newsGNU C Library - News: The GNU C Library version 2.28 is now available

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The GNU C Library version 2.28 is now available posted by codonell, Wed 01 Aug 2018 07:08:32 AM UTC - 0 replies
The GNU C Library version 2.26 is now available posted by siddhesh, Wed 02 Aug 2017 02:47:12 PM UTC - 0 replies
The GNU C Library version 2.24 is now available posted by codonell, Fri 05 Aug 2016 04:12:44 PM UTC - 0 replies
The GNU C Library version 2.22 is now available posted by codonell, Fri 14 Aug 2015 08:42:07 PM UTC - 0 replies

The GNU C Library version 2.28 is now available

Item posted by Carlos O'Donell <codonell> on Wed 01 Aug 2018 07:08:32 AM UTC.

The GNU C Library

The GNU C Library version 2.28 is now available.

The GNU C Library is used as the C library in the GNU system and
in GNU/Linux systems, as well as many other systems that use Linux
as the kernel.

The GNU C Library is primarily designed to be a portable
and high performance C library. It follows all relevant
standards including ISO C11 and POSIX.1-2008. It is also
internationalized and has one of the most complete
internationalization interfaces known.

The GNU C Library webpage is at

Packages for the 2.28 release may be downloaded from:

The mirror list is at

NEWS for version 2.28

Major new features:

  • The localization data for ISO 14651 is updated to match the 2016

Edition 4 release of the standard, this matches data provided by
Unicode 9.0.0. This update introduces significant improvements to the
collation of Unicode characters. This release deviates slightly from
the standard in that the collation element ordering for lowercase and
uppercase LATIN script characters is adjusted to ensure that regular
expressions with ranges like [a-z] and [A-Z] don't interleave e.g. A
is not matched by [a-z]. With the update many locales have been
updated to take advantage of the new collation information. The new
collation information has increased the size of the compiled locale
archive or binary locales.

  • The GNU C Library can now be compiled with support for Intel CET, AKA

Intel Control-flow Enforcement Technology. When the library is built
with --enable-cet, the resulting glibc is protected with indirect
branch tracking (IBT) and shadow stack (SHSTK). CET-enabled glibc is
compatible with all existing executables and shared libraries. This
feature is currently supported on i386, x86_64 and x32 with GCC 8 and
binutils 2.29 or later. Note that CET-enabled glibc requires CPUs
capable of multi-byte NOPs, like x86-64 processors as well as Intel
Pentium Pro or newer. NOTE: --enable-cet has been tested for i686,
x86_64 and x32 on non-CET processors. --enable-cet has been tested
for x86_64 and x32 on CET SDVs, but Intel CET support hasn't been
validated for i686.

  • The GNU C Library now has correct support for ABSOLUTE symbols

(SHN_ABS-relative symbols). Previously such ABSOLUTE symbols were
relocated incorrectly or in some cases discarded. The GNU linker can
make use of the newer semantics, but it must communicate it to the
dynamic loader by setting the ELF file's identification (EI_ABIVERSION
field) to indicate such support is required.

  • Unicode 11.0.0 Support: Character encoding, character type info, and

transliteration tables are all updated to Unicode 11.0.0, using
generator scripts contributed by Mike FABIAN (Red Hat).

  • <math.h> functions that round their results to a narrower type are added

from TS 18661-1:2014 and TS 18661-3:2015:

- fadd, faddl, daddl and corresponding fMaddfN, fMaddfNx, fMxaddfN and
fMxaddfNx functions.

- fsub, fsubl, dsubl and corresponding fMsubfN, fMsubfNx, fMxsubfN and
fMxsubfNx functions.

- fmul, fmull, dmull and corresponding fMmulfN, fMmulfNx, fMxmulfN and
fMxmulfNx functions.

- fdiv, fdivl, ddivl and corresponding fMdivfN, fMdivfNx, fMxdivfN and
fMxdivfNx functions.

