2714 Commits

Author SHA1 Message Date
Florian Weimer
7485d6cfe9 elf: Support recursive use of dynamic TLS in interposed malloc
It turns out that quite a few applications use bundled mallocs that
have been built to use global-dynamic TLS (instead of the recommended
initial-exec TLS).  The previous workaround from
commit afe42e935b3ee97bac9a7064157587777259c60e ("elf: Avoid some
free (NULL) calls in _dl_update_slotinfo") does not fix all
encountered cases unfortunatelly.

This change avoids the TLS generation update for recursive use
of TLS from a malloc that was called during a TLS update.  This
is possible because an interposed malloc has a fixed module ID and
TLS slot.  (It cannot be unloaded.)  If an initially-loaded module ID
is encountered in __tls_get_addr and the dynamic linker is already
in the middle of a TLS update, use the outdated DTV, thus avoiding
another call into malloc.  It's still necessary to update the
DTV to the most recent generation, to get out of the slow path,
which is why the check for recursion is needed.

The bookkeeping is done using a global counter instead of per-thread
flag because TLS access in the dynamic linker is tricky.

All this will go away once the dynamic linker stops using malloc
for TLS, likely as part of a change that pre-allocates all TLS
during pthread_create/dlopen.

Fixes commit d2123d68275acc0f061e73d5f86ca504e0d5a344 ("elf: Fix slow
tls access after dlopen [BZ #19924]").

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
(cherry picked from commit 018f0fc3b818d4d1460a4e2384c24802504b1d20)
2025-01-11 15:39:01 -08:00
Florian Weimer
311b603855 elf: Avoid some free (NULL) calls in _dl_update_slotinfo
This has been confirmed to work around some interposed mallocs.  Here
is a discussion of the impact test ust/libc-wrapper/test_libc-wrapper
in lttng-tools:

  New TLS usage in libgcc_s.so.1, compatibility impact
  <https://inbox.sourceware.org/libc-alpha/8734v1ieke.fsf@oldenburg.str.redhat.com/>

Reportedly, this patch also papers over a similar issue when tcmalloc
2.9.1 is not compiled with -ftls-model=initial-exec.  Of course the
goal really should be to compile mallocs with the initial-exec TLS
model, but this commit appears to be a useful interim workaround.

Fixes commit d2123d68275acc0f061e73d5f86ca504e0d5a344 ("elf: Fix slow
tls access after dlopen [BZ #19924]").

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit afe42e935b3ee97bac9a7064157587777259c60e)
2025-01-11 15:33:44 -08:00
Szabolcs Nagy
2293b0a0d0 elf: Fix slow tls access after dlopen [BZ #19924]
In short: __tls_get_addr checks the global generation counter and if
the current dtv is older then _dl_update_slotinfo updates dtv up to the
generation of the accessed module. So if the global generation is newer
than generation of the module then __tls_get_addr keeps hitting the
slow dtv update path. The dtv update path includes a number of checks
to see if any update is needed and this already causes measurable tls
access slow down after dlopen.

It may be possible to detect up-to-date dtv faster.  But if there are
many modules loaded (> TLS_SLOTINFO_SURPLUS) then this requires at
least walking the slotinfo list.

This patch tries to update the dtv to the global generation instead, so
after a dlopen the tls access slow path is only hit once.  The modules
with larger generation than the accessed one were not necessarily
synchronized before, so additional synchronization is needed.

This patch uses acquire/release synchronization when accessing the
generation counter.

Note: in the x86_64 version of dl-tls.c the generation is only loaded
once, since relaxed mo is not faster than acquire mo load.

I have not benchmarked this. Tested by Adhemerval Zanella on aarch64,
powerpc, sparc, x86 who reported that it fixes the performance issue
of bug 19924.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit d2123d68275acc0f061e73d5f86ca504e0d5a344)
2025-01-11 15:29:08 -08:00
Florian Weimer
9ac08d122a elf: Disable some subtests of ifuncmain1, ifuncmain5 for !PIE
(cherry picked from commit 9cc9d61ee12f2f8620d8e0ea3c42af02bf07fe1e)
2024-05-02 23:13:48 +02:00
Adhemerval Zanella
0f82b26a8d Revert "elf: Fix wrong break removal from 8ee878592c"
(2.34 does not have 8ee878592c)

This reverts commit 62ac4b09c4ee66c91478212359b8ac44b4f6a9e2.
2024-02-12 10:46:34 -03:00
Adhemerval Zanella
62ac4b09c4 elf: Fix wrong break removal from 8ee878592c
Reported-by: Alexander Monakov <amonakov@ispras.ru>
(cherry picked from commit 546a1ba664626603660b595662249d524e429013)
2024-02-05 09:55:09 -03:00
Hector Martin
f95fe70608 elf: Fix TLS modid reuse generation assignment (BZ 29039)
_dl_assign_tls_modid() assigns a slotinfo entry for a new module, but
does *not* do anything to the generation counter. The first time this
happens, the generation is zero and map_generation() returns the current
generation to be used during relocation processing. However, if
a slotinfo entry is later reused, it will already have a generation
assigned. If this generation has fallen behind the current global max
generation, then this causes an obsolete generation to be assigned
during relocation processing, as map_generation() returns this
generation if nonzero. _dl_add_to_slotinfo() eventually resets the
generation, but by then it is too late. This causes DTV updates to be
skipped, leading to NULL or broken TLS slot pointers and segfaults.

