Commit Graph

2293 Commits

Author SHA1 Message Date
Adhemerval Zanella
1002f1af1c linux: Add process_mrelease
Added in Linux 5.15 (884a7e5964e06ed93c7771c0d7cf19c09a8946f1), the new
syscalls allows a caller to free the memory of a dying target process.

Checked on x86_64-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-06-02 15:43:28 -03:00
Adhemerval Zanella
d19ee3473d linux: Add process_madvise
It was added on Linux 5.10 (ecb8ac8b1f146915aa6b96449b66dd48984caacc)
with the same functionality as madvise but using a pidfd of the target
process.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-06-02 15:43:28 -03:00
Adhemerval Zanella
56cf9e8eec linux: Add pidfd_send_signal
This was added on Linux 5.1(3eb39f47934f9d5a3027fe00d906a45fe3a15fad)
as a way to avoid the race condition of using kill (where PID might be
reused by the kernel between between obtaining the pid and sending the
signal).

If the siginfo_t argument is NULL then pidfd_send_signal is equivalent
to kill.  If it is not NULL pidfd_send_signal is equivalent to
rt_sigqueueinfo.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-05-17 10:33:46 -03:00
Adhemerval Zanella
32dd8c251a linux: Add pidfd_getfd
This was added on Linux 5.6 (8649c322f75c96e7ced2fec201e123b2b073bf09)
as a way to retrieve a file descriptors for another process though
pidfd (created either with CLONE_PIDFD or pidfd_getfd).  The
functionality is similar to recvmmsg SCM_RIGHTS.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-05-17 10:33:07 -03:00
Adhemerval Zanella
97f5d19c45 linux: Add pidfd_open
This was added on Linux 5.3 (32fcb426ec001cb6d5a4a195091a8486ea77e2df)
as a way to retrieve a pid file descriptors for process that has not
been created CLONE_PIDFD (by usual fork/clone).

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-05-17 10:32:28 -03:00
Adhemerval Zanella
d2db60d8d8 Remove dl-librecon.h header.
The Linux version used by i686 and m68k provide three overrrides for
generic code:

  1. DISTINGUISH_LIB_VERSIONS to print additional information when
     libc5 is used by a dependency.

  2. EXTRA_LD_ENVVARS to that enabled LD_LIBRARY_VERSION environment
     variable.

  3. EXTRA_UNSECURE_ENVVARS to add two environment variables related
     to aout support.

None are really requires, it has some decades since libc5 or aout
suppported was removed and Linux even remove support for aout files.
The LD_LIBRARY_VERSION is also dead code, dl_correct_cache_id is not
used anywhere.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-05-16 15:03:49 -03:00
Adhemerval Zanella
b46d250656 Remove kernel version check
The kernel version check is used to avoid glibc to run on older
kernels where some syscall are not available and fallback code are
not enabled to handle graciously fail.  However, it does not prevent
if the kernel does not correctly advertise its version through
vDSO note, uname or procfs.

Also kernel version checks are sometime not desirable by users,
where they want to deploy on different system with different kernel
version knowing the minimum set of syscall is always presented on
such systems.

The kernel version check has been removed along with the
LD_ASSUME_KERNEL environment variable.  The minimum kernel used to
built glibc is still provided through NT_GNU_ABI_TAG ELF note and
also printed when libc.so is issued.

Checked on x86_64-linux-gnu.
2022-05-16 15:03:49 -03:00
H.J. Lu
4c5b1cf5a6 NEWS: Mention DT_RELR support 2022-04-26 10:16:11 -07:00
Carlos O'Donell
2fe48f5283 NEWS: Move PLT tracking slowdown to glibc 2.35.
In commit 063f9ba220 the NEWS section
was accidentally added to the glibc 2.34 NEWS section. The NEWS entry
should have been added to glibc 2.35 which contained the committed
fix. This moves the NEWS entry to correct section.
2022-04-12 13:26:10 -04:00
Adhemerval Zanella
144761540a elf: Remove LD_USE_LOAD_BIAS
It is solely for prelink with PIE executables [1].

[1] https://sourceware.org/legacy-ml/libc-hacker/2003-11/msg00127.html

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-02-10 09:18:15 -03:00
Adhemerval Zanella
d7703d3176 malloc: Remove LD_TRACE_PRELINKING usage from mtrace
The fix for BZ#22716 replacde LD_TRACE_LOADED_OBJECTS with
LD_TRACE_PRELINKING so mtrace could record executable address
position.

