From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Florian Weimer <fweimer@redhat.com>, libc-alpha@sourceware.org
Subject: Re: [PATCH v3 19/37] dlfcn: Failures after dlmopen should not terminate process [BZ #24772]
Date: Fri, 19 Mar 2021 16:56:40 -0300 [thread overview]
Message-ID: <e9dfe9ac-4a8e-9705-aa12-449fa823970d@linaro.org> (raw)
In-Reply-To: <b0c049610de0cb47bfaf2d460d3dd66fa72a8cdb.1615914632.git.fweimer@redhat.com>
On 16/03/2021 14:30, Florian Weimer via Libc-alpha wrote:
> Commit 9e78f6f6e7134a5f299cc8de77370218f8019237 ("Implement
> _dl_catch_error, _dl_signal_error in libc.so [BZ #16628]") has the
> side effect that distinct namespaces, as created by dlmopen, now have
> separate implementations of the rtld exception mechanism. This means
> that the call to _dl_catch_error from libdl in a secondary namespace
> does not actually install an exception handler because the
> thread-local variable catch_hook in the libc.so copy in the secondary
> namespace is distinct from that of the base namepace. As a result, a
> dlsym/dlopen/… failure in a secondary namespace terminates the process
> with a dynamic linker error because it looks to the exception handler
> mechanism as if no handler has been installed.
>
> This commit restores GLRO (dl_catch_error) and uses it to set the
> handler in the base namespace.
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> dlfcn/dlerror.c | 6 +++--
> elf/Makefile | 8 ++++++-
> elf/dl-error-skeleton.c | 12 ++++++++++
> elf/rtld.c | 1 +
> elf/tst-dlmopen-dlerror-mod.c | 41 +++++++++++++++++++++++++++++++++++
> elf/tst-dlmopen-dlerror.c | 37 +++++++++++++++++++++++++++++++
> sysdeps/generic/ldsodefs.h | 9 ++++++++
> 7 files changed, 111 insertions(+), 3 deletions(-)
> create mode 100644 elf/tst-dlmopen-dlerror-mod.c
> create mode 100644 elf/tst-dlmopen-dlerror.c
>
> diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c
> index 48b4c25bea..947b7c10c6 100644
> --- a/dlfcn/dlerror.c
> +++ b/dlfcn/dlerror.c
> @@ -167,8 +167,10 @@ _dlerror_run (void (*operate) (void *), void *args)
> result->errstring = NULL;
> }
>
> - result->errcode = _dl_catch_error (&result->objname, &result->errstring,
> - &result->malloced, operate, args);
> + result->errcode = GLRO (dl_catch_error) (&result->objname,
> + &result->errstring,
> + &result->malloced,
> + operate, args);
>
> /* If no error we mark that no error string is available. */
> result->returned = result->errstring == NULL;
Ok.
> diff --git a/elf/Makefile b/elf/Makefile
> index 936d4cf276..deb76aed99 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -222,7 +222,8 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
> tst-audit14 tst-audit15 tst-audit16 \
> tst-single_threaded tst-single_threaded-pthread \
> tst-tls-ie tst-tls-ie-dlmopen argv0test \
> - tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask
> + tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
> + tst-dlmopen-dlerror
> # reldep9
> tests-internal += loadtest unload unload2 circleload1 \
> neededtest neededtest2 neededtest3 neededtest4 \
> @@ -344,6 +345,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
> libmarkermod2-1 libmarkermod2-2 \
> libmarkermod3-1 libmarkermod3-2 libmarkermod3-3 \
> libmarkermod4-1 libmarkermod4-2 libmarkermod4-3 libmarkermod4-4 \
> + tst-ldconfig-ld-mod tst-dlmopen-dlerror-mod \
>
> # Most modules build with _ISOMAC defined, but those filtered out
> # depend on internal headers.
> @@ -1580,6 +1582,10 @@ $(objpfx)tst-sonamemove-dlopen.out: \
> $(objpfx)tst-sonamemove-runmod1.so \
> $(objpfx)tst-sonamemove-runmod2.so
>
> +$(objpfx)tst-dlmopen-dlerror: $(libdl)
> +$(objpfx)tst-dlmopen-dlerror-mod.so: $(libdl) $(libsupport)
> +$(objpfx)tst-dlmopen-dlerror.out: $(objpfx)tst-dlmopen-dlerror-mod.so
> +
> # Override -z defs, so that we can reference an undefined symbol.
