+ exec-kill-load_binary-=-null-check-in-search_binary_handler.patch added to -mm tree

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Subject: + exec-kill-load_binary-=-null-check-in-search_binary_handler.patch added to -mm tree
To: oleg@xxxxxxxxxx,keescook@xxxxxxxxxxxx,viro@xxxxxxxxxxxxxxxxxx,zbr@xxxxxxxxxxx,zml@xxxxxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 05 Aug 2013 13:45:12 -0700


The patch titled
     Subject: exec: kill ->load_binary != NULL check in search_binary_handler()
has been added to the -mm tree.  Its filename is
     exec-kill-load_binary-=-null-check-in-search_binary_handler.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/exec-kill-load_binary-=-null-check-in-search_binary_handler.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/exec-kill-load_binary-=-null-check-in-search_binary_handler.patch

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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: exec: kill ->load_binary != NULL check in search_binary_handler()

search_binary_handler() checks ->load_binary != NULL for no reason, this
method should be always defined.  Turn this check into WARN_ON() and move
it into __register_binfmt().

Also, kill the function pointer.  The current code looks confusing, as if
->load_binary can go away after read_unlock(&binfmt_lock).  But we rely on
module_get(fmt->module), this fmt can't be changed or unregistered,
otherwise this code is buggy anyway.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Evgeniy Polyakov <zbr@xxxxxxxxxxx>
Cc: Zach Levis <zml@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 fs/exec.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff -puN fs/exec.c~exec-kill-load_binary-=-null-check-in-search_binary_handler fs/exec.c
--- a/fs/exec.c~exec-kill-load_binary-=-null-check-in-search_binary_handler
+++ a/fs/exec.c
@@ -74,6 +74,8 @@ static DEFINE_RWLOCK(binfmt_lock);
 void __register_binfmt(struct linux_binfmt * fmt, int insert)
 {
 	BUG_ON(!fmt);
+	if (WARN_ON(!fmt->load_binary))
+		return;
 	write_lock(&binfmt_lock);
 	insert ? list_add(&fmt->lh, &formats) :
 		 list_add_tail(&fmt->lh, &formats);
@@ -1389,14 +1391,11 @@ int search_binary_handler(struct linux_b
 	for (try=0; try<2; try++) {
 		read_lock(&binfmt_lock);
 		list_for_each_entry(fmt, &formats, lh) {
-			int (*fn)(struct linux_binprm *) = fmt->load_binary;
-			if (!fn)
-				continue;
 			if (!try_module_get(fmt->module))
 				continue;
 			read_unlock(&binfmt_lock);
 			bprm->recursion_depth++;
-			retval = fn(bprm);
+			retval = fmt->load_binary(bprm);
 			bprm->recursion_depth--;
 			if (retval >= 0) {
 				put_binfmt(fmt);
_

Patches currently in -mm which might be from oleg@xxxxxxxxxx are

x86-get_unmapped_area-use-proper-mmap-base-for-bottom-up-direction.patch
include-linux-schedh-dont-use-task-pid-tgid-in-same_thread_group-has_group_leader_pid.patch
mm-mempolicy-turn-vma_set_policy-into-vma_dup_policy.patch
mm-shift-vm_grows-check-from-mmap_region-to-do_mmap_pgoff-v2.patch
mm-do_mmap_pgoff-cleanup-the-usage-of-file_inode.patch
mm-mmap_region-kill-correct_wcount-inode-use-allow_write_access.patch
kernel-wide-fix-missing-validations-on-__get-__put-__copy_to-__copy_from_user.patch
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch
signals-eventpoll-set-saved_sigmask-at-the-start.patch
move-exit_task_namespaces-outside-of-exit_notify-fix.patch
exec-introduce-exec_binprm-for-depth-==-0-code.patch
exec-kill-int-depth-in-search_binary_handler.patch
exec-proc_exec_connector-should-be-called-only-once.patch
exec-move-allow_write_access-fput-to-exec_binprm.patch
exec-kill-load_binary-=-null-check-in-search_binary_handler.patch
exec-cleanup-the-config_modules-logic.patch
exec-dont-retry-if-request_module-fails.patch
exec-cleanup-the-error-handling-in-search_binary_handler.patch
linux-next.patch

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