To provide the same information, LD_TRACE_LOADED_OBJECTS is
extended where a value or '2' also prints the executable address
as well.  It avoid adding another loader environment variable
to be used solely for mtrace.  The vDSO will be printed as
a default library (with '=>' pointing the same name), which is
ok since both mtrace and ldd already handles it.

The mtrace script is changed to also parse the new format.  To
correctly support PIE and non-PIE executables, both the default
mtrace address and the one calculated as used (it fixes mtrace
for non-PIE exectuable as for BZ#22716 for PIE).

Checked on x86_64-linux-gnu.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-02-10 09:16:13 -03:00
Adhemerval Zanella
6628c742b2 elf: Remove prelink support
Prelinked binaries and libraries still work, the dynamic tags
DT_GNU_PRELINKED, DT_GNU_LIBLIST, DT_GNU_CONFLICT just ignored
(meaning the process is reallocated as default).

The loader environment variable TRACE_PRELINKING is also removed,
since it used solely on prelink.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-02-10 09:16:12 -03:00
Carlos O'Donell
bc6c1af537 Open master branch for glibc 2.36 development 2022-02-03 01:21:33 -05:00
Carlos O'Donell
a134ce8237 Update NEWS bug list. 2022-02-02 23:55:20 -05:00
Carlos O'Donell
32ffd42741 Update NEWS.
Moved LD_AUDIT notes into requirements section since the LAV_CURRENT
bump is a requirements change that impacts loading old audit modules
or new audit modules on older loaders.
2022-02-02 23:46:19 -05:00
Adhemerval Zanella
6289d28d3c posix: Replace posix_spawnattr_tc{get,set}pgrp_np with posix_spawn_file_actions_addtcsetpgrp_np
The posix_spawnattr_tcsetpgrp_np works on a file descriptor (the
controlling terminal), so it would make more sense to actually fit
it on the file actions API.

Also, POSIX_SPAWN_TCSETPGROUP is not really required since it is
implicit by the presence of tcsetpgrp file action.

The posix/tst-spawn6.c is also fixed when TTY can is not present.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-02-02 08:34:16 -03:00
Ben Woodard
ce9a68c57c elf: Fix runtime linker auditing on aarch64 (BZ #26643)
The rtld audit support show two problems on aarch64:

  1. _dl_runtime_resolve does not preserve x8, the indirect result
      location register, which might generate wrong result calls
      depending of the function signature.

  2. The NEON Q registers pushed onto the stack by _dl_runtime_resolve
     were twice the size of D registers extracted from the stack frame by
     _dl_runtime_profile.

While 2. might result in wrong information passed on the PLT tracing,
1. generates wrong runtime behaviour.

The aarch64 rtld audit support is changed to:

  * Both La_aarch64_regs and La_aarch64_retval are expanded to include
    both x8 and the full sized NEON V registers, as defined by the
    ABI.

  * dl_runtime_profile needed to extract registers saved by
    _dl_runtime_resolve and put them into the new correctly sized
    La_aarch64_regs structure.

  * The LAV_CURRENT check is change to only accept new audit modules
    to avoid the undefined behavior of not save/restore x8.

  * Different than other architectures, audit modules older than
    LAV_CURRENT are rejected (both La_aarch64_regs and La_aarch64_retval
    changed their layout and there are no requirements to support multiple
    audit interface with the inherent aarch64 issues).

  * A new field is also reserved on both La_aarch64_regs and
    La_aarch64_retval to support variant pcs symbols.

Similar to x86, a new La_aarch64_vector type to represent the NEON
register is added on the La_aarch64_regs (so each type can be accessed
directly).

Since LAV_CURRENT was already bumped to support bind-now, there is
no need to increase it again.

Checked on aarch64-linux-gnu.

Co-authored-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-02-01 14:49:46 -03:00
Adhemerval Zanella
32612615c5 elf: Issue la_symbind for bind-now (BZ #23734)
The audit symbind callback is not called for binaries built with
-Wl,-z,now or when LD_BIND_NOW=1 is used, nor the PLT tracking callbacks
(plt_enter and plt_exit) since this would change the expected
program semantics (where no PLT is expected) and would have performance
implications (such as for BZ#15533).

LAV_CURRENT is also bumped to indicate the audit ABI change (where
la_symbind flags are set by the loader to indicate no possible PLT
trace).