Fix this by resetting the generation to zero in _dl_assign_tls_modid(),
so it behaves the same as the first time a slot is assigned.
_dl_add_to_slotinfo() will still assign the correct static generation
later during module load, but relocation processing will no longer use
an obsolete generation.

Note that slotinfo entry (aka modid) reuse typically happens after a
dlclose and only TLS access via dynamic tlsdesc is affected. Because
tlsdesc is optimized to use the optional part of static TLS, dynamic
tlsdesc can be avoided by increasing the glibc.rtld.optional_static_tls
tunable to a large enough value, or by LD_PRELOAD-ing the affected
modules.

Fixes bug 29039.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
(cherry picked from commit 3921c5b40f293c57cb326f58713c924b0662ef59)
2023-12-22 14:42:53 +00:00
Siddhesh Poyarekar
dcc367f148 tunables: Terminate if end of input is reached (CVE-2023-4911)
The string parsing routine may end up writing beyond bounds of tunestr
if the input tunable string is malformed, of the form name=name=val.
This gets processed twice, first as name=name=val and next as name=val,
resulting in tunestr being name=name=val:name=val, thus overflowing
tunestr.

Terminate the parsing loop at the first instance itself so that tunestr
does not overflow.

This also fixes up tst-env-setuid-tunables to actually handle failures
correct and add new tests to validate the fix for this CVE.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa)
2023-10-02 15:44:25 -04:00
Simon Kissane
4dd89b2a8f gmon: improve mcount overflow handling [BZ# 27576]
When mcount overflows, no gmon.out file is generated, but no message is printed
to the user, leaving the user with no idea why, and thinking maybe there is
some bug - which is how BZ 27576 ended up being logged. Print a message to
stderr in this case so the user knows what is going on.

As a comment in sys/gmon.h acknowledges, the hardcoded MAXARCS value is too
small for some large applications, including the test case in that BZ. Rather
than increase it, add tunables to enable MINARCS and MAXARCS to be overridden
at runtime (glibc.gmon.minarcs and glibc.gmon.maxarcs). So if a user gets the
mcount overflow error, they can try increasing maxarcs (they might need to
increase minarcs too if the heuristic is wrong in their case.)

Note setting minarcs/maxarcs too large can cause monstartup to fail with an
out of memory error. If you set them large enough, it can cause an integer
overflow in calculating the buffer size. I haven't done anything to defend
against that - it would not generally be a security vulnerability, since these
tunables will be ignored in suid/sgid programs (due to the SXID_ERASE default),
and if you can set GLIBC_TUNABLES in the environment of a process, you can take
it over anyway (LD_PRELOAD, LD_LIBRARY_PATH, etc). I thought about modifying
the code of monstartup to defend against integer overflows, but doing so is
complicated, and I realise the existing code is susceptible to them even prior
to this change (e.g. try passing a pathologically large highpc argument to
monstartup), so I decided just to leave that possibility in-place.

Add a test case which demonstrates mcount overflow and the tunables.

Document the new tunables in the manual.

Signed-off-by: Simon Kissane <skissane@gmail.com>
Reviewed-by: DJ Delorie <dj@redhat.com>
(cherry picked from commit 31be941e4367c001b2009308839db5c67bf9dcbc)
2023-04-28 16:44:12 +02:00
Florian Weimer
2d7550e6cf elf: Smoke-test ldconfig -p against system /etc/ld.so.cache
The test is sufficient to detect the ldconfig bug fixed in
commit 9fe6f6363886aae6b2b210cae3ed1f5921299083 ("elf: Fix 64 time_t
support for installed statically binaries").

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 9fd63e35371b9939e9153907c6a753e6960b68ad)
2023-02-08 18:11:27 +01:00
Adhemerval Zanella
11ad405fd4 elf: Fix 64 time_t support for installed statically binaries
The usage of internal static symbol for statically linked binaries
does not work correctly for objects built with -D_TIME_BITS=64,
since the internal definition does not provide the expected aliases.

This patch makes it to use the default stat functions instead (which
uses the default 64 time_t alias and types).

Checked on i686-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 9fe6f6363886aae6b2b210cae3ed1f5921299083)
2023-02-08 09:32:42 +01:00
Fangrui Song
bbe4bbb6e8 elf: Drop elf/tls-macros.h in favor of __thread and tls_model attributes [BZ #28152] [BZ #28205]
elf/tls-macros.h was added for TLS testing when GCC did not support
__thread. __thread and tls_model attributes are mature now and have been
used by many newer tests.

Also delete tst-tls2.c which tests .tls_common (unused by modern GCC and
unsupported by Clang/LLD). .tls_common and .tbss definition are almost
identical after linking, so the runtime test doesn't add additional
coverage.  Assembler and linker tests should be on the binutils side.

