The GNU C Library version 2.31 is now available

From: Siddhesh Poyarekar Subject: The GNU C Library version 2.31 is now available Date: Sat, 1 Feb 2020 18:42:22 +0530 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1

The GNU C Library ================= The GNU C Library version 2.31 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.1-2017. It is also internationalized and has one of the most complete internationalization interfaces known. The GNU C Library webpage is at http://www.gnu.org/software/libc/ Packages for the 2.31 release may be downloaded from: http://ftpmirror.gnu.org/libc/ http://ftp.gnu.org/gnu/libc/ The mirror list is at http://www.gnu.org/order/ftp.html NEWS for version 2.31 ===================== Major new features: * The GNU C Library now supports a feature test macro _ISOC2X_SOURCE to enable features from the draft ISO C2X standard. Only some features from this draft standard are supported by the GNU C Library, and as the draft is under active development, the set of features enabled by this macro is liable to change. Features from C2X are also enabled by _GNU_SOURCE, or by compiling with "gcc -std=gnu2x". * The <math.h> functions that round their results to a narrower type now have corresponding type-generic macros in <tgmath.h>, as defined in TS 18661-1:2014 and TS 18661-3:2015 as amended by the resolution of Clarification Request 13 to TS 18661-3. * The function pthread_clockjoin_np has been added, enabling join with a terminated thread with a specific clock. It allows waiting against CLOCK_MONOTONIC and CLOCK_REALTIME. This function is a GNU extension. * New locale added: mnw_MM (Mon language spoken in Myanmar). * The DNS stub resolver will optionally send the AD (authenticated data) bit in queries if the trust-ad option is set via the options directive in /etc/resolv.conf (or if RES_TRUSTAD is set in _res.options). In this mode, the AD bit, as provided by the name server, is available to applications which call res_search and related functions. In the default mode, the AD bit is not set in queries, and it is automatically cleared in responses, indicating a lack of DNSSEC validation. (Therefore, the name servers and the network path to them are treated as untrusted.) Deprecated and removed features, and other changes affecting compatibility: * The totalorder and totalordermag functions, and the corresponding functions for other floating-point types, now take pointer arguments to avoid signaling NaNs possibly being converted to quiet NaNs in argument passing. This is in accordance with the resolution of Clarification Request 25 to TS 18661-1, as applied for C2X. Existing binaries that pass floating-point arguments directly will continue to work. * The obsolete function stime is no longer available to newly linked binaries, and its declaration has been removed from <time.h>. Programs that set the system time should use clock_settime instead. * We plan to remove the obsolete function ftime, and the header <sys/timeb.h>, in a future version of glibc. In this release, the header still exists but calling ftime will cause a compiler warning. All programs should use gettimeofday or clock_gettime instead. * The gettimeofday function no longer reports information about a system-wide time zone. This 4.2-BSD-era feature has been deprecated for many years, as it cannot handle the full complexity of the world's timezones, but hitherto we have supported it on a best-effort basis. Changes required to support 64-bit time_t on 32-bit architectures have made this no longer practical. As of this release, callers of gettimeofday with a non-null 'tzp' argument should expect to receive a 'struct timezone' whose tz_minuteswest and tz_dsttime fields are zero. (For efficiency reasons, this does not always happen on a few Linux-based ports. This will be corrected in a future release.) All callers should supply a null pointer for the 'tzp' argument to gettimeofday. For accurate information about the time zone associated with the current time, use the localtime function. gettimeofday itself is obsolescent according to POSIX. We have no plans to remove access to this function, but portable programs should consider using clock_gettime instead. * The settimeofday function can still be used to set a system-wide time zone when the operating system supports it. This is because the Linux kernel reused the API, on