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elf: fix ld.so crash while loading a DSO with a read-only dynamic section

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liqingqing_1229 2021-11-15 15:38:31 +08:00
parent 8688e5e637
commit 35e1891d71
5 changed files with 1164 additions and 1 deletions
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34
Avoid-warning-overriding-recipe-for-.-tst-ro-dynamic.patch Normal file
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@ -0,0 +1,34 @@
From 15e6d6785ac2935bb963506b47a37b3d1f728952 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 24 Sep 2021 08:56:42 -0700
Subject: [PATCH] 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.
---
elf/Makefile | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/elf/Makefile b/elf/Makefile
index 0cdccaa..26986c0 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -402,8 +402,9 @@ endif
modules-execstack-yes = tst-execstack-mod
extra-test-objs += $(addsuffix .os,$(strip $(modules-names)))
-# filtmod1.so, tst-big-note-lib.so have special rules.
-modules-names-nobuild := filtmod1 tst-big-note-lib
+# filtmod1.so, tst-big-note-lib.so, tst-ro-dynamic-mod.so have special
+# rules.
+modules-names-nobuild := filtmod1 tst-big-note-lib tst-ro-dynamic-mod
tests += $(tests-static)
--
1.8.3.1

482
elf-Avoid-deadlock-between-pthread_create-and-ctors-.patch Normal file
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@ -0,0 +1,482 @@
From 83b5323261bb72313bffcf37476c1b8f0847c736 Mon Sep 17 00:00:00 2001
From: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date: Wed, 15 Sep 2021 15:16:19 +0100
Subject: [PATCH] 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>
---
elf/dl-close.c | 6 ++
elf/dl-open.c | 35 +++++++++++-
elf/dl-support.c | 7 +++
elf/dl-tls.c | 16 +++---
elf/rtld.c | 1 +
posix/fork.c | 3 +
sysdeps/generic/ldsodefs.h | 9 ++-
sysdeps/pthread/Makefile | 10 +++-
sysdeps/pthread/tst-create1.c | 119 +++++++++++++++++++++++++++++++++++++++
sysdeps/pthread/tst-create1mod.c | 41 ++++++++++++++
10 files changed, 235 insertions(+), 12 deletions(-)
create mode 100644 sysdeps/pthread/tst-create1.c
create mode 100644 sysdeps/pthread/tst-create1mod.c
diff --git a/elf/dl-close.c b/elf/dl-close.c
index 93ff5c9..cfe0f1c 100644
--- a/elf/dl-close.c
+++ b/elf/dl-close.c
@@ -549,6 +549,9 @@ _dl_close_worker (struct link_map *map, bool force)
size_t tls_free_end;
tls_free_start = tls_free_end = NO_TLS_OFFSET;
+ /* Protects global and module specitic TLS state. */
+ __rtld_lock_lock_recursive (GL(dl_load_tls_lock));
+
/* We modify the list of loaded objects. */
__rtld_lock_lock_recursive (GL(dl_load_write_lock));
@@ -784,6 +787,9 @@ _dl_close_worker (struct link_map *map, bool force)
GL(dl_tls_static_used) = tls_free_start;
}
+ /* TLS is cleaned up for the unloaded modules. */
+ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock));
+
#ifdef SHARED
/* Auditing checkpoint: we have deleted all objects. */
if (__glibc_unlikely (do_audit))
diff --git a/elf/dl-open.c b/elf/dl-open.c
index 5295e93..6ea5dd2 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -66,6 +66,9 @@ struct dl_open_args
libc_map value in the namespace in case of a dlopen failure. */
bool libc_already_loaded;
+ /* Set to true if the end of dl_open_worker_begin was reached. */
+ bool worker_continue;
+
/* Original parameters to the program and the current environment. */
int argc;
char **argv;
@@ -482,7 +485,7 @@ call_dl_init (void *closure)
}
static void
-dl_open_worker (void *a)
+dl_open_worker_begin (void *a)
{
struct dl_open_args *args = a;
const char *file = args->file;
@@ -774,6 +777,36 @@ dl_open_worker (void *a)
_dl_call_libc_early_init (libc_map, false);
}
+ args->worker_continue = true;
+}
+
+static void
+dl_open_worker (void *a)
+{
+ struct dl_open_args *args = a;
+
+ args->worker_continue = false;
+
+ {
+ /* Protects global and module specific TLS state. */
+ __rtld_lock_lock_recursive (GL(dl_load_tls_lock));
+
+ struct dl_exception ex;
+ int err = _dl_catch_exception (&ex, dl_open_worker_begin, args);
+
+ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock));
+
+ if (__glibc_unlikely (ex.errstring != NULL))
+ /* Reraise the error. */
+ _dl_signal_exception (err, &ex, NULL);
+ }
+
+ if (!args->worker_continue)
+ return;
+
+ int mode = args->mode;
+ struct link_map *new = args->map;
+
/* Run the initializer functions of new objects. Temporarily
disable the exception handler, so that lazy binding failures are
fatal. */
diff --git a/elf/dl-support.c b/elf/dl-support.c
index 02e2ed7..d99c1f1 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -228,6 +228,13 @@ __rtld_lock_define_initialized_recursive (, _dl_load_lock)
list of loaded objects while an object is added to or removed from
that list. */
__rtld_lock_define_initialized_recursive (, _dl_load_write_lock)
+ /* This lock protects global and module specific TLS related data.
+ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation),
+ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are
+ accessed and when TLS related relocations are processed for a
+ module. It was introduced to keep pthread_create accessing TLS
+ state that is being set up. */
+__rtld_lock_define_initialized_recursive (, _dl_load_tls_lock)
#ifdef HAVE_AUX_VECTOR
diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index d554ae4..9260d2d 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -532,7 +532,7 @@ _dl_allocate_tls_init (void *result)
size_t maxgen = 0;
/* Protects global dynamic TLS related state. */
- __rtld_lock_lock_recursive (GL(dl_load_lock));
+ __rtld_lock_lock_recursive (GL(dl_load_tls_lock));
/* Check if the current dtv is big enough. */
if (dtv[-1].counter < GL(dl_tls_max_dtv_idx))
@@ -606,7 +606,7 @@ _dl_allocate_tls_init (void *result)
listp = listp->next;
assert (listp != NULL);
}
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
+ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock));
/* The DTV version is up-to-date now. */
dtv[0].counter = maxgen;
@@ -745,7 +745,7 @@ _dl_update_slotinfo (unsigned long int req_modid)
Here the dtv needs to be updated to new_gen generation count.
- This code may be called during TLS access when GL(dl_load_lock)
+ This code may be called during TLS access when GL(dl_load_tls_lock)
is not held. In that case the user code has to synchronize with
dlopen and dlclose calls of relevant modules. A module m is
relevant if the generation of m <= new_gen and dlclose of m is
@@ -867,11 +867,11 @@ tls_get_addr_tail (GET_ADDR_ARGS, dtv_t *dtv, struct link_map *the_map)
if (__glibc_unlikely (the_map->l_tls_offset
!= FORCED_DYNAMIC_TLS_OFFSET))
{
- __rtld_lock_lock_recursive (GL(dl_load_lock));
+ __rtld_lock_lock_recursive (GL(dl_load_tls_lock));
if (__glibc_likely (the_map->l_tls_offset == NO_TLS_OFFSET))
{
the_map->l_tls_offset = FORCED_DYNAMIC_TLS_OFFSET;
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
+ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock));
}
else if (__glibc_likely (the_map->l_tls_offset
!= FORCED_DYNAMIC_TLS_OFFSET))
@@ -883,7 +883,7 @@ tls_get_addr_tail (GET_ADDR_ARGS, dtv_t *dtv, struct link_map *the_map)
#else
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
#endif
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
+ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock));
dtv[GET_ADDR_MODULE].pointer.to_free = NULL;
dtv[GET_ADDR_MODULE].pointer.val = p;
@@ -891,7 +891,7 @@ tls_get_addr_tail (GET_ADDR_ARGS, dtv_t *dtv, struct link_map *the_map)
return (char *) p + GET_ADDR_OFFSET;
}
else
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
+ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock));
}
struct dtv_pointer result = allocate_and_init (the_map);
dtv[GET_ADDR_MODULE].pointer = result;
@@ -962,7 +962,7 @@ _dl_tls_get_addr_soft (struct link_map *l)
return NULL;
dtv_t *dtv = THREAD_DTV ();
- /* This may be called without holding the GL(dl_load_lock). Reading
+ /* This may be called without holding the GL(dl_load_tls_lock). Reading
arbitrary gen value is fine since this is best effort code. */
size_t gen = atomic_load_relaxed (&GL(dl_tls_generation));
if (__glibc_unlikely (dtv[0].counter != gen))
diff --git a/elf/rtld.c b/elf/rtld.c
index 8d2bba3..9642eb9 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -322,6 +322,7 @@ struct rtld_global _rtld_global =
#ifdef _LIBC_REENTRANT
._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
+ ._dl_load_tls_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
#endif
._dl_nns = 1,
._dl_ns =
diff --git a/posix/fork.c b/posix/fork.c
index c471f7b..021691b 100644
--- a/posix/fork.c
+++ b/posix/fork.c
@@ -99,6 +99,9 @@ __libc_fork (void)
/* Reset the lock the dynamic loader uses to protect its data. */
__rtld_lock_initialize (GL(dl_load_lock));
+ /* Reset the lock protecting dynamic TLS related data. */
+ __rtld_lock_initialize (GL(dl_load_tls_lock));
+
reclaim_stacks ();
/* Run the handlers registered for the child. */
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index d49529d..9ec1511 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -369,6 +369,13 @@ struct rtld_global
list of loaded objects while an object is added to or removed
from that list. */
__rtld_lock_define_recursive (EXTERN, _dl_load_write_lock)
+ /* This lock protects global and module specific TLS related data.
+ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation),
+ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are
+ accessed and when TLS related relocations are processed for a
+ module. It was introduced to keep pthread_create accessing TLS
+ state that is being set up. */
+ __rtld_lock_define_recursive (EXTERN, _dl_load_tls_lock)
/* Incremented whenever something may have been added to dl_loaded. */
EXTERN unsigned long long _dl_load_adds;
@@ -1268,7 +1275,7 @@ extern int _dl_scope_free (void *) attribute_hidden;
/* Add module to slot information data. If DO_ADD is false, only the
required memory is allocated. Must be called with GL
- (dl_load_lock) acquired. If the function has already been called
+ (dl_load_tls_lock) acquired. If the function has already been called
for the link map L with !do_add, then this function will not raise
an exception, otherwise it is possible that it encounters a memory
allocation failure. */
diff --git a/sysdeps/pthread/Makefile b/sysdeps/pthread/Makefile
index 0af9c59..df8943f 100644
--- a/sysdeps/pthread/Makefile
+++ b/sysdeps/pthread/Makefile
@@ -152,15 +152,17 @@ tests += tst-cancelx2 tst-cancelx3 tst-cancelx6 tst-cancelx8 tst-cancelx9 \
tst-cleanupx0 tst-cleanupx1 tst-cleanupx2 tst-cleanupx3
ifeq ($(build-shared),yes)
-tests += tst-atfork2 tst-pt-tls4 tst-_res1 tst-fini1
+tests += tst-atfork2 tst-pt-tls4 tst-_res1 tst-fini1 tst-create1
tests-nolibpthread += tst-fini1
endif
modules-names += tst-atfork2mod tst-tls4moda tst-tls4modb \
- tst-_res1mod1 tst-_res1mod2 tst-fini1mod
+ tst-_res1mod1 tst-_res1mod2 tst-fini1mod \
+ tst-create1mod
test-modules = $(addprefix $(objpfx),$(addsuffix .so,$(modules-names)))
tst-atfork2mod.so-no-z-defs = yes
+tst-create1mod.so-no-z-defs = yes
ifeq ($(build-shared),yes)
# Build all the modules even when not actually running test programs.
@@ -279,4 +281,8 @@ LDFLAGS-tst-join7mod.so = -Wl,-soname,tst-join7mod.so
CFLAGS-tst-unwind-thread.c += -funwind-tables
+LDFLAGS-tst-create1 = -Wl,-export-dynamic
+$(objpfx)tst-create1: $(shared-thread-library)
+$(objpfx)tst-create1.out: $(objpfx)tst-create1mod.so
+
endif
diff --git a/sysdeps/pthread/tst-create1.c b/sysdeps/pthread/tst-create1.c
new file mode 100644
index 0000000..932586c
--- /dev/null
+++ b/sysdeps/pthread/tst-create1.c
@@ -0,0 +1,119 @@
+/* Verify that pthread_create does not deadlock when ctors take locks.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <stdio.h>
+#include <support/xdlfcn.h>
+#include <support/xthread.h>
+
+/*
+Check if ctor and pthread_create deadlocks in
+
+thread 1: dlopen -> ctor -> lock(user_lock)
+thread 2: lock(user_lock) -> pthread_create
+
+or in
+
+thread 1: dlclose -> dtor -> lock(user_lock)
+thread 2: lock(user_lock) -> pthread_create
+*/
+
+static pthread_barrier_t bar_ctor;
+static pthread_barrier_t bar_dtor;
+static pthread_mutex_t user_lock = PTHREAD_MUTEX_INITIALIZER;
+
+void
+ctor (void)
+{
+ xpthread_barrier_wait (&bar_ctor);
+ dprintf (1, "thread 1: in ctor: started.\n");
+ xpthread_mutex_lock (&user_lock);
+ dprintf (1, "thread 1: in ctor: locked user_lock.\n");
+ xpthread_mutex_unlock (&user_lock);
+ dprintf (1, "thread 1: in ctor: unlocked user_lock.\n");
+ dprintf (1, "thread 1: in ctor: done.\n");
+}
+
+void
+dtor (void)
+{
+ xpthread_barrier_wait (&bar_dtor);
+ dprintf (1, "thread 1: in dtor: started.\n");
+ xpthread_mutex_lock (&user_lock);
+ dprintf (1, "thread 1: in dtor: locked user_lock.\n");
+ xpthread_mutex_unlock (&user_lock);
+ dprintf (1, "thread 1: in dtor: unlocked user_lock.\n");
+ dprintf (1, "thread 1: in dtor: done.\n");
+}
+
+static void *
+thread3 (void *a)
+{
+ dprintf (1, "thread 3: started.\n");
+ dprintf (1, "thread 3: done.\n");
+ return 0;
+}
+
+static void *
+thread2 (void *a)
+{
+ pthread_t t3;
+ dprintf (1, "thread 2: started.\n");
+
+ xpthread_mutex_lock (&user_lock);
+ dprintf (1, "thread 2: locked user_lock.\n");
+ xpthread_barrier_wait (&bar_ctor);
+ t3 = xpthread_create (0, thread3, 0);
+ xpthread_mutex_unlock (&user_lock);
+ dprintf (1, "thread 2: unlocked user_lock.\n");
+ xpthread_join (t3);
+
+ xpthread_mutex_lock (&user_lock);
+ dprintf (1, "thread 2: locked user_lock.\n");
+ xpthread_barrier_wait (&bar_dtor);
+ t3 = xpthread_create (0, thread3, 0);
+ xpthread_mutex_unlock (&user_lock);
+ dprintf (1, "thread 2: unlocked user_lock.\n");
+ xpthread_join (t3);
+
+ dprintf (1, "thread 2: done.\n");
+ return 0;
+}
+
+static void
+thread1 (void)
+{
+ dprintf (1, "thread 1: started.\n");
+ xpthread_barrier_init (&bar_ctor, NULL, 2);
+ xpthread_barrier_init (&bar_dtor, NULL, 2);
+ pthread_t t2 = xpthread_create (0, thread2, 0);
+ void *p = xdlopen ("tst-create1mod.so", RTLD_NOW | RTLD_GLOBAL);
+ dprintf (1, "thread 1: dlopen done.\n");
+ xdlclose (p);
+ dprintf (1, "thread 1: dlclose done.\n");
+ xpthread_join (t2);
+ dprintf (1, "thread 1: done.\n");
+}
+
+static int
+do_test (void)
+{
+ thread1 ();
+ return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/pthread/tst-create1mod.c b/sysdeps/pthread/tst-create1mod.c
new file mode 100644
index 0000000..62c9006
--- /dev/null
+++ b/sysdeps/pthread/tst-create1mod.c
@@ -0,0 +1,41 @@
+/* Verify that pthread_create does not deadlock when ctors take locks.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <stdio.h>
+
+/* Require TLS setup for the module. */
+__thread int tlsvar;
+
+void ctor (void);
+void dtor (void);
+
+static void __attribute__ ((constructor))
+do_init (void)
+{
+ dprintf (1, "constructor started: %d.\n", tlsvar++);
+ ctor ();
+ dprintf (1, "constructor done: %d.\n", tlsvar++);
+}
+
+static void __attribute__ ((destructor))
+do_end (void)
+{
+ dprintf (1, "destructor started: %d.\n", tlsvar++);
+ dtor ();
+ dprintf (1, "destructor done: %d.\n", tlsvar++);
+}
--
1.8.3.1

10
glibc.spec
View File

@ -65,7 +65,7 @@
##############################################################################
Name: glibc
Version: 2.34
Release: 23
Release: 24
Summary: The GNU libc libraries
License: %{all_license}
URL: http://www.gnu.org/software/glibc/
@ -128,6 +128,10 @@ Patch41: nptl-Avoid-setxid-deadlock-with-blocked-signals-in-t.patch
Patch42: nptl-pthread_kill-must-send-signals-to-a-specific-th.patch
Patch43: iconvconfig-Fix-behaviour-with-prefix-BZ-28199.patch
Patch44: gconv-Do-not-emit-spurious-NUL-character-in-ISO-2022.patch
Patch45: elf-Avoid-deadlock-between-pthread_create-and-ctors-.patch
Patch46: ld.so-Replace-DL_RO_DYN_SECTION-with-dl_relocate_ld-.patch
Patch47: ld.so-Initialize-bootstrap_map.l_ld_readonly-BZ-2834.patch
Patch48: Avoid-warning-overriding-recipe-for-.-tst-ro-dynamic.patch
#Patch9000: turn-REP_STOSB_THRESHOLD-from-2k-to-1M.patch
Patch9001: delete-no-hard-link-to-avoid-all_language-package-to.patch
@ -1317,6 +1321,10 @@ fi
%endif
%changelog
* Mon Nov 15 2021 Qingqing Li <liqingqing3@huawei.com> - 2.34-24
- elf: fix ld.so crash while loading a DSO with a read-only dynamic section
https://sourceware.org/bugzilla/show_bug.cgi?id=28340
* Wed Nov 10 2021 Qingqing Li <liqingqing3@huawei.com> - 2.34-23
- gconv: Do not emit spurious NUL character in ISO-2022-JP-3,
this also fix CVE-2021-43396.

124
ld.so-Initialize-bootstrap_map.l_ld_readonly-BZ-2834.patch Normal file
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@ -0,0 +1,124 @@
From 2ec99d8c42b2ff1a1231e4df462a0910a9b7fdef Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 23 Sep 2021 09:06:49 -0700
Subject: [PATCH] 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.