When LLD 13.0.0 is allowed in configure.ac
(https://sourceware.org/pipermail/libc-alpha/2021-August/129866.html),
`make check` result is on par with glibc built with GNU ld on aarch64
and x86_64.

As a future clean-up, TLS_GD/TLS_LD/TLS_IE/TLS_IE macros can be removed from
sysdeps/*/tls-macros.h. We can add optional -mtls-dialect={gnu2,trad}
tests to ensure coverage.

Tested on aarch64-linux-gnu, powerpc64le-linux-gnu, and x86_64-linux-gnu.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
(cherry picked from commit 33c50ef42878b07ee6ead8b3f1a81d8c2c74697c)
2023-01-10 19:09:21 +01:00
Adhemerval Zanella
42eb735a5d Use LFS and 64 bit time for installed programs (BZ #15333)
The installed programs are built with a combination of different
values for MODULE_NAME, as below.  To enable both Long File Support
and 64 bt time, -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64 is added for
nonlibi, nscd, lddlibc4, libresolv, ldconfig, locale_programs,
iconvprogs, libnss_files, libnss_compat, libnss_db, libnss_hesiod,
libutil, libpcprofile, and libSegFault.

  nscd/nscd
    nscd/nscd.o                           MODULE_NAME=nscd
    nscd/connections.o                    MODULE_NAME=nscd
    nscd/pwdcache.o                       MODULE_NAME=nscd
    nscd/getpwnam_r.o                     MODULE_NAME=nscd
    nscd/getpwuid_r.o                     MODULE_NAME=nscd
    nscd/grpcache.o                       MODULE_NAME=nscd
    nscd/getgrnam_r.o                     MODULE_NAME=nscd
    nscd/getgrgid_r.o                     MODULE_NAME=nscd
    nscd/hstcache.o                       MODULE_NAME=nscd
    nscd/gethstbyad_r.o                   MODULE_NAME=nscd
    nscd/gethstbynm3_r.o                  MODULE_NAME=nscd
    nscd/getsrvbynm_r.o                   MODULE_NAME=nscd
    nscd/getsrvbypt_r.o                   MODULE_NAME=nscd
    nscd/servicescache.o                  MODULE_NAME=nscd
    nscd/dbg_log.o                        MODULE_NAME=nscd
    nscd/nscd_conf.o                      MODULE_NAME=nscd
    nscd/nscd_stat.o                      MODULE_NAME=nscd
    nscd/cache.o                          MODULE_NAME=nscd
    nscd/mem.o                            MODULE_NAME=nscd
    nscd/nscd_setup_thread.o              MODULE_NAME=nscd
    nscd/xmalloc.o                        MODULE_NAME=nscd
    nscd/xstrdup.o                        MODULE_NAME=nscd
    nscd/aicache.o                        MODULE_NAME=nscd
    nscd/initgrcache.o                    MODULE_NAME=nscd
    nscd/gai.o                            MODULE_NAME=nscd
    nscd/res_hconf.o                      MODULE_NAME=nscd
    nscd/netgroupcache.o                  MODULE_NAME=nscd
    nscd/cachedumper.o                    MODULE_NAME=nscd
  elf/lddlibc4
    elf/lddlibc4                          MODULE_NAME=lddlibc4
  elf/pldd
    elf/pldd.o                            MODULE_NAME=nonlib
    elf/xmalloc.o                         MODULE_NAME=nonlib
  elf/sln
    elf/sln.o                             MODULE_NAME=nonlib
    elf/static-stubs.o                    MODULE_NAME=nonlib
  elf/sprof                               MODULE_NAME=nonlib
  elf/ldconfig
    elf/ldconfig.o                        MODULE_NAME=ldconfig
    elf/cache.o                           MODULE_NAME=nonlib
    elf/readlib.o                         MODULE_NAME=nonlib
    elf/xmalloc.o                         MODULE_NAME=nonlib
    elf/xstrdup.o                         MODULE_NAME=nonlib
    elf/chroot_canon.o                    MODULE_NAME=nonlib
    elf/static-stubs.o                    MODULE_NAME=nonlib
    elf/stringtable.o                     MODULE_NAME=nonlib
  io/pwd
    io/pwd.o                              MODULE_NAME=nonlib
  locale/locale
    locale/locale.o                       MODULE_NAME=locale_programs
    locale/locale-spec.o                  MODULE_NAME=locale_programs
    locale/charmap-dir.o                  MODULE_NAME=locale_programs
    locale/simple-hash.o                  MODULE_NAME=locale_programs
    locale/xmalloc.o                      MODULE_NAME=locale_programs
    locale/xstrdup.o                      MODULE_NAME=locale_programs
    locale/record-status.o                MODULE_NAME=locale_programs
    locale/xasprintf.o                    MODULE_NAME=locale_programs
  locale/localedef
    locale/localedef.o                    MODULE_NAME=locale_programs
    locale/ld-ctype.o                     MODULE_NAME=locale_programs
    locale/ld-messages.o                  MODULE_NAME=locale_programs
