exec: move the final allow_write_access/fput into free_bprm()

Both success/failure paths cleanup bprm->file, we can move this
code into free_bprm() to simlify and cleanup this logic.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 15 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 389fe7b0ba14..f860866e04ba 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1138,9 +1138,7 @@ void setup_new_exec(struct linux_binprm * bprm)
 
         /* An exec changes our domain. We are no longer part of the thread
            group */
-
         current->self_exec_id++;
-                        
         flush_signal_handlers(current, 0);
         do_close_on_exec(current->files);
 }
@@ -1172,6 +1170,10 @@ void free_bprm(struct linux_binprm *bprm)
                 mutex_unlock(&current->signal->cred_guard_mutex);
                 abort_creds(bprm->cred);
         }
+        if (bprm->file) {
+                allow_write_access(bprm->file);
+                fput(bprm->file);
+        }
         /* If a binfmt changed the interp, free it. */
         if (bprm->interp != bprm->filename)
                 kfree(bprm->interp);
@@ -1424,12 +1426,6 @@ static int exec_binprm(struct linux_binprm *bprm)
                 ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
                 current->did_exec = 1;
                 proc_exec_connector(current);
-
-                if (bprm->file) {
-                        allow_write_access(bprm->file);
-                        fput(bprm->file);
-                        bprm->file = NULL; /* to catch use-after-free */
-                }
         }
 
         return ret;
@@ -1492,7 +1488,7 @@ static int do_execve_common(const char *filename,
 
         retval = bprm_mm_init(bprm);
         if (retval)
-                goto out_file;
+                goto out_unmark;
 
         bprm->argc = count(argv, MAX_ARG_STRINGS);
         if ((retval = bprm->argc) < 0)
@@ -1539,12 +1535,6 @@ out:
                 mmput(bprm->mm);
         }
 
-out_file:
-        if (bprm->file) {
-                allow_write_access(bprm->file);
-                fput(bprm->file);
-        }
-
 out_unmark:
         current->fs->in_exec = 0;
         current->in_execve = 0;