some architectures, to describe a system-wide time-zone-like offset between the software clock maintained by the kernel, and the "RTC" clock that keeps time when the system is shut down. However, to reduce the odds of this offset being set by accident, settimeofday can no longer be used to set the time and the offset simultaneously. If both of its two arguments are non-null, the call will fail (setting errno to EINVAL). Callers attempting to set this offset should also be prepared for the call to fail and set errno to ENOSYS; this already happens on the Hurd and on some Linux architectures. The Linux kernel maintainers are discussing a more principled replacement for the reused API. After a replacement becomes available, we will change settimeofday to fail with ENOSYS on all platforms when its 'tzp' argument is not a null pointer. settimeofday itself is obsolescent according to POSIX. Programs that set the system time should use clock_settime and/or the adjtime family of functions instead. We may cease to make settimeofday available to newly linked binaries after there is a replacement for Linux's time-zone-like offset API. * SPARC ISA v7 is no longer supported. v8 is still supported, but only if the optional CAS instruction is implemented (for instance, LEON processors are still supported, but SuperSPARC processors are not). As the oldest 64-bit SPARC ISA is v9, this only affects 32-bit configurations. * If a lazy binding failure happens during dlopen, during the execution of an ELF constructor, the process is now terminated. Previously, the dynamic loader would return NULL from dlopen, with the lazy binding error captured in a dlerror message. In general, this is unsafe because resetting the stack in an arbitrary function call is not possible. * For MIPS hard-float ABIs, the GNU C Library will be configured to need an executable stack unless explicitly configured at build time to require minimum kernel version 4.8 or newer. This is because executing floating-point branches on a non-executable stack on Linux kernels prior to 4.8 can lead to application crashes for some MIPS configurations. While currently PT_GNU_STACK is not widely used on MIPS, future releases of GCC are expected to enable non-executable stack by default with PT_GNU_STACK by default and is thus likely to trigger a crash on older kernels. The GNU C Library can be built with --enable-kernel=4.8.0 in order to keep a non-executable stack while dropping support for older kernels. * System call wrappers for time system calls now use the new time64 system calls when available. On 32-bit targets, these wrappers attempt to call the new system calls first and fall back to the older 32-bit time system calls if they are not present. This may cause issues in environments that cannot handle unsupported system calls gracefully by returning -ENOSYS. Seccomp sandboxes are affected by this issue. Changes to build and runtime requirements: * It is no longer necessary to have recent Linux kernel headers to build working (non-stub) system call wrappers on all architectures except 64-bit RISC-V. 64-bit RISC-V requires a minimum kernel headers version of 5.0. * The ChangeLog file is no longer present in the toplevel directory of the source tree. ChangeLog files are located in the ChangeLog.old directory as ChangeLog.N where the highest N has the latest entries. Security related changes: CVE-2019-19126: ld.so failed to ignore the LD_PREFER_MAP_32BIT_EXEC environment variable during program execution after a security transition, allowing local attackers to restrict the possible mapping addresses for loaded libraries and thus bypass ASLR for a setuid program. Reported by Marcin Kościelnicki. The following bugs are resolved with this release: [12031] localedata: iconv -t ascii//translit with Greek characters [15813] libc: Multiple issues in __gen_tempname [17726] libc: [arm, sparc] profil_counter should be compat symbol [18231] libc: ipc_perm struct's mode member has wrong type in sys/ipc.h [19767] libc: vdso is not used with static linking [19903] hurd: Shared mappings not being inherited by children processes [20358] network: RES_USE_DNSSEC sets DO; should also have a way to set AD [20839] dynamic-link: Incomplete rollback of dynamic linker state on linking failure [23132] localedata: Missing transliterations in Miscellaneous Mathematical Symbols-A/B Unicode blocks [23518] libc: Eliminate __libc_utmp_jump_table [24026] malloc: malloc_info() returns wrong numbers [24054] localedata: Many locales are missing date_fmt [24214] dynamic-link: user defined ifunc resolvers may run in ldd mode [24304] dynamic-link: Lazy binding failure during ELF constructors/destructors is not fatal [24376] libc: RISC-V symbol size confusion with _start [24682] localedata: zh_CN first weekday should be Monday per GB/T 7408-2005 [24824] libc: test-in-container does not install charmap files compatible with localedef [24844] regex: regex bad pointer / leakage if malloc fails [24867] malloc: Unintended malloc_info formatting changes [24879] libc: login: utmp alarm timer can arrive after lock acquisition [24880] libc: login: utmp implementation uses struct flock with fcntl64 [24882] libc: login: pututline uses potentially outdated cache [24899] libc: Missing nonstring attributes in <utmp.h>, <utmpx.h> [24902] libc: login: Repeating pututxline on EINTR/EAGAIN causes stale utmp entries [24916] dynamic-link: [MIPS] Highest EI_ABIVERSION value not raised to ABSOLUTE ABI [24930] dynamic-link: dlopen of PIE executable can result in _dl_allocate_tls_init assertion failure [24950] localedata: Top-of-tree glibc does not build with top-of-tree GCC (stringop-overflow error) [24959] time: librt IFUNC resolvers for clock_gettime and clock_* functions other can lead to crashes [24967] libc: jemalloc static linking causes runtime failure [24986] libc: alpha: new getegid, geteuid and getppid syscalls used unconditionally [25035] libc: sbrk() failure handled poorly in tunables_strdup [25087] dynamic-link: ldconfig mishandles unusual .dynstr placement [25097] libc: new -Warray-bounds with GCC 10 [25112] dynamic-link: dlopen must not make new objects accessible when it still can fail with an error [25139] localedata: Please add the new mnw_MM locale [25149] regex: Array bounds violation in proceed_next_node [25157] dynamic-link: Audit cookie for the dynamic loader is not initialized correctly [25189] libc: glibc's __glibc_has_include causes issues with clang -frewrite-includes [25194] malloc: malloc.c: do_set_mxfast incorrectly casts the mallopt value to an unsigned [25204] dynamic-link: LD_PREFER_MAP_32BIT_EXEC not ignored in setuid binaries (CVE-2019-19126) [25225] libc: ld.so fails to link on x86 if GCC defaults to -fcf- protection [25226] string: strstr: Invalid result if needle crosses page on s390- z15 ifunc variant. [25232] string: <string.h> does not enable const correctness for strchr et al. for Clang++ [25233] localedata: Consider "." as the thousands separator for sl_SI (Slovenian) [25241] nptl: __SIZEOF_PTHREAD_MUTEX_T defined twice for x86 [25251] build: Failure to run tests when CFLAGS contains -DNDEBUG. [25271] libc: undeclared identifier PTHREAD_MUTEX_DEFAULT when compiling with -std=c11 [25323] localedata: km_KH: d_t_fmt contains "m" instead of "%M" [25324] localedata: lv_LV: d_t_fmt contains suspicious words in the time part [25396] dynamic-link: Failing dlopen can leave behind dangling GL (dl_initfirst) link map pointer [25401] malloc: pvalloc must not have __attribute_alloc_size__ [25423] libc: Array overflow in backtrace on powerpc [25425] network: Missing call to __resolv_context_put in getaddrinfo.c:gethosts Release Notes ============= https://sourceware.org/glibc/wiki/Release/2.31 Contributors ============ 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 Alexandra Hájková Alistair Francis Andreas Schwab Andrew Eggenberger Arjun Shankar Aurelien Jarno Carlos O'Donell Chung-Lin Tang DJ Delorie Dmitry V. Levin Dragan Mladjenovic Egor Kobylkin Emilio Cobos Álvarez Emilio Pozuelo Monfort Feng Xue Florian Weimer Gabriel F. T. Gomes Gustavo Romero H.J. Lu Ian Kent James Clarke Jeremie Koenig John David Anglin Joseph Myers Kamlesh Kumar Krzysztof Koch Leandro Pereira Lucas A. M. Magalhaes Lukasz Majewski Marcin Kościelnicki Matheus Castanho Mihailo Stojanovic Mike Crowe Mike FABIAN Niklas Hambüchen Paul A. Clarke Paul Eggert Petr Vorel Rafal Luzynski Rafał Lużyński Rajalakshmi Srinivasaraghavan Raoni Fassina Firmino Richard Braun Samuel Thibault Sandra Loosemore Siddhesh Poyarekar Stefan Liebler Svante Signell Szabolcs Nagy Talachan Mon Thomas Schwinge Tim Rühsen Tulio Magno Quites Machado Filho Wilco Dijkstra Xuelei Zhang Zack Weinberg liqingqing

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