    locale/ld-monetary.o                  MODULE_NAME=locale_programs
    locale/ld-numeric.o                   MODULE_NAME=locale_programs
    locale/ld-time.o                      MODULE_NAME=locale_programs
    locale/ld-paper.o                     MODULE_NAME=locale_programs
    locale/ld-name.o                      MODULE_NAME=locale_programs
    locale/ld-address.o                   MODULE_NAME=locale_programs
    locale/ld-telephone.o                 MODULE_NAME=locale_programs
    locale/ld-measurement.o               MODULE_NAME=locale_programs
    locale/ld-identification.o            MODULE_NAME=locale_programs
    locale/ld-collate.o                   MODULE_NAME=locale_programs
    locale/charmap.o                      MODULE_NAME=locale_programs
    locale/linereader.o                   MODULE_NAME=locale_programs
    locale/locfile.o                      MODULE_NAME=locale_programs
    locale/repertoire.o                   MODULE_NAME=locale_programs
    locale/locarchive.o                   MODULE_NAME=locale_programs
    locale/md5.o                          MODULE_NAME=locale_programs
    locale/charmap-dir.o                  MODULE_NAME=locale_programs
    locale/simple-hash.o                  MODULE_NAME=locale_programs
    locale/xmalloc.o                      MODULE_NAME=locale_programs
    locale/xstrdup.o                      MODULE_NAME=locale_programs
    locale/record-status.o                MODULE_NAME=locale_programs
    locale/xasprintf.o                    MODULE_NAME=locale_programs
  catgets/gencat
    catgets/gencat.o                      MODULE_NAME=nonlib
    catgets/xmalloc.o                     MODULE_NAME=nonlib
  nss/makedb
    nss/makedb.o                          MODULE_NAME=nonlib
    nss/xmalloc.o                         MODULE_NAME=nonlib
    nss/hash-string.o                     MODULE_NAME=nonlib
  nss/getent
    nss/getent.o                          MODULE_NAME=nonlib
  posix/getconf
    posix/getconf.o                       MODULE_NAME=nonlib
  login/utmpdump
    login/utmpdump.o                      MODULE_NAME=nonlib
  debug/pcprofiledump
    debug/pcprofiledump.o                 MODULE_NAME=nonlib
  timezone/zic
    timezone/zic.o                        MODULE_NAME=nonlib
  timezone/zdump
    timezone/zdump.o                      MODULE_NAME=nonlib
  iconv/iconv_prog
    iconv/iconv_prog.o                    MODULE_NAME=nonlib
    iconv/iconv_charmap.o                 MODULE_NAME=iconvprogs
    iconv/charmap.o                       MODULE_NAME=iconvprogs
    iconv/charmap-dir.o                   MODULE_NAME=iconvprogs
    iconv/linereader.o                    MODULE_NAME=iconvprogs
    iconv/dummy-repertoire.o              MODULE_NAME=iconvprogs
    iconv/simple-hash.o                   MODULE_NAME=iconvprogs
    iconv/xstrdup.o                       MODULE_NAME=iconvprogs
    iconv/xmalloc.o                       MODULE_NAME=iconvprogs
    iconv/record-status.o                 MODULE_NAME=iconvprogs
  iconv/iconvconfig
    iconv/iconvconfig.o                   MODULE_NAME=nonlib
    iconv/strtab.o                        MODULE_NAME=iconvprogs
    iconv/xmalloc.o                       MODULE_NAME=iconvprogs
    iconv/hash-string.o                   MODULE_NAME=iconvprogs
  nss/libnss_files.so                     MODULE_NAME=libnss_files
  nss/libnss_compat.so.2                  MODULE_NAME=libnss_compat
  nss/libnss_db.so                        MODULE_NAME=libnss_db
  hesiod/libnss_hesiod.so                 MODULE_NAME=libnss_hesiod
  login/libutil.so                        MODULE_NAME=libutil
  debug/libpcprofile.so                   MODULE_NAME=libpcprofile
  debug/libSegFault.so                    MODULE_NAME=libSegFault

Also, to avoid adding both LFS and 64 bit time support on internal
tests they are moved to a newer 'testsuite-internal' module.  It
should be similar to 'nonlib' regarding internal definition and
linking namespace.

This patch also enables LFS and 64 bit support of libsupport container
programs (echo-container, test-container, shell-container, and
true-container).

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

Reviewed-by: DJ Delorie <dj@redhat.com>
(cherry picked from commit a6d2f948b71adcb5ea395cb04833bc645eab45e6)
2022-12-28 17:23:25 -03:00
Adhemerval Zanella
405b8ae135 elf: Fix wrong fscanf usage on tst-pldd
The fix done b2cd93fce666fdc8c9a5c64af2741a8a6940ac99 does not really
work since macro strification does not expand the sizeof nor the
arithmetic operation.

Checked on x86_64-linux-gnu.

