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SubjectRe: [patch 1/5] binfmt: fix uaccess handling
On Thu, 26 Oct 2006 15:01:46 +0200
Heiko Carstens <heiko.carstens@de.ibm.com> wrote:

> @@ -254,7 +255,8 @@
> p = current->mm->arg_end = current->mm->arg_start;
> while (argc-- > 0) {
> size_t len;
> - __put_user((elf_addr_t)p, argv++);
> + if (__put_user((elf_addr_t)p, argv++))
> + return -EFAULT;
> len = strnlen_user((void __user *)p, PAGE_SIZE*MAX_ARG_PAGES);
> if (!len || len > PAGE_SIZE*MAX_ARG_PAGES)
> return 0;

We return EFAULT, but if strnlen_user() gets a fault, we return zero. But
then, the return value of create_elf_tables() gets cheerfully ignored
anyway. So I assume we start up some new program with a
partially-constructed environment and it then mysteriously malfunctions.

Nice, eh?
-
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