---
elf/rtld.c | 1 +
sysdeps/generic/dl-relocate-ld.h | 11 ++---------
sysdeps/generic/ldsodefs.h | 10 ++++++++++
sysdeps/mips/dl-relocate-ld.h | 11 ++---------
sysdeps/riscv/dl-relocate-ld.h | 11 ++---------
5 files changed, 17 insertions(+), 27 deletions(-)
diff --git a/elf/rtld.c b/elf/rtld.c
index c66a1d0..b8ba2d8 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -547,6 +547,7 @@ _dl_start (void *arg)
/* Read our own dynamic section and fill in the info array. */
bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
+ bootstrap_map.l_ld_readonly = DL_RO_DYN_SECTION;
elf_get_dynamic_info (&bootstrap_map);
#if NO_TLS_OFFSET != 0
diff --git a/sysdeps/generic/dl-relocate-ld.h b/sysdeps/generic/dl-relocate-ld.h
index 5fae206..cfb86c2 100644
--- a/sysdeps/generic/dl-relocate-ld.h
+++ b/sysdeps/generic/dl-relocate-ld.h
@@ -19,14 +19,7 @@
#ifndef _DL_RELOCATE_LD_H
#define _DL_RELOCATE_LD_H
-/* Return true if dynamic section in the shared library L should be
- relocated. */
-
-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;
-}
+/* The dynamic section is writable. */
+#define DL_RO_DYN_SECTION 0
#endif /* _DL_RELOCATE_LD_H */
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 9ec1511..0410f77 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -69,6 +69,16 @@ __BEGIN_DECLS
`ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
#define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
+/* Return true if dynamic section in the shared library L should be
+ relocated. */
+
+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);
+}
+
/* All references to the value of l_info[DT_PLTGOT],
l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
diff --git a/sysdeps/mips/dl-relocate-ld.h b/sysdeps/mips/dl-relocate-ld.h
index 0c18d9a..376ad75 100644
--- a/sysdeps/mips/dl-relocate-ld.h
+++ b/sysdeps/mips/dl-relocate-ld.h
@@ -19,14 +19,7 @@
#ifndef _DL_RELOCATE_LD_H
#define _DL_RELOCATE_LD_H
-/* Return true if dynamic section in the shared library L should be
- relocated. */
-
-static inline bool
-dl_relocate_ld (const struct link_map *l)
-{
- /* Never relocate dynamic section. */
- return false;
-}
+/* The dynamic section is readonly. */
+#define DL_RO_DYN_SECTION 1
#endif /* _DL_RELOCATE_LD_H */
diff --git a/sysdeps/riscv/dl-relocate-ld.h b/sysdeps/riscv/dl-relocate-ld.h
index 1032745..2ab2b8a 100644
--- a/sysdeps/riscv/dl-relocate-ld.h
+++ b/sysdeps/riscv/dl-relocate-ld.h
@@ -19,14 +19,7 @@
#ifndef _DL_RELOCATE_LD_H
#define _DL_RELOCATE_LD_H
-/* Return true if dynamic section in the shared library L should be
- relocated. */
-
-static inline bool
-dl_relocate_ld (const struct link_map *l)
-{
- /* Never relocate dynamic section for ABI compatibility. */
- return false;
-}
+/* The dynamic section is readonly for ABI compatibility. */
+#define DL_RO_DYN_SECTION 1
#endif /* _DL_RELOCATE_LD_H */
--
1.8.3.1

515
ld.so-Replace-DL_RO_DYN_SECTION-with-dl_relocate_ld-.patch Normal file
View File

@ -0,0 +1,515 @@
From b413280cfb16834450f66f554bc0d618bb513851 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 16 Sep 2021 08:15:29 -0700
Subject: [PATCH] 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>
---
elf/Makefile | 11 +++++++++--
elf/dl-load.c | 3 ++-
elf/dl-reloc-static-pie.c | 12 +++++++++++-
elf/get-dynamic-info.h | 21 +++------------------
elf/rtld.c | 6 ++++--
elf/setup-vdso.h | 5 ++---
elf/tst-ro-dynamic-mod.c | 19 +++++++++++++++++++
elf/tst-ro-dynamic-mod.map | 16 ++++++++++++++++
elf/tst-ro-dynamic.c | 31 +++++++++++++++++++++++++++++++
include/link.h | 3 +++
sysdeps/generic/dl-relocate-ld.h | 32 ++++++++++++++++++++++++++++++++
sysdeps/generic/ldsodefs.h | 7 ++-----
sysdeps/mips/dl-relocate-ld.h | 32 ++++++++++++++++++++++++++++++++
sysdeps/mips/ldsodefs.h | 4 ----
sysdeps/riscv/dl-relocate-ld.h | 32 ++++++++++++++++++++++++++++++++
sysdeps/riscv/ldsodefs.h | 5 -----
16 files changed, 198 insertions(+), 41 deletions(-)
create mode 100644 elf/tst-ro-dynamic-mod.c
create mode 100644 elf/tst-ro-dynamic-mod.map
create mode 100644 elf/tst-ro-dynamic.c
create mode 100644 sysdeps/generic/dl-relocate-ld.h
create mode 100644 sysdeps/mips/dl-relocate-ld.h
create mode 100644 sysdeps/riscv/dl-relocate-ld.h
diff --git a/elf/Makefile b/elf/Makefile
index 835b85b..0cdccaa 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -224,7 +224,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
