Before this commit, the following writes "foo" to the
console and deletes the input file:
echo foo | xz > con_xz
xz --suffix=_xz --decompress con_xz
It cannot happen without --suffix because names like con.xz
are also special and so attempting to decompress con.xz
(or compress con to con.xz) will already fail when opening
the input file.
Similar thing is possible when compressing. The following
writes to "nul" and the input file "n" is deleted.
echo foo | xz > n
xz --suffix=ul n
Now xz checks if the destination is a special file before
continuing. DOS/DJGPP version had a check for this but
Windows (and OS/2) didn't.
(cherry picked from commit 660c8c29e5)
There are several new policies. CMP0149 may affect the Windows SDK
version that CMake will choose by default. The new behavior is more
predictable, always choosing the latest SDK version by default.
The other new policies shouldn't affect this package.
(cherry picked from commit 5be6275f19)
For compatibility with C23's [[noreturn]], tuklib_attr_noreturn
must be at the beginning of declaration (before "extern" or
"static", and even before any GNU C's __attribute__).
This commit also moves all other function attributes to
the beginning of function declarations. "extern" is kept
at the beginning of a line so the attributes are listed on
separate lines before "extern" or "static".
(cherry picked from commit b71b8922ef)
xrealloc() is obviously incorrect, modern GCC docs even
mention realloc() as an example where this attribute
cannot be used.
liblzma's lzma_alloc() and lzma_alloc_zero() would be
correct uses most of the time but custom allocators
may use a memory pool or otherwise hold the pointer
so aliasing issues could happen in theory.
The xstrdup() case likely was correct but I removed it anyway.
Now there are no __malloc__ attributes left in the code.
The allocations aren't in hot paths so this should make
no practical difference.
(cherry picked from commit 359e5c6cb1)
If CMake was configured more than once, HAVE_CLOCK_GETTIME and
HAVE_CLOCK_MONOTONIC would not be set as compile definitions. The check
for librt being needed to provide HAVE_CLOCK_GETTIME was also
simplified.
(cherry picked from commit a70e96d2da)
SSIZE_MAX isn't readily available on MSVC. Removing it means
that there is one thing less to worry when porting to MSVC.
(cherry picked from commit ef71f83973)
The argument to vli_ceil4() should always guarantee the return value
is also a valid lzma_vli. Thus the highest three valid lzma_vli values
are invalid arguments. All uses of the function ensure this so the
assert is updated to match this.
(cherry picked from commit 773f1e8622)
This was not a security bug since there was no path to overflow
UINT64_MAX in lzma_index_append() or when it calls index_file_size().
The bug was discovered by a failing assert() in vli_ceil4() when called
from index_file_size() when unpadded_sum (the sum of the compressed size
of current Stream and the unpadded_size parameter) exceeds LZMA_VLI_MAX.
Previously, the unpadded_size parameter was checked to be not greater
than UNPADDED_SIZE_MAX, but no check was done once compressed_base was
added.
This could not have caused an integer overflow in index_file_size() when
called by lzma_index_append(). The calculation for file_size breaks down
into the sum of:
- Compressed base from all previous Streams
- 2 * LZMA_STREAM_HEADER_SIZE (size of the current Streams header and
footer)
- stream_padding (can be set by lzma_index_stream_padding())
- Compressed base from the current Stream
- Unpadded size (parameter to lzma_index_append())
The sum of everything except for Unpadded size must be less than
LZMA_VLI_MAX. This is guarenteed by overflow checks in the functions
that can set these values including lzma_index_stream_padding(),
lzma_index_append(), and lzma_index_cat(). The maximum value for
Unpadded size is enforced by lzma_index_append() to be less than or
equal UNPADDED_SIZE_MAX. Thus, the sum cannot exceed UINT64_MAX since
LZMA_VLI_MAX is half of UINT64_MAX.
Thanks to Joona Kannisto for reporting this.
(cherry picked from commit 68bda971bb)
The "once_" variable was accidentally referred to as just "once". This
prevented building with Vista threads when
HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR was not defined.
(cherry picked from commit c0c0cd4a48)
groff defaults to SGR escapes. Using -P-c passes -c to grotty
which restores the old behavior. Perhaps there is a better way to
get pure plain text output but this works for now.
