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authorFangrui Song <maskray@google.com>2022-05-27 12:34:49 -0700
committerFangrui Song <maskray@google.com>2022-05-27 12:34:49 -0700
commitefa7936e4c91b1c260d03614bb26858fbb8a0204 (patch)
tree185200d244eb184a647b7b76d2cc7465d15f2f41 /elf/Makefile
parentf8587a61892cbafd98ce599131bf4f103466f084 (diff)
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dlsym: Make RTLD_NEXT prefer default version definition [BZ #14932]
When the first object providing foo defines both foo@v1 and foo@@v2,
dlsym(RTLD_NEXT, "foo") returns foo@v1 while dlsym(RTLD_DEFAULT, "foo")
returns foo@@v2.  The issue is that RTLD_DEFAULT uses the
DL_LOOKUP_RETURN_NEWEST flag while RTLD_NEXT doesn't.  Fix the RTLD_NEXT
branch to use DL_LOOKUP_RETURN_NEWEST.

Note: the new behavior matches FreeBSD rtld.  Future sanitizers will not
need to add versioned interceptors like https://reviews.llvm.org/D96348

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
Diffstat (limited to 'elf/Makefile')
-rw-r--r--elf/Makefile7
1 files changed, 7 insertions, 0 deletions
diff --git a/elf/Makefile b/elf/Makefile
index 838fe39afb..bfc9179fc5 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -426,6 +426,7 @@ tests += \
   tst-initorder2 \
   tst-latepthread \
   tst-main1 \
+  tst-next-ver \
   tst-nodelete2 \
   tst-nodelete-dlclose \
   tst-nodelete-opened \
@@ -712,6 +713,7 @@ modules-names += \
   neededobj6 \
   nextmod1 \
   nextmod2 \
+  nextmod3 \
   nodel2mod1 \
   nodel2mod2 \
   nodel2mod3 \
@@ -1690,6 +1692,9 @@ $(objpfx)reldep4.out: $(objpfx)reldep4mod1.so $(objpfx)reldep4mod2.so
 $(objpfx)next: $(objpfx)nextmod1.so $(objpfx)nextmod2.so
 LDFLAGS-next = -Wl,--no-as-needed
 
+$(objpfx)tst-next-ver: $(objpfx)nextmod3.so
+LDFLAGS-tst-next-ver = -Wl,--no-as-needed
+
 $(objpfx)unload2.out: $(objpfx)unload2mod.so $(objpfx)unload2dep.so
 
 $(objpfx)lateglobal.out: $(objpfx)ltglobmod1.so $(objpfx)ltglobmod2.so
@@ -2437,6 +2442,8 @@ $(objpfx)tst-linkall-static: \
 endif
 endif
 
+LDFLAGS-nextmod3.so = -Wl,--version-script=nextmod3.map
+
 # The application depends on the DSO, and the DSO loads the plugin.
 # The plugin also depends on the DSO. This creates the circular
 # dependency via dlopen that we're testing to make sure works.