Commit Graph

2696 Commits

Author SHA1 Message Date
H.J. Lu
4435c29892 Support target specific ALIGN for variable alignment test [BZ #28676]
Add <tst-file-align.h> to support target specific ALIGN for variable
alignment test:

1. Alpha: Use 0x10000.
2. MicroBlaze and Nios II: Use 0x8000.
3. All others: Use 0x200000.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-12-14 14:50:33 -08:00
H.J. Lu
fd6062ede3 elf: Align argument of __munmap to page size [BZ #28676]
On Linux/x86-64, for elf/tst-align3, we now get

munmap(0x7f88f9401000, 1126424)         = 0

instead of

munmap(0x7f1615200018, 544768)          = -1 EINVAL (Invalid argument)

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-12-14 07:16:51 -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
Florian Weimer
f1eeef945d elf: Use errcode instead of (unset) errno in rtld_chain_load 2021-12-10 21:34:30 +01:00
H.J. Lu
fc2334ab32 Add a testcase to check alignment of PT_LOAD segment [BZ #28676] 2021-12-10 11:26:08 -08:00
Rongwei Wang
718fdd87b1 elf: Properly align PT_LOAD segments [BZ #28676]
When PT_LOAD segment alignment > the page size, allocate enough space to
ensure that the segment can be properly aligned.  This change helps code
segments use huge pages become simple and available.

This fixes [BZ #28676].

Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
2021-12-10 11:25:37 -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
627f5ede70 Remove TLS_TCB_ALIGN and TLS_INIT_TCB_ALIGN
TLS_INIT_TCB_ALIGN is not actually used.  TLS_TCB_ALIGN was likely
introduced to support a configuration where the thread pointer
has not the same alignment as THREAD_SELF.  Only ia64 seems to use
that, but for the stack/pointer guard, not for storing tcbhead_t.
Some ports use TLS_TCB_OFFSET and TLS_PRE_TCB_SIZE to shift
the thread pointer, potentially landing in a different residue class
modulo the alignment, but the changes should not impact that.

In general, given that TLS variables have their own alignment
requirements, having different alignment for the (unshifted) thread
pointer and struct pthread would potentially result in dynamic
offsets, leading to more complexity.

hppa had different values before: __alignof__ (tcbhead_t), which
seems to be 4, and __alignof__ (struct pthread), which was 8
(old default) and is now 32.  However, it defines THREAD_SELF as:

/* Return the thread descriptor for the current thread.  */
# define THREAD_SELF \
  ({ struct pthread *__self;			\
	__self = __get_cr27();			\
	__self - 1;				\
   })

So the thread pointer points after struct pthread (hence __self - 1),
and they have to have the same alignment on hppa as well.

Similarly, on ia64, the definitions were different.  We have:

# define TLS_PRE_TCB_SIZE \
  (sizeof (struct pthread)						\
   + (PTHREAD_STRUCT_END_PADDING < 2 * sizeof (uintptr_t)		\
      ? ((2 * sizeof (uintptr_t) + __alignof__ (struct pthread) - 1)	\
	 & ~(__alignof__ (struct pthread) - 1))				\
      : 0))
# define THREAD_SELF \
  ((struct pthread *) ((char *) __thread_self - TLS_PRE_TCB_SIZE))

And TLS_PRE_TCB_SIZE is a multiple of the struct pthread alignment
(confirmed by the new _Static_assert in sysdeps/ia64/libc-tls.c).

On m68k, we have a larger gap between tcbhead_t and struct pthread.
But as far as I can tell, the port is fine with that.  The definition
of TCB_OFFSET is sufficient to handle the shifted TCB scenario.

This fixes commit 23c77f6018
("nptl: Increase default TCB alignment to 32").

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-12-09 23:47:49 +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
Luca Boccassi
0656b649c5 elf: add definition for ELF_NOTE_FDO and NT_FDO_PACKAGING_METADATA note
As defined on: https://systemd.io/COREDUMP_PACKAGE_METADATA/
this note will be used starting from Fedora 36.