To handle powerpc64 ELFv1 function descriptor, _dl_audit_symbind
requires to know whether bind-now is used so the symbol value is
updated to function text segment instead of the OPD (for lazy binding
this is done by PPC64_LOAD_FUNCPTR on _dl_runtime_resolve).

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
powerpc64-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-02-01 14:49:46 -03:00
Siddhesh Poyarekar
829ea0caca Mention _FORTIFY_SOURCE=3 for gcc12 in NEWS
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-01-31 19:58:29 +05:30
Adhemerval Zanella
be211e0922 Add prelink removal plan on NEWS
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-01-28 18:18:30 -03:00
Adhemerval Zanella
342cc934a3 posix: Add terminal control setting support for posix_spawn
Currently there is no proper way to set the controlling terminal through
posix_spawn in race free manner [1].  This forces shell implementations
to keep using fork+exec when launching background process groups,
even when using posix_spawn yields better performance.

This patch adds a new GNU extension so the creating process can
configure the created process terminal group.  This is done with a new
flag, POSIX_SPAWN_TCSETPGROUP, along with two new attribute functions:
posix_spawnattr_tcsetpgrp_np, and posix_spawnattr_tcgetpgrp_np.
The function sets a new attribute, spawn-tcgroupfd, that references to
the controlling terminal.

The controlling terminal is set after the spawn-pgroup attribute, and
uses the spawn-tcgroupfd along with current creating process group
(so it is composable with POSIX_SPAWN_SETPGROUP).

To create a process and set the controlling terminal, one can use the
following sequence:

    posix_spawnattr_t attr;
    posix_spawnattr_init (&attr);
    posix_spawnattr_setflags (&attr, POSIX_SPAWN_TCSETPGROUP);
    posix_spawnattr_tcsetpgrp_np (&attr, tcfd);

If the idea is also to create a new process groups:

    posix_spawnattr_t attr;
    posix_spawnattr_init (&attr);
    posix_spawnattr_setflags (&attr, POSIX_SPAWN_TCSETPGROUP
				     | POSIX_SPAWN_SETPGROUP);
    posix_spawnattr_tcsetpgrp_np (&attr, tcfd);
    posix_spawnattr_setpgroup (&attr, 0);

The controlling terminal file descriptor is ignored if the new flag is
not set.

This interface is slight different than the one provided by QNX [2],
which only provides the POSIX_SPAWN_TCSETPGROUP flag.  The QNX
documentation does not specify how the controlling terminal is obtained
nor how it iteracts with POSIX_SPAWN_SETPGROUP.  Since a glibc
implementation is library based, it is more straightforward and avoid
requires additional file descriptor operations to request the caller
to setup the controlling terminal file descriptor (and it also allows
a bit less error handling by posix_spawn).

Checked on x86_64-linux-gnu and i686-linux-gnu.

[1] https://github.com/ksh93/ksh/issues/79
[2] https://www.qnx.com/developers/docs/7.0.0/index.html#com.qnx.doc.neutrino.lib_ref/topic/p/posix_spawn.html

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-01-25 14:07:53 -03:00
Siddhesh Poyarekar
23e0e8f5f1 getcwd: Set errno to ERANGE for size == 1 (CVE-2021-3999)
No valid path returned by getcwd would fit into 1 byte, so reject the
size early and return NULL with errno set to ERANGE.  This change is
prompted by CVE-2021-3999, which describes a single byte buffer
underflow and overflow when all of the following conditions are met:

- The buffer size (i.e. the second argument of getcwd) is 1 byte
- The current working directory is too long
- '/' is also mounted on the current working directory

Sequence of events:

- In sysdeps/unix/sysv/linux/getcwd.c, the syscall returns ENAMETOOLONG
  because the linux kernel checks for name length before it checks
  buffer size

- The code falls back to the generic getcwd in sysdeps/posix

- In the generic func, the buf[0] is set to '\0' on line 250

- this while loop on line 262 is bypassed:

    while (!(thisdev == rootdev && thisino == rootino))

  since the rootfs (/) is bind mounted onto the directory and the flow
  goes on to line 449, where it puts a '/' in the byte before the
  buffer.

- Finally on line 458, it moves 2 bytes (the underflowed byte and the
  '\0') to the buf[0] and buf[1], resulting in a 1 byte buffer overflow.