tst-tls-ie tst-tls-ie-dlmopen argv0test \
tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
tst-tls20 tst-tls21 tst-dlmopen-dlerror tst-dlmopen-gethostbyname \
- tst-dl-is_dso
+ tst-dl-is_dso tst-ro-dynamic
# reldep9
tests-internal += loadtest unload unload2 circleload1 \
neededtest neededtest2 neededtest3 neededtest4 \
@@ -360,7 +360,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
libmarkermod4-1 libmarkermod4-2 libmarkermod4-3 libmarkermod4-4 \
tst-tls20mod-bad tst-tls21mod tst-dlmopen-dlerror-mod \
tst-auxvalmod \
- tst-dlmopen-gethostbyname-mod \
+ tst-dlmopen-gethostbyname-mod tst-ro-dynamic-mod \
# Most modules build with _ISOMAC defined, but those filtered out
# depend on internal headers.
@@ -1911,3 +1911,10 @@ $(objpfx)tst-getauxval-static.out: $(objpfx)tst-auxvalmod.so
tst-getauxval-static-ENV = LD_LIBRARY_PATH=$(objpfx):$(common-objpfx)
$(objpfx)tst-dlmopen-gethostbyname.out: $(objpfx)tst-dlmopen-gethostbyname-mod.so
+
+$(objpfx)tst-ro-dynamic: $(objpfx)tst-ro-dynamic-mod.so
+$(objpfx)tst-ro-dynamic-mod.so: $(objpfx)tst-ro-dynamic-mod.os \
+ tst-ro-dynamic-mod.map
+ $(LINK.o) -nostdlib -nostartfiles -shared -o $@ \
+ -Wl,--script=tst-ro-dynamic-mod.map \
+ $(objpfx)tst-ro-dynamic-mod.os
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 39e0d07..6ea7107 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -1149,6 +1149,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
such a segment to avoid a crash later. */
l->l_ld = (void *) ph->p_vaddr;
l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
+ l->l_ld_readonly = (ph->p_flags & PF_W) == 0;
}
break;
@@ -1292,7 +1293,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
else
l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr);
- elf_get_dynamic_info (l, NULL);
+ elf_get_dynamic_info (l);
/* Make sure we are not dlopen'ing an object that has the
DF_1_NOOPEN flag set, or a PIE object. */
diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c
index 289651b..68ded17 100644
--- a/elf/dl-reloc-static-pie.c
+++ b/elf/dl-reloc-static-pie.c
@@ -40,7 +40,17 @@ _dl_relocate_static_pie (void)
/* Read our own dynamic section and fill in the info array. */
main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ());
- elf_get_dynamic_info (main_map, NULL);
+
+ const ElfW(Phdr) *ph, *phdr = GL(dl_phdr);
+ size_t phnum = GL(dl_phnum);
+ for (ph = phdr; ph < &phdr[phnum]; ++ph)
+ if (ph->p_type == PT_DYNAMIC)
+ {
+ main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
+ break;
+ }
+
+ elf_get_dynamic_info (main_map);
# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
ELF_MACHINE_BEFORE_RTLD_RELOC (main_map->l_info);
diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h
index d8ec323..4aa2058 100644
--- a/elf/get-dynamic-info.h
+++ b/elf/get-dynamic-info.h
@@ -28,7 +28,7 @@ static
auto
#endif
inline void __attribute__ ((unused, always_inline))
-elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
+elf_get_dynamic_info (struct link_map *l)
{
#if __ELF_NATIVE_CLASS == 32
typedef Elf32_Word d_tag_utype;
@@ -69,28 +69,15 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
info[i] = dyn;
}
-#define DL_RO_DYN_TEMP_CNT 8
-
-#ifndef DL_RO_DYN_SECTION
/* Don't adjust .dynamic unnecessarily. */
- if (l->l_addr != 0)
+ if (l->l_addr != 0 && dl_relocate_ld (l))
{
ElfW(Addr) l_addr = l->l_addr;
- int cnt = 0;
# define ADJUST_DYN_INFO(tag) \
do \
if (info[tag] != NULL) \
- { \
- if (temp) \
- { \
- temp[cnt].d_tag = info[tag]->d_tag; \
- temp[cnt].d_un.d_ptr = info[tag]->d_un.d_ptr + l_addr; \
- info[tag] = temp + cnt++; \
- } \
- else \
- info[tag]->d_un.d_ptr += l_addr; \
- } \
+ info[tag]->d_un.d_ptr += l_addr; \
while (0)
ADJUST_DYN_INFO (DT_HASH);
@@ -107,9 +94,7 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
ADJUST_DYN_INFO (ADDRIDX (DT_GNU_HASH));
# undef ADJUST_DYN_INFO
- assert (cnt <= DL_RO_DYN_TEMP_CNT);
}
-#endif
if (info[DT_PLTREL] != NULL)
{
