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authorWaldemar Brodkorb <wbx@uclibc-ng.org>2016-01-03 19:44:54 +0100
committerWaldemar Brodkorb <wbx@uclibc-ng.org>2016-01-06 23:54:38 +0100
commitd41cec56d5c04d88aa2d06986b692cd1fa279748 (patch)
tree0ae2816dabaff91329d1e51f1f234fc8ead55174
parent7b495396fbf7bf604939d8150955ce891f7e8ccd (diff)
pthread_atfork handlers not removed during dlclose
Invoke pthread_atfork handler cleanup when removing the associated DSO... If a program loads a DSO (dlopen) that sets up a pthread_atfork handler(s), and then subsequently closes the DSO, the handler(s) are left in place. If fork() is subsequently called, the handlers are invoked even though the DSO has been removed causing crashes or unpredictable code execution. This is because the code in __cxa_finalize(atexit.c)to invoke the unregister_atfork() routine is ifdef'd out with the comment that it hasn't been "looked into this yet...". Refs.: http://bugs.busybox.net/show_bug.cgi?id=8211 http://sourceware.org/bugzilla/show_bug.cgi?id=13502 Add test-case, enable cleanup for NPTL only. Signed-off-by: John Ata <john.ata@baesystems.com> Signed-off-by: Leonid Lisovskiy <lly.dev@gmail.com>
-rw-r--r--libc/stdlib/_atexit.c9
-rw-r--r--test/nptl/Makefile.in8
-rw-r--r--test/nptl/libatfork.c27
-rw-r--r--test/nptl/tst-atfork2.c24
4 files changed, 63 insertions, 5 deletions
diff --git a/libc/stdlib/_atexit.c b/libc/stdlib/_atexit.c
index 3faa9f05f..8a3196781 100644
--- a/libc/stdlib/_atexit.c
+++ b/libc/stdlib/_atexit.c
@@ -43,6 +43,9 @@
#include <stdio.h>
#include <errno.h>
#include <atomic.h>
+#if defined __UCLIBC_HAS_THREADS__ && defined __UCLIBC_HAS_THREADS_NATIVE__
+# include <fork.h>
+#endif
#include <bits/uClibc_mutex.h>
__UCLIBC_MUTEX_EXTERN(__atexit_lock) attribute_hidden;
@@ -208,17 +211,15 @@ void __cxa_finalize(void *dso_handle)
}
}
-#if 0 /* haven't looked into this yet... */
/*
* Remove the registered fork handlers. We do not have to
* unregister anything if the program is going to terminate anyway.
*/
#ifdef UNREGISTER_ATFORK
- if (d != NULL) {
- UNREGISTER_ATFORK(d);
+ if (dso_handle != NULL) {
+ UNREGISTER_ATFORK(dso_handle);
}
#endif
-#endif
}
#endif
diff --git a/test/nptl/Makefile.in b/test/nptl/Makefile.in
index 09e2804a6..ac2aa8b1e 100644
--- a/test/nptl/Makefile.in
+++ b/test/nptl/Makefile.in
@@ -42,7 +42,8 @@ TESTS := tst-align tst-align2 tst-atfork1 tst-attr1 tst-attr2 tst-attr3 \
tst-oddstacklimit tst-oncex3 tst-oncex4 tst-rwlock2a \
tst-basic7 tst-signal7 tst-vfork1x tst-vfork2x tst-sem10 tst-sem11 \
tst-sem12 tst-typesizes tst-initializers1-c89 tst-initializers1-c99 \
- tst-initializers1-gnu89 tst-initializers1-gnu99
+ tst-initializers1-gnu89 tst-initializers1-gnu99 \
+ tst-atfork2
#
# These are for the RT library and POSIX timers.
@@ -151,6 +152,8 @@ CFLAGS_tst-initializers1-gnu99 = $(CFLAGS-tst-initializers1) -std=gnu99
EXTRA_LDFLAGS = $(if $(findstring -lpthread,$(LDFLAGS_$@)),,-lpthread)
+LDFLAGS_tst-atfork2 := -ldl
+LDFLAGS_libatfork.so := -shared -static-libgcc -lpthread
LDFLAGS_tst-cleanup4 := tst-cleanup4aux.o
LDFLAGS_tst-cleanupx4 := tst-cleanup4aux.o
LDFLAGS_tst-clock2 := -lrt
@@ -207,6 +210,9 @@ tst-tls5: tst-tls5mod.so
tst-cleanupx4 : tst-cleanup4aux.o
tst-fini1: tst-fini1mod.so
+tst-atfork2: libatfork.so
+tst-atfork2_glibc: libatfork.so.glibc
+
OPTS_tst-cancel7 = -c ./tst-cancel7
OPTS_tst-mqueue7 = -- ./tst-mqueue7
OPTS_tst-exec4 = ./tst-exec4
diff --git a/test/nptl/libatfork.c b/test/nptl/libatfork.c
new file mode 100644
index 000000000..f4ddca057
--- /dev/null
+++ b/test/nptl/libatfork.c
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <pthread.h>
+
+static void atfork_prepare(void)
+{
+ /* nothing to do */
+}
+
+static void atfork_parent(void)
+{
+ /* nothing to do */
+}
+
+static void atfork_child(void)
+{
+ /* nothing to do */
+}
+
+static __attribute__((constructor)) void init(void)
+{
+ pthread_atfork(atfork_prepare, atfork_parent, atfork_child);
+}
+
+static __attribute__((destructor)) void done(void)
+{
+ /* nothing to do */
+}
diff --git a/test/nptl/tst-atfork2.c b/test/nptl/tst-atfork2.c
new file mode 100644
index 000000000..1c303de63
--- /dev/null
+++ b/test/nptl/tst-atfork2.c
@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <dlfcn.h>
+
+int main(int argc, char *argv[])
+{
+ void *h;
+ pid_t pid;
+
+ h = dlopen("libatfork.so", RTLD_NOW);
+ if (!h)
+ {
+ printf("Failed to open libatfork.so\n");
+ return 1;
+ }
+ dlclose(h);
+
+ if ((pid = fork()) < 0) {
+ printf("Fork failed\n");
+ return 1;
+ }
+
+ return 0;
+}