asprintf memory leaks

A number of backends want to return bfd_reloc_dangerous messaqes from
relocation special_function, and construct the message using asprintf.
Such messages are not freed anywhere, leading to small memory leaks
inside libbfd.  To limit the leaks, I'd implemented a static buffer in
the ppc backends that was freed before use in asprintf output.  This
patch extends that scheme to other backends using a shared static
buffer and goes further in freeing the buffer on any bfd_close.

The patch also fixes a few other cases where asprintf output was not
freed after use.

bfd/
	* bfd.c (_input_error_msg): Make global and rename to..
	(_bfd_error_buf): ..this.
	(bfd_asprintf): New function.
	(bfd_errmsg): Use bfd_asprintf.
	* opncls.c (bfd_close_all_done): Free _buf_error_buf.
	* elf32-arm.c (find_thumb_glue, find_arm_glue): Use bfd_asprintf.
	* elf32-nios2.c (nios2_elf32_relocate_section): Likewise.
	* elf32-ppc.c (ppc_elf_unhandled_reloc): Likewise.
	* elf64-ppc.c (ppc64_elf_unhandled_reloc): Likewise.
	* elfnn-riscv.c (riscv_resolve_pcrel_lo_relocs): Likewise.
	(riscv_elf_relocate_section): Likewise.
	* libbfd.h: Regenerate.
gas/
	* read.c (read_end): Free current_name and current_label.
	(do_s_func): Likewise on error path.  strdup label.
ld/
	* pe-dll.c (make_head, make_tail, make_one),
	(make_singleton_name_thunk, make_import_fixup_entry),
	(make_runtime_pseudo_reloc),
	(pe_create_runtime_relocator_reference: Free oname after use.

1 files changed, 18 insertions, 27 deletions

diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
index 30d2faa..09aa7be 100644
--- a/bfd/elfnn-riscv.c
+++ b/bfd/elfnn-riscv.c
@@ -2090,14 +2090,14 @@ riscv_resolve_pcrel_lo_relocs (riscv_pcrel_relocs *p)
 	       != RISCV_CONST_HIGH_PART (entry->value + r->reloc->r_addend))
 	{
 	  /* Check the overflow when adding reloc addend.  */
-	  if (asprintf (&string,
-			_("%%pcrel_lo overflow with an addend, the "
-			  "value of %%pcrel_hi is 0x%" PRIx64 " without "
-			  "any addend, but may be 0x%" PRIx64 " after "
-			  "adding the %%pcrel_lo addend"),
-			(int64_t) RISCV_CONST_HIGH_PART (entry->value),
-			(int64_t) RISCV_CONST_HIGH_PART
-				(entry->value + r->reloc->r_addend)) == -1)
+	  string = bfd_asprintf (_("%%pcrel_lo overflow with an addend,"
+				   " the value of %%pcrel_hi is 0x%" PRIx64
+				   " without any addend, but may be 0x%" PRIx64
+				   " after adding the %%pcrel_lo addend"),
+				 (int64_t) RISCV_CONST_HIGH_PART (entry->value),
+				 (int64_t) RISCV_CONST_HIGH_PART
+				 (entry->value + r->reloc->r_addend));
+	  if (string == NULL)
 	    string = _("%pcrel_lo overflow with an addend");
 	}
 
@@ -2184,7 +2184,6 @@ riscv_elf_relocate_section (bfd *output_bfd,
       int r_type = ELFNN_R_TYPE (rel->r_info), tls_type;
       reloc_howto_type *howto = riscv_elf_rtype_to_howto (input_bfd, r_type);
       const char *msg = NULL;
-      char *msg_buf = NULL;
       bool resolved_to_zero;
 
       if (howto == NULL)
@@ -2705,14 +2704,12 @@ riscv_elf_relocate_section (bfd *output_bfd,
 
 		     Perhaps we also need the similar checks for the
 		     R_RISCV_BRANCH and R_RISCV_RVC_BRANCH relocations.  */
-		  if (asprintf (&msg_buf,
-				_("%%X%%P: relocation %s against `%s' which "
-				  "may bind externally can not be used when "
-				  "making a shared object; recompile "
-				  "with -fPIC\n"),
-				howto->name, h->root.root.string) == -1)
-		    msg_buf = NULL;
-		  msg = msg_buf;
+		  msg = bfd_asprintf (_("%%X%%P: relocation %s against `%s'"
+					" which may bind externally"
+					" can not be used"
+					" when making a shared object;"
+					" recompile with -fPIC\n"),
+				      howto->name, h->root.root.string);
 		  r = bfd_reloc_notsupported;
 		}
 	    }
@@ -2999,13 +2996,10 @@ riscv_elf_relocate_section (bfd *output_bfd,
 	  && _bfd_elf_section_offset (output_bfd, info, input_section,
 				      rel->r_offset) != (bfd_vma) -1)
 	{
-	  if (asprintf (&msg_buf,
-			_("%%X%%P: unresolvable %s relocation against "
-			  "symbol `%s'\n"),
-			howto->name,
-			h->root.root.string) == -1)
-	    msg_buf = NULL;
-	  msg = msg_buf;
+	  msg = bfd_asprintf (_("%%X%%P: unresolvable %s relocation against "
+				"symbol `%s'\n"),
+			      howto->name,
+			      h->root.root.string);
 	  r = bfd_reloc_notsupported;
 	}
 
@@ -3062,9 +3056,6 @@ riscv_elf_relocate_section (bfd *output_bfd,
       if (msg && r != bfd_reloc_dangerous)
 	info->callbacks->einfo (msg);
 
-      /* Free the unused `msg_buf`.  */
-      free (msg_buf);
-
       /* We already reported the error via a callback, so don't try to report
 	 it again by returning false.  That leads to spurious errors.  */
       ret = true;