From f25238ffe0455013174438376b3ee88df496f9d1 Mon Sep 17 00:00:00 2001 From: Maxim Ostapenko Date: Mon, 10 Aug 2015 10:47:54 +0300 Subject: Clear DF_1_NODELETE flag only for failed to load library. https://sourceware.org/bugzilla/show_bug.cgi?id=18778 If dlopen fails to load an object that has triggered loading libpthread it causes ld.so to unload libpthread because its DF_1_NODELETE flags has been forcefully cleared. The next call to __rtdl_unlock_lock_recursive will crash since pthread_mutex_unlock no longer exists. This patch moves l->l_flags_1 &= ~DF_1_NODELETE out of loop through all loaded libraries and performs the action only on inconsistent one. [BZ #18778] * elf/Makefile (tests): Add Add tst-nodelete2. (modules-names): Add tst-nodelete2mod. (tst-nodelete2mod.so-no-z-defs): New. ($(objpfx)tst-nodelete2): Likewise. ($(objpfx)tst-nodelete2.out): Likewise. (LDFLAGS-tst-nodelete2): Likewise. * elf/dl-close.c (_dl_close_worker): Move DF_1_NODELETE clearing out of loop through all loaded libraries. * elf/tst-nodelete2.c: New file. * elf/tst-nodelete2mod.c: Likewise. --- elf/Makefile | 11 +++++++++-- elf/dl-close.c | 15 ++++++++------- elf/tst-nodelete2.c | 37 +++++++++++++++++++++++++++++++++++++ elf/tst-nodelete2mod.c | 7 +++++++ elf/tst-znodelete-zlib.cc | 6 ------ 5 files changed, 61 insertions(+), 15 deletions(-) create mode 100644 elf/tst-nodelete2.c create mode 100644 elf/tst-nodelete2mod.c delete mode 100644 elf/tst-znodelete-zlib.cc (limited to 'elf') diff --git a/elf/Makefile b/elf/Makefile index 4ceeaf8..71a18a1 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -148,7 +148,8 @@ tests += loadtest restest1 preloadtest loadfail multiload origtest resolvfail \ tst-unique1 tst-unique2 $(if $(CXX),tst-unique3 tst-unique4 \ tst-nodelete) \ tst-initorder tst-initorder2 tst-relsort1 tst-null-argv \ - tst-ptrguard1 tst-tlsalign tst-tlsalign-extern tst-nodelete-opened + tst-ptrguard1 tst-tlsalign tst-tlsalign-extern tst-nodelete-opened \ + tst-nodelete2 # reldep9 ifeq ($(build-hardcoded-path-in-tests),yes) tests += tst-dlopen-aout @@ -218,7 +219,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ tst-initorder2d \ tst-relsort1mod1 tst-relsort1mod2 tst-array2dep \ tst-array5dep tst-null-argv-lib \ - tst-tlsalign-lib tst-nodelete-opened-lib + tst-tlsalign-lib tst-nodelete-opened-lib tst-nodelete2mod ifeq (yes,$(have-protected-data)) modules-names += tst-protected1moda tst-protected1modb tests += tst-protected1a tst-protected1b @@ -594,6 +595,7 @@ tst-auditmod9b.so-no-z-defs = yes tst-nodelete-uniquemod.so-no-z-defs = yes tst-nodelete-rtldmod.so-no-z-defs = yes tst-nodelete-zmod.so-no-z-defs = yes +tst-nodelete2mod.so-no-z-defs = yes ifeq ($(build-shared),yes) # Build all the modules even when not actually running test programs. @@ -1164,6 +1166,11 @@ $(objpfx)tst-nodelete.out: $(objpfx)tst-nodelete-uniquemod.so \ LDFLAGS-tst-nodelete = -rdynamic LDFLAGS-tst-nodelete-zmod.so = -Wl,--enable-new-dtags,-z,nodelete +$(objpfx)tst-nodelete2: $(libdl) +$(objpfx)tst-nodelete2.out: $(objpfx)tst-nodelete2mod.so + +LDFLAGS-tst-nodelete2 = -rdynamic + $(objpfx)tst-initorder-cmp.out: tst-initorder.exp $(objpfx)tst-initorder.out cmp $^ > $@; \ $(evaluate-test) diff --git a/elf/dl-close.c b/elf/dl-close.c index 9105277..c897247 100644 --- a/elf/dl-close.c +++ b/elf/dl-close.c @@ -144,6 +144,14 @@ _dl_close_worker (struct link_map *map, bool force) char done[nloaded]; struct link_map *maps[nloaded]; + /* Clear DF_1_NODELETE to force object deletion. We don't need to touch + l_tls_dtor_count because forced object deletion only happens when an + error occurs during object load. Destructor registration for TLS + non-POD objects should not have happened till then for this + object. */ + if (force) + map->l_flags_1 &= ~DF_1_NODELETE; + /* Run over the list and assign indexes to the link maps and enter them into the MAPS array. */ int idx = 0; @@ -153,13 +161,6 @@ _dl_close_worker (struct link_map *map, bool force) maps[idx] = l; ++idx; - /* Clear DF_1_NODELETE to force object deletion. We don't need to touch - l_tls_dtor_count because forced object deletion only happens when an - error occurs during object load. Destructor registration for TLS - non-POD objects should not have happened till then for this - object. */ - if (force) - l->l_flags_1 &= ~DF_1_NODELETE; } assert (idx == nloaded); diff --git a/elf/tst-nodelete2.c b/elf/tst-nodelete2.c new file mode 100644 index 0000000..388e8af --- /dev/null +++ b/elf/tst-nodelete2.c @@ -0,0 +1,37 @@ +#include "../dlfcn/dlfcn.h" +#include +#include +#include + +static int +do_test (void) +{ + int result = 0; + + printf ("\nOpening pthread library.\n"); + void *pthread = dlopen (LIBPTHREAD_SO, RTLD_LAZY); + + /* This is a test for correct DF_1_NODELETE clearing when dlopen failure + happens. We should clear DF_1_NODELETE for failed library only, because + doing this for others (e.g. libpthread) might cause them to be unloaded, + that may lead to some global references (e.g. __rtld_lock_unlock) to be + broken. The dlopen should fail because of undefined symbols in shared + library, that cause DF_1_NODELETE to be cleared. For libpthread, this + flag should be set, because if not, SIGSEGV will happen in dlclose. */ + if (dlopen ("tst-nodelete2mod.so", RTLD_NOW) != NULL) + { + printf ("Unique symbols test failed\n"); + result = 1; + } + + if (pthread) + dlclose (pthread); + + if (result == 0) + printf ("SUCCESS\n"); + + return result; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" diff --git a/elf/tst-nodelete2mod.c b/elf/tst-nodelete2mod.c new file mode 100644 index 0000000..e88c756 --- /dev/null +++ b/elf/tst-nodelete2mod.c @@ -0,0 +1,7 @@ +/* Undefined symbol. */ +extern int not_exist (void); + +int foo (void) +{ + return not_exist (); +} diff --git a/elf/tst-znodelete-zlib.cc b/elf/tst-znodelete-zlib.cc deleted file mode 100644 index 1e8f368..0000000 --- a/elf/tst-znodelete-zlib.cc +++ /dev/null @@ -1,6 +0,0 @@ -extern int not_exist (void); - -int foo (void) -{ - return not_exist (); -} -- cgit v1.1