- buf is returned on line 469 and errno is not set.

This resolves BZ #28769.

Reviewed-by: Andreas Schwab <schwab@linux-m68k.org>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
Signed-off-by: Qualys Security Advisory <qsa@qualys.com>
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-01-24 11:00:17 +05:30
Siddhesh Poyarekar
ee8d5e33ad realpath: Set errno to ENAMETOOLONG for result larger than PATH_MAX [BZ #28770]
realpath returns an allocated string when the result exceeds PATH_MAX,
which is unexpected when its second argument is not NULL.  This results
in the second argument (resolved) being uninitialized and also results
in a memory leak since the caller expects resolved to be the same as the
returned value.

Return NULL and set errno to ENAMETOOLONG if the result exceeds
PATH_MAX.  This fixes [BZ #28770], which is CVE-2021-3998.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-01-21 23:01:30 +05:30
Adhemerval Zanella
5f3a7ebc35 Linux: Add epoll_pwait2 (BZ #27359)
It is similar to epoll_wait, with the difference the timeout has
nanosecond resoluting by using struct timespec instead of int.

Although Linux interface only provides 64 bit time_t support, old
32 bit interface is also provided (so keep in sync with current
practice and to no force opt-in on 64 bit time_t).

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-01-17 14:34:54 -03:00
Florian Weimer
f545ad4928 CVE-2022-23218: Buffer overflow in sunrpc svcunix_create (bug 28768)
The sunrpc function svcunix_create suffers from a stack-based buffer
overflow with overlong pathname arguments.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-01-17 10:47:58 +01:00
Florian Weimer
226b46770c CVE-2022-23219: Buffer overflow in sunrpc clnt_create for "unix" (bug 22542)
Processing an overlong pathname in the sunrpc clnt_create function
results in a stack-based buffer overflow.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-01-17 10:22:00 +01:00
Florian Weimer
9ba202c78f Add --with-rtld-early-cflags configure option
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-01-14 20:17:15 +01:00
Szabolcs Nagy
347a5b592c math: Fix float conversion regressions with gcc-12 [BZ #28713]
Converting double precision constants to float is now affected by the
runtime dynamic rounding mode instead of being evaluated at compile
time with default rounding mode (except static object initializers).

This can change the computed result and cause performance regression.
The known correctness issues (increased ulp errors) are already fixed,
this patch fixes remaining cases of unnecessary runtime conversions.

Add float M_* macros to math.h as new GNU extension API.  To avoid
conversions the new M_* macros are used and instead of casting double
literals to float, use float literals (only required if the conversion
is inexact).

The patch was tested on aarch64 where the following symbols had new
spurious conversion instructions that got fixed:

  __clog10f
  __gammaf_r_finite@GLIBC_2.17
  __j0f_finite@GLIBC_2.17
  __j1f_finite@GLIBC_2.17
  __jnf_finite@GLIBC_2.17
  __kernel_casinhf
  __lgamma_negf
  __log1pf
  __y0f_finite@GLIBC_2.17
  __y1f_finite@GLIBC_2.17
  cacosf
  cacoshf
  casinhf
  catanf
  catanhf
  clogf
  gammaf_positive

Fixes bug 28713.

Reviewed-by: Paul Zimmermann <Paul.Zimmermann@inria.fr>
2022-01-10 14:27:17 +00:00
Adhemerval Zanella
65ccd641ba debug: Remove catchsegv and libSegfault (BZ #14913)
Trapping SIGSEGV within the process is error-prone, adds security
issues, and modern analysis design tends to happen out of the
process (either by attaching a debugger or by post-mortem analysis).

The libSegfault also has some design problems, it uses non
async-signal-safe function (backtrace) on signal handler.

There are multiple alternatives if users do want to use similar
functionality, such as sigsegv gnulib module or libsegfault.
2022-01-06 07:59:49 -03:00
Stafford Horne
c1fc366ec9 Documentation for OpenRISC port
OpenRISC architecture specification:

 https://raw.githubusercontent.com/openrisc/doc/master/openrisc-arch-1.3-rev1.pdf

Currently the port as of the 2022-01-03 rebasing there are no known
architecture specific test failures.

Writing credits for the port are:

 Stafford Horne  <shorne@gmail.com>
 Christian Svensson  <blue@cmd.nu>

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-01-05 06:40:06 +09:00
Paul Eggert
581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00
Florian Weimer
5d28a8962d elf: Add _dl_find_object function
It can be used to speed up the libgcc unwinder, and the internal
_dl_find_dso_for_object function (which is used for caller
identification in dlopen and related functions, and in dladdr).