(cherry picked from commit c353689e49e72f3aafa1a9e68d4f7a4f33a79cbe)
2022-11-25 14:17:56 +01:00
DJ Delorie
42b9d7def8 Allow for unpriviledged nested containers
If the build itself is run in a container, we may not be able to
fully set up a nested container for test-container testing.
Notably is the mounting of /proc, since it's critical that it
be mounted from within the same PID namespace as its users, and
thus cannot be bind mounted from outside the container like other
mounts.

This patch defaults to using the parent's PID namespace instead of
creating a new one, as this is more likely to be allowed.

If the test needs an isolated PID namespace, it should add the "pidns"
command to its init script.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 2fe64148a81f0d78050c302f34a6853d21f7cae4)
2022-11-25 14:17:56 +01:00
Adhemerval Zanella
309c4708ac elf: Fix wrong fscanf usage on tst-pldd
To take in consideration the extra '\0'.

Checked on x86_64-linux-gnu.

(cherry picked from commit b2cd93fce666fdc8c9a5c64af2741a8a6940ac99)
2022-11-25 14:17:56 +01:00
Sergei Trofimovich
f42d871b22 Makerules: fix MAKEFLAGS assignment for upcoming make-4.4 [BZ# 29564]
make-4.4 will add long flags to MAKEFLAGS variable:

    * WARNING: Backward-incompatibility!
      Previously only simple (one-letter) options were added to the MAKEFLAGS
      variable that was visible while parsing makefiles.  Now, all options
      are available in MAKEFLAGS.

This causes locale builds to fail when long options are used:

    $ make --shuffle
    ...
    make  -C localedata install-locales
    make: invalid shuffle mode: '1662724426r'

The change fixes it by passing eash option via whitespace and dashes.
That way option is appended to both single-word form and whitespace
separated form.

While at it fixed --silent mode detection in $(MAKEFLAGS) by filtering
out --long-options. Otherwise options like --shuffle flag enable silent
mode unintentionally. $(silent-make) variable consolidates the checks.

Resolves: BZ# 29564

CC: Paul Smith <psmith@gnu.org>
CC: Siddhesh Poyarekar <siddhesh@gotplt.org>
Signed-off-by: Sergei Trofimovich <slyich@gmail.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
(cherry picked from commit 2d7ed98add14f75041499ac189696c9bd3d757fe)
2022-11-08 22:46:33 -05:00
Florian Weimer
9f55d2e7c4 elf: Do not completely clear reused namespace in dlmopen (bug 29600)
The data in the _ns_debug member must be preserved, otherwise
_dl_debug_initialize enters an infinite loop.  To be conservative,
only clear the libc_map member for now, to fix bug 29528.

Fixes commit d0e357ff45a75553dee3b17ed7d303bfa544f6fe
("elf: Call __libc_early_init for reused namespaces (bug 29528)"),
by reverting most of it.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 2c42257314536b94cc8d52edede86e94e98c1436)
(Conflict in elf/dl-open.c due to missing _r_debug namespace support.)
2022-10-14 12:43:57 +02:00
Javier Pello
2ff6775ad3 elf: Fix hwcaps string size overestimation
Commit dad90d528259b669342757c37dedefa8577e2636 added glibc-hwcaps
support for LD_LIBRARY_PATH and, for this, it adjusted the total
string size required in _dl_important_hwcaps. However, in doing so
it inadvertently altered the calculation of the size required for
the power set strings, as the computation of the power set string
size depended on the first value assigned to the total variable,
which is later shifted, resulting in overallocation of string
space. Fix this now by using a different variable to hold the
string size required for glibc-hwcaps.

Signed-off-by: Javier Pello <devel@otheo.eu>
(cherry picked from commit a23820f6052a740246fdc7dcd9c43ce8eed0c45a)
2022-09-15 15:44:14 +02:00
Florian Weimer
bc5cb538e5 elf: Run tst-audit-tlsdesc, tst-audit-tlsdesc-dlopen everywhere
The test is valid for all TLS models, but we want to make a reasonable
effort to test the GNU2 model specifically.  For example, aarch64
defaults to GNU2, but does not have -mtls-dialect=gnu2, and the test
was not run there.

Suggested-by: Martin Coufal <mcoufal@redhat.com>
(cherry picked from commit dd2315a866a4ac2b838ea1cb10c5ea1c35d51a2f)

Fixes early backport commit 536ddc5c02f1ee82483319863a893ccb381beece
("elf: Call __libc_early_init for reused namespaces (bug 29528)");
it had a wrong conflict resolution.
2022-09-13 20:47:59 +02:00
Florian Weimer
536ddc5c02 elf: Call __libc_early_init for reused namespaces (bug 29528)
libc_map is never reset to NULL, neither during dlclose nor on a
dlopen call which reuses the namespace structure.  As a result, if a
namespace is reused, its libc is not initialized properly.  The most
visible result is a crash in the <ctype.h> functions.

To prevent similar bugs on namespace reuse from surfacing,
unconditionally initialize the chosen namespace to zero using memset.

