NVHPC compiler has several issues that make it impossible to
build liblzma:
- the compiler fails to produce valid code for delta_decode if the
vectorization is enabled, which results in failed tests.
This introduces NVHPC-specific workarounds that address the issues.
(This commit was contributed under 0BSD but the author confirmed
that it is fine to backport it to the public domain branches. See
https://github.com/tukaani-project/xz/pull/90#issuecomment-2100185936
and the next two messages.)
(cherry picked from commit 096bc0e3f8fb4bfc4d2f3f64a7f219401ffb4c31)
(cherry picked from commit 65ac20807c1303e80fb8fc28ec810d740078e328)
It is built and run only manually so this didn't matter
unless one wanted to regenerate the price_table.c.
(cherry picked from commit 8e4ec794836bc1701d8c9bd5e347b8ce8cc5bbb4)
(cherry picked from commit 65b5ee071697e4fe4c2a31c14c1d68b727f1654c)
The initial commit 5d018dc03549c1ee4958364712fb0c94e1bf2741
in 2007 had a comment in sha256.c that the code is based on
Crypto++ Library 5.5.1. In 2009 the Authors list in sha256.c
and the AUTHORS file was updated with information that the
code had come from Crypto++ but via 7-Zip. I know I had viewed
7-Zip's SHA-256 code but back then the C code has been identical
enough with Crypto++, so I don't why I thought the author info
would need that extra step via 7-Zip for this single file.
Another error is that I had mixed sha.* and shacal2.* files
when checking for author info in Crypto++. The shacal2.* files
aren't related to liblzma's sha256.c and thus Kevin Springle's
code in Crypto++ isn't either.
(cherry picked from commit 76946dc4336c831fe2cc26696a035d807dd3cf13)
(cherry picked from commit 402fb45c743b736fa033b4b04881f6d1098581fd)
This is unlikely to be a bug in an existing application since it relies
on calling lzma_filters_update() on an LZMA1 encoder in the first place.
For instance, it does not affect xz because lzma_filters_update() can
only be used when encoding to the .xz format.
(based on commit 8191720eac950a5db89c4d33d6beea6316a49b19)
lzma_raw_encoder() and lzma_raw_encoder_init() used "options" as the
parameter name instead of "filters" (used by the declaration). "filters"
is more clear since the parameter represents the list of filters passed
to the raw encoder, each of which contains filter options.
(cherry picked from commit 27ab54af848ec4adc9c17362f6c64a42a7003df5)
lzma_encoder_init() did not check for NULL options, but
lzma2_encoder_init() did. This is more of a code style improvement than
anything else to help make lzma_encoder_init() and lzma2_encoder_init()
more similar.
(cherry picked from commit 019afd72e02339a6bf00c32bfb56f649c637dd6b)
The macro lzma_attr_visibility_hidden has to be defined to make
fastpos.h usable. The visibility attribute is irrelevant to
fastpos_tablegen.c so simply #define the macro to an empty value.
fastpos_tablegen.c is never built by the included build systems
and so the problem wasn't noticed earlier. It's just a standalone
program for generating fastpos_table.c.
Fixes: https://github.com/tukaani-project/xz/pull/69
Thanks to GitHub user Jamaika1.
(cherry picked from commit d90ed84db9770712e2421e170076b43bda9b64a7)
In ELF shared libs:
-fvisibility=hidden affects definitions of symbols but not
declarations.[*] This doesn't affect direct calls to functions
inside liblzma as a linker can replace a call to lzma_foo@plt
with a call directly to lzma_foo when -fvisibility=hidden is used.
[*] It has to be like this because otherwise every installed
header file would need to explictly set the symbol visibility
to default.
When accessing extern variables that aren't defined in the
same translation unit, compiler assumes that the variable has
the default visibility and thus indirection is needed. Unlike
function calls, linker cannot optimize this.
Using __attribute__((__visibility__("hidden"))) with the extern
variable declarations tells the compiler that indirection isn't
needed because the definition is in the same shared library.
About 15+ years ago, someone told me that it would be good if
the CRC tables would be defined in the same translation unit
as the C code of the CRC functions. While I understood that it
could help a tiny amount, I didn't want to change the code because
a separate translation unit for the CRC tables was needed for the
x86 assembly code anyway. But when visibility attributes are
supported, simply marking the extern declaration with the
hidden attribute will get identical result. When there are only
a few affected variables, this is trivial to do. I wish I had
understood this back then already.
