[binutils-gdb] PR25823, Use after free in bfd_hash_lookup

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=7ecb51549ab1ec22aba5aaf34b70323cf0b8509a

commit 7ecb51549ab1ec22aba5aaf34b70323cf0b8509a
Author: Alan Modra <amodra@gmail.com>
Date:   Wed Apr 15 18:58:11 2020 +0930

    PR25823, Use after free in bfd_hash_lookup
    
            PR 25823
            * peXXigen.c (_bfd_XXi_swap_sym_in <C_SECTION>): Don't use a
            pointer into strings that may be freed for section name, always
            allocate a new string.

Diff:
---
 bfd/ChangeLog  |  7 +++++++
 bfd/peXXigen.c | 20 ++++++++++----------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index c3015012ab3..e837fdc1334 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2020-04-15  Alan Modra  <amodra@gmail.com>
+
+	PR 25823
+	* peXXigen.c (_bfd_XXi_swap_sym_in <C_SECTION>): Don't use a
+	pointer into strings that may be freed for section name, always
+	allocate a new string.
+
 2020-04-14  Juan Manuel Guerrero  <juan.guerrero@gmx.de>
             Jan W. Jagersma  <jwjagersma@gmail.com>
 
diff --git a/bfd/peXXigen.c b/bfd/peXXigen.c
index b9eeb775d9b..8aa5914acd9 100644
--- a/bfd/peXXigen.c
+++ b/bfd/peXXigen.c
@@ -177,25 +177,25 @@ _bfd_XXi_swap_sym_in (bfd * abfd, void * ext1, void * in1)
 	  int unused_section_number = 0;
 	  asection *sec;
 	  flagword flags;
+	  size_t name_len;
+	  char *sec_name;
 
 	  for (sec = abfd->sections; sec; sec = sec->next)
 	    if (unused_section_number <= sec->target_index)
 	      unused_section_number = sec->target_index + 1;
 
-	  if (name == namebuf)
+	  name_len = strlen (name) + 1;
+	  sec_name = bfd_alloc (abfd, name_len);
+	  if (sec_name == NULL)
 	    {
-	      name = (const char *) bfd_alloc (abfd, strlen (namebuf) + 1);
-	      if (name == NULL)
-		{
-		  _bfd_error_handler (_("%pB: out of memory creating name for empty section"),
-				      abfd);
-		  return;
-		}
-	      strcpy ((char *) name, namebuf);
+	      _bfd_error_handler (_("%pB: out of memory creating name "
+				    "for empty section"), abfd);
+	      return;
 	    }
+	  memcpy (sec_name, name, name_len);
 
 	  flags = SEC_HAS_CONTENTS | SEC_ALLOC | SEC_DATA | SEC_LOAD;
-	  sec = bfd_make_section_anyway_with_flags (abfd, name, flags);
+	  sec = bfd_make_section_anyway_with_flags (abfd, sec_name, flags);
 	  if (sec == NULL)
 	    {
 	      _bfd_error_handler (_("%pB: unable to create fake empty section"),