(cherry picked from commit d0e357ff45a75553dee3b17ed7d303bfa544f6fe)
2022-08-30 16:30:03 +02:00
Szabolcs Nagy
c73c79af7d rtld: Use generic argv adjustment in ld.so [BZ #23293]
When an executable is invoked as

  ./ld.so [ld.so-args] ./exe [exe-args]

then the argv is adujusted in ld.so before calling the entry point of
the executable so ld.so args are not visible to it.  On most targets
this requires moving argv, env and auxv on the stack to ensure correct
stack alignment at the entry point.  This had several issues:

- The code for this adjustment on the stack is written in asm as part
  of the target specific ld.so _start code which is hard to maintain.

- The adjustment is done after _dl_start returns, where it's too late
  to update GLRO(dl_auxv), as it is already readonly, so it points to
  memory that was clobbered by the adjustment. This is bug 23293.

- _environ is also wrong in ld.so after the adjustment, but it is
  likely not used after _dl_start returns so this is not user visible.

- _dl_argv was updated, but for this it was moved out of relro, which
  changes security properties across targets unnecessarily.

This patch introduces a generic _dl_start_args_adjust function that
handles the argument adjustments after ld.so processed its own args
and before relro protection is applied.

The same algorithm is used on all targets, _dl_skip_args is now 0, so
existing target specific adjustment code is no longer used.  The bug
affects aarch64, alpha, arc, arm, csky, ia64, nios2, s390-32 and sparc,
other targets don't need the change in principle, only for consistency.

The GNU Hurd start code relied on _dl_skip_args after dl_main returned,
now it checks directly if args were adjusted and fixes the Hurd startup
data accordingly.

Follow up patches can remove _dl_skip_args and DL_ARGV_NOT_RELRO.

Tested on aarch64-linux-gnu and cross tested on i686-gnu.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit ad43cac44a6860eaefcadadfb2acb349921e96bf)
2022-05-19 16:48:47 +01:00
Florian Weimer
ede8d94d15 csu: Implement and use _dl_early_allocate during static startup
This implements mmap fallback for a brk failure during TLS
allocation.

scripts/tls-elf-edit.py is updated to support the new patching method.
The script no longer requires that in the input object is of ET_DYN
type.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit f787e138aa0bf677bf74fa2a08595c446292f3d7)
2022-05-19 12:13:53 +02:00
Fangrui Song
be9240c84c elf: Remove __libc_init_secure
After 73fc4e28b9464f0e13edc719a5372839970e7ddb,
__libc_enable_secure_decided is always 0 and a statically linked
executable may overwrite __libc_enable_secure without considering
AT_SECURE.

The __libc_enable_secure has been correctly initialized in _dl_aux_init,
so just remove __libc_enable_secure_decided and __libc_init_secure.
This allows us to remove some startup_get*id functions from
22b79ed7f413cd980a7af0cf258da5bf82b6d5e5.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit 3e9acce8c50883b6cd8a3fb653363d9fa21e1608)
2022-05-19 12:13:52 +02:00
Florian Weimer
ff900fad89 Linux: Consolidate auxiliary vector parsing (redo)
And optimize it slightly.

This is commit 8c8510ab2790039e58995ef3a22309582413d3ff revised.

In _dl_aux_init in elf/dl-support.c, use an explicit loop
and -fno-tree-loop-distribute-patterns to avoid memset.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
(cherry picked from commit 73fc4e28b9464f0e13edc719a5372839970e7ddb)
2022-05-19 12:13:51 +02:00
Florian Weimer
1cc4ddfeeb Revert "Linux: Consolidate auxiliary vector parsing"
This reverts commit 8c8510ab2790039e58995ef3a22309582413d3ff.  The
revert is not perfect because the commit included a bug fix for
_dl_sysdep_start with an empty argv, introduced in commit
2d47fa68628e831a692cba8fc9050cef435afc5e ("Linux: Remove
DL_FIND_ARG_COMPONENTS"), and this bug fix is kept.

The revert is necessary because the reverted commit introduced an
early memset call on aarch64, which leads to crash due to lack of TCB
initialization.

(cherry picked from commit d96d2995c1121d3310102afda2deb1f35761b5e6)
2022-05-19 11:49:06 +02:00
Florian Weimer
4b9cd5465d Linux: Consolidate auxiliary vector parsing
And optimize it slightly.

The large switch statement in _dl_sysdep_start can be replaced with
a large array.  This reduces source code and binary size.  On
i686-linux-gnu:

Before:

   text	   data	    bss	    dec	    hex	filename
   7791	     12	      0	   7803	   1e7b	elf/dl-sysdep.os

After:

   text	   data	    bss	    dec	    hex	filename
   7135	     12	      0	   7147	   1beb	elf/dl-sysdep.os

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit 8c8510ab2790039e58995ef3a22309582413d3ff)
2022-05-19 11:49:06 +02:00
Florian Weimer
b0bd6a1323 elf: Merge dl-sysdep.c into the Linux version
The generic version is the de-facto Linux implementation.  It
requires an auxiliary vector, so Hurd does not use it.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit 91c0a47ffb66e7cd802de870686465db3b3976a0)
2022-05-19 11:43:53 +02:00
Florian Weimer
1f83d40dfa elf: Remove unused NEED_DL_BASE_ADDR and _dl_base_addr
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit cd0c333d2ea82d0ae14719bdbef86d99615bdb00)
2022-05-18 22:53:02 +02:00
Florian Weimer
bc56ab1f4a dlfcn: Do not use rtld_active () to determine ld.so state (bug 29078)
When audit modules are loaded, ld.so initialization is not yet
complete, and rtld_active () returns false even though ld.so is
mostly working.  Instead, the static dlopen hook is used, but that
does not work at all because this is not a static dlopen situation.