(cherry picked from commit 6961a5ac7df178bfc2b7a181c40575847bc3035f)
MinGW (formely a MinGW.org Project, later the MinGW.OSDN Project
at <https://osdn.net/projects/mingw/>) has GCC 9.2.0 as the
most recent GCC package (released 2021-02-02). The project might
still be alive but majority of people have switched to MinGW-w64.
Thus it seems clearer to refer to MinGW-w64 in our API headers too.
Building with MinGW is likely to still work but I haven't tested it
in the recent years.
(cherry picked from commit 5b9e16764905d06fa8e8339ba185ddfee304e5fb)
It properly adds -DLZMA_API_STATIC when compiling code that
will be linked against static liblzma. Having it there on
systems other than Windows does no harm.
See: https://www.msys2.org/docs/pkgconfig/
(cherry picked from commit 4083c8e9501a48934a5fb563d2c3ce2ae143cd27)
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 359e5c6cb128dab64ea6070d21d1c240f96cea6b)
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 773f1e8622cb1465df528cb16a749517650acd93)
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 68bda971bb8b666a009331455fcedb4e18d837a4)
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 19899340cf74d98304f9f5b726c72e85c7017d72)
Maybe ICC always #defines _MSC_VER on Windows but now
it's very clear which code will get used.
(cherry picked from commit b406828a6dfd3caa4f77efe3ff3e3eea263eee62)
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 64ee0caaea06654b28afaee850fb187a11bf9cb2)
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 1155471651ad456c5f90aee6435931fae65682bf)
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.
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
This is similar to 2ce4f36f179a81d0c6e182a409f363df759d1ad0.
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.
The API docs gave an impression that such checks are done
but they actually weren't done. In practice it made little
difference since the calling code has a bug if these are NULL.
Thanks to Jia Tan for the original patch that checked for
block->filters == NULL.
If someone sets up Clang to define __GNUC__ to 10 or greater
then symvers broke. __has_attribute is supported by such GCC
and Clang versions that don't support __symver__ so this should
be much better and simpler way to detect if __symver__ is
actually supported.
Thanks to Tomasz Gajc for the bug report.
It not only makes no sense to put symbol versions into a static library
but it can also cause breakage.
By default Libtool #defines PIC if building a shared library and
doesn't define it for static libraries. This is documented in the
Libtool manual. It can be overriden using --with-pic or --without-pic.
configure.ac detects if --with-pic or --without-pic is used and then
gives an error if neither --disable-shared nor --disable-static was
used at the same time. Thus, in normal situations it works to build
both shared and static library at the same time on GNU/Linux,
only --with-pic or --without-pic requires that only one type of
library is built.
Thanks to John Paul Adrian Glaubitz from Debian for reporting
the problem that occurred on ia64:
https://www.mail-archive.com/xz-devel@tukaani.org/msg00610.html
This time it can happen when lzma_stream_encoder_mt() is used
to reinitialize an existing multi-threaded Stream encoder
and one of 1-4 tiny allocations in lzma_filters_copy() fail.
It's very similar to the previous bug
10430fbf3820dafd4eafd38ec8be161a6978ed2b, happening with
an array of lzma_filter structures whose old options are freed
but the replacement never arrives due to a memory allocation
failure in lzma_filters_copy().
The documentation mentions that lzma_block_encoder() supports
LZMA_SYNC_FLUSH but it was never added to supported_actions[]
in the internal structure. Because of this, LZMA_SYNC_FLUSH could
not be used with the Block encoder unless it was the next coder
after something like stream_encoder() or stream_encoder_mt().
The bug was in the single-threaded .xz Stream encoder
in the code that is used for both re-initialization and for
lzma_filters_update(). To trigger it, an application had
to either re-initialize an existing encoder instance with
lzma_stream_encoder() or use lzma_filters_update(), and
then one of the 1-4 tiny allocations in lzma_filters_copy()
(called from stream_encoder_update()) must fail. An error
was correctly reported but the encoder state was corrupted.
This is related to the recent fix in
f8ee61e74eb40600445fdb601c374d582e1e9c8a which is good but
it wasn't enough to fix the main problem in stream_encoder.c.
The encoder doesn't support dictionary sizes larger than 1536 MiB.
This is validated, for example, when calculating the memory usage
via lzma_raw_encoder_memusage(). It is also enforced by the LZ
part of the encoder initialization. However, LZMA encoder with
LZMA_MODE_NORMAL did an unsafe calculation with dict_size before
such validation and that results in an infinite loop if dict_size
was 2 << 30 or greater.