Signed-off-by: Luca Boccassi <bluca@debian.org>
2021-12-02 23:01:51 +01:00
Florian Weimer
df4cb2280e elf: Include <stdbool.h> in tst-tls20.c
The test uses the bool type.
2021-11-30 15:39:17 +01:00
Florian Weimer
3c7c511782 elf: Include <stdint.h> in tst-tls20.c
The test uses standard integer types.
2021-11-30 14:35:54 +01:00
Adhemerval Zanella
ed3ce71f5c elf: Move la_activity (LA_ACT_ADD) after _dl_add_to_namespace_list() (BZ #28062)
It ensures that the the namespace is guaranteed to not be empty.

Checked on x86_64-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-11-18 17:17:58 -03:00
Florian Weimer
f1d333b5bf elf: Introduce GLRO (dl_libc_freeres), called from __libc_freeres
This will be used to deallocate memory allocated using the non-minimal
malloc.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-17 12:20:29 +01:00
Adhemerval Zanella
d8c2e8e043 elf: hidden visibility for __minimal_malloc functions
Since b05fae4d8e, __minimal malloc code is used during static
startup before PIE self-relocation (_dl_relocate_static_pie).
So it requires the same fix done for other objects by 47618209d0.

Checked on aarch64, x86_64, and i686 with and without static-pie.
2021-11-16 16:03:31 -03:00
H.J. Lu
1f67d8286b elf: Use a temporary file to generate Makefile fragments [BZ #28550]
1. Use a temporary file to generate Makefile fragments for DSO sorting
tests and use -include on them.
2. Add Makefile fragments to postclean-generated so that a "make clean"
removes the autogenerated fragments and a subsequent "make" regenerates
them.

This partially fixes BZ #28550.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-16 05:18:01 -08:00
Adhemerval Zanella
54816ae98d elf: Move LAV_CURRENT to link_lavcurrent.h
No functional change.
2021-11-15 15:28:17 -03:00
Adhemerval Zanella
824dd3ec49 Fix build a chec failures after b05fae4d8e
The include cleanup on dl-minimal.c removed too much for some
targets.

Also for Hurd, __sbrk is removed from localplt.data now that
tunables allocated memory through mmap.

Checked with a build for all affected architectures.
2021-11-09 23:21:22 -03:00
Adhemerval Zanella
b05fae4d8e elf: Use the minimal malloc on tunables_strdup
The rtld_malloc functions are moved to its own file so it can be
used on csu code.  Also, the functiosn are renamed to __minimal_*
(since there are now used not only on loader code).

Using the __minimal_malloc on tunables_strdup() avoids potential
issues with sbrk() calls while processing the tunables (I see
sporadic elf/tst-dso-ordering9 on powerpc64le with different
tests failing due ASLR).

Also, using __minimal_malloc over plain mmap optimizes the memory
allocation on both static and dynamic case (since it will any unused
space in either the last page of data segments, avoiding mmap() call,
or from the previous mmap() call).

Checked on x86_64-linux-gnu, i686-linux-gnu, and powerpc64le-linux-gnu.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2021-11-09 14:11:25 -03:00
Florian Weimer
ea32ec354c elf: Earlier missing dynamic segment check in _dl_map_object_from_fd
Separated debuginfo files have PT_DYNAMIC with p_filesz == 0.  We
need to check for that before the _dl_map_segments call because
that could attempt to write to mappings that extend beyond the end
of the file, resulting in SIGBUS.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-11-05 19:34:16 +01:00
Adhemerval Zanella
d3bf2f5927 elf: Do not run DSO sorting if tunables is not enabled
Since the argorithm selection requires tunables.

Checked on x86_64-linux-gnu with --enable-tunables=no.
2021-11-03 09:25:06 -03:00
Adhemerval Zanella
f64f4ce069 elf: Assume disjointed .rela.dyn and .rela.plt for loader
The patch removes the the ELF_DURING_STARTUP optimization and assume
both .rel.dyn and .rel.plt might not be subsequent.  This allows some
code simplification since relocation will be handled independently
where it is done on bootstrap.

At least on x86_64_64, I can not measure any performance implications.
Running 10000 time the command

  LD_DEBUG=statistics ./elf/ld.so ./libc.so

And filtering the "total startup time in dynamic loader" result,
the geometric mean is:

                  patched       master
  Ryzen 7 5900x     24140        24952
  i7-4510U          45957        45982

(The results do show some variation, I did not make any statistical
analysis).

It also allows build arm with lld, since it inserts ".ARM.exidx"
between ".rel.dyn" and ".rel.plt" for the loader.

Checked on x86_64-linux-gnu and arm-linux-gnueabihf.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-11-02 11:21:57 -03:00
Adhemerval Zanella
66a273d16a elf: Disable ifuncmain{1,5,5pic,5pie} when using LLD
These tests takes the address of a protected symbol (foo_protected)
and lld does not support copy relocations on protected data symbols.

Checked on x86_64-linux-gnu.

Reviewed-by: Fangrui Song <maskray@google.com>
2021-10-29 09:21:37 -03:00
H.J. Lu
f9b152c83f elf: Make global.out depend on reldepmod4.so [BZ #28457]
The global test is linked with globalmod1.so which dlopens reldepmod4.so.
Make global.out depend on reldepmod4.so.  This fixes BZ #28457.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-10-25 07:13:54 -07:00
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
Chung-Lin Tang
e6fd79f379 elf: Testing infrastructure for ld.so DSO sorting (BZ #17645)
This is the first of a 2-part patch set that fixes slow DSO sorting behavior in
the dynamic loader, as reported in BZ #17645. In order to facilitate such a
large modification to the dynamic loader, this first patch implements a testing
framework for validating shared object sorting behavior, to enable comparison
between old/new sorting algorithms, and any later enhancements.

This testing infrastructure consists of a Python script
scripts/dso-ordering-test.py' which takes in a description language, consisting
of strings that describe a set of link dependency relations between DSOs, and
generates testcase programs and Makefile fragments to automatically test the
described situation, for example:

  a->b->c->d          # four objects linked one after another

  a->[bc]->d;b->c     # a depends on b and c, which both depend on d,
                      # b depends on c (b,c linked to object a in fixed order)

  a->b->c;{+a;%a;-a}  # a, b, c serially dependent, main program uses
                      # dlopen/dlsym/dlclose on object a

  a->b->c;{}!->[abc]  # a, b, c serially dependent; multiple tests generated
                      # to test all permutations of a, b, c ordering linked
                      # to main program

 (Above is just a short description of what the script can do, more
  documentation is in the script comments.)

Two files containing several new tests, elf/dso-sort-tests-[12].def are added,
including test scenarios for BZ #15311 and Redhat issue #1162810 [1].

Due to the nature of dynamic loader tests, where the sorting behavior and test
output occurs before/after main(), generating testcases to use
support/test-driver.c does not suffice to control meaningful timeout for ld.so.
Therefore a new utility program 'support/test-run-command', based on
test-driver.c/support_test_main.c has been added. This does the same testcase
control, but for a program specified through a command-line rather than at the
source code level. This utility is used to run the dynamic loader testcases
generated by dso-ordering-test.py.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1162810

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
Joseph Myers
2c6cabb3a4 Correct access attribute on memfrob (bug 28475)
As noted in bug 28475, the access attribute on memfrob in <string.h>
is incorrect: the function both reads and writes the memory pointed to
by its argument, so it needs to use __read_write__, not
__write_only__.  This incorrect attribute results in a build failure
for accessing uninitialized memory for s390x-linux-gnu-O3 with
build-many-glibcs.py using GCC mainline.

Correct the attribute.  Fixing this shows up that some calls to
memfrob in elf/ tests are reading uninitialized memory; I'm not
entirely sure of the purpose of those calls, but guess they are about
ensuring that the stack space is indeed allocated at that point in the
function, and so it matters that they are calling a function whose
semantics are unknown to the compiler.  Thus, change the first memfrob
call in those tests to use explicit_bzero instead, as suggested by
Florian in
<https://sourceware.org/pipermail/libc-alpha/2021-October/132119.html>,
to avoid the use of uninitialized memory.