#if ELF_MACHINE_NO_RELA
diff --git a/elf/rtld.c b/elf/rtld.c
index 742c413..8d2bba3 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -463,6 +463,7 @@ _dl_start_final (void *arg, struct dl_start_final_info *info)
#ifndef DONT_USE_BOOTSTRAP_MAP
GL(dl_rtld_map).l_addr = info->l.l_addr;
GL(dl_rtld_map).l_ld = info->l.l_ld;
+ GL(dl_rtld_map).l_ld_readonly = info->l.l_ld_readonly;
memcpy (GL(dl_rtld_map).l_info, info->l.l_info,
sizeof GL(dl_rtld_map).l_info);
GL(dl_rtld_map).l_mach = info->l.l_mach;
@@ -546,7 +547,7 @@ _dl_start (void *arg)
/* Read our own dynamic section and fill in the info array. */
bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
- elf_get_dynamic_info (&bootstrap_map, NULL);
+ elf_get_dynamic_info (&bootstrap_map);
#if NO_TLS_OFFSET != 0
bootstrap_map.l_tls_offset = NO_TLS_OFFSET;
@@ -1468,6 +1469,7 @@ dl_main (const ElfW(Phdr) *phdr,
/* This tells us where to find the dynamic section,
which tells us everything we need to do. */
main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
+ main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
break;
case PT_INTERP:
/* This "interpreter segment" was used by the program loader to
@@ -1613,7 +1615,7 @@ dl_main (const ElfW(Phdr) *phdr,
if (! rtld_is_main)
{
/* Extract the contents of the dynamic section for easy access. */
- elf_get_dynamic_info (main_map, NULL);
+ elf_get_dynamic_info (main_map);
/* If the main map is libc.so, update the base namespace to
refer to this map. If libc.so is loaded later, this happens
diff --git a/elf/setup-vdso.h b/elf/setup-vdso.h
index 86c491e..f44748b 100644
--- a/elf/setup-vdso.h
+++ b/elf/setup-vdso.h
@@ -33,8 +33,6 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
0, LM_ID_BASE);
if (__glibc_likely (l != NULL))
{
- static ElfW(Dyn) dyn_temp[DL_RO_DYN_TEMP_CNT] attribute_relro;
-
l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)
+ GLRO(dl_sysinfo_dso)->e_phoff);
l->l_phnum = GLRO(dl_sysinfo_dso)->e_phnum;
@@ -45,6 +43,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
{
l->l_ld = (void *) ph->p_vaddr;
l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
+ l->l_ld_readonly = (ph->p_flags & PF_W) == 0;
}
else if (ph->p_type == PT_LOAD)
{
@@ -65,7 +64,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
l->l_map_end += l->l_addr;
l->l_text_end += l->l_addr;
l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
- elf_get_dynamic_info (l, dyn_temp);
+ elf_get_dynamic_info (l);
_dl_setup_hash (l);
l->l_relocated = 1;
diff --git a/elf/tst-ro-dynamic-mod.c b/elf/tst-ro-dynamic-mod.c
new file mode 100644
index 0000000..6d99925
--- /dev/null
+++ b/elf/tst-ro-dynamic-mod.c
@@ -0,0 +1,19 @@
+/* Test case for DSO with readonly dynamic section.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+int foo = -1;
diff --git a/elf/tst-ro-dynamic-mod.map b/elf/tst-ro-dynamic-mod.map
new file mode 100644
index 0000000..2fe4a29
--- /dev/null
+++ b/elf/tst-ro-dynamic-mod.map
@@ -0,0 +1,16 @@
+SECTIONS
+{
+ . = SIZEOF_HEADERS;
+ .dynamic : { *(.dynamic) } :text :dynamic
+ .rodata : { *(.data*) *(.bss*) } :text
+ /DISCARD/ : {
+ *(.note.gnu.property)
+ }
+ .note : { *(.note.*) } :text :note
+}
+PHDRS
+{
+ text PT_LOAD FLAGS(5) FILEHDR PHDRS;
+ dynamic PT_DYNAMIC FLAGS(4);
+ note PT_NOTE FLAGS(4);
+}
diff --git a/elf/tst-ro-dynamic.c b/elf/tst-ro-dynamic.c
new file mode 100644
index 0000000..3a18f87
--- /dev/null
+++ b/elf/tst-ro-dynamic.c
@@ -0,0 +1,31 @@
+/* Test case for DSO with readonly dynamic section.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <support/check.h>
+#include <support/test-driver.h>
+
+extern int foo;
+
+static int
+do_test (void)
+{
+ TEST_COMPARE (foo, -1);
+ return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/include/link.h b/include/link.h
index 7b8250d..484ee6c 100644
--- a/include/link.h
+++ b/include/link.h
@@ -205,6 +205,7 @@ struct link_map
unsigned int l_free_initfini:1; /* Nonzero if l_initfini can be