Commit 466c1ea15f461edb8e3ffaf5d86d708876343bbf ("dlfcn: Rework
static dlopen hooks") moved the hook pointer into _rtld_global_ro,
which means that separate protection is not needed anymore and the
hook pointer can be checked directly.

The guard for disabling libio vtable hardening in _IO_vtable_check
should stay for now.

Fixes commit 8e1472d2c1e25e6eabc2059170731365f6d5b3d1 ("ld.so:
Examine GLRO to detect inactive loader [BZ #20204]").

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit 8dcb6d0af07fda3607b541857e4f3970a74ed55b)
2022-04-26 15:28:39 +02:00
Florian Weimer
f0c71b34f9 Default to --with-default-link=no (bug 25812)
This is necessary to place the libio vtables into the RELRO segment.
New tests elf/tst-relro-ldso and elf/tst-relro-libc are added to
verify that this is what actually happens.

The new tests fail on ia64 due to lack of (default) RELRO support
inbutils, so they are XFAILed there.

(cherry picked from commit 198abcbb94618730dae1b3f4393efaa49e0ec8c7)
2022-04-22 11:31:14 +02:00
Florian Weimer
3e0a91b79b scripts: Add glibcelf.py module
Hopefully, this will lead to tests that are easier to maintain.  The
current approach of parsing readelf -W output using regular expressions
is not necessarily easier than parsing the ELF data directly.

This module is still somewhat incomplete (e.g., coverage of relocation
types and versioning information is missing), but it is sufficient to
perform basic symbol analysis or program header analysis.

The EM_* mapping for architecture-specific constant classes (e.g.,
SttX86_64) is not yet implemented.  The classes are defined for the
benefit of elf/tst-glibcelf.py.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
(cherry picked from commit 30035d67728a846fa39749cd162afd278ac654c4)
2022-04-22 11:28:57 +02:00
Stefan Liebler
0c03cb54c8 S390: Add new s390 platform z16.
The new IBM z16 is added to platform string array.
The macro _DL_PLATFORMS_COUNT is incremented.

_dl_hwcaps_subdir is extended by "z16" if HWCAP_S390_VXRS_PDE2
is set. HWCAP_S390_NNPA is not tested in _dl_hwcaps_subdirs_active
as those instructions may be replaced or removed in future.

tst-glibc-hwcaps.c is extended in order to test z16 via new marker5.

A fatal glibc error is dumped if glibc was build with architecture
level set for z16, but run on an older machine. (See dl-hwcap-check.h)

(cherry picked from commit 2376944b9e5c0364b9fb473e4d8dabca31b57167)
2022-04-14 14:21:57 +02:00
Adhemerval Zanella
4dca2d3a7b hppa: Fix bind-now audit (BZ #28857)
On hppa, a function pointer returned by la_symbind is actually a function
descriptor has the plabel bit set (bit 30).  This must be cleared to get
the actual address of the descriptor.  If the descriptor has been bound,
the first word of the descriptor is the physical address of theA function,
otherwise, the first word of the descriptor points to a trampoline in the
PLT.

This patch also adds a workaround on tests because on hppa (and it seems
to be the only ABI I have see it), some shared library adds a dynamic PLT
relocation to am empty symbol name:

$ readelf -r elf/tst-audit25mod1.so
[...]
Relocation section '.rela.plt' at offset 0x464 contains 6 entries:
 Offset     Info    Type            Sym.Value  Sym. Name + Addend
00002008  00000081 R_PARISC_IPLT                508
[...]

It breaks some assumptions on the test, where a symbol with an empty
name ("") is passed on la_symbind.

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

(cherry picked from commit 9e94f57484a2aba0fe67ea2059b5843f651887c2)
2022-04-12 13:33:17 -04:00
H.J. Lu
aabdad371f elf: Replace tst-audit24bmod2.so with tst-audit24bmod2
Replace tst-audit24bmod2.so with tst-audit24bmod2 to silence:

make[2]: Entering directory '/export/gnu/import/git/gitlab/x86-glibc/elf'
Makefile:2201: warning: overriding recipe for target '/export/build/gnu/tools-build/glibc-gitlab/build-x86_64-linux/elf/tst-audit24bmod2.so'
../Makerules:765: warning: ignoring old recipe for target '/export/build/gnu/tools-build/glibc-gitlab/build-x86_64-linux/elf/tst-audit24bmod2.so'

(cherry picked from commit fa7ad1df1915c8a62f50e3a5b7e10f9c7118cd7f)
2022-04-12 13:33:17 -04:00
Szabolcs Nagy
165e7ad459 Fix elf/tst-audit25a with default bind now toolchains
This test relies on lazy binding for the executable so request that
explicitly in case the toolchain defaults to bind now.