_dl_find_object is in the internal namespace due to bug 28503.
If libgcc switches to _dl_find_object, this namespace issue will
be fixed.  It is located in libc for two reasons: it is necessary
to forward the call to the static libc after static dlopen, and
there is a link ordering issue with -static-libgcc and libgcc_eh.a
because libc.so is not a linker script that includes ld.so in the
glibc build tree (so that GCC's internal -lc after libgcc_eh.a does
not pick up ld.so).

It is necessary to do the i386 customization in the
sysdeps/x86/bits/dl_find_object.h header shared with x86-64 because
otherwise, multilib installations are broken.

The implementation uses software transactional memory, as suggested
by Torvald Riegel.  Two copies of the supporting data structures are
used, also achieving full async-signal-safety.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-12-28 22:52:56 +01:00
Adhemerval Zanella
063f9ba220 elf: Avoid unnecessary slowdown from profiling with audit (BZ#15533)
The rtld-audit interfaces introduces a slowdown due to enabling
profiling instrumentation (as if LD_AUDIT implied LD_PROFILE).
However, instrumenting is only necessary if one of audit libraries
provides PLT callbacks (la_pltenter or la_pltexit symbols).  Otherwise,
the slowdown can be avoided.

The following patch adjusts the logic that enables profiling to iterate
over all audit modules and check if any of those provides a PLT hook.
To keep la_symbind to work even without PLT callbacks, _dl_fixup now
calls the audit callback if the modules implements it.

Co-authored-by: Alexander Monakov <amonakov@ispras.ru>

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-12-28 08:40:38 -03:00
Florian Weimer
9702a7901e stdio: Implement %#m for vfprintf and related functions
%#m prints errno as an error constant if one is available, or
a decimal number as a fallback.  This intends to address the gap
that strerrorname_np does not work well with printf for unknown
error codes due to its NULL return values in those cases.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-12-23 15:02:50 +01:00
Adhemerval Zanella
98d5fcb8d0 malloc: Add Huge Page support for mmap
With the morecore hook removed, there is not easy way to provide huge
pages support on with glibc allocator without resorting to transparent
huge pages.  And some users and programs do prefer to use the huge pages
directly instead of THP for multiple reasons: no splitting, re-merging
by the VM, no TLB shootdowns for running processes, fast allocation
from the reserve pool, no competition with the rest of the processes
unlike THP, no swapping all, etc.

This patch extends the 'glibc.malloc.hugetlb' tunable: the value
'2' means to use huge pages directly with the system default size,
while a positive value means and specific page size that is matched
against the supported ones by the system.

Currently only memory allocated on sysmalloc() is handled, the arenas
still uses the default system page size.

To test is a new rule is added tests-malloc-hugetlb2, which run the
addes tests with the required GLIBC_TUNABLE setting.  On systems without
a reserved huge pages pool, is just stress the mmap(MAP_HUGETLB)
allocation failure.  To improve test coverage it is required to create
a pool with some allocated pages.

Checked on x86_64-linux-gnu.

Reviewed-by: DJ Delorie <dj@redhat.com>
2021-12-15 17:35:38 -03:00
Adhemerval Zanella
5f6d8d97c6 malloc: Add madvise support for Transparent Huge Pages
Linux Transparent Huge Pages (THP) current supports three different
states: 'never', 'madvise', and 'always'.  The 'never' is
self-explanatory and 'always' will enable THP for all anonymous
pages.  However, 'madvise' is still the default for some system and
for such case THP will be only used if the memory range is explicity
advertise by the program through a madvise(MADV_HUGEPAGE) call.

To enable it a new tunable is provided, 'glibc.malloc.hugetlb',
where setting to a value diffent than 0 enables the madvise call.

This patch issues the madvise(MADV_HUGEPAGE) call after a successful
mmap() call at sysmalloc() with sizes larger than the default huge
page size.  The madvise() call is disable is system does not support
THP or if it has the mode set to "never" and on Linux only support
one page size for THP, even if the architecture supports multiple
sizes.

To test is a new rule is added tests-malloc-hugetlb1, which run the
addes tests with the required GLIBC_TUNABLE setting.

Checked on x86_64-linux-gnu.

