dlfcn: Failures after dlmopen should not terminate process [BZ #24772]

Commit 9e78f6f6e7134a5f299cc8de77370218f8019237 ("Implement
_dl_catch_error, _dl_signal_error in libc.so [BZ #16628]") has the
side effect that distinct namespaces, as created by dlmopen, now have
separate implementations of the rtld exception mechanism.  This means
that the call to _dl_catch_error from libdl in a secondary namespace
does not actually install an exception handler because the
thread-local variable catch_hook in the libc.so copy in the secondary
namespace is distinct from that of the base namepace.  As a result, a
dlsym/dlopen/... failure in a secondary namespace terminates the process
with a dynamic linker error because it looks to the exception handler
mechanism as if no handler has been installed.

This commit restores GLRO (dl_catch_error) and uses it to set the
handler in the base namespace.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/elf/rtld.c b/elf/rtld.c
index 94a00e2..fd02438 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -368,6 +368,7 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
     ._dl_lookup_symbol_x = _dl_lookup_symbol_x,
     ._dl_open = _dl_open,
     ._dl_close = _dl_close,
+    ._dl_catch_error = _rtld_catch_error,
     ._dl_tls_get_addr_soft = _dl_tls_get_addr_soft,
 #ifdef HAVE_DL_DISCOVER_OSVERSION
     ._dl_discover_osversion = _dl_discover_osversion