Keep only ELF_RTYPE_CLASS_{PLT|COPY} bits for prelink

prelink runs ld.so with the environment variable LD_TRACE_PRELINKING
set to dump the relocation type class from _dl_debug_bindings.  prelink
has the following relocation type classes:

 #define RTYPE_CLASS_VALID       8
 #define RTYPE_CLASS_PLT         (8|1)
 #define RTYPE_CLASS_COPY        (8|2)
 #define RTYPE_CLASS_TLS         (8|4)

where ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA has a conflict with
RTYPE_CLASS_TLS.

Since prelink only uses ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY
bits, we should clear the other bits when the DL_DEBUG_PRELINK bit is
set.

	[BZ #19178]
	* elf/dl-lookup.c (RTYPE_CLASS_VALID): New.
	(RTYPE_CLASS_PLT): Likewise.
	(RTYPE_CLASS_COPY): Likewise.
	(RTYPE_CLASS_TLS): Likewise.
	(_dl_debug_bindings): Use RTYPE_CLASS_TLS and RTYPE_CLASS_VALID
	to set relocation type class for DL_DEBUG_PRELINK.  Keep only
	ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY bits for
	DL_DEBUG_PRELINK.

(cherry picked from commit f3d18efb8a720121066dc3401e822043beb98cde)
(cherry picked from commit 387011e0b6f9cbefd26691f0df8ce76bb7ddfa03)

diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index 11cb44b451730a4085a395ee8e8ac9bbb458b79c..acf52807df40da016a9e5969269601b0361bb2ee 100644 (file)
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -1016,6 +1016,18 @@ _dl_debug_bindings (const char *undef_name, struct link_map *undef_map,
 #ifdef SHARED
   if (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK)
     {
+/* ELF_RTYPE_CLASS_XXX must match RTYPE_CLASS_XXX used by prelink with
+   LD_TRACE_PRELINKING.  */
+#define RTYPE_CLASS_VALID      8
+#define RTYPE_CLASS_PLT                (8|1)
+#define RTYPE_CLASS_COPY       (8|2)
+#define RTYPE_CLASS_TLS                (8|4)
+#if ELF_RTYPE_CLASS_PLT != 0 && ELF_RTYPE_CLASS_PLT != 1
+# error ELF_RTYPE_CLASS_PLT must be 0 or 1!
+#endif
+#if ELF_RTYPE_CLASS_COPY != 0 && ELF_RTYPE_CLASS_COPY != 2
+# error ELF_RTYPE_CLASS_COPY must be 0 or 2!
+#endif
       int conflict = 0;
       struct sym_val val = { NULL, NULL };
 
@@ -1071,12 +1083,17 @@ _dl_debug_bindings (const char *undef_name, struct link_map *undef_map,
 
       if (value->s)
        {
+         /* Keep only ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY
+            bits since since prelink only uses them.  */
+         type_class &= ELF_RTYPE_CLASS_PLT | ELF_RTYPE_CLASS_COPY;
          if (__glibc_unlikely (ELFW(ST_TYPE) (value->s->st_info)
                                == STT_TLS))
-           type_class = 4;
+           /* Clear the RTYPE_CLASS_VALID bit in RTYPE_CLASS_TLS.  */
+           type_class = RTYPE_CLASS_TLS & ~RTYPE_CLASS_VALID;
          else if (__glibc_unlikely (ELFW(ST_TYPE) (value->s->st_info)
                                     == STT_GNU_IFUNC))
-           type_class |= 8;
+           /* Set the RTYPE_CLASS_VALID bit.  */
+           type_class |= RTYPE_CLASS_VALID;
        }
 
       if (conflict