Tested for x86_64, and with build-many-glibcs.py (GCC mainline) for
s390x-linux-gnu-O3.
2021-10-20 13:38:50 +00:00
H.J. Lu
2ec99d8c42 ld.so: Initialize bootstrap_map.l_ld_readonly [BZ #28340]
1. Define DL_RO_DYN_SECTION to initalize bootstrap_map.l_ld_readonly
before calling elf_get_dynamic_info to get dynamic info in bootstrap_map,
2. Define a single

static inline bool
dl_relocate_ld (const struct link_map *l)
{
  /* Don't relocate dynamic section if it is readonly  */
  return !(l->l_ld_readonly || DL_RO_DYN_SECTION);
}

This updates BZ #28340 fix.
2021-10-19 06:40:38 -07:00
Adhemerval Zanella
5118dcac68 elf: Fix elf_get_dynamic_info() for bootstrap
THe d6d89608ac broke powerpc for --enable-bind-now because it turned
out that different than patch assumption rtld elf_get_dynamic_info()
does require to handle RTLD_BOOTSTRAP to avoid DT_FLAGS and
DT_RUNPATH (more specially the GLRO usage which is not reallocate
yet).

This patch fixes by passing two arguments to elf_get_dynamic_info()
to inform that by rtld (bootstrap) or static pie initialization
(static_pie_bootstrap).  I think using explicit argument is way more
clear and burried C preprocessor, and compiler should remove the
dead code.

I checked on x86_64 and i686 with default options, --enable-bind-now,
and --enable-bind-now and --enable--static-pie.  I also check on
aarch64, armhf, powerpc64, and powerpc with default and
--enable-bind-now.
2021-10-18 09:51:56 -03:00
Adhemerval Zanella
d6d89608ac elf: Fix dynamic-link.h usage on rtld.c
The 4af6982e4c fix does not fully handle RTLD_BOOTSTRAP usage on
rtld.c due two issues:

  1. RTLD_BOOTSTRAP is also used on dl-machine.h on various
     architectures and it changes the semantics of various machine
     relocation functions.

  2. The elf_get_dynamic_info() change was done sideways, previously
     to 490e6c62aa get-dynamic-info.h was included by the first
     dynamic-link.h include *without* RTLD_BOOTSTRAP being defined.
     It means that the code within elf_get_dynamic_info() that uses
     RTLD_BOOTSTRAP is in fact unused.

To fix 1. this patch now includes dynamic-link.h only once with
RTLD_BOOTSTRAP defined.  The ELF_DYNAMIC_RELOCATE call will now have
the relocation fnctions with the expected semantics for the loader.

And to fix 2. part of 4af6982e4c is reverted (the check argument
elf_get_dynamic_info() is not required) and the RTLD_BOOTSTRAP
pieces are removed.

To reorganize the includes the static TLS definition is moved to
its own header to avoid a circular dependency (it is defined on
dynamic-link.h and dl-machine.h requires it at same time other
dynamic-link.h definition requires dl-machine.h defitions).

Also ELF_MACHINE_NO_REL, ELF_MACHINE_NO_RELA, and ELF_MACHINE_PLT_REL
are moved to its own header.  Only ancient ABIs need special values
(arm, i386, and mips), so a generic one is used as default.

The powerpc Elf64_FuncDesc is also moved to its own header, since
csu code required its definition (which would require either include
elf/ folder or add a full path with elf/).

Checked on x86_64, i686, aarch64, armhf, powerpc64, powerpc32,
and powerpc64le.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-10-14 14:52:07 -03:00
Stafford Horne
171ab1af56 elf: Update audit tests to not depend on stdout
The tst-audit14, tst-audit15 and tst-audit16 tests all have audit
modules that write to stdout; the test reads from stdout to confirm
what was written.  This assumes the stdout is a file which is not the
case when run over ssh.

