From f7d5bf334dc4bc5b7399d4c8268e1b0bf676548f Mon Sep 17 00:00:00 2001 From: Dmitriy Ivanov Date: Mon, 29 Jun 2015 14:48:25 -0700 Subject: [PATCH] Lock on dl_interate_phdr 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 --- linker/dlfcn.cpp | 5 +++++ linker/linker.cpp | 2 +- linker/linker.h | 2 ++ 3 files changed, 8 insertions(+), 1 deletion(-) diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp index a70abf51b..ef454abcd 100644 --- a/linker/dlfcn.cpp +++ b/linker/dlfcn.cpp @@ -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); diff --git a/linker/linker.cpp b/linker/linker.cpp index e1b8ca97d..f7b58c4c9 100644 --- a/linker/linker.cpp +++ b/linker/linker.cpp @@ -353,7 +353,7 @@ _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; diff --git a/linker/linker.h b/linker/linker.h index 6042cb844..023b6721f 100644 --- a/linker/linker.h +++ b/linker/linker.h @@ -421,6 +421,8 @@ 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); -- 2.11.0