> # Force lazy binding for the same reason.
> LDFLAGS-tst-latepthreadmod.so = \
Ok.
> diff --git a/elf/dl-error-skeleton.c b/elf/dl-error-skeleton.c
> index 2fd62777cf..b699936c6e 100644
> --- a/elf/dl-error-skeleton.c
> +++ b/elf/dl-error-skeleton.c
> @@ -248,4 +248,16 @@ _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args)
> catch_hook = old_catch;
> receiver = old_receiver;
> }
> +
> +/* Forwarder used for initializing GLRO (_dl_catch_error). */
> +int
> +_rtld_catch_error (const char **objname, const char **errstring,
> + bool *mallocedp, void (*operate) (void *),
> + void *args)
> +{
> + /* The reference to _dl_catch_error will eventually be relocated to
> + point to the implementation in libc.so. */
> + return _dl_catch_error (objname, errstring, mallocedp, operate, args);
> +}
> +
> #endif /* DL_ERROR_BOOTSTRAP */
Ok, but why change the usual prepend string to 'rtld'?
> diff --git a/elf/rtld.c b/elf/rtld.c
> index 94a00e2049..fd02438936 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -368,6 +368,7 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
> ._dl_lookup_symbol_x = _dl_lookup_symbol_x,
> ._dl_open = _dl_open,
> ._dl_close = _dl_close,
> + ._dl_catch_error = _rtld_catch_error,
> ._dl_tls_get_addr_soft = _dl_tls_get_addr_soft,
> #ifdef HAVE_DL_DISCOVER_OSVERSION
> ._dl_discover_osversion = _dl_discover_osversion
Ok.
> diff --git a/elf/tst-dlmopen-dlerror-mod.c b/elf/tst-dlmopen-dlerror-mod.c
> new file mode 100644
> index 0000000000..dcb94320b4
> --- /dev/null
> +++ b/elf/tst-dlmopen-dlerror-mod.c
> @@ -0,0 +1,41 @@
> +/* Check that dlfcn errors are reported properly after dlmopen. Test module.
> + Copyright (C) 2019 Free Software Foundation, Inc.
s/2019/2021.
> + 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
> + <http://www.gnu.org/licenses/>. */
> +
> +#include <dlfcn.h>
> +#include <stddef.h>
> +#include <support/check.h>
> +
> +/* Note: This object is not linked into the main program, so we cannot
> + use delayed test failure reporting via TEST_VERIFY etc., and have
> + to use FAIL_EXIT1 (or something else that calls exit). */
> +
> +void
> +call_dlsym (void)
> +{
> + void *ptr = dlsym (NULL, "does not exist");
> + if (ptr != NULL)
> + FAIL_EXIT1 ("dlsym did not fail as expected");
> +}
> +
> +void
> +call_dlopen (void)
> +{
> + void *handle = dlopen ("tst-dlmopen-dlerror does not exist", RTLD_NOW);
> + if (handle != NULL)
> + FAIL_EXIT1 ("dlopen did not fail as expected");
> +}
Ok.
> diff --git a/elf/tst-dlmopen-dlerror.c b/elf/tst-dlmopen-dlerror.c
> new file mode 100644
> index 0000000000..65638f7f38
> --- /dev/null
> +++ b/elf/tst-dlmopen-dlerror.c
> @@ -0,0 +1,37 @@
> +/* Check that dlfcn errors are reported properly after dlmopen.
> + Copyright (C) 2019 Free Software Foundation, Inc.
s/2019/2021.
> + 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
> + <http://www.gnu.org/licenses/>. */
> +
> +#include <stddef.h>
> +#include <support/check.h>
> +#include <support/xdlfcn.h>
> +
> +static int
> +do_test (void)
> +{
> + void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-dlerror-mod.so",
> + RTLD_NOW);
> + void (*call_dlsym) (void) = xdlsym (handle, "call_dlsym");
> + void (*call_dlopen) (void) = xdlsym (handle, "call_dlopen");
> +
> + call_dlsym ();
> + call_dlopen ();
> +
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
Ok.
> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
> index ea3f7a69d0..b207f229c3 100644
> --- a/sysdeps/generic/ldsodefs.h
> +++ b/sysdeps/generic/ldsodefs.h
> @@ -662,6 +662,12 @@ struct rtld_global_ro
> void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
> Lmid_t nsid, int argc, char *argv[], char *env[]);
> void (*_dl_close) (void *map);
> + /* libdl in a secondary namespace (after dlopen) must use
> + _dl_catch_error from the main namespace, so it has to be
> + exported in some way. */
> + int (*_dl_catch_error) (const char **objname, const char **errstring,
> + bool *mallocedp, void (*operate) (void *),
> + void *args);
> void *(*_dl_tls_get_addr_soft) (struct link_map *);
> #ifdef HAVE_DL_DISCOVER_OSVERSION
> int (*_dl_discover_osversion) (void);
> @@ -900,6 +906,9 @@ extern int _dl_catch_error (const char **objname, const char **errstring,
> void *args);
> libc_hidden_proto (_dl_catch_error)
>
> +/* Used for initializing GLRO (_dl_catch_error). */
> +extern __typeof__ (_dl_catch_error) _rtld_catch_error attribute_hidden;
> +
> /* Call OPERATE (ARGS). If no error occurs, set *EXCEPTION to zero.
> Otherwise, store a copy of the raised exception in *EXCEPTION,
> which has to be freed by _dl_exception_free. As a special case, if
>
Ok.
next prev parent reply other threads:[~2021-03-19 19:56 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 17:27 [PATCH v3 00/37] libpthread removal: NPTL forwarders are gone Florian Weimer
2021-03-16 17:27 ` [PATCH v3 01/37] nptl: Move pthread_mutex_consistent into libc Florian Weimer
2021-03-17 11:36 ` Adhemerval Zanella
2021-03-16 17:27 ` [PATCH v3 02/37] nptl: Move __pthread_cleanup_routine " Florian Weimer
2021-03-16 17:27 ` [PATCH v3 03/37] nptl: Move legacy unwinding implementation " Florian Weimer
2021-03-16 17:27 ` [PATCH v3 04/37] nptl: Move legacy cancelation handling into libc as compat symbols Florian Weimer
2021-03-16 17:27 ` [PATCH v3 05/37] nptl: Remove longjmp, siglongjmp from libpthread Florian Weimer
2021-03-17 11:38 ` Adhemerval Zanella
2021-03-16 17:28 ` [PATCH v3 06/37] x86: Restore compile-time check for shadow stack pointer in longjmp Florian Weimer
2021-03-16 17:28 ` [PATCH v3 07/37] nptl: Move __pthread_cleanup_upto into libc Florian Weimer
2021-03-16 17:28 ` [PATCH v3 08/37] nptl: Move pthread_once and __pthread_once " Florian Weimer
2021-03-17 13:30 ` Adhemerval Zanella
2021-03-17 13:37 ` Adhemerval Zanella
2021-03-17 14:45 ` Florian Weimer
2021-03-17 16:39 ` Adhemerval Zanella
2021-03-17 16:56 ` Florian Weimer
2021-03-17 17:22 ` Adhemerval Zanella
2021-03-17 17:43 ` Florian Weimer
2021-03-17 19:09 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 09/37] nptl: Move __pthread_unwind_next " Florian Weimer
2021-03-17 19:42 ` Adhemerval Zanella
2021-03-17 19:54 ` Florian Weimer
2021-03-17 20:16 ` Adhemerval Zanella
2021-03-17 20:33 ` Florian Weimer
2021-03-17 20:44 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 10/37] csu: Move calling main out of __libc_start_main_impl Florian Weimer
2021-03-17 20:45 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 11/37] nptl: Move internal __nptl_nthreads variable into libc Florian Weimer
2021-03-18 12:42 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 12/37] nptl_db: Introduce DB_MAIN_ARRAY_VARIABLE Florian Weimer
2021-03-18 12:43 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 13/37] nptl: Move __pthread_keys global variable into libc Florian Weimer
2021-03-18 12:44 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 14/37] nptl: Move __nptl_deallocate_tsd " Florian Weimer
2021-03-18 12:46 ` Adhemerval Zanella
2021-03-18 17:16 ` Florian Weimer
2021-03-18 17:54 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 15/37] nptl: Move pthread_exit " Florian Weimer
2021-03-18 12:49 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 16/37] nptl: Move pthread_setcancelstate " Florian Weimer
