dl: fix dlsym lookups with RTLD_NEXT

The current code for dlsym() when invoked with RTLD_NEXT lookup
searches for the module where it's being called from, and executes the
_dl_find_hash only for the next module in the chain. However, if the
looked symbol is not there, the rest of the modules are not checked.

Generally this is not a problem as symbols are merged for the parent
modules; so this affects only RTLD_NEXT.

This patch adds a loop iterating through all the following modules.

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Reviewed-by: Filippo ARCIDIACONO <filippo.arcidiacono@st.com>
Tested-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

diff --git a/ldso/libdl/libdl.c b/ldso/libdl/libdl.c
index 8bc3071..2337223 100644 (file)
--- a/ldso/libdl/libdl.c
+++ b/ldso/libdl/libdl.c
@@ -671,7 +671,7 @@ static void *do_dlsym(void *vhandle, const char *name, void *caller_address)
 {
        struct elf_resolve *tpnt, *tfrom;
        struct dyn_elf *handle;
-       ElfW(Addr) from;
+       ElfW(Addr) from = 0;
        struct dyn_elf *rpnt;
        void *ret;
        struct symbol_ref sym_ref = { NULL, NULL };
@@ -729,7 +729,13 @@ static void *do_dlsym(void *vhandle, const char *name, void *caller_address)
        tpnt = NULL;
        if (handle == _dl_symbol_tables)
                tpnt = handle->dyn; /* Only search RTLD_GLOBAL objs if global object */
-       ret = _dl_find_hash(name2, &handle->dyn->symbol_scope, tpnt, ELF_RTYPE_CLASS_DLSYM, &sym_ref);
+
+       do {
+               ret = _dl_find_hash(name2, &handle->dyn->symbol_scope, tpnt, ELF_RTYPE_CLASS_DLSYM, &sym_ref);
+               if (ret != NULL)
+                       break;
+               handle = handle->next;
+       } while (from && handle);
 
 #if defined(USE_TLS) && USE_TLS && defined SHARED
        if (sym_ref.sym && (ELF_ST_TYPE(sym_ref.sym->st_info) == STT_TLS) && (sym_ref.tpnt)) {