[PATCH] sanitize handling of shared descriptor tables in failing execve()

* unshare_files() can fail; doing it after irreversible actions is wrong
  and de_thread() is certainly irreversible.
* since we do it unconditionally anyway, we might as well do it in do_execve()
  and save ourselves the PITA in binfmt handlers, etc.
* while we are at it, binfmt_som actually leaked files_struct on failure.

As a side benefit, unshare_files(), put_files_struct() and reset_files_struct()
become unexported.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 0 insertions, 10 deletions

diff --git a/fs/binfmt_som.c b/fs/binfmt_som.c
index 14c63527c762..fdc36bfd6a7b 100644
--- a/fs/binfmt_som.c
+++ b/fs/binfmt_som.c
@@ -194,7 +194,6 @@ load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs)
         unsigned long som_entry;
         struct som_hdr *som_ex;
         struct som_exec_auxhdr *hpuxhdr;
-        struct files_struct *files;
 
         /* Get the exec-header */
         som_ex = (struct som_hdr *) bprm->buf;
@@ -221,15 +220,6 @@ load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs)
                 goto out_free;
         }
 
-        files = current->files; /* Refcounted so ok */
-        retval = unshare_files();
-        if (retval < 0)
-                goto out_free;
-        if (files == current->files) {
-                put_files_struct(files);
-                files = NULL;
-        }
-
         retval = get_unused_fd();
         if (retval < 0)
                 goto out_free;