exec: binfmt_misc: shift filp_close(interp_file) from kill_node() to bm_evict_inode()
authorOleg Nesterov <oleg@redhat.com>
Tue, 3 Oct 2017 23:15:48 +0000 (16:15 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 4 Oct 2017 00:54:25 +0000 (17:54 -0700)
commit83f918274e4b841d6fb817861ea0c896fba0c179
tree0dd2089b951b17b706cf1701149092cf56e75503
parentbaba1b29731c79d605100087b8f02f9e1cf5a344
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i_private), this Node is no
longer valid.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@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ben Woodard <woodard@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jim Foraker <foraker1@llnl.gov>
Cc: <tdhooge@llnl.gov>
Cc: Travis Gummels <tgummels@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/binfmt_misc.c