  • Two grammatical forms of month names are now supported for the following

languages: Armenian, Asturian, Catalan, Czech, Kashubian, Occitan, Ossetian,
Scottish Gaelic, Upper Sorbian, and Walloon. The following languages now
support two grammatical forms in abbreviated month names: Catalan, Greek,
and Kashubian.

  • Newly added locales: Lower Sorbian (dsb_DE) and Yakut (sah_RU) also

include the support for two grammatical forms of month names.

  • Building and running on GNU/Hurd systems now works without out-of-tree


  • The renameat2 function has been added, a variant of the renameat function

which has a flags argument. If the flags are zero, the renameat2 function
acts like renameat. If the flag is not zero and there is no kernel
support for renameat2, the function will fail with an errno value of
EINVAL. This is different from the existing gnulib function renameatu,
which performs a plain rename operation in case of a RENAME_NOREPLACE
flags and a non-existing destination (and therefore has a race condition
that can clobber the destination inadvertently).

  • The statx function has been added, a variant of the fstatat64

function with an additional flags argument. If there is no direct
kernel support for statx, glibc provides basic stat support based on
the fstatat64 function.

  • IDN domain names in getaddrinfo and getnameinfo now use the system libidn2

library if installed. libidn2 version 2.0.5 or later is recommended. If
libidn2 is not available, internationalized domain names are not encoded
or decoded even if the AI_IDN or NI_IDN flags are passed to getaddrinfo or
getnameinfo. (getaddrinfo calls with non-ASCII names and AI_IDN will fail
with an encoding error.) Flags which used to change the IDN encoding and
deprecated. They no longer have any effect.

  • Parsing of dynamic string tokens in DT_RPATH, DT_RUNPATH, DT_NEEDED,

DT_AUXILIARY, and DT_FILTER has been expanded to support the full
range of ELF gABI expressions including such constructs as
'$ORIGIN$ORIGIN' (if valid). For SUID/GUID applications the rules
have been further restricted, and where in the past a dynamic string
token sequence may have been interpreted as a literal string it will
now cause a load failure. These load failures were always considered
unspecified behaviour from the perspective of the dynamic loader, and
for safety are now load errors e.g. /foo/${ORIGIN}.so in DT_NEEDED
results in a load failure now.

  • Support for ISO C threads (ISO/IEC 9899:2011) has been added. The

implementation includes all the standard functions provided by

- thrd_current, thrd_equal, thrd_sleep, thrd_yield, thrd_create,
thrd_detach, thrd_exit, and thrd_join for thread management.

- mtx_init, mtx_lock, mtx_timedlock, mtx_trylock, mtx_unlock, and
mtx_destroy for mutual exclusion.

- call_once for function call synchronization.

- cnd_broadcast, cnd_destroy, cnd_init, cnd_signal, cnd_timedwait, and
cnd_wait for conditional variables.

- tss_create, tss_delete, tss_get, and tss_set for thread-local storage.

Application developers must link against libpthread to use ISO C threads.

Deprecated and removed features, and other changes affecting compatibility:

  • The nonstandard header files <libio.h> and <_G_config.h> are no longer

installed. Software that was using either header should be updated to
use standard <stdio.h> interfaces instead.

  • The stdio functions 'getc' and 'putc' are no longer defined as macros.

This was never required by the C standard, and the macros just expanded
to call alternative names for the same functions. If you hoped getc and
putc would provide performance improvements over fgetc and fputc, instead
investigate using (f)getc_unlocked and (f)putc_unlocked, and, if
necessary, flockfile and funlockfile.

  • All stdio functions now treat end-of-file as a sticky condition. If you

read from a file until EOF, and then the file is enlarged by another
process, you must call clearerr or another function with the same effect
(e.g. fseek, rewind) before you can read the additional data. This
corrects a longstanding C99 conformance bug. It is most likely to affect
programs that use stdio to read interactive input from a terminal.
(Bug #1190.)

