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authorH.J. Lu <hjl.tools@gmail.com>2015-11-07 06:32:30 -0800
committerMike Frysinger <vapier@gentoo.org>2016-01-24 03:52:26 -0500
commitfb3642bf3c7743da1928d01525d912ca979b468e (patch)
tree2d8e9eed289bd15b4bacf0fb9f8c5a8f5328ec64
parentb4f19537f9d26dbf95bd2e7d9c056400ad1b5723 (diff)
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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)
-rw-r--r--elf/dl-lookup.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index 11cb44b451..acf52807df 100644
--- 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