(cherry picked from commit 80a08d0faa9b224019f895800c4d97de4e23e1aa)
2022-04-12 13:33:17 -04:00
Ben Woodard
b118bce87a 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>
(cherry picked from commit ce9a68c57c260c8417afc93972849ac9ad243ec4)

Resolved conflicts:
	NEWS
	elf/rtld.c
2022-04-12 13:33:10 -04:00
Adhemerval Zanella
056fc1c0e3 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>
(cherry picked from commit 32612615c58b394c3eb09f020f31310797ad3854)

Resolved conflicts:
	NEWS - Manual merge.
2022-04-12 13:32:59 -04:00
Adhemerval Zanella
efb21b5fb2 elf: Fix initial-exec TLS access on audit modules (BZ #28096)
For audit modules and dependencies with initial-exec TLS, we can not
set the initial TLS image on default loader initialization because it
would already be set by the audit setup.  However, subsequent thread
creation would need to follow the default behaviour.

This patch fixes it by setting l_auditing link_map field not only
for the audit modules, but also for all its dependencies.  This is
used on _dl_allocate_tls_init to avoid the static TLS initialization
at load time.

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

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 254d3d5aef2fd8430c469e1938209ac100ebf132)
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
98047ba95c elf: Add la_activity during application exit
la_activity is not called during application exit, even though
la_objclose is.

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

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 5fa11a2bc94c912c3b25860065086902674537ba)
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
2255621f0e elf: Do not fail for failed dlmopen on audit modules (BZ #28061)
The dl_main sets the LM_ID_BASE to RT_ADD just before starting to
add load new shared objects.  The state is set to RT_CONSISTENT just
after all objects are loaded.

However if a audit modules tries to dlmopen an inexistent module,
the _dl_open will assert that the namespace is in an inconsistent
state.

This is different than dlopen, since first it will not use
LM_ID_BASE and second _dl_map_object_from_fd is the sole responsible
to set and reset the r_state value.

So the assert on _dl_open can not really be seen if the state is
consistent, since _dt_main resets it.  This patch removes the assert.

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

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit 484e672ddabe0a919a692520e6ac8f2580866235)

Resolved conflicts:
	elf/Makefile
	elf/dl-open.c
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
d1b9bee29a elf: Issue audit la_objopen for vDSO
The vDSO is is listed in the link_map chain, but is never the subject of
an la_objopen call.  A new internal flag __RTLD_VDSO is added that
acts as __RTLD_OPENEXEC to allocate the required 'struct auditstate'
extra space for the 'struct link_map'.

The return value from the callback is currently ignored, since there
is no PLT call involved by glibc when using the vDSO, neither the vDSO
are exported directly.

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

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit f0e23d34a7bdf6b90fba954ee741419171ac41b2)

Resolved conflicts:
	elf/Makefile
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
02c6a3d353 elf: Add audit tests for modules with TLSDESC
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit d1b38173c9255b1a4ae00018ad9b35404a7c74d0)
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
29496b3103 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>
(cherry picked from commit 063f9ba220f434c7f30dd65c4cff17c0c458a7cf)

Resolved conflicts:
	NEWS
	elf/Makefile
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
a8e211daea elf: Add _dl_audit_pltexit
It consolidates the code required to call la_pltexit audit
callback.

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

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit 8c0664e2b861fd3789602cc0b0b1922b0e20cb3a)

Resolved conflicts:
	sysdeps/hppa/dl-runtime.c
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
fd9c4e8a1b elf: Add _dl_audit_pltenter
It consolidates the code required to call la_pltenter audit
callback.

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

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit eff687e8462b0eaf65992a6031b54a4b1cd16796)
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
31473c273b elf: Add _dl_audit_preinit
It consolidates the code required to call la_preinit audit
callback.

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

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit 0b98a8748759e88b58927882a8714109abe0a2d6)
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
b2d99731b6 elf: Add _dl_audit_symbind_alt and _dl_audit_symbind
It consolidates the code required to call la_symbind{32,64} audit
callback.

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

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit cda4f265c65fb6c4ce38ca1cf0a7e527c5e77cd5)
2022-04-08 14:18:12 -04:00
Adhemerval Zanella
198660741b elf: Add _dl_audit_objclose
It consolidates the code required to call la_objclose audit
callback.

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

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit 311c9ee54ea963ff69bd3a2e6981c37e893b4c3e)
2022-04-08 14:18:11 -04:00
Adhemerval Zanella
ec0fc2a153 elf: Add _dl_audit_objsearch
It consolidates the code required to call la_objsearch audit
callback.

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

Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit c91008d3490e4e3ce29520068405f081f0d368ca)
2022-04-08 14:18:11 -04:00