#4799: glibc-2.33
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Reporter: bdubbs | Owner: lfs-book
Type: task | Status: new
Priority: normal | Milestone: 10.1
Component: Book | Version: SVN
Severity: normal | Resolution:
Keywords: |
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Comment (by bdubbs):
Version 2.33
Major new features:
* The dynamic linker accepts the --list-tunables argument which prints
all the supported tunables. This option is disable if glibc is
configured with tunables disabled (--enable-tunables=no).
* The dynamic linker accepts the --argv0 argument and provides opportunity
to change argv[0] string.
* The dynamic linker loads optimized implementations of shared objects
from subdirectories under the glibc-hwcaps directory on the library
search path if the system's capabilities meet the requirements for
that subdirectory. Initially supported subdirectories include
"power9" and "power10" for the powerpc64le-linux-gnu architecture,
"z13", "z14", "z15" for s390x-linux-gnu, and "x86-64-v2", "x86-64-v3",
"x86-64-v4" for x86_64-linux-gnu. In the x86_64-linux-gnu case, the
subdirectory names correspond to the vendor-independent x86-64
microarchitecture levels defined in the x86-64 psABI supplement.
* The new --help option of the dynamic linker provides usage and
information and library search path diagnostics.
* The mallinfo2 function is added to report statistics as per mallinfo,
but with larger field widths to accurately report values that are
larger than fit in an integer.
* Add <sys/platform/x86.h> to provide query macros for x86 CPU features.
* Support for the RISC-V ISA running on Linux has been expanded to run on
32-bit hardware. This is supported for the following ISA and ABI pairs:
- rv32imac ilp32
- rv32imafdc ilp32
- rv32imafdc ilp32d
The 32-bit RISC-V port requires at least Linux 5.4, GCC 7.1 and binutils
2.28.
* A new fortification level _FORTIFY_SOURCE=3 is available. At this
level,
glibc may use additional checks that may have an additional performance
overhead. At present these checks are available only on LLVM 9 and
later.
The latest GCC available at this time (10.2) does not support this level
of
fortification.
Deprecated and removed features, and other changes affecting
compatibility:
* The mallinfo function is marked deprecated. Callers should call
mallinfo2 instead.
* When dlopen is used in statically linked programs, alternative library
implementations from HWCAP subdirectories are no longer loaded.
Instead, the default implementation is used.
* The deprecated <sys/vtimes.h> header and the function vtimes have been
removed. To support old binaries, the vtimes function continues to
exist
as a compatibility symbol. Applications should use the getrlimit or
prlimit.
* Following a change in the tzdata 2018a release upstream, the zdump
program is now installed in the /usr/bin subdirectory. Previously,
the /usr/sbin subdirectory was used.
* On s390(x), the type float_t is now derived from the macro
__FLT_EVAL_METHOD__ that is defined by the compiler, instead of being
hardcoded to double. This does not affect the ABI of any libraries
that are part of the GNU C Library, but may affect the ABI of other
libraries that use this type in their interfaces. The new definition
improves consistency with compiler behavior in many scenarios.
* A future version of glibc will stop loading shared objects from the
"tls" subdirectories on the library search path, the subdirectory that
corresponds to the AT_PLATFORM system name, and also stop employing
the legacy AT_HWCAP search mechanism. Applications should switch to
the new glibc-hwcaps mechanism instead; if they do not do that, only
the baseline version (directly from the search path directory) will be
loaded.
Changes to build and runtime requirements:
* On Linux, the system administrator needs to configure /dev/pts with
the intended access modes for pseudo-terminals. glibc no longer
attemps to adjust permissions of terminal devices. The previous glibc
defaults ("tty" group, user read/write and group write) already
corresponded to what most systems used, so that grantpt did not
perform any adjustments.
* On Linux, the posix_openpt and getpt functions no longer attempt to
use legacy (BSD) pseudo-terminals and assume that if /dev/ptmx exists
(and pseudo-terminals are supported), a devpts file system is mounted
on /dev/pts. Current systems already meet these requirements.
* s390x requires GCC 7.1 or newer. See gcc Bug 98269.
Security related changes:
CVE-2021-3326: An assertion failure during conversion from the
ISO-20220-JP-3 character set using the iconv function has been fixed.
This assertion was triggered by certain valid inputs in which the
converted output contains a combined sequence of two wide characters
crossing a buffer boundary. Reported by Tavis Ormandy.
CVE-2020-27618: An infinite loop has been fixed in the iconv program
when
invoked with input containing redundant shift sequences in the IBM1364,
IBM1371, IBM1388, IBM1390, or IBM1399 character sets.
CVE-2020-29562: An assertion failure has been fixed in the iconv
function
when invoked with UCS4 input containing an invalid character.
CVE-2019-25013: A buffer overflow has been fixed in the iconv function
when
invoked with EUC-KR input containing invalid multibyte input sequences.
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