2021-03-18 12:52 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 17/37] nptl: Move pthread_setcanceltype " Florian Weimer
2021-03-18 12:53 ` Adhemerval Zanella
2021-03-16 17:29 ` [PATCH v3 18/37] nptl: Invoke the set_robust_list system call directly in fork Florian Weimer
2021-03-18 12:54 ` Adhemerval Zanella
2021-03-16 17:30 ` [PATCH v3 19/37] dlfcn: Failures after dlmopen should not terminate process [BZ #24772] Florian Weimer
2021-03-19 19:56 ` Adhemerval Zanella [this message]
2021-03-27 16:57 ` Florian Weimer
2021-03-16 17:30 ` [PATCH v3 20/37] dlfcn: dlerror needs to call free from the base namespace [BZ #24773] Florian Weimer
2021-03-23 14:47 ` Adhemerval Zanella
2021-03-16 17:30 ` [PATCH v3 21/37] Remove pthread_key_create-related internals from libc-lock.h Florian Weimer
2021-03-23 16:39 ` Adhemerval Zanella
2021-03-16 17:30 ` [PATCH v3 22/37] elf: Introduce __tls_init_tp for second-phase TCB initialization Florian Weimer
2021-03-23 18:25 ` Adhemerval Zanella
2021-03-16 17:30 ` [PATCH v3 23/37] nptl: Move part of TCB initialization from libpthread to __tls_init_tp Florian Weimer
2021-03-24 13:56 ` Adhemerval Zanella
2021-03-27 17:19 ` Florian Weimer
2021-03-16 17:30 ` [PATCH v3 24/37] nptl: Move pthread_key_create, __pthread_key_create into libc Florian Weimer
2021-03-24 14:09 ` Adhemerval Zanella
2021-03-24 14:32 ` Florian Weimer
2021-03-24 14:42 ` Adhemerval Zanella
2021-03-24 15:08 ` Florian Weimer
2021-03-24 15:46 ` Adhemerval Zanella
2021-03-16 17:30 ` [PATCH v3 25/37] nptl: Move pthread_getspecific, __pthread_getspecific " Florian Weimer
2021-03-24 14:12 ` Adhemerval Zanella
2021-03-24 14:38 ` Florian Weimer
2021-03-24 14:43 ` Adhemerval Zanella
2021-03-16 17:30 ` [PATCH v3 26/37] nptl: Move pthread_setspecific, __pthread_setspecific " Florian Weimer
2021-03-24 14:26 ` Adhemerval Zanella
2021-03-16 17:30 ` [PATCH v3 27/37] nptl: Move pthread_key_delete " Florian Weimer
2021-03-24 14:45 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 28/37] nptl: Move rwlock functions with forwarders " Florian Weimer
2021-03-25 19:52 ` Adhemerval Zanella
2021-03-27 21:41 ` Florian Weimer
2021-03-16 17:31 ` [PATCH v3 29/37] nptl: Move the internal thread priority protection symbols " Florian Weimer
2021-03-25 20:21 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 30/37] pthread: Introduce __pthread_early_init Florian Weimer
2021-03-25 20:22 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 31/37] nptl: Move internal symbol __mutex_aconf into libc Florian Weimer
2021-03-25 20:24 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 32/37] nptl: pthread_mutex_lock, pthread_mutex_unock single-threaded optimization Florian Weimer
2021-03-26 18:00 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 33/37] x86: Remove low-level lock optimization Florian Weimer
2021-03-25 20:30 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 34/37] nptl: Move core mutex functions into libc Florian Weimer
2021-03-25 20:46 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 35/37] nptl: Move core condition variable " Florian Weimer
2021-03-26 17:14 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 36/37] nptl: Move setxid broadcast implementation " Florian Weimer
2021-03-26 18:15 ` Adhemerval Zanella
2021-04-06 18:41 ` Florian Weimer
2021-04-06 18:54 ` Adhemerval Zanella
2021-04-06 19:23 ` Florian Weimer
2021-04-06 19:40 ` Adhemerval Zanella
2021-03-16 17:31 ` [PATCH v3 37/37] nptl: Remove remnants of the libc/libpthread forwarder interface Florian Weimer
2021-03-26 18:19 ` Adhemerval Zanella
2021-03-18 22:06 ` [PATCH v3 00/37] libpthread removal: NPTL forwarders are gone Florian Weimer
2021-03-26 18:25 ` Adhemerval Zanella
2021-03-31 10:18 ` Florian Weimer
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