commit 22a8094b41b2606084dc0c0c70487e5ed0fcb652
parent f3c0bfdb96ec00aaefdb75024059aa33895726c5
Author: jvoisin <julien.voisin@dustri.org>
Date: Wed, 27 Dec 2023 17:07:32 +0100
Re-enable previously disabled overlap checks
They were previously disabled in 80a83a5
Diffstat:
6 files changed, 33 insertions(+), 31 deletions(-)
diff --git a/include/string.h b/include/string.h
@@ -189,19 +189,17 @@ _FORTIFY_FN(stpncpy) char *stpncpy(char * _FORTIFY_POS0 __d, const char *__s,
#if __has_builtin(__builtin___stpncpy_chk) && USE_NATIVE_CHK
return __builtin___stpncpy_chk(__d, __s, __n, __fh_bos(__d, 0));
#else
-#if 0
- // They check overlap across the whole range of the given length, but
- // the given length is not what will actually be copied, rather it's
- // the maximum length (if src is shorter, only length of src will be
- // copied). This triggers false positives and traps where it shouldn't
- // (e.g. in ICU tests).
- if (__fh_overlap(__d, __s, __n))
+ __fh_size_t max_len_s = strnlen(__s, __n);
+ if (__fh_overlap(__d, max_len_s, __s, max_len_s))
__builtin_trap();
-#endif
+ // If the length strlen(src) is smaller than n, the remaining
+ // characters in the array pointed to by dest are filled with null
+ // bytes ('\0')
__fh_size_t __b = __fh_bos(__d, 0);
- if (__n > __b && strlen(__s) + 1 > __b)
+ if (__n > __b)
__builtin_trap();
+
return __orig_stpncpy(__d, __s, __n);
#endif
}
@@ -297,19 +295,16 @@ _FORTIFY_FN(strncpy) char *strncpy(char * _FORTIFY_POS0 __d,
#if __has_builtin(__builtin___strncpy_chk) && USE_NATIVE_CHK
return __builtin___strncpy_chk(__d, __s, __n, __fh_bos(__d, 0));
#else
-#if 0
- // They check overlap across the whole range of the given length, but
- // the given length is not what will actually be copied, rather it's
- // the maximum length (if src is shorter, only length of src will be
- // copied). This triggers false positives and traps where it shouldn't
- // (e.g. in ICU tests).
- if (__fh_overlap(__d, __s, __n))
+ __fh_size_t max_len_s = strnlen(__s, __n);
+ if (__fh_overlap(__d, max_len_s, __s, max_len_s))
__builtin_trap();
-#endif
+ // If the length of src is less than n, strncpy() writes additional
+ // null bytes to dest to ensure that a total of n bytes are written.
__fh_size_t __b = __fh_bos(__d, 0);
if (__n > __b)
__builtin_trap();
+
return __orig_strncpy(__d, __s, __n);
#endif
}
diff --git a/tests/test_stpncpy_dynamic_write.c b/tests/test_stpncpy_dynamic_write.c
@@ -3,8 +3,9 @@
#include <string.h>
int main(int argc, char** argv) {
- char buffer[8] = {0};
- stpncpy(buffer, "1234567", 5);
+ char buffer[] = {'A', 'B', 'C', 'D', 'E', 'F', '\0'};
+
+ stpncpy(buffer, "1234567", 3);
puts(buffer);
CHK_FAIL_START
diff --git a/tests/test_stpncpy_overwrite_over.c b/tests/test_stpncpy_overwrite_over.c
@@ -3,15 +3,16 @@
#include <string.h>
int main(int argc, char** argv) {
-#if 0
char buffer[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
puts(buffer);
+ stpncpy(buffer, buffer+5, 2);
+ puts(buffer);
+
CHK_FAIL_START
stpncpy(buffer+1, buffer, 5);
CHK_FAIL_END
puts(buffer);
-#endif
return ret;
}
diff --git a/tests/test_stpncpy_overwrite_under.c b/tests/test_stpncpy_overwrite_under.c
@@ -3,15 +3,17 @@
#include <string.h>
int main(int argc, char** argv) {
-#if 0
char buffer[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
puts(buffer);
+ stpncpy(buffer+5, buffer, 2);
+ puts(buffer);
+
+ char buffer2[] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
CHK_FAIL_START
- stpncpy(buffer-1, buffer, 5);
+ stpncpy(buffer2-1, buffer2, 5);
CHK_FAIL_END
- puts(buffer);
-#endif
+ puts(buffer2);
return ret;
}
diff --git a/tests/test_strncpy_overwrite_over.c b/tests/test_strncpy_overwrite_over.c
@@ -3,15 +3,20 @@
#include <string.h>
int main(int argc, char** argv) {
-#if 0
char buffer[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
puts(buffer);
+ strncpy(buffer, buffer+4, 1);
+ puts(buffer);
+
+ strncpy(buffer+6, buffer, 1);
+ puts(buffer);
+
+ char buffer2[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
CHK_FAIL_START
- strncpy(buffer+1, buffer, 5);
+ strncpy(buffer2+1, buffer2, 5);
CHK_FAIL_END
- puts(buffer);
-#endif
+ puts(buffer2);
return ret;
}
diff --git a/tests/test_strncpy_overwrite_under.c b/tests/test_strncpy_overwrite_under.c
@@ -3,7 +3,6 @@
#include <string.h>
int main(int argc, char** argv) {
-#if 0
char buffer[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
puts(buffer);
@@ -12,6 +11,5 @@ int main(int argc, char** argv) {
CHK_FAIL_END
puts(buffer);
-#endif
return ret;
}