(cherry picked from commit 6a1093c000)
To workaround Automake lacking Windows resource compiler support, an
empty source file is compiled to overwrite the resource files for static
library builds. Translation units without an external declaration are
not allowed by the C standard and result in a warning when used with
-Wempty-translation-unit (Clang) or -pedantic (GCC).
(cherry picked from commit 19899340cf)
In lzma_memcmplen(), the <intrin.h> header file is only included if
_MSC_VER and _M_X64 are both defined but _BitScanForward64() was
previously used if _M_X64 was defined. GCC for MSYS2 defines _M_X64 but
not _MSC_VER so _BitScanForward64() was used without including
<intrin.h>.
Now, lzma_memcmplen() will use __builtin_ctzll() for MSYS2 GCC builds as
expected.
(cherry picked from commit 64ee0caaea)
This change only impacts the compiler warning since it was impossible
for the wait_abs struct in stream_encode_mt() to be used before it was
initialized since mythread_condtime_set() will always be called before
mythread_cond_timedwait().
Since the mythread.h code is different between the POSIX and
Windows versions, this warning was only present on Windows builds.
Thanks to Arthur S for reporting the warning and providing an initial
patch.
(cherry picked from commit 1155471651)
Boost iostream uses `find_package` in quiet mode and then again uses
`find_package` with required. This second call triggers a
`add_library cannot create imported target "LibLZMA::LibLZMA"
because another target with the same name already exists.`
This can simply be fixed by skipping the alias part on secondary
`find_package` runs.
(cherry picked from commit d04eb78ab3)
Legacy Windows did not need to #include <intrin.h> to use the MSVC
intrinsics. Newer versions likely just issue a warning, but the MSVC
documentation says to include the header file for the intrinsics we use.
GCC and Clang can "pretend" to be MSVC on Windows, so extra checks are
needed in tuklib_integer.h to only include <intrin.h> when it will is
actually needed.
Clang has support for __builtin_clz(), but previously Clang would
fallback to either the MSVC intrinsic or the regular C code. This was
discovered due to a bug where a new version of Clang required the
<intrin.h> header file in order to use the MSVC intrinsics.
Thanks to Anton Kochkov for notifying us about the bug.
This makes no functional difference in the generated configure
(at least with the Autotools versions I have installed) but this
change might prevent future bugs like the one that was just
fixed in the commit 5a5bd7f871.
This is broken in the releases 5.2.6 to 5.4.2. A workaround
for these releases is to pass EGREP='grep -E' as an argument
to configure in addition to --disable-threads.
The problem appeared when m4/ax_pthread.m4 was updated in
the commit 6629ed929c which
introduced the use of AC_EGREP_CPP. AC_EGREP_CPP calls
AC_REQUIRE([AC_PROG_EGREP]) to set the shell variable EGREP
but this was only executed if POSIX threads were enabled.
Libtool code also has AC_REQUIRE([AC_PROG_EGREP]) but Autoconf
omits it as AC_PROG_EGREP has already been required earlier.
Thus, if not using POSIX threads, the shell variable EGREP
would be undefined in the Libtool code in configure.
ax_pthread.m4 is fine. The bug was in configure.ac which called
AX_PTHREAD conditionally in an incorrect way. Using AS_CASE
ensures that all AC_REQUIREs get always run.
Thanks to Frank Busse for reporting the bug.
Fixes: https://github.com/tukaani-project/xz/issues/45
In the C99 and C17 standards, section 6.5.6 paragraph 8 means that
adding 0 to a null pointer is undefined behavior. As of writing,
"clang -fsanitize=undefined" (Clang 15) diagnoses this. However,
I'm not aware of any compiler that would take advantage of this
when optimizing (Clang 15 included). It's good to avoid this anyway
since compilers might some day infer that pointer arithmetic implies
that the pointer is not NULL. That is, the following foo() would then
unconditionally return 0, even for foo(NULL, 0):
void bar(char *a, char *b);
int foo(char *a, size_t n)
{
bar(a, a + n);
return a == NULL;
}
In contrast to C, C++ explicitly allows null pointer + 0. So if
the above is compiled as C++ then there is no undefined behavior
in the foo(NULL, 0) call.
