Hi all,
I tried to build OpenJDK fastdebug with GCC 10.1 on Ubuntu 18.04, but I
saw some compiler warnings as follows:
In file included from
/home/jyukutyo/code/jdk/src/hotspot/share/classfile/systemDictionary.hpp:31,
from
/home/jyukutyo/code/jdk/src/hotspot/share/classfile/javaClasses.hpp:28,
from
/home/jyukutyo/code/jdk/src/hotspot/share/precompiled/precompiled.hpp:35:
In member function 'void Symbol::byte_at_put(int, u1)',
inlined from 'Symbol::Symbol(const u1*, int, int)' at
/home/jyukutyo/code/jdk/src/hotspot/share/oops/symbol.cpp:55:16:
/home/jyukutyo/code/jdk/src/hotspot/share/oops/symbol.hpp:130:18: error:
writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
130 | _body[index] = value;
| ~~~~~~~~~~~~~^~~~~~~
/home/jyukutyo/code/jdk/src/java.base/share/native/libfdlibm/k_standard.c:
In function '__j__kernel_standard':
/home/jyukutyo/code/jdk/src/java.base/share/native/libfdlibm/k_standard.c:743:19:
error: 'exc.retval' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
743 | return exc.retval;
| ~~~^~~~~~~
In file included from /usr/include/string.h:494,
from
/home/jyukutyo/code/jdk/src/java.base/unix/native/libnet/NetworkInterface.c:30:
In function 'strncpy',
inlined from 'getFlags' at
/home/jyukutyo/code/jdk/src/java.base/unix/native/libnet/NetworkInterface.c:1362:5,
inlined from 'addif' at
/home/jyukutyo/code/jdk/src/java.base/unix/native/libnet/NetworkInterface.c:974:13:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error:
'__builtin_strncpy' output may be truncated copying 15 bytes from a
string of length 15 [-Werror=stringop-truncation]
106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos
(__dest));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I can resolve them with the following patch. I believe it fixes those
potential bugs, so I'd like to contribute it.
(Our company has signed OCA.)
Thanks,
Koichi
===== PATCH =====
diff -r 20d92fe3ac52 src/hotspot/share/oops/symbol.cpp
--- a/src/hotspot/share/oops/symbol.cpp Tue Jun 16 03:16:41 2020 +0000
+++ b/src/hotspot/share/oops/symbol.cpp Thu Jun 18 07:08:50 2020 +0900
@@ -50,9 +50,10 @@
Symbol::Symbol(const u1* name, int length, int refcount) {
_hash_and_refcount = pack_hash_and_refcount((short)os::random(),
refcount);
_length = length;
- _body[0] = 0; // in case length == 0
- for (int i = 0; i < length; i++) {
- byte_at_put(i, name[i]);
+ if (length == 0) {
+ _body[0] = 0;
+ } else {
+ memcpy(_body, name, length);
}
}
diff -r 20d92fe3ac52 src/hotspot/share/oops/symbol.hpp
--- a/src/hotspot/share/oops/symbol.hpp Tue Jun 16 03:16:41 2020 +0000
+++ b/src/hotspot/share/oops/symbol.hpp Thu Jun 18 07:08:50 2020 +0900
@@ -125,11 +125,6 @@
return (int)heap_word_size(byte_size(length));
}
- void byte_at_put(int index, u1 value) {
- assert(index >=0 && index < length(), "symbol index overflow");
- _body[index] = value;
- }
-
Symbol(const u1* name, int length, int refcount);
void* operator new(size_t size, int len) throw();
void* operator new(size_t size, int len, Arena* arena) throw();
diff -r 20d92fe3ac52 src/java.base/share/native/libfdlibm/k_standard.c
--- a/src/java.base/share/native/libfdlibm/k_standard.c Tue Jun 16
03:16:41 2020 +0000
+++ b/src/java.base/share/native/libfdlibm/k_standard.c Thu Jun 18
07:08:50 2020 +0900
@@ -739,6 +739,10 @@
errno = EDOM;
}
break;
+ default:
+ exc.retval = zero;
+ errno = EINVAL;
+ break;
}
return exc.retval;
}
diff -r 20d92fe3ac52 src/java.base/unix/native/libnet/NetworkInterface.c
--- a/src/java.base/unix/native/libnet/NetworkInterface.c Tue Jun 16
03:16:41 2020 +0000
+++ b/src/java.base/unix/native/libnet/NetworkInterface.c Thu Jun 18
07:08:50 2020 +0900
@@ -1296,7 +1296,10 @@
static int getIndex(int sock, const char *name) {
struct ifreq if2;
memset((char *)&if2, 0, sizeof(if2));
- strncpy(if2.ifr_name, name, sizeof(if2.ifr_name) - 1);
+ if (sizeof(if2.ifr_name) < sizeof(name)) {
+ return -1;
+ }
+ strcpy(if2.ifr_name, name);
if (ioctl(sock, SIOCGIFINDEX, (char *)&if2) < 0) {
return -1;
@@ -1359,7 +1362,10 @@
static int getFlags(int sock, const char *ifname, int *flags) {
struct ifreq if2;
memset((char *)&if2, 0, sizeof(if2));
- strncpy(if2.ifr_name, ifname, sizeof(if2.ifr_name) - 1);
+ if (sizeof(if2.ifr_name) < sizeof(ifname)) {
+ return -1;
+ }
+ strcpy(if2.ifr_name, ifname);
if (ioctl(sock, SIOCGIFFLAGS, (char *)&if2) < 0) {
return -1;
