Fix illegal memory accesses in the assembler when attempting to parse corrup tinput files.

	PR 23054
	* cond.c (s_ifsef): Replace use of obstack_copy with obstack_alloc
	followed by memcpy.
	(s_if, s_ifb, s_ifc, s_ifeqs): Likewise.
	* obj-elf.c (elf_adjust_symtab): Check for local symbols before
	attempting to dereference the sy_next field of a symbol.
	* stabs.c (get_stab_string_offset): Fail if there is no string
	following the stab directive.

1 files changed, 22 insertions, 16 deletions

diff --git a/gas/cond.c b/gas/cond.c
index b74bde7..71680a5 100644
--- a/gas/cond.c
+++ b/gas/cond.c
@@ -28,7 +28,8 @@
    scanned.  */
 struct obstack cond_obstack;
 
-struct file_line {
+struct file_line
+{
   const char *file;
   unsigned int line;
 };
@@ -36,7 +37,8 @@ struct file_line {
 /* We push one of these structures for each .if, and pop it at the
    .endif.  */
 
-struct conditional_frame {
+struct conditional_frame
+{
   /* The source file & line number of the "if".  */
   struct file_line if_file_line;
   /* The source file & line of the "else".  */
@@ -108,9 +110,9 @@ s_ifdef (int test_defined)
       cframe.ignoring = ! (test_defined ^ is_defined);
     }
 
-  current_cframe = ((struct conditional_frame *)
-		    obstack_copy (&cond_obstack, &cframe,
-				  sizeof (cframe)));
+  current_cframe =
+    (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
+  memcpy (current_cframe, &cframe, sizeof cframe);
 
   if (LISTING_SKIP_COND ()
       && cframe.ignoring
@@ -166,8 +168,9 @@ s_if (int arg)
      using an undefined result.  No big deal.  */
   initialize_cframe (&cframe);
   cframe.ignoring = cframe.dead_tree || ! t;
-  current_cframe = ((struct conditional_frame *)
-		    obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
+  current_cframe =
+    (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
+  memcpy (current_cframe, & cframe, sizeof cframe);
 
   if (LISTING_SKIP_COND ()
       && cframe.ignoring
@@ -202,9 +205,9 @@ s_ifb (int test_blank)
       cframe.ignoring = (test_blank == !is_eol);
     }
 
-  current_cframe = ((struct conditional_frame *)
-		    obstack_copy (&cond_obstack, &cframe,
-				  sizeof (cframe)));
+  current_cframe =
+    (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
+  memcpy (current_cframe, &cframe, sizeof cframe);
 
   if (LISTING_SKIP_COND ()
       && cframe.ignoring
@@ -283,10 +286,11 @@ s_ifc (int arg)
 
   initialize_cframe (&cframe);
   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
-  current_cframe = ((struct conditional_frame *)
-		    obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
-
-  if (LISTING_SKIP_COND ()
+  current_cframe =
+    (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
+  memcpy (current_cframe, &cframe, sizeof cframe);
+  
+ if (LISTING_SKIP_COND ()
       && cframe.ignoring
       && (cframe.previous_cframe == NULL
 	  || ! cframe.previous_cframe->ignoring))
@@ -477,8 +481,9 @@ s_ifeqs (int arg)
 
   initialize_cframe (&cframe);
   cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
-  current_cframe = ((struct conditional_frame *)
-		    obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
+  current_cframe =
+    (struct conditional_frame *) obstack_alloc (&cond_obstack, sizeof cframe);
+  memcpy (current_cframe, &cframe, sizeof cframe);
 
   if (LISTING_SKIP_COND ()
       && cframe.ignoring
@@ -548,6 +553,7 @@ cond_finish_check (int nest)
 	as_bad (_("end of macro inside conditional"));
       else
 	as_bad (_("end of file inside conditional"));
+
       as_bad_where (current_cframe->if_file_line.file,
 		    current_cframe->if_file_line.line,
 		    _("here is the start of the unterminated conditional"));