This patch updates the tests to use a post run cmp command to compare
the output against and .exp file.  This is similar to how many other
tests work and it fixes the stdout limitation.  Also, this means the
test code can be greatly simplified.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-10-12 13:25:43 -03:00
Adhemerval Zanella
4af6982e4c elf: Fix elf_get_dynamic_info definition
Before to 490e6c62aa ('elf: Avoid nested functions in the loader
[BZ #27220]'), elf_get_dynamic_info() was defined twice on rtld.c: on
the first dynamic-link.h include and later within _dl_start().  The
former definition did not define DONT_USE_BOOTSTRAP_MAP and it is used
on setup_vdso() (since it is a global definition), while the former does
define DONT_USE_BOOTSTRAP_MAP and it is used on loader self-relocation.

With the commit change, the function is now included and defined once
instead of defined as a nested function.  So rtld.c defines without
defining RTLD_BOOTSTRAP and it brokes at least powerpc32.

This patch fixes by moving the get-dynamic-info.h include out of
dynamic-link.h, which then the caller can corirectly set the expected
semantic by defining STATIC_PIE_BOOTSTRAP, RTLD_BOOTSTRAP, and/or
RESOLVE_MAP.

It also required to enable some asserts only for the loader bootstrap
to avoid issues when called from setup_vdso().

As a side note, this is another issues with nested functions: it is
not clear from pre-processed output (-E -dD) how the function will
be build and its semantic (since nested function will be local and
extra C defines may change it).

I checked on x86_64-linux-gnu (w/o --enable-static-pie),
i686-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu-power4,
aarch64-linux-gnu, arm-linux-gnu, sparc64-linux-gnu, and
s390x-linux-gnu.

Reviewed-by: Fangrui Song <maskray@google.com>
2021-10-12 13:25:43 -03:00
Fangrui Song
490e6c62aa elf: Avoid nested functions in the loader [BZ #27220]
dynamic-link.h is included more than once in some elf/ files (rtld.c,
dl-conflict.c, dl-reloc.c, dl-reloc-static-pie.c) and uses GCC nested
functions. This harms readability and the nested functions usage
is the biggest obstacle prevents Clang build (Clang doesn't support GCC
nested functions).

The key idea for unnesting is to add extra parameters (struct link_map
*and struct r_scope_elm *[]) to RESOLVE_MAP,
ELF_MACHINE_BEFORE_RTLD_RELOC, ELF_DYNAMIC_RELOCATE, elf_machine_rel[a],
elf_machine_lazy_rel, and elf_machine_runtime_setup. (This is inspired
by Stan Shebs' ppc64/x86-64 implementation in the
google/grte/v5-2.27/master which uses mixed extra parameters and static
variables.)

Future simplification:
* If mips elf_machine_runtime_setup no longer needs RESOLVE_GOTSYM,
  elf_machine_runtime_setup can drop the `scope` parameter.
* If TLSDESC no longer need to be in elf_machine_lazy_rel,
  elf_machine_lazy_rel can drop the `scope` parameter.

Tested on aarch64, i386, x86-64, powerpc64le, powerpc64, powerpc32,
sparc64, sparcv9, s390x, s390, hppa, ia64, armhf, alpha, and mips64.
In addition, tested build-many-glibcs.py with {arc,csky,microblaze,nios2}-linux-gnu
and riscv64-linux-gnu-rv64imafdc-lp64d.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-10-07 11:55:02 -07:00
H.J. Lu
349b0441da Add run-time check for indirect external access
When performing symbol lookup for references in executable without
indirect external access:

1. Disallow copy relocations in executable against protected data symbols
in a shared object with indirect external access.
2. Disallow non-zero symbol values of undefined function symbols in
executable, which are used as the function pointer, against protected
function symbols in a shared object with indirect external access.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-10-07 10:26:48 -07:00
H.J. Lu
1bd888d0b7 Initial support for GNU_PROPERTY_1_NEEDED
1. Add GNU_PROPERTY_1_NEEDED:

 #define GNU_PROPERTY_1_NEEDED      GNU_PROPERTY_UINT32_OR_LO

to indicate the needed properties by the object file.
2. Add GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS:

