c1 = (unsigned char)s1[i];
>> c2 = (unsigned char)s2[i];
>> if (CharCaseCmp(c1, c2) != 0 || c1 == '\0') break;
>> }
>> - COMMON_INTERCEPTOR_READ_RANGE(ctx, s1, Min(i + 1, n));
>> - COMMON_INTERCEPTOR_READ_RANGE(ctx, s2, Min(i + 1, n));
>> + uptr i1 = i;
>> + uptr i2 = i;
>> + if (common_flags()->strict_string_checks) {
>> + for (; i1 < size && s1[i1]; i1++) {}
>> + for (; i2 < size && s2[i2]; i2++) {}
>> + }
>> + COMMON_INTERCEPTOR_READ_RANGE((ctx), (s1), Min(i1 + 1, size));
>> + COMMON_INTERCEPTOR_READ_RANGE((ctx), (s2), Min(i2 + 1, size));
>> int result = CharCaseCmp(c1, c2);
>> CALL_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_strncasecmp,
>> GET_CALLER_PC(),
>> - s1, s2, n, result);
>> + s1, s2, size, result);
>> return result;
>> }
>>
>>
>> Modified: compiler-rt/trunk/test/asan/TestCases/strncmp_strict.c
>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/
>> test/asan/TestCases/strncmp_strict.c?rev=286708&r1=286707&
>> r2=286708&view=diff
>> ============================================================
>> ==================
>> --- compiler-rt/trunk/test/asan/TestCases/strncmp_strict.c (original)
>> +++ compiler-rt/trunk/test/asan/TestCases/strncmp_strict.c Fri Nov 11
>> 22:32:31 2016
>> @@ -1,26 +1,81 @@
>> // Test strict_string_checks option in strncmp function
>> -// RUN: %clang_asan %s -o %t && %run %t 2>&1
>> -// RUN: %env_asan_opts=strict_string_checks=false %run %t 2>&1
>> -// RUN: %env_asan_opts=strict_string_checks=true not %run %t 2>&1 |
>> FileCheck %s
>> +// RUN: %clang_asan %s -o %t
>> +
>> +// RUN: %env_asan_opts=strict_string_checks=false %run %t a 2>&1
>> +// RUN: %env_asan_opts=strict_string_checks=true %run %t a 2>&1
>> +// RUN: not %run %t b 2>&1 | FileCheck %s
>> +// RUN: not %run %t c 2>&1 | FileCheck %s
>> +// RUN: not %run %t d 2>&1 | FileCheck %s
>> +// RUN: not %run %t e 2>&1 | FileCheck %s
>> +// RUN: not %run %t f 2>&1 | FileCheck %s
>> +// RUN: not %run %t g 2>&1 | FileCheck %s
>> +// RUN: %env_asan_opts=strict_string_checks=false %run %t h 2>&1
>> +// RUN: %env_asan_opts=strict_string_checks=true not %run %t h 2>&1 |
>> FileCheck %s
>> +// RUN: %env_asan_opts=strict_string_checks=false %run %t i 2>&1
>> +// RUN: %env_asan_opts=strict_string_checks=true not %run %t i 2>&1 |
>> FileCheck %s
>> +
>> +// RUN: %env_asan_opts=strict_string_checks=false %run %t A 2>&1
>> +// RUN: %env_asan_opts=strict_string_checks=true %run %t A 2>&1
>> +// RUN: not %run %t B 2>&1 | FileCheck %s
>> +// RUN: not %run %t C 2>&1 | FileCheck %s
>> +// RUN: not %run %t D 2>&1 | FileCheck %s
>> +// RUN: not %run %t E 2>&1 | FileCheck %s
>> +// RUN: not %run %t F 2>&1 | FileCheck %s
>> +// RUN: not %run %t G 2>&1 | FileCheck %s
>> +// RUN: %env_asan_opts=strict_string_checks=false %run %t H 2>&1
>> +// RUN: %env_asan_opts=strict_string_checks=true not %run %t H 2>&1 |
>> FileCheck %s
>> +// RUN: %env_asan_opts=strict_string_checks=false %run %t I 2>&1
>> +// RUN: %env_asan_opts=strict_string_checks=true not %run %t I 2>&1 |
>> FileCheck %s
>>
>> #include <assert.h>
>> #include <stdlib.h>
>> +#include <stdio.h>
>> #include <string.h>
>> +#include <ctype.h>
>>
>> int main(int argc, char **argv) {
>> - size_t size = 100;
>> + assert(argc >= 2);
>> + const size_t size = 100;
>> char fill = 'o';
>> - char *s1 = (char*)malloc(size);
>> + char s1[size];
>> + char s2[size];
>> memset(s1, fill, size);
>> - char *s2 = (char*)malloc(size);
>> memset(s2, fill, size);
>> - s1[size - 1] = 'z';
>> - s2[size - 1] = 'x';
>> - int r = strncmp(s1, s2, size + 1);
>> - // CHECK: {{.*ERROR: AddressSanitizer: heap-buffer-overflow on
>> address}}
>> - // CHECK: READ of size 101
>> - assert(r == 1);
>> - free(s1);
>> - free(s2);
>> +
>> + int (*cmp_fn)(const char *, const char *, size_t);
>> + cmp_fn = islower(argv[1][0]) ? &strncmp : &strncasecmp;
>> +
>> + switch(tolower(argv[1][0])) {
>> + case 'a':
>> + s1[size - 1] = 'z';
>> + s2[size - 1] = 'x';
>> + for (int i = 0; i <= size; ++i)
>> + assert((cmp_fn(s1, s2, i) == 0) == (i < size));
>> + s1[size - 1] = '\0';
>> + s2[size - 1] = '\0';
>> + assert(cmp_fn(s1, s2, 2*size) == 0);
>> + break;
>> + case 'b':
>> + return cmp_fn(s1-1, s2, 1);
>> + case 'c':
>> + return cmp_fn(s1, s2-1, 1);
>> + case 'd':
>> + return cmp_fn(s1+size, s2, 1);
>> + case 'e':
>> + return cmp_fn(s1, s2+size, 1);
>> + case 'f':
>> + return cmp_fn(s1+1, s2, size);
>> + case 'g':
>> + return cmp_fn(s1, s2+1, size);
>> + case 'h':
>> + s1[size - 1] = '\0';
>> + assert(cmp_fn(s1, s2, 2*size) != 0);
>> + break;
>> + case 'i':
>> + s2[size - 1] = '\0';
>> + assert(cmp_fn(s1, s2, 2*size) != 0);
>> + break;
>> + // CHECK: {{.*}}ERROR: AddressSanitizer:
>> stack-buffer-{{ov|und}}erflow on address
>> + }
>> return 0;
>> }
>>
>>
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