| Message ID | 3f27d400f91fbf02eabd188f002c3003dd6f994d.1723116962.git.fweimer@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fixes for recursive dlopen (bug 31986) | expand |
On 08/08/24 08:40, Florian Weimer wrote: > This is conceptually similar to the reported bug, but does not > depend on auditing. The fix is simple: just complete execution > of the constructors. This exposed the fact that the link map > for statically linked executables does not have l_init_called > set, even though constructors have run. LGTM, thanks. Just a minor suggestion below. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > elf/Makefile | 6 ++++ > elf/dl-open.c | 8 +++++ > elf/dl-support.c | 1 + > elf/tst-dlopen-recurse.c | 34 +++++++++++++++++++ > elf/tst-dlopen-recursemod1.c | 50 +++++++++++++++++++++++++++ > elf/tst-dlopen-recursemod2.c | 66 ++++++++++++++++++++++++++++++++++++ > 6 files changed, 165 insertions(+) > create mode 100644 elf/tst-dlopen-recurse.c > create mode 100644 elf/tst-dlopen-recursemod1.c > create mode 100644 elf/tst-dlopen-recursemod2.c > > diff --git a/elf/Makefile b/elf/Makefile > index 0792b57678..cc3685550d 100644 > --- a/elf/Makefile > +++ b/elf/Makefile > @@ -414,6 +414,7 @@ tests += \ > tst-dlmopen1 \ > tst-dlmopen3 \ > tst-dlmopen4 \ > + tst-dlopen-recurse \ > tst-dlopen-self \ > tst-dlopen-tlsmodid \ > tst-dlopen-tlsreinit1 \ > @@ -864,6 +865,8 @@ modules-names += \ > tst-dlmopen-twice-mod1 \ > tst-dlmopen-twice-mod2 \ > tst-dlmopen1mod \ > + tst-dlopen-recursemod1 \ > + tst-dlopen-recursemod2 \ > tst-dlopen-tlsreinitmod1 \ > tst-dlopen-tlsreinitmod2 \ > tst-dlopen-tlsreinitmod3 \ > @@ -3155,3 +3158,6 @@ $(objpfx)tst-dlopen-tlsreinit3.out: $(objpfx)tst-auditmod1.so > tst-dlopen-tlsreinit3-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so > $(objpfx)tst-dlopen-tlsreinit4.out: $(objpfx)tst-auditmod1.so > tst-dlopen-tlsreinit4-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so > + > +$(objpfx)tst-dlopen-recurse.out: $(objpfx)tst-dlopen-recursemod1.so > +$(objpfx)tst-dlopen-recursemod1.so: $(objpfx)tst-dlopen-recursemod2.so > diff --git a/elf/dl-open.c b/elf/dl-open.c > index 8b4704c09d..2c20aa1df9 100644 > --- a/elf/dl-open.c > +++ b/elf/dl-open.c > @@ -590,6 +590,14 @@ dl_open_worker_begin (void *a) > = _dl_debug_update (args->nsid)->r_state; > assert (r_state == RT_CONSISTENT); > > + /* Do not return without calling the (supposedly new) map's > + constructor. This case occurs if a dependency of a directly > + opened map has a constructor that calls dlopen again on the > + initially opened map. The new map is initialized last, so > + checking only it is enough. */ > + if (!new->l_init_called) > + _dl_catch_exception (NULL, call_dl_init, args); > + > return; > } > > diff --git a/elf/dl-support.c b/elf/dl-support.c > index 451932dd03..94e8197c63 100644 > --- a/elf/dl-support.c > +++ b/elf/dl-support.c > @@ -99,6 +99,7 @@ static struct link_map _dl_main_map = > .l_used = 1, > .l_tls_offset = NO_TLS_OFFSET, > .l_serial = 1, > + .l_init_called = 1, > }; > > /* Namespace information. */ > diff --git a/elf/tst-dlopen-recurse.c b/elf/tst-dlopen-recurse.c > new file mode 100644 > index 0000000000..c7fb379d37 > --- /dev/null > +++ b/elf/tst-dlopen-recurse.c > @@ -0,0 +1,34 @@ > +/* Test that recursive dlopen runs constructors before return (bug 31986). > + Copyright (C) 2024 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/check.h> > +#include <support/xdlfcn.h> > + > +static int > +do_test (void) > +{ > + void *handle = xdlopen ("tst-dlopen-recursemod1.so", RTLD_NOW); > + int *status = dlsym (handle, "recursemod1_status"); Maybe use xdlsym here. > + printf ("info: recursemod1_status == %d (from main)\n", *status); > + TEST_COMPARE (*status, 2); > + xdlclose (handle); > + return 0; > +} > + > +#include <support/test-driver.c> > diff --git a/elf/tst-dlopen-recursemod1.c b/elf/tst-dlopen-recursemod1.c > new file mode 100644 > index 0000000000..5e0cc0eb8c > --- /dev/null > +++ b/elf/tst-dlopen-recursemod1.c > @@ -0,0 +1,50 @@ > +/* Directly opened test module that gets recursively opened again. > + Copyright (C) 2024 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 <stdlib.h> > +#include <support/xdlfcn.h> > + > +int recursemod1_status; > + > +/* Force linking against st-dlopen-recursemod2.so. Also allows > + checking for relocation. */ > +extern int recursemod2_status; > +int *force_recursemod2_reference = &recursemod2_status; > + > +static void __attribute__ ((constructor)) > +init (void) > +{ > + ++recursemod1_status; > + printf ("info: tst-dlopen-recursemod1.so constructor called (status %d)\n", > + recursemod1_status); > +} > + > +static void __attribute__ ((destructor)) > +fini (void) > +{ > + /* The recursemod1_status variable was incremented in the > + tst-dlopen-recursemod2.so constructor. */ > + printf ("info: tst-dlopen-recursemod1.so destructor called (status %d)\n", > + recursemod1_status); > + if (recursemod1_status != 2) > + { > + puts ("error: recursemod1_status == 2 expected"); > + exit (1); > + } > +} > diff --git a/elf/tst-dlopen-recursemod2.c b/elf/tst-dlopen-recursemod2.c > new file mode 100644 > index 0000000000..edd2f2526b > --- /dev/null > +++ b/elf/tst-dlopen-recursemod2.c > @@ -0,0 +1,66 @@ > +/* Indirectly opened module that recursively opens the directly opened module. > + Copyright (C) 2024 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 <dlfcn.h> > +#include <stdio.h> > +#include <stdlib.h> > + > +int recursemod2_status; > + > +static void __attribute__ ((constructor)) > +init (void) > +{ > + ++recursemod2_status; > + printf ("info: tst-dlopen-recursemod2.so constructor called (status %d)\n", > + recursemod2_status); > + void *handle = dlopen ("tst-dlopen-recursemod1.so", RTLD_NOW); > + if (handle == NULL) > + { > + printf ("error: dlopen: %s\n", dlerror ()); > + exit (1); > + } > + int *status = dlsym (handle, "recursemod1_status"); > + if (status == NULL) > + { > + printf ("error: dlsym: %s\n", dlerror ()); > + exit (1); > + } > + printf ("info: recursemod1_status == %d\n", *status); > + if (*status != 1) > + { > + puts ("error: recursemod1_status == 1 expected"); > + exit (1); > + } > + ++*status; > + printf ("info: recursemod1_status == %d\n", *status); > + > + int **mod2_status = dlsym (handle, "force_recursemod2_reference"); > + if (mod2_status == NULL || *mod2_status != &recursemod2_status) > + { > + puts ("error: invalid recursemod2_status address in" > + " tst-dlopen-recursemod1.so"); > + exit (1); > + } > +} > + > +static void __attribute__ ((destructor)) > +fini (void) > +{ > + printf ("info: tst-dlopen-recursemod2.so destructor called (status %d)\n", > + recursemod2_status); > +}
On Aug 08 2024, Florian Weimer wrote: > This is conceptually similar to the reported bug, but does not > depend on auditing. The fix is simple: just complete execution > of the constructors. This exposed the fact that the link map > for statically linked executables does not have l_init_called > set, even though constructors have run. This breaks https://github.com/NVIDIA/libglvnd. It has a constructor __glDispatchOnLoadInit in libGLdispatch.so.0 (a dependency of libEGL.so.1 and libGLX.so.0), which calls dlopen(NULL) to get a handle of libc for looking up the pthread functions to initialize __glvndPthreadFuncs. That dlopen call now runs the constructors of the remaining librararies, including libEGL.so.1 (__eglInit) and libGLX.so.0 (__glXIinit), which depend on __glvndPthreadFuncs being initialized.