 #define GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS (1U << 0)

to indicate that the object file requires canonical function pointers and
cannot be used with copy relocation.
3. Scan GNU_PROPERTY_1_NEEDED property and store it in l_1_needed.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-10-07 10:26:08 -07:00
H.J. Lu
3234a31b48 ld.so: Don't fill the DT_DEBUG entry in ld.so [BZ #28129]
Linker creates the DT_DEBUG entry only in executables.  Don't fill the
non-existent DT_DEBUG entry in ld.so with the run-time address of the
r_debug structure.  This fixes BZ #28129.
2021-10-06 09:02:21 -07:00
Szabolcs Nagy
83b5323261 elf: Avoid deadlock between pthread_create and ctors [BZ #28357]
The fix for bug 19329 caused a regression such that pthread_create can
deadlock when concurrent ctors from dlopen are waiting for it to finish.
Use a new GL(dl_load_tls_lock) in pthread_create that is not taken
around ctors in dlopen.

The new lock is also used in __tls_get_addr instead of GL(dl_load_lock).

The new lock is held in _dl_open_worker and _dl_close_worker around
most of the logic before/after the init/fini routines.  When init/fini
routines are running then TLS is in a consistent, usable state.
In _dl_open_worker the new lock requires catching and reraising dlopen
failures that happen in the critical section.

The new lock is reinitialized in a fork child, to keep the existing
behaviour and it is kept recursive in case malloc interposition or TLS
access from signal handlers can retake it.  It is not obvious if this
is necessary or helps, but avoids changing the preexisting behaviour.

The new lock may be more appropriate for dl_iterate_phdr too than
GL(dl_load_write_lock), since TLS state of an incompletely loaded
module may be accessed.  If the new lock can replace the old one,
that can be a separate change.

Fixes bug 28357.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-10-04 15:07:05 +01:00
H.J. Lu
1e1ecea62e elf: Replace nsid with args.nsid [BZ #27609]
commit ec935dea63
Author: Florian Weimer <fweimer@redhat.com>
Date:   Fri Apr 24 22:31:15 2020 +0200

    elf: Implement __libc_early_init

has

@@ -856,6 +876,11 @@ no more namespaces available for dlmopen()"));
   /* See if an error occurred during loading.  */
   if (__glibc_unlikely (exception.errstring != NULL))
     {
+      /* Avoid keeping around a dangling reference to the libc.so link
+   map in case it has been cached in libc_map.  */
+      if (!args.libc_already_loaded)
+  GL(dl_ns)[nsid].libc_map = NULL;
+

do_dlopen calls _dl_open with nsid == __LM_ID_CALLER (-2), which calls
dl_open_worker with args.nsid = nsid.  dl_open_worker updates args.nsid
if it is __LM_ID_CALLER.  After dl_open_worker returns, it is wrong to
use nsid.

Replace nsid with args.nsid after dl_open_worker returns.  This fixes
BZ #27609.
2021-09-30 12:40:50 -07:00
H.J. Lu
88361b408b elf: Copy l_addr/l_ld when adding ld.so to a new namespace
When add ld.so to a new namespace, we don't actually load ld.so.  We
create a new link map and refers the real one for almost everything.
Copy l_addr and l_ld from the real ld.so link map to avoid GDB warning:

warning: .dynamic section for ".../elf/ld-linux-x86-64.so.2" is not at the expected address (wrong library or version mismatch?)

when handling shared library loaded by dlmopen.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-09-29 16:15:44 -07:00
H.J. Lu
15e6d6785a Avoid warning: overriding recipe for .../tst-ro-dynamic-mod.so
Add tst-ro-dynamic-mod to modules-names-nobuild to avoid

../Makerules:767: warning: ignoring old recipe for target '.../elf/tst-ro-dynamic-mod.so'

This updates BZ #28340 fix.
2021-09-25 09:06:54 -07:00
H.J. Lu
b413280cfb ld.so: Replace DL_RO_DYN_SECTION with dl_relocate_ld [BZ #28340]
We can't relocate entries in dynamic section if it is readonly:

1. Add a l_ld_readonly field to struct link_map to indicate if dynamic
section is readonly and set it based on p_flags of PT_DYNAMIC segment.
2. Replace DL_RO_DYN_SECTION with dl_relocate_ld to decide if dynamic
section should be relocated.
3. Remove DL_RO_DYN_TEMP_CNT.
4. Don't use a static dynamic section to make readonly dynamic section
in vDSO writable.
5. Remove the temp argument from elf_get_dynamic_info.

