linux/fs
Kees Cook 0fd338b2d2 exec: move path_noexec() check earlier
The path_noexec() check, like the regular file check, was happening too
late, letting LSMs see impossible execve()s.  Check it earlier as well in
may_open() and collect the redundant fs/exec.c path_noexec() test under
the same robustness comment as the S_ISREG() check.

My notes on the call path, and related arguments, checks, etc:

do_open_execat()
    struct open_flags open_exec_flags = {
        .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
        .acc_mode = MAY_EXEC,
        ...
    do_filp_open(dfd, filename, open_flags)
        path_openat(nameidata, open_flags, flags)
            file = alloc_empty_file(open_flags, current_cred());
            do_open(nameidata, file, open_flags)
                may_open(path, acc_mode, open_flag)
                    /* new location of MAY_EXEC vs path_noexec() test */
                    inode_permission(inode, MAY_OPEN | acc_mode)
                        security_inode_permission(inode, acc_mode)
                vfs_open(path, file)
                    do_dentry_open(file, path->dentry->d_inode, open)
                        security_file_open(f)
                        open()
    /* old location of path_noexec() test */

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: http://lkml.kernel.org/r/20200605160013.3954297-4-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:01 -07:00
..
9p
adfs
affs
afs
autofs
befs
bfs
btrfs
cachefiles
ceph
cifs
coda
configfs
cramfs
crypto
debugfs
devpts
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efivarfs
efs
erofs
exfat
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ext4
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freevxfs
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gfs2
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hugetlbfs
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jbd2
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nfs_common
nfsd
nilfs2
nls
notify
ntfs
ocfs2
omfs
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proc
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qnx4
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quota
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reiserfs
romfs
squashfs
sysfs
sysv
tracefs
ubifs
udf
ufs
unicode
vboxsf
verity
xfs
zonefs
aio.c
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
block_dev.c
buffer.c
char_dev.c
compat_binfmt_elf.c
compat.c
coredump.c coredump: add %f for executable filename 2020-08-12 10:58:01 -07:00
d_path.c
dax.c
dcache.c
dcookies.c
direct-io.c
drop_caches.c
eventfd.c
eventpoll.c
exec.c exec: move path_noexec() check earlier 2020-08-12 10:58:01 -07:00
fcntl.c
fhandle.c
file_table.c
file.c
filesystems.c
fs_context.c
fs_parser.c
fs_pin.c
fs_struct.c
fs_types.c
fs-writeback.c
fsopen.c
init.c
inode.c
internal.h
io_uring.c
io-wq.c
io-wq.h
ioctl.c
Kconfig
Kconfig.binfmt
libfs.c
locks.c
Makefile
mbcache.c
mount.h
mpage.c
namei.c exec: move path_noexec() check earlier 2020-08-12 10:58:01 -07:00
namespace.c
no-block.c
nsfs.c
open.c exec: move S_ISREG() check earlier 2020-08-12 10:58:01 -07:00
pipe.c
pnode.c
pnode.h
posix_acl.c
proc_namespace.c
read_write.c
readdir.c
select.c
seq_file.c
signalfd.c
splice.c
stack.c
stat.c
statfs.c
super.c
sync.c
timerfd.c
userfaultfd.c
utimes.c
xattr.c