elf: Always set l in _dl_init_paths (bug 23462)

After d1d5471579eb0426671bf94f2d71e61dfb204c30 ("Remove dead
DL_DST_REQ_STATIC code.") we always setup the link map l to make the
static and shared cases the same.  The bug is that in elf/dl-load.c
(_dl_init_paths) we conditionally set l only in the #ifdef SHARED
case, but unconditionally use it later.  The simple solution is to
remove the #ifdef SHARED conditional, because it's no longer needed,
and unconditionally setup l for both the static and shared cases. A
regression test is added to run a static binary with
LD_LIBRARY_PATH='$ORIGIN' which crashes before the fix and runs after
the fix.

Co-Authored-By: Florian Weimer <fweimer@redhat.com>

1 files changed, 29 insertions, 34 deletions

diff --git a/elf/dl-load.c b/elf/dl-load.c
index 9e2089cfaa..376a2e64d6 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -758,50 +758,45 @@ _dl_init_paths (const char *llp, const char *source,
   max_dirnamelen = SYSTEM_DIRS_MAX_LEN;
   *aelem = NULL;
 
-#ifdef SHARED
   /* This points to the map of the main object.  */
   l = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
-  if (l != NULL)
+  assert (l->l_type != lt_loaded);
+
+  if (l->l_info[DT_RUNPATH])
+    {
+      /* Allocate room for the search path and fill in information
+	 from RUNPATH.  */
+      decompose_rpath (&l->l_runpath_dirs,
+		       (const void *) (D_PTR (l, l_info[DT_STRTAB])
+				       + l->l_info[DT_RUNPATH]->d_un.d_val),
+		       l, "RUNPATH");
+      /* During rtld init the memory is allocated by the stub malloc,
+	 prevent any attempt to free it by the normal malloc.  */
+      l->l_runpath_dirs.malloced = 0;
+
+      /* The RPATH is ignored.  */
+      l->l_rpath_dirs.dirs = (void *) -1;
+    }
+  else
     {
-      assert (l->l_type != lt_loaded);
+      l->l_runpath_dirs.dirs = (void *) -1;
 
-      if (l->l_info[DT_RUNPATH])
+      if (l->l_info[DT_RPATH])
 	{
 	  /* Allocate room for the search path and fill in information
-	     from RUNPATH.  */
-	  decompose_rpath (&l->l_runpath_dirs,
+	     from RPATH.  */
+	  decompose_rpath (&l->l_rpath_dirs,
 			   (const void *) (D_PTR (l, l_info[DT_STRTAB])
-					   + l->l_info[DT_RUNPATH]->d_un.d_val),
-			   l, "RUNPATH");
-	  /* During rtld init the memory is allocated by the stub malloc,
-	     prevent any attempt to free it by the normal malloc.  */
-	  l->l_runpath_dirs.malloced = 0;
-
-	  /* The RPATH is ignored.  */
-	  l->l_rpath_dirs.dirs = (void *) -1;
+					   + l->l_info[DT_RPATH]->d_un.d_val),
+			   l, "RPATH");
+	  /* During rtld init the memory is allocated by the stub
+	     malloc, prevent any attempt to free it by the normal
+	     malloc.  */
+	  l->l_rpath_dirs.malloced = 0;
 	}
       else
-	{
-	  l->l_runpath_dirs.dirs = (void *) -1;
-
-	  if (l->l_info[DT_RPATH])
-	    {
-	      /* Allocate room for the search path and fill in information
-		 from RPATH.  */
-	      decompose_rpath (&l->l_rpath_dirs,
-			       (const void *) (D_PTR (l, l_info[DT_STRTAB])
-					       + l->l_info[DT_RPATH]->d_un.d_val),
-			       l, "RPATH");
-	      /* During rtld init the memory is allocated by the stub
-		 malloc, prevent any attempt to free it by the normal
-		 malloc.  */
-	      l->l_rpath_dirs.malloced = 0;
-	    }
-	  else
-	    l->l_rpath_dirs.dirs = (void *) -1;
-	}
+	l->l_rpath_dirs.dirs = (void *) -1;
     }
-#endif	/* SHARED */
 
   if (llp != NULL && *llp != '\0')
     {