freed, ie. not allocated with
the dummy malloc in ld.so. */
+ unsigned int l_ld_readonly:1; /* Nonzero if dynamic section is readonly. */
/* NODELETE status of the map. Only valid for maps of type
lt_loaded. Lazy binding sets l_nodelete_active directly,
@@ -342,6 +343,8 @@ struct link_map
unsigned long long int l_serial;
};
+#include <dl-relocate-ld.h>
+
/* Information used by audit modules. For most link maps, this data
immediate follows the link map in memory. For the dynamic linker,
it is allocated separately. See link_map_audit_state in
diff --git a/sysdeps/generic/dl-relocate-ld.h b/sysdeps/generic/dl-relocate-ld.h
new file mode 100644
index 0000000..5fae206
--- /dev/null
+++ b/sysdeps/generic/dl-relocate-ld.h
@@ -0,0 +1,32 @@
+/* Check if dynamic section should be relocated. Generic version.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _DL_RELOCATE_LD_H
+#define _DL_RELOCATE_LD_H
+
+/* Return true if dynamic section in the shared library L should be
+ relocated. */
+
+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;
+}
+
+#endif /* _DL_RELOCATE_LD_H */
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 6e50fcd..d49529d 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -75,11 +75,8 @@ __BEGIN_DECLS
have to be accessed via the D_PTR macro. The macro is needed since for
most architectures the entry is already relocated - but for some not
and we need to relocate at access time. */
-#ifdef DL_RO_DYN_SECTION
-# define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
-#else
-# define D_PTR(map, i) (map)->i->d_un.d_ptr
-#endif
+#define D_PTR(map, i) \
+ ((map)->i->d_un.d_ptr + (dl_relocate_ld (map) ? 0 : (map)->l_addr))
/* Result of the lookup functions and how to retrieve the base address. */
typedef struct link_map *lookup_t;
diff --git a/sysdeps/mips/dl-relocate-ld.h b/sysdeps/mips/dl-relocate-ld.h
new file mode 100644
index 0000000..0c18d9a
--- /dev/null
+++ b/sysdeps/mips/dl-relocate-ld.h
@@ -0,0 +1,32 @@
+/* Check if dynamic section should be relocated. MIPS version.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _DL_RELOCATE_LD_H
+#define _DL_RELOCATE_LD_H
+
+/* Return true if dynamic section in the shared library L should be
+ relocated. */
+
+static inline bool
+dl_relocate_ld (const struct link_map *l)
+{
+ /* Never relocate dynamic section. */
+ return false;
+}
+
+#endif /* _DL_RELOCATE_LD_H */
diff --git a/sysdeps/mips/ldsodefs.h b/sysdeps/mips/ldsodefs.h
index 4db7c60..36fd09a 100644
--- a/sysdeps/mips/ldsodefs.h
+++ b/sysdeps/mips/ldsodefs.h
@@ -75,10 +75,6 @@ struct La_mips_64_retval;
struct La_mips_64_retval *, \
const char *);
-/* The MIPS ABI specifies that the dynamic section has to be read-only. */
-
-#define DL_RO_DYN_SECTION 1
-
#include_next <ldsodefs.h>
/* The 64-bit MIPS ELF ABI uses an unusual reloc format. Each
diff --git a/sysdeps/riscv/dl-relocate-ld.h b/sysdeps/riscv/dl-relocate-ld.h
new file mode 100644
index 0000000..1032745
--- /dev/null
+++ b/sysdeps/riscv/dl-relocate-ld.h
@@ -0,0 +1,32 @@
+/* Check if dynamic section should be relocated. RISC-V version.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _DL_RELOCATE_LD_H
+#define _DL_RELOCATE_LD_H
+
+/* Return true if dynamic section in the shared library L should be
+ relocated. */
+
+static inline bool
+dl_relocate_ld (const struct link_map *l)
+{
+ /* Never relocate dynamic section for ABI compatibility. */
+ return false;
+}
+
+#endif /* _DL_RELOCATE_LD_H */
diff --git a/sysdeps/riscv/ldsodefs.h b/sysdeps/riscv/ldsodefs.h
index 0c69671..8947ffe 100644
--- a/sysdeps/riscv/ldsodefs.h
+++ b/sysdeps/riscv/ldsodefs.h
@@ -38,11 +38,6 @@ struct La_riscv_retval;
struct La_riscv_retval *, \
const char *);
-/* Although the RISC-V ABI does not specify that the dynamic section has
- to be read-only, it needs to be kept for ABI compatibility. */
-
-#define DL_RO_DYN_SECTION 1
-
#include_next <ldsodefs.h>
#endif
--
1.8.3.1