  • The macros 'major', 'minor', and 'makedev' are now only available from

the header <sys/sysmacros.h>; not from <sys/types.h> or various other
headers that happen to include <sys/types.h>. These macros are rarely
used, not part of POSIX nor XSI, and their names frequently collide with
user code; see for
further explanation.

<sys/sysmacros.h> is a GNU extension. Portable programs that require
these macros should first include <sys/types.h>, and then include
<sys/sysmacros.h> if _GNU_LIBRARY_ is defined.

  • The tilegx*-*-linux-gnu configurations are no longer supported.
  • The obsolete function ustat is no longer available to newly linked

binaries; the headers <ustat.h> and <sys/ustat.h> have been removed. This
function has been deprecated in favor of fstatfs and statfs.

  • The obsolete function nfsservctl is no longer available to newly linked

binaries. This function was specific to systems using the Linux kernel
and could not usefully be used with the GNU C Library on systems with
version 3.1 or later of the Linux kernel.

  • The obsolete function name llseek is no longer available to newly linked

binaries. This function was specific to systems using the Linux kernel
and was not declared in a header. Programs should use the lseek64 name
for this function instead.


getaddrinfo and getnameinfo functions have been deprecated. The behavior
previously selected by them is now always enabled.


the getaddrinfo and getnameinfo functions have been deprecated. The STD3
restriction (rejecting '_' in host names, among other things) has been
removed, for increased compatibility with non-IDN name resolution.

  • The fcntl function now have a Long File Support variant named fcntl64. It

is added to fix some Linux Open File Description (OFD) locks usage on non
LFS mode. As for others *64 functions, fcntl64 semantics are analogous with
fcntl and LFS support is handled transparently. Also for Linux, the OFD
locks act as a cancellation entrypoint.

  • The obsolete functions encrypt, encrypt_r, setkey, setkey_r, cbc_crypt,

ecb_crypt, and des_setparity are no longer available to newly linked
binaries, and the headers <rpc/des_crypt.h> and <rpc/rpc_des.h> are no
longer installed. These functions encrypted and decrypted data with the
DES block cipher, which is no longer considered secure. Software that
still uses these functions should switch to a modern cryptography library,
such as libgcrypt.

  • Reflecting the removal of the encrypt and setkey functions above, the

macro _XOPEN_CRYPT is no longer defined. As a consequence, the crypt
function is no longer declared unless _DEFAULT_SOURCE or _GNU_SOURCE is

  • The obsolete function fcrypt is no longer available to newly linked

binaries. It was just another name for the standard function crypt,
and it has not appeared in any header file in many years.

  • We have tentative plans to hand off maintenance of the passphrase-hashing

library, libcrypt, to a separate development project that will, we hope,
keep up better with new passphrase-hashing algorithms. We will continue
to declare 'crypt' in <unistd.h>, and programs that use 'crypt' or
'crypt_r' should not need to change at all; however, distributions will
need to install <crypt.h> and libcrypt from a separate project.

In this release, if the configure option --disable-crypt is used, glibc
will not install <crypt.h> or libcrypt, making room for the separate
project's versions of these files. The plan is to make this the default
behavior in a future release.

Changes to build and runtime requirements:

GNU make 4.0 or later is now required to build glibc.

Security related changes:

CVE-2016-6261, CVE-2016-6263, CVE-2017-14062: Various vulnerabilities have
been fixed by removing the glibc-internal IDNA implementation and using
the system-provided libidn2 library instead. Originally reported by Hanno
Böck and Christian Weisgerber.

CVE-2017-18269: An SSE2-based memmove implementation for the i386
architecture could corrupt memory. Reported by Max Horn.

CVE-2018-11236: Very long pathname arguments to realpath function could
result in an integer overflow and buffer overflow. Reported by Alexey

CVE-2018-11237: The mempcpy implementation for the Intel Xeon Phi
architecture could write beyond the target buffer, resulting in a buffer
overflow. Reported by Andreas Schwab.