This fixes BZ #28340.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2021-09-22 11:12:43 -07:00
Florian Weimer
7e84ac3a3a elf: Include <sysdep.h> in elf/dl-debug-symbols.S
This is necessary to generate assembler marker sections on some
targets.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-09-20 15:50:02 +02:00
H.J. Lu
a93d9e03a3 Extend struct r_debug to support multiple namespaces [BZ #15971]
Glibc does not provide an interface for debugger to access libraries
loaded in multiple namespaces via dlmopen.

The current rtld-debugger interface is described in the file:

elf/rtld-debugger-interface.txt

under the "Standard debugger interface" heading.  This interface only
provides access to the first link-map (LM_ID_BASE).

1. Bump r_version to 2 when multiple namespaces are used.  This triggers
the GDB bug:

https://sourceware.org/bugzilla/show_bug.cgi?id=28236

2. Add struct r_debug_extended to extend struct r_debug into a linked-list,
where each element correlates to an unique namespace.
3. Initialize the r_debug_extended structure.  Bump r_version to 2 for
the new namespace and add the new namespace to the namespace linked list.
4. Add _dl_debug_update to return the address of struct r_debug' of a
namespace.
5. Add a hidden symbol, _r_debug_extended, for struct r_debug_extended.
6. Provide the symbol, _r_debug, with size of struct r_debug, as an alias
of _r_debug_extended, for programs which reference _r_debug.

This fixes BZ #15971.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-09-19 13:51:35 -07:00
Sergey Bugaev
c484da9087 elf: Remove THREAD_GSCOPE_IN_TCB
All the ports now have THREAD_GSCOPE_IN_TCB set to 1. Remove all
support for !THREAD_GSCOPE_IN_TCB, along with the definition itself.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20210915171110.226187-4-bugaevc@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
2021-09-16 01:04:20 +02:00
Sergey Bugaev
520a588705 elf: Replace most uses of THREAD_GSCOPE_IN_TCB
While originally this definition was indeed used to distinguish between
the cases where the GSCOPE flag was stored in TCB or not, it has since
become used as a general way to distinguish between HTL and NPTL.

THREAD_GSCOPE_IN_TCB will be removed in the following commits, as HTL,
which currently is the only port that does not put the flag into TCB,
will get ported to put the GSCOPE flag into the TCB as well. To prepare
for that change, migrate all code that wants to distinguish between HTL
and NPTL to use PTHREAD_IN_LIBC instead, which is a better choice since
the distinction mostly has to do with whether libc has access to the
list of thread structures and therefore can initialize thread-local
storage.

The parts of code that actually depend on whether the GSCOPE flag is in
TCB are left unchanged.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20210907133325.255690-2-bugaevc@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
2021-09-15 01:29:23 +02:00
Siddhesh Poyarekar
30891f35fa Remove "Contributed by" lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date.  Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.

Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions.  These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.

The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively.  These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:

https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc
https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-09-03 22:06:44 +05:30
Fangrui Song
9926f6e2ee elf: Skip tst-auditlogmod-* if the linker doesn't support --depaudit [BZ #28151]
gold and ld.lld do not support --audit or --depaudit.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-08-24 09:35:32 -07:00
Andreas Schwab
a4f5a3103f rtld: copy terminating null in tunables_strdup (bug 28256)
Avoid triggering a false positive from valgrind by copying the terminating
null in tunables_strdup.  At this point the heap is still clean, but
valgrind is stricter here.
2021-08-23 15:31:09 +02:00
Arjun Shankar
82fbcd7118 elf: Fix missing colon in LD_SHOW_AUXV output [BZ #28253]
This commit adds a missing colon in the AT_MINSIGSTKSZ entry in
the _dl_show_auxv function.
2021-08-20 16:29:43 +02:00
Fangrui Song
33c50ef428 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>
2021-08-16 09:59:30 -07:00