Reviewed-by: DJ Delorie <dj@redhat.com>
2021-12-15 17:35:14 -03:00
H.J. Lu
f6ff87868a NEWS: Document LD_PREFER_MAP_32BIT_EXEC as x86-64 only 2021-12-14 07:58:05 -08:00
Florian Weimer
0884724a95 elf: Use new dependency sorting algorithm by default
The default has to change eventually, and there are no known failures
that require a delay.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-12-14 14:44:04 +01:00
H.J. Lu
1f3d460761 NEWS: Move LD_PREFER_MAP_32BIT_EXEC
Move LD_PREFER_MAP_32BIT_EXEC to

Deprecated and removed features, and other changes affecting compatibility:
2021-12-13 16:33:57 -08:00
Siddhesh Poyarekar
23645707f1 Replace --enable-static-pie with --disable-default-pie
Build glibc programs and tests as PIE by default and enable static-pie
automatically if the architecture and toolchain supports it.

Also add a new configuration option --disable-default-pie to prevent
building programs as PIE.

Only the following architectures now have PIE disabled by default
because they do not work at the moment.  hppa, ia64, alpha and csky
don't work because the linker is unable to handle a pcrel relocation
generated from PIE objects.  The microblaze compiler is currently
failing with an ICE.  GNU hurd tries to enable static-pie, which does
not work and hence fails.  All these targets have default PIE disabled
at the moment and I have left it to the target maintainers to enable PIE
on their targets.

build-many-glibcs runs clean for all targets.  I also tested x86_64 on
Fedora and Ubuntu, to verify that the default build as well as
--disable-default-pie work as expected with both system toolchains.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-12-13 08:08:59 +05:30
H.J. Lu
ea5814467a x86-64: Remove LD_PREFER_MAP_32BIT_EXEC support [BZ #28656]
Remove the LD_PREFER_MAP_32BIT_EXEC environment variable support since
the first PT_LOAD segment is no longer executable due to defaulting to
-z separate-code.

This fixes [BZ #28656].

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-12-10 14:01:34 -08:00
Florian Weimer
2e75604f83 elf: Install a symbolic link to ld.so as /usr/bin/ld.so
This makes ld.so features such as --preload, --audit,
and --list-diagnostics more accessible to end users because they
do not need to know the ABI name of the dynamic loader.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-12-10 16:06:58 +01:00
Florian Weimer
c901c3e764 nptl: Add public rseq symbols and <sys/rseq.h>
The relationship between the thread pointer and the rseq area
is made explicit.  The constant offset can be used by JIT compilers
to optimize rseq access (e.g., for really fast sched_getcpu).

Extensibility is provided through __rseq_size and __rseq_flags.
(In the future, the kernel could request a different rseq size
via the auxiliary vector.)

Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-12-09 09:49:32 +01:00
Florian Weimer
c1cb2deeca elf: execve statically linked programs instead of crashing [BZ #28648]
Programs without dynamic dependencies and without a program
interpreter are now run via execve.

Previously, the dynamic linker either crashed while attempting to
read a non-existing dynamic segment (looking for DT_AUDIT/DT_DEPAUDIT
data), or the self-relocated in the static PIE executable crashed
because the outer dynamic linker had already applied RELRO protection.

<dl-execve.h> is needed because execve is not available in the
dynamic loader on Hurd.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-12-05 11:28:34 +01:00
Joseph Myers
309548bec3 Support C2X printf %b, %B
C2X adds a printf %b format (see
<http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2630.pdf>, accepted
for C2X), for outputting integers in binary.  It also has recommended
practice for a corresponding %B format (like %b, but %#B starts the
output with 0B instead of 0b).  Add support for these formats to
glibc.

One existing test uses %b as an example of an unknown format, to test
how glibc printf handles unknown formats; change that to %v.  Use of
%b and %B as user-registered format specifiers continues to work (and
we already have a test that covers that, tst-printfsz.c).

Note that C2X also has scanf %b support, plus support for binary
constants starting 0b in strtol (base 0 and 2) and scanf %i (strtol
base 0 and scanf %i coming from a previous paper that added binary
integer literals).  I intend to implement those features in a separate
patch or patches; as discussed in the thread starting at
<https://sourceware.org/pipermail/libc-alpha/2020-December/120414.html>,
they will be more complicated because they involve adding extra public
symbols to ensure compatibility with existing code that might not
expect 0b constants to be handled by strtol base 0 and 2 and scanf %i,
whereas simply adding a new format specifier poses no such
compatibility concerns.