The following bugs are resolved with this release:

[1190] stdio: fgetc()/fread() behaviour is not POSIX compliant
[6889] manual: 'PWD' mentioned but not specified
[13575] libc: SSIZE_MAX defined as LONG_MAX is inconsistent with ssize_t,
when __WORDSIZE != 64
[13762] regex: re_search etc. should return -2 on memory exhaustion
[13888] build: /tmp usage during testing
[13932] math: dbl-64 pow unexpectedly slow for some inputs
[14092] nptl: Support C11 threads
[14095] localedata: Review / update collation data from Unicode / ISO
[14508] libc: -Wformat warnings
[14553] libc: Namespace pollution loff_t in sys/types.h
[14890] libc: Make NT_PRFPREG canonical.
[15105] libc: Extra PLT references with -Os
[15512] libc: __bswap_constant_16 not compiled when -Werror -Wsign-
conversion is given
[16335] manual: Feature test macro documentation incomplete and out of
[16552] libc: Unify umount implementations in terms of umount2
[17082] libc: htons et al.: statement-expressions prevent use on global
scope with -O1 and higher
[17343] libc: Signed integer overflow in /stdlib/random_r.c
[17438] localedata: pt_BR: wrong d_fmt delimiter
[17662] libc: please implement binding for the new renameat2 syscall
[17721] libc: __restrict defined as /* Ignore */ even in c11
[17979] libc: inconsistency between uchar.h and stdint.h
[18018] dynamic-link: Additional $ORIGIN handling issues (CVE-2011-0536)
[18023] libc: extend_alloca is broken (questionable pointer comparison,
horrible machine code)
[18124] libc: hppa: setcontext erroneously returns -1 as exit code for
last constant.
[18471] libc: llseek should be a compat symbol
[18473] soft-fp: [powerpc-nofpu] __sqrtsf2, __sqrtdf2 should be compat
[18991] nss: nss_files skips large entry in database
[19239] libc: Including stdlib.h ends up with macros major and minor being
[19463] libc: linknamespace failures when compiled with -Os
[19485] localedata: csb_PL: Update month translations + add yesstr/nostr
[19527] locale: Normalized charset name not recognized by setlocale
[19667] string: Missing Sanity Check for malloc calls in file 'testcopy.c'
[19668] libc: Missing Sanity Check for malloc() in file 'tst-setcontext-
[19728] network: out of bounds stack read in libidn function
idna_to_ascii_4i (CVE-2016-6261)
[19729] network: out of bounds heap read on invalid utf-8 inputs in
stringprep_utf8_nfkc_normalize (CVE-2016-6263)
[19818] dynamic-link: Absolute (SHN_ABS) symbols incorrectly relocated by
the base address
[20079] libc: Add SHT_X86_64_UNWIND to elf.h
[20251] libc: 32bit programs pass garbage in struct flock for OFD locks
[20419] dynamic-link: files with large allocated notes crash in
[20530] libc: bswap_16 should use __builtin_bswap16() when available
[20890] dynamic-link: ldconfig: fsync the files before atomic rename
[20980] manual: CFLAGS environment variable replaces vital options
[21163] regex: Assertion failure in pop_fail_stack when executing a
malformed regexp (CVE-2015-8985)
[21234] manual: use of CFLAGS makes glibc detect no optimization
[21269] dynamic-link: i386 sigaction sa_restorer handling is wrong
[21313] build: Compile Error GCC 5.4.0 MIPS with -0S
[21314] build: Compile Error GCC 5.2.0 MIPS with -0s
[21508] locale: intl/tst-gettext failure with latest msgfmt
[21547] localedata: Tibetan script collation broken (Dzongkha and Tibetan)
[21812] network: getifaddrs() returns entries with ifa_name == NULL
[21895] libc: ppc64 setjmp/longjmp not fully interoperable with static
[21942] dynamic-link: _dl_dst_substitute incorrectly handles $ORIGIN: with
[22241] localedata: New locale: Yakut (Sakha) locale for Russia (sah_RU)
[22247] network: Integer overflow in the decode_digit function in
puny_decode.c in libidn (CVE-2017-14062)
[22342] nscd: NSCD not properly caching netgroup
[22391] nptl: Signal function clear NPTL internal symbols inconsistently
[22550] localedata: es_ES locale (and other es_* locales): collation
should treat ñ as a primary different character, sync the collation
for Spanish with CLDR
[22638] dynamic-link: sparc: static binaries are broken if glibc is built
by gcc configured with --enable-default-pie
[22639] time: year 2039 bug for localtime etc. on 64-bit platforms
[22644] string: memmove-sse2-unaligned on 32bit x86 produces garbage when
crossing 2GB threshold (CVE-2017-18269)
[22646] localedata: redundant data (LC_TIME) for es_CL, es_CU, es_EC and
[22735] time: Misleading typo in time.h source comment regarding
[22753] libc: preadv2/pwritev2 fallback code should handle offset=-1
