The patch titled
Subject: exec: binfmt_misc: shift filp_close(interp_file) from kill_node() to bm_evict_inode()
has been added to the -mm tree. Its filename is
exec-binfmt_misc-shift-filp_closeinterp_file-from-kill_node-to-bm_evict_inode.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/exec-binfmt_misc-shift-filp_closeinterp_file-from-kill_node-to-bm_evict_inode.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/exec-binfmt_misc-shift-filp_closeinterp_file-from-kill_node-to-bm_evict_inode.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: exec: binfmt_misc: shift filp_close(interp_file) from kill_node() to bm_evict_inode()
To ensure that load_misc_binary() can't use the partially destroyed Node,
see also the next patch.
The current logic looks wrong in any case, once we close interp_file it
doesn't make any sense to delay kfree(inode->i_private), this Node is no
longer valid. Even if the MISC_FMT_OPEN_FILE/interp_file checks were not
racy (they are), load_misc_binary() should not try to reopen ->interpreter
if MISC_FMT_OPEN_FILE is set but ->interp_file is NULL.
And I can't understand why do we use filp_close(), not fput().
Link: http://lkml.kernel.org/r/20170922143644.GA17216@xxxxxxxxxx
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Ben Woodard <woodard@xxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jim Foraker <foraker1@xxxxxxxx>
Cc: <tdhooge@xxxxxxxx>
Cc: Travis Gummels <tgummels@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/binfmt_misc.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff -puN fs/binfmt_misc.c~exec-binfmt_misc-shift-filp_closeinterp_file-from-kill_node-to-bm_evict_inode fs/binfmt_misc.c
--- a/fs/binfmt_misc.c~exec-binfmt_misc-shift-filp_closeinterp_file-from-kill_node-to-bm_evict_inode
+++ a/fs/binfmt_misc.c
@@ -594,8 +594,13 @@ static struct inode *bm_get_inode(struct
static void bm_evict_inode(struct inode *inode)
{
+ Node *e = inode->i_private;
+
+ if ((e->flags & MISC_FMT_OPEN_FILE) && e->interp_file)
+ filp_close(e->interp_file, NULL);
+
clear_inode(inode);
- kfree(inode->i_private);
+ kfree(e);
}
static void kill_node(Node *e)
@@ -606,11 +611,6 @@ static void kill_node(Node *e)
list_del_init(&e->list);
write_unlock(&entries_lock);
- if ((e->flags & MISC_FMT_OPEN_FILE) && e->interp_file) {
- filp_close(e->interp_file, NULL);
- e->interp_file = NULL;
- }
-
dentry = e->dentry;
drop_nlink(d_inode(dentry));
d_drop(dentry);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
exec-load_script-kill-the-onstack-interp-array.patch
exec-binfmt_misc-dont-nullify-node-dentry-in-kill_node.patch
exec-binfmt_misc-shift-filp_closeinterp_file-from-kill_node-to-bm_evict_inode.patch
exec-binfmt_misc-remove-the-confusing-e-interp_file-=-null-checks.patch
exec-binfmt_misc-fix-race-between-load_misc_binary-and-kill_node.patch
exec-binfmt_misc-kill-the-onstack-iname-array.patch
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