To me it seems that changing the C standard would be the sane
thing to do (just add one sentence) as it would ensure that a huge
amount of old code won't break in the future. Based on web searches
it seems that a large number of codebases (where null pointer + 0
occurs) are being fixed instead to be future-proof in case compilers
will some day optimize based on it (like making the above foo(NULL, 0)
return 0) which in the worst case will cause security bugs.
Some projects don't plan to change it. For example, gnulib and thus
many GNU tools currently require that null pointer + 0 is defined:
https://lists.gnu.org/archive/html/bug-gnulib/2021-11/msg00000.htmlhttps://www.gnu.org/software/gnulib/manual/html_node/Other-portability-assumptions.html
In XZ Utils null pointer + 0 issue should be fixed after this
commit. This adds a few if-statements and thus branches to avoid
null pointer + 0. These check for size > 0 instead of ptr != NULL
because this way bugs where size > 0 && ptr == NULL will likely
get caught quickly. None of them are in hot spots so it shouldn't
matter for performance.
A little less readable version would be replacing
ptr + offset
with
offset != 0 ? ptr + offset : ptr
or creating a macro for it:
#define my_ptr_add(ptr, offset) \
((offset) != 0 ? ((ptr) + (offset)) : (ptr))
Checking for offset != 0 instead of ptr != NULL allows GCC >= 8.1,
Clang >= 7, and Clang-based ICX to optimize it to the very same code
as ptr + offset. That is, it won't create a branch. So for hot code
this could be a good solution to avoid null pointer + 0. Unfortunately
other compilers like ICC 2021 or MSVC 19.33 (VS2022) will create a
branch from my_ptr_add().
Thanks to Marcin Kowalczyk for reporting the problem:
https://github.com/tukaani-project/xz/issues/36
On MicroBlaze, GCC 12 is broken in sense that
__has_attribute(__symver__) returns true but it still doesn't
support the __symver__ attribute even though the platform is ELF
and symbol versioning is supported if using the traditional
__asm__(".symver ...") method. Avoiding the traditional method is
good because it breaks LTO (-flto) builds with GCC.
See also: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101766
For now the only extra symbols in liblzma_linux.map are the
compatibility symbols with the patch that spread from RHEL/CentOS 7.
These require the use of __symver__ attribute or __asm__(".symver ...")
in the C code. Compatibility with the patch from CentOS 7 doesn't
seem valuable on MicroBlaze so use liblzma_generic.map on MicroBlaze
instead. It doesn't require anything special in the C code and thus
no LTO issues either.
An alternative would be to detect support for __symver__
attribute in configure.ac and CMakeLists.txt and fall back
to __asm__(".symver ...") but then LTO would be silently broken
on MicroBlaze. It sounds likely that MicroBlaze is a special
case so let's treat it as a such because that is simpler. If
a similar issue exists on some other platform too then hopefully
someone will report it and this can be reconsidered.
(This doesn't do the same fix in CMakeLists.txt. Perhaps it should
but perhaps CMake build of liblzma doesn't matter much on MicroBlaze.
The problem breaks the build so it's easy to notice and can be fixed
later.)
Thanks to Vincent Fazio for reporting the problem and proposing
a patch (in the end that solution wasn't used):
https://github.com/tukaani-project/xz/pull/32
tuklib_physmem depends on GetProcAddress() for both MSVC and MinGW-w64
to retrieve a function address. The proper way to do this is to cast the
return value to the type of function pointer retrieved. Unfortunately,
this causes a cast-function-type warning, so the best solution is to
simply ignore the warning.
Calling coder_set_compression_settings() in list mode with verbose mode
on caused the filter chain and memory requirements to print. This was
unnecessary since the command results in an error and not consistent
with other formats like lzma and alone.
This is similar to 2ce4f36f17.
The actual initialization of the variables is done inside
mythread_sync() macro. Clang doesn't seem to see that
the initialization code inside the macro is always executed.
Lasse Collin
Jia Tan
Jamaika1
Benjamin Buch