Note that the actual conversion from integer to string uses existing
code in _itoa.c.  That code has special cases for bases 8, 10 and 16,
probably so that the compiler can optimize division by an integer
constant in the code for those bases.  If desired such special cases
could easily be added for base 2 as well, but that would be an
optimization, not actually needed for these printf formats to work.

Tested for x86_64 and x86.  Also tested with build-many-glibcs.py for
aarch64-linux-gnu with GCC mainline to make sure that the test does
indeed build with GCC 12 (where format checking warnings are enabled
for most of the test).
2021-11-10 15:52:21 +00:00
Noah Goldstein
11c88336e3 NEWS: Add item for __memcmpeq 2021-10-26 16:51:29 -05:00
Chung-Lin Tang
15a0c5730d elf: Fix slow DSO sorting behavior in dynamic loader (BZ #17645)
This second patch contains the actual implementation of a new sorting algorithm
for shared objects in the dynamic loader, which solves the slow behavior that
the current "old" algorithm falls into when the DSO set contains circular
dependencies.

The new algorithm implemented here is simply depth-first search (DFS) to obtain
the Reverse-Post Order (RPO) sequence, a topological sort. A new l_visited:1
bitfield is added to struct link_map to more elegantly facilitate such a search.

The DFS algorithm is applied to the input maps[nmap-1] backwards towards
maps[0]. This has the effect of a more "shallow" recursion depth in general
since the input is in BFS. Also, when combined with the natural order of
processing l_initfini[] at each node, this creates a resulting output sorting
closer to the intuitive "left-to-right" order in most cases.

Another notable implementation adjustment related to this _dl_sort_maps change
is the removing of two char arrays 'used' and 'done' in _dl_close_worker to
represent two per-map attributes. This has been changed to simply use two new
bit-fields l_map_used:1, l_map_done:1 added to struct link_map. This also allows
discarding the clunky 'used' array sorting that _dl_sort_maps had to sometimes
do along the way.

Tunable support for switching between different sorting algorithms at runtime is
also added. A new tunable 'glibc.rtld.dynamic_sort' with current valid values 1
(old algorithm) and 2 (new DFS algorithm) has been added. At time of commit
of this patch, the default setting is 1 (old algorithm).

Signed-off-by: Chung-Lin Tang  <cltang@codesourcery.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-10-21 11:23:53 -03:00
Fangrui Song
bf433b849a elf: Remove Intel MPX support (lazy PLT, ld.so profile, and LD_AUDIT)
Intel MPX failed to gain wide adoption and has been deprecated for a
while. GCC 9.1 removed Intel MPX support. Linux kernel removed MPX in
2019.

This patch removes the support code from the dynamic loader.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-10-11 11:14:02 -07:00
Mike FABIAN
b517256015 Update to Unicode 14.0.0 [BZ #28390]
Unicode 14.0.0 Support: Character encoding, character type info, and
transliteration tables are all updated to Unicode 14.0.0, using
the generator scripts contributed by Mike FABIAN (Red Hat).

Total added characters in newly generated CHARMAP: 838
Total removed characters in newly generated WIDTH: 1
    (Characters not in WIDTH get width 1 by default, i.e. these have width 1 now.)
    removed: <U1734> 0 : eaw=N category=Mc bidi=L   name=HANUNOO SIGN PAMUDPOD
    That seems intentional, the character had category Mn (Mark, nonspacing) before
    and now has Mc (Mark, spacing combining)
Total changed characters in newly generated WIDTH: 0
Total added characters in newly generated WIDTH: 175
2021-10-04 08:54:27 +02:00
Joseph Myers
01d34e934a Add C2X _PRINTF_NAN_LEN_MAX
C2X adds a macro _PRINTF_NAN_LEN_MAX to <stdio.h>, giving the maximum
length of printf output for a NaN.  glibc never includes an
n-char-sequence in its printf output for NaNs, so the correct value
for glibc is 4 ("-nan" or "-NAN"); define the macro accordingly.

This patch makes the macro definition conditional on __GLIBC_USE
(ISOC2X), as is generally done with features from new standard
versions.  The name is in the implementation namespace for older
standards, so it would also be possible to define it unconditionally.

Tested for x86_64.
2021-09-30 20:53:34 +00:00