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Lock on dl_interate_phdr

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There is possibility of someone dlclosing a library
while dl_iterate_phdr in progress which can lead to
dl_iterate_phdr calling callback with invalid address
if it was unmapped by dlclose.

Bug: http://b/22047255
Change-Id: I3fc0d9fd2c51fb36fd34cb035f37271fa893a7be
(cherry picked from commit f7d5bf334d)
This commit is contained in:
Dmitriy Ivanov 2015-06-29 14:48:25 -07:00
parent 46d24d12e1
commit 7271caf93d
3 changed files with 8 additions and 1 deletions
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5
linker/dlfcn.cpp
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@ -158,6 +158,11 @@ int dlclose(void* handle) {
return 0;
}
int dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data) {
ScopedPthreadMutexLocker locker(&g_dl_mutex);
return do_dl_iterate_phdr(cb, data);
}
void android_set_application_target_sdk_version(uint32_t target) {
// lock to avoid modification in the middle of dlopen.
ScopedPthreadMutexLocker locker(&g_dl_mutex);

2
linker/linker.cpp
View file

@ -393,7 +393,7 @@ _Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr pc, int* pcount) {
// Here, we only have to provide a callback to iterate across all the
// loaded libraries. gcc_eh does the rest.
int dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data) {
int do_dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data) {
int rv = 0;
for (soinfo* si = solist; si != nullptr; si = si->next) {
dl_phdr_info dl_info;

2
linker/linker.h
View file

@ -428,6 +428,8 @@ void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path);
soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo);
void do_dlclose(soinfo* si);
int do_dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data);
const ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* caller, void* handle);
soinfo* find_containing_library(const void* addr);