Re: PATCH: BPs in malloc.c

[Greg McGary <greg at mcgary dot org>]

Wolfram Gloger <wmglo@dent.med.uni-muenchen.de> writes:

> Looks fine to me, except for the bounded pointer size in
> chunk2mem_check().  I think the following additional patch is
> necessary.

> If you do runtime tests, please also do a test with MALLOC_CHECK_ set
> (to 1 or 2).

I will arrange the makefiles so that the testsuite runs malloc tests
with MALLOC_CHECK_=3.  Is there any reason to test without MALLOC_CHECK_?
If not, then we'll just test once with MALLOC_CHECK_=3.

Since you haven't yet checked this in, should I do it for you?
OK with you, Uli?

> 2000-07-27  Wolfram Gloger  <wg@malloc.de>
> 
> 	* malloc/malloc.c (chunk2mem_check): Fix bounded pointer size.
> 	* malloc/malloc.c [! _LIBC]: Define RETURN_ADDRSS.
> 
> Index: libc/malloc/malloc.c
> ===================================================================
> RCS file: /cvs/glibc/libc/malloc/malloc.c,v
> retrieving revision 1.68
> diff -u -r1.68 malloc.c
> --- malloc.c	2000/07/26 18:19:03	1.68
> +++ malloc.c	2000/07/27 08:44:08
> @@ -316,6 +316,7 @@
>  
>  #ifndef _LIBC
>  # define __secure_getenv(Str) getenv (Str)
> +# define RETURN_ADDRESS(Ptr) __builtin_return_address (Ptr)
>  #endif
>  
>  /* Macros for handling mutexes and thread-specific data.  This is
> @@ -4381,12 +4382,12 @@
>  chunk2mem_check(p, sz) mchunkptr p; size_t sz;
>  #endif
>  {
> -  unsigned char* m_ptr = (unsigned char*)BOUNDED_N(chunk2mem(p), sz);
> +  /* Available size for detector bytes.  */
> +  size_t asz = chunksize(p) - (chunk_is_mmapped(p) ? 2*SIZE_SZ : SIZE_SZ);
> +  unsigned char* m_ptr = (unsigned char*)BOUNDED_N(chunk2mem(p), asz);
>    size_t i;
>  
> -  for(i = chunksize(p) - (chunk_is_mmapped(p) ? 2*SIZE_SZ+1 : SIZE_SZ+1);
> -      i > sz;
> -      i -= 0xFF) {
> +  for(i = asz-1; i > sz; i -= 0xFF) {
>      if(i-sz < 0x100) {
>        m_ptr[i] = (unsigned char)(i-sz);
>        break;