[22761] libc: No trailing `%n' conversion specifier in FMT passed from
`__assert_perror_fail ()' to `__assert_fail_base ()'
[22766] libc: all glibc internal dlopen should use RTLD_NOW for robust
dlopen failures
[22786] libc: Stack buffer overflow in realpath() if input size is close
to SSIZE_MAX (CVE-2018-11236)
[22787] dynamic-link: _dl_check_caller returns false when libc is linked
through an absolute DT_NEEDED path
[22792] build: tcb-offsets.h dependency dropped
[22797] libc: pkey_get() uses non-reserved name of argument
[22807] libc: PTRACE_* constants missing for powerpc
[22818] glob: posix/tst-glob_lstat_compat failure on alpha
[22827] dynamic-link: RISC-V ELF64 parser mis-reads flag in ldconfig
[22830] malloc: malloc_stats doesn't restore cancellation state on stderr
[22848] localedata: ca_ES: update date definitions from CLDR
[22862] build: _DEFAULT_SOURCE is defined even when _ISOC11_SOURCE is
[22884] math: RISCV fmax/fmin handle signalling NANs incorrectly
[22896] localedata: Update locale data for an_ES
[22902] math: float128 test failures with GCC 8
[22918] libc: multiple common of `__nss_shadow_database'
[22919] libc: sparc32: backtrace yields infinite backtrace with
[22926] libc: FTBFS on powerpcspe
[22932] localedata: lt_LT: Update of abbreviated month names from CLDR
[22937] localedata: Greek (el_GR, el_CY) locales actually need ab_alt_mon
[22947] libc: FAIL: misc/tst-preadvwritev2
[22963] localedata: cs_CZ: Add alternative month names
[22987] math: [powerpc/sparc] fdim inlines errno, exceptions handling
[22996] localedata: change LC_PAPER to en_US in es_BO locale
[22998] dynamic-link: execstack tests are disabled when SELinux is
[23005] network: Crash in __res_context_send after memory allocation
[23007] math: strtod cannot handle -nan
[23024] nss: getlogin_r is performing NSS lookups when loginid isn't set
[23036] regex: regex equivalence class regression
[23037] libc: initialize msg_flags to zero for sendmmsg() calls
[23069] libc: sigaction broken on riscv64-linux-gnu
[23094] localedata: hr_HR: wrong thousands_sep and mon_thousands_sep
[23102] dynamic-link: Incorrect parsing of multiple consecutive $variable
patterns in runpath entries (e.g. $ORIGIN$ORIGIN)
[23137] nptl: s390: pthread_join sometimes block indefinitely (on 31bit
and libc build with -Os)
[23140] localedata: More languages need two forms of month names
[23145] libc: _init/_fini aren't marked as hidden
[23152] localedata: gd_GB: Fix typo in "May" (abbreviated)
[23171] math: C++ iseqsig for long double converts arguments to double
[23178] nscd: sudo will fail when it is run in concurrent with commands
that changes /etc/passwd
[23196] string: __mempcpy_avx512_no_vzeroupper mishandles large copies
[23206] dynamic-link: static-pie + dlopen breaks debugger interaction
[23208] localedata: New locale - Lower Sorbian (dsb)
[23233] regex: Memory leak in build_charclass_op function in file
[23236] stdio: Harden function pointers in _IO_str_fields
[23250] nptl: Offset of __private_ss differs from GCC
[23253] math: tgamma test suite failures on i686 with -march=x86-64
-mtune=generic -mfpmath=sse
[23259] dynamic-link: Unsubstituted ${ORIGIN} remains in DT_NEEDED for
[23264] libc: posix_spawnp wrongly executes ENOEXEC in non compat mode
[23266] nis: stringop-truncation warning with new gcc8.1 in nisplus-
[23272] math: fma(INFINITY,INFIITY,0.0) should be INFINITY
[23277] math: nan function should not have const attribute
[23279] math: scanf and strtod wrong for some hex floating-point
[23280] math: wscanf rounds wrong; wcstod is ok for negative numbers and
directed rounding
[23290] localedata: IBM273 is not equivalent to ISO-8859-1
[23303] build: undefined reference to symbol
[23307] dynamic-link: Absolute symbols whose value is zero ignored in
[23313] stdio: libio vtables validation and standard file object
[23329] libc: The __libc_freeres infrastructure is not properly run across
DSO boundaries.
[23349] libc: Various glibc headers no longer compatible with
[23351] malloc: Remove unused code related to heap dumps and malloc
[23363] stdio: stdio-common/tst-printf.c has non-free license
[23396] regex: Regex equivalence regression in single-byte locales
[23422] localedata: oc_FR: More updates of locale data
[23442] build: New warning with GCC 8
[23448] libc: Out of bounds access in IBM-1390 converter
[23456] libc: Wrong index_cpu_LZCNT
[23458] build: tst-get-cpu-features-static isn't added to tests
[23459] libc: COMMON_CPUID_INDEX_80000001 isn't populated for Intel
[23467] dynamic-link: x86/CET: A property note parser bug

Release Notes


This release was made possible by the contributions of many people.
The maintainers are grateful to everyone who has contributed
changes or bug reports. These include:

Adhemerval Zanella
Agustina Arzille
Alan Modra
Alexandre Oliva
Amit Pawar
Andreas Schwab
Andrew Senkevich
Andrew Waterman
Aurelien Jarno
Carlos O'Donell
Chung-Lin Tang
DJ Delorie
Daniel Alvarez
David Michael
Dmitry V. Levin
Dragan Stanojevic - Nevidljivi
Florian Weimer
Flávio Cruz
Francois Goichon
Gabriel F. T. Gomes
H.J. Lu
Herman ten Brugge
Hongbo Zhang
Igor Gnatenko
Jesse Hathaway
John David Anglin
Joseph Myers
Leonardo Sandoval
Maciej W. Rozycki
Mark Wielaard
Martin Sebor
Michael Wolf
Patrick McGehearty
Patsy Franklin
Paul Pluzhnikov
Quentin PAGÈS
Rafal Luzynski
Rajalakshmi Srinivasaraghavan
Raymond Nicholson
Rical Jasan
Richard Braun
Robert Buj
Rogerio Alves
Samuel Thibault
Sean McKean
Siddhesh Poyarekar
Stefan Liebler
Steve Ellcey
Sylvain Lesage
Szabolcs Nagy
Thomas Schwinge
Tulio Magno Quites Machado Filho
Valery Timiriliyev
Vincent Chen
Wilco Dijkstra
Zack Weinberg
Zong Li

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