commit 8b142566e346beeabca774e01f81934280bcd6b6
author dimitry <dimitry@google.com> Wed May 09 15:22:38 2018 +0200
committer dimitry <dimitry@google.com> Sat May 12 10:58:00 2018 +0200
tree f55079f62d362e1f076a2152055c1133ae648674
parent e0906d8f558675f77636f79e9f232329a3b95e2e

vdso should be available in all namespaces

vdso should be available in all namespaces when present. This
bug went undetected because the way libc currently uses vdso (it
does all the lookups itself). This makes it available for the
programs that want to take advantage by dlopening it.

Bug: http://b/73105445
Bug: http://b/79561555
Test: adb shell /data/nativetest/arm/bionic-unit-tests/bionic-unit-tests --gtest_filter=dl.exec_with_ld_config_file
Test: adb shell /data/nativetest/bionic-unit-tests/bionic-unit-tests --gtest_filter=dl*
Change-Id: I8eae0c9848f256190d1c9ec85d10dc6ce383a8bc
(cherry picked from commit 69c68c46ac18a440bf1c0447d8343a6dbad595f1)

linker/linker.cpp

diff --git a/linker/linker.cpp b/linker/linker.cpp
index 79330fc..96f424e 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -3822,8 +3822,14 @@
   // we can no longer rely on the fact that libdl.so is part of default namespace
   // this is why we want to add ld-android.so to all namespaces from ld.config.txt
   soinfo* ld_android_so = solist_get_head();
+
+  // we also need vdso to be available for all namespaces (if present)
+  soinfo* vdso = solist_get_vdso();
   for (auto it : namespaces) {
     it.second->add_soinfo(ld_android_so);
+    if (vdso != nullptr) {
+      it.second->add_soinfo(vdso);
+    }
     // somain and ld_preloads are added to these namespaces after LD_PRELOAD libs are linked
   }
 

linker/linker_main.cpp

diff --git a/linker/linker_main.cpp b/linker/linker_main.cpp
index dc1fa75..00c72d0 100644
--- a/linker/linker_main.cpp
+++ b/linker/linker_main.cpp
@@ -64,6 +64,7 @@
 static soinfo* solist;
 static soinfo* sonext;
 static soinfo* somain; // main process, always the one after libdl_info
+static soinfo* vdso; // vdso if present
 
 void solist_add_soinfo(soinfo* si) {
   sonext->next = si;
@@ -104,6 +105,10 @@
   return somain;
 }
 
+soinfo* solist_get_vdso() {
+  return vdso;
+}
+
 int g_ld_debug_verbosity;
 abort_msg_t* g_abort_message = nullptr; // For debuggerd.
 
@@ -158,6 +163,8 @@
   si->set_dt_flags_1(si->get_dt_flags_1() | DF_1_NODELETE);
   si->set_linked();
   si->call_constructors();
+
+  vdso = si;
 }
 
 /* gdb expects the linker to be in the debug shared object list.
@@ -280,6 +287,8 @@
     }
   }
 
+  add_vdso(args);
+
   struct stat file_stat;
   // Stat "/proc/self/exe" instead of executable_path because
   // the executable could be unlinked by this point and it should
@@ -366,8 +375,6 @@
     }
   }
 
-  add_vdso(args);
-
   // Load ld_preloads and dependencies.
   std::vector<const char*> needed_library_name_list;
   size_t ld_preloads_count = 0;

linker/linker_main.h

diff --git a/linker/linker_main.h b/linker/linker_main.h
index 8d486e8..b37b947 100644
--- a/linker/linker_main.h
+++ b/linker/linker_main.h
@@ -70,3 +70,4 @@
 bool solist_remove_soinfo(soinfo* si);
 soinfo* solist_get_head();
 soinfo* solist_get_somain();
+soinfo* solist_get_vdso();