[binutils-gdb] PR29677, Field `the_bfd` of `asymbol` is uninitialised

[Alan Modra <amodra@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d12f8998d2d086f0a6606589e5aedb7147e6f2f1

commit d12f8998d2d086f0a6606589e5aedb7147e6f2f1
Author: Alan Modra <amodra@gmail.com>
Date:   Fri Oct 14 10:30:21 2022 +1030

    PR29677, Field `the_bfd` of `asymbol` is uninitialised
    
    Besides not initialising the_bfd of synthetic symbols, counting
    symbols when sizing didn't match symbols created if there were any
    dynsyms named "".  We don't want synthetic symbols without names
    anyway, so get rid of them.  Also, simplify and correct sanity checks.
    
            PR 29677
            * mach-o.c (bfd_mach_o_get_synthetic_symtab): Rewrite.

Diff:
---
 bfd/mach-o.c | 72 ++++++++++++++++++++++++++----------------------------------
 1 file changed, 31 insertions(+), 41 deletions(-)

diff --git a/bfd/mach-o.c b/bfd/mach-o.c
index acb35e7f0c6..5279343768c 100644
--- a/bfd/mach-o.c
+++ b/bfd/mach-o.c
@@ -938,11 +938,9 @@ bfd_mach_o_get_synthetic_symtab (bfd *abfd,
   bfd_mach_o_symtab_command *symtab = mdata->symtab;
   asymbol *s;
   char * s_start;
-  char * s_end;
   unsigned long count, i, j, n;
   size_t size;
   char *names;
-  char *nul_name;
   const char stub [] = "$stub";
 
   *ret = NULL;
@@ -955,27 +953,27 @@ bfd_mach_o_get_synthetic_symtab (bfd *abfd,
   /* We need to allocate a bfd symbol for every indirect symbol and to
      allocate the memory for its name.  */
   count = dysymtab->nindirectsyms;
-  size = count * sizeof (asymbol) + 1;
-
+  size = 0;
   for (j = 0; j < count; j++)
     {
-      const char * strng;
       unsigned int isym = dysymtab->indirect_syms[j];
+      const char *str;
 
       /* Some indirect symbols are anonymous.  */
-      if (isym < symtab->nsyms && (strng = symtab->symbols[isym].symbol.name))
-	/* PR 17512: file: f5b8eeba.  */
-	size += strnlen (strng, symtab->strsize - (strng - symtab->strtab)) + sizeof (stub);
+      if (isym < symtab->nsyms
+	  && (str = symtab->symbols[isym].symbol.name) != NULL)
+	{
+	  /* PR 17512: file: f5b8eeba.  */
+	  size += strnlen (str, symtab->strsize - (str - symtab->strtab));
+	  size += sizeof (stub);
+	}
     }
 
-  s_start = bfd_malloc (size);
+  s_start = bfd_malloc (size + count * sizeof (asymbol));
   s = *ret = (asymbol *) s_start;
   if (s == NULL)
     return -1;
   names = (char *) (s + count);
-  nul_name = names;
-  *names++ = 0;
-  s_end = s_start + size;
 
   n = 0;
   for (i = 0; i < mdata->nsects; i++)
@@ -997,47 +995,39 @@ bfd_mach_o_get_synthetic_symtab (bfd *abfd,
 	  entry_size = bfd_mach_o_section_get_entry_size (abfd, sec);
 
 	  /* PR 17512: file: 08e15eec.  */
-	  if (first >= count || last >= count || first > last)
+	  if (first >= count || last > count || first > last)
 	    goto fail;
 
 	  for (j = first; j < last; j++)
 	    {
 	      unsigned int isym = dysymtab->indirect_syms[j];
-
-	      /* PR 17512: file: 04d64d9b.  */
-	      if (((char *) s) + sizeof (* s) > s_end)
-		goto fail;
-
-	      s->flags = BSF_GLOBAL | BSF_SYNTHETIC;
-	      s->section = sec->bfdsection;
-	      s->value = addr - sec->addr;
-	      s->udata.p = NULL;
+	      const char *str;
+	      size_t len;
 
 	      if (isym < symtab->nsyms
-		  && symtab->symbols[isym].symbol.name)
+		  && (str = symtab->symbols[isym].symbol.name) != NULL)
 		{
-		  const char *sym = symtab->symbols[isym].symbol.name;
-		  size_t len;
-
-		  s->name = names;
-		  len = strlen (sym);
-		  /* PR 17512: file: 47dfd4d2.  */
-		  if (names + len >= s_end)
+		  /* PR 17512: file: 04d64d9b.  */
+		  if (n >= count)
 		    goto fail;
-		  memcpy (names, sym, len);
-		  names += len;
-		  /* PR 17512: file: 18f340a4.  */
-		  if (names + sizeof (stub) >= s_end)
+		  len = strnlen (str, symtab->strsize - (str - symtab->strtab));
+		  /* PR 17512: file: 47dfd4d2, 18f340a4.  */
+		  if (size < len + sizeof (stub))
 		    goto fail;
-		  memcpy (names, stub, sizeof (stub));
-		  names += sizeof (stub);
+		  memcpy (names, str, len);
+		  memcpy (names + len, stub, sizeof (stub));
+		  s->name = names;
+		  names += len + sizeof (stub);
+		  size -= len + sizeof (stub);
+		  s->the_bfd = symtab->symbols[isym].symbol.the_bfd;
+		  s->flags = BSF_GLOBAL | BSF_SYNTHETIC;
+		  s->section = sec->bfdsection;
+		  s->value = addr - sec->addr;
+		  s->udata.p = NULL;
+		  s++;
+		  n++;
 		}
-	      else
-		s->name = nul_name;
-
 	      addr += entry_size;
-	      s++;
-	      n++;
 	    }
 	  break;
 	default: