[binutils-gdb] Don't return the main file as the separate debug info

[H.J. Lu]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=40eb8b92a1c795cda00bf931ab9cdd74da434d54

commit 40eb8b92a1c795cda00bf931ab9cdd74da434d54
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Dec 10 13:34:22 2021 -0800

    Don't return the main file as the separate debug info
    
    On Fedora 35,
    
    $ readelf -d /usr/bin/npc
    
    caused readelf to run out of stack since load_separate_debug_info
    returned the input main file as the separate debug info:
    
    (gdb) bt
     #0  load_separate_debug_info (
        main_filename=main_filename@entry=0x510f50 "/export/home/hjl/.cache/debuginfod_client/dcc33c51c49e7dafc178fdb5cf8bd8946f965295/debuginfo",
        xlink=xlink@entry=0x4e5180 <debug_displays+4480>,
        parse_func=parse_func@entry=0x431550 <parse_gnu_debuglink>,
        check_func=check_func@entry=0x432ae0 <check_gnu_debuglink>,
        func_data=func_data@entry=0x7fffffffdb60, file=file@entry=0x51d430)
        at /export/gnu/import/git/sources/binutils-gdb/binutils/dwarf.c:11057
     #1  0x000000000043328d in check_for_and_load_links (file=0x51d430,
        filename=0x510f50 "/export/home/hjl/.cache/debuginfod_client/dcc33c51c49e7dafc178fdb5cf8bd8946f965295/debuginfo")
        at /export/gnu/import/git/sources/binutils-gdb/binutils/dwarf.c:11381
     #2  0x00000000004332ae in check_for_and_load_links (file=0x51b070,
        filename=0x518dd0 "/export/home/hjl/.cache/debuginfod_client/dcc33c51c49e7dafc178fdb5cf8bd8946f965295/debuginfo")
    
    Return NULL if the separate debug info is the same as the input main
    file to avoid infinite recursion.
    
            PR binutils/28679
            * dwarf.c (load_separate_debug_info): Don't return the input
            main file.

Diff:
---
 binutils/dwarf.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index 6497e541063..eeef98d4a18 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -11053,6 +11053,9 @@ load_separate_debug_info (const char *            main_filename,
   char *         canon_dir;
   size_t         canon_dirlen;
   size_t         dirlen;
+  char *         canon_filename;
+  char *         canon_debug_filename;
+  bool		 self;
 
   if ((separate_filename = parse_func (xlink, func_data)) == NULL)
     {
@@ -11064,7 +11067,8 @@ load_separate_debug_info (const char *            main_filename,
   /* Attempt to locate the separate file.
      This should duplicate the logic in bfd/opncls.c:find_separate_debug_file().  */
 
-  canon_dir = lrealpath (main_filename);
+  canon_filename = lrealpath (main_filename);
+  canon_dir = xstrdup (canon_filename);
 
   for (canon_dirlen = strlen (canon_dir); canon_dirlen > 0; canon_dirlen--)
     if (IS_DIR_SEPARATOR (canon_dir[canon_dirlen - 1]))
@@ -11096,6 +11100,7 @@ load_separate_debug_info (const char *            main_filename,
     {
       warn (_("Out of memory"));
       free (canon_dir);
+      free (canon_filename);
       return NULL;
     }
 
@@ -11214,11 +11219,22 @@ load_separate_debug_info (const char *            main_filename,
 
   free (canon_dir);
   free (debug_filename);
+  free (canon_filename);
   return NULL;
 
  found:
   free (canon_dir);
 
+  canon_debug_filename = lrealpath (debug_filename);
+  self = strcmp (canon_debug_filename, canon_filename) == 0;
+  free (canon_filename);
+  free (canon_debug_filename);
+  if (self)
+    {
+      free (debug_filename);
+      return NULL;
+    }
+
   void * debug_handle;
 
   /* Now open the file.... */