* Andreas Schwab: > On Aug 08 2024, Florian Weimer wrote: > >> This is conceptually similar to the reported bug, but does not >> depend on auditing. The fix is simple: just complete execution >> of the constructors. This exposed the fact that the link map >> for statically linked executables does not have l_init_called >> set, even though constructors have run. > > This breaks https://github.com/NVIDIA/libglvnd. It has a constructor > __glDispatchOnLoadInit in libGLdispatch.so.0 (a dependency of > libEGL.so.1 and libGLX.so.0), which calls dlopen(NULL) to get a handle > of libc for looking up the pthread functions to initialize > __glvndPthreadFuncs. That dlopen call now runs the constructors of the > remaining librararies, including libEGL.so.1 (__eglInit) and libGLX.so.0 > (__glXIinit), which depend on __glvndPthreadFuncs being initialized. Indeed, I've just pushed the revert I posted earlier. I've also posted a patch which adds the libglvnd usage as a test case: [PATCH 2/2] elf: Test dlopen (NULL, RTLD_LAZY) from an ELF constructor <https://inbox.sourceware.org/libc-alpha/9cae3d01f7110eed03256a03903a805b5f6120e5.1729950708.git.fweimer@redhat.com/T/#u> Thanks, Florian
diff --git a/elf/Makefile b/elf/Makefile index 0792b57678..cc3685550d 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -414,6 +414,7 @@ tests += \ tst-dlmopen1 \ tst-dlmopen3 \ tst-dlmopen4 \ + tst-dlopen-recurse \ tst-dlopen-self \ tst-dlopen-tlsmodid \ tst-dlopen-tlsreinit1 \ @@ -864,6 +865,8 @@ modules-names += \ tst-dlmopen-twice-mod1 \ tst-dlmopen-twice-mod2 \ tst-dlmopen1mod \ + tst-dlopen-recursemod1 \ + tst-dlopen-recursemod2 \ tst-dlopen-tlsreinitmod1 \ tst-dlopen-tlsreinitmod2 \ tst-dlopen-tlsreinitmod3 \ @@ -3155,3 +3158,6 @@ $(objpfx)tst-dlopen-tlsreinit3.out: $(objpfx)tst-auditmod1.so tst-dlopen-tlsreinit3-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so $(objpfx)tst-dlopen-tlsreinit4.out: $(objpfx)tst-auditmod1.so tst-dlopen-tlsreinit4-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so + +$(objpfx)tst-dlopen-recurse.out: $(objpfx)tst-dlopen-recursemod1.so +$(objpfx)tst-dlopen-recursemod1.so: $(objpfx)tst-dlopen-recursemod2.so diff --git a/elf/dl-open.c b/elf/dl-open.c index 8b4704c09d..2c20aa1df9 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -590,6 +590,14 @@ dl_open_worker_begin (void *a) = _dl_debug_update (args->nsid)->r_state; assert (r_state == RT_CONSISTENT); + /* Do not return without calling the (supposedly new) map's + constructor. This case occurs if a dependency of a directly + opened map has a constructor that calls dlopen again on the + initially opened map. The new map is initialized last, so + checking only it is enough. */ + if (!new->l_init_called) + _dl_catch_exception (NULL, call_dl_init, args); + return; } diff --git a/elf/dl-support.c b/elf/dl-support.c index 451932dd03..94e8197c63 100644 --- a/elf/dl-support.c +++ b/elf/dl-support.c @@ -99,6 +99,7 @@ static struct link_map _dl_main_map = .l_used = 1, .l_tls_offset = NO_TLS_OFFSET, .l_serial = 1, + .l_init_called = 1, }; /* Namespace information. */ diff --git a/elf/tst-dlopen-recurse.c b/elf/tst-dlopen-recurse.c new file mode 100644 index 0000000000..c7fb379d37 --- /dev/null +++ b/elf/tst-dlopen-recurse.c @@ -0,0 +1,34 @@ +/* Test that recursive dlopen runs constructors before return (bug 31986). + Copyright (C) 2024 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/check.h> +#include <support/xdlfcn.h> + +static int +do_test (void) +{ + void *handle = xdlopen ("tst-dlopen-recursemod1.so", RTLD_NOW); + int *status = dlsym (handle, "recursemod1_status"); + printf ("info: recursemod1_status == %d (from main)\n", *status); + TEST_COMPARE (*status, 2); + xdlclose (handle); + return 0; +} + +#include <support/test-driver.c> diff --git a/elf/tst-dlopen-recursemod1.c b/elf/tst-dlopen-recursemod1.c new file mode 100644 index 0000000000..5e0cc0eb8c --- /dev/null +++ b/elf/tst-dlopen-recursemod1.c @@ -0,0 +1,50 @@ +/* Directly opened test module that gets recursively opened again. + Copyright (C) 2024 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 <stdlib.h> +#include <support/xdlfcn.h> + +int recursemod1_status; + +/* Force linking against st-dlopen-recursemod2.so. Also allows + checking for relocation. */ +extern int recursemod2_status; +int *force_recursemod2_reference = &recursemod2_status; + +static void __attribute__ ((constructor)) +init (void) +{ + ++recursemod1_status; + printf ("info: tst-dlopen-recursemod1.so constructor called (status %d)\n", + recursemod1_status); +} + +static void __attribute__ ((destructor)) +fini (void) +{ + /* The recursemod1_status variable was incremented in the + tst-dlopen-recursemod2.so constructor. */ + printf ("info: tst-dlopen-recursemod1.so destructor called (status %d)\n", + recursemod1_status); + if (recursemod1_status != 2) + { + puts ("error: recursemod1_status == 2 expected"); + exit (1); + } +} diff --git a/elf/tst-dlopen-recursemod2.c b/elf/tst-dlopen-recursemod2.c new file mode 100644 index 0000000000..edd2f2526b --- /dev/null +++ b/elf/tst-dlopen-recursemod2.c @@ -0,0 +1,66 @@ +/* Indirectly opened module that recursively opens the directly opened module. + Copyright (C) 2024 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 <dlfcn.h> +#include <stdio.h> +#include <stdlib.h> + +int recursemod2_status; + +static void __attribute__ ((constructor)) +init (void) +{ + ++recursemod2_status; + printf ("info: tst-dlopen-recursemod2.so constructor called (status %d)\n", + recursemod2_status); + void *handle = dlopen ("tst-dlopen-recursemod1.so", RTLD_NOW); + if (handle == NULL) + { + printf ("error: dlopen: %s\n", dlerror ()); + exit (1); + } + int *status = dlsym (handle, "recursemod1_status"); + if (status == NULL) + { + printf ("error: dlsym: %s\n", dlerror ()); + exit (1); + } + printf ("info: recursemod1_status == %d\n", *status); + if (*status != 1) + { + puts ("error: recursemod1_status == 1 expected"); + exit (1); + } + ++*status; + printf ("info: recursemod1_status == %d\n", *status); + + int **mod2_status = dlsym (handle, "force_recursemod2_reference"); + if (mod2_status == NULL || *mod2_status != &recursemod2_status) + { + puts ("error: invalid recursemod2_status address in" + " tst-dlopen-recursemod1.so"); + exit (1); + } +} + +static void __attribute__ ((destructor)) +fini (void) +{ + printf ("info: tst-dlopen-recursemod2.so destructor called (status %d)\n", + recursemod2_status); +}