* [merged mm-stable] mm-memfd-add-write-seals-when-apply-seal_exec-to-executable-memfd.patch removed from -mm tree
@ 2023-01-19 1:13 Andrew Morton
0 siblings, 0 replies; only message in thread
From: Andrew Morton @ 2023-01-19 1:13 UTC (permalink / raw)
To: mm-commits, skhan, lkp, keescook, jorgelo, jannh, hughd,
dverkamp, dmitry.torokhov, dh.herrmann, jeffxu, akpm
The quilt patch titled
Subject: mm/memfd: add write seals when apply SEAL_EXEC to executable memfd
has been removed from the -mm tree. Its filename was
mm-memfd-add-write-seals-when-apply-seal_exec-to-executable-memfd.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Jeff Xu <jeffxu@google.com>
Subject: mm/memfd: add write seals when apply SEAL_EXEC to executable memfd
Date: Thu, 15 Dec 2022 00:12:04 +0000
In order to avoid WX mappings, add F_SEAL_WRITE when apply F_SEAL_EXEC to
an executable memfd, so W^X from start.
This implys application need to fill the content of the memfd first, after
F_SEAL_EXEC is applied, application can no longer modify the content of
the memfd.
Typically, application seals the memfd right after writing to it.
For example:
1. memfd_create(MFD_EXEC).
2. write() code to the memfd.
3. fcntl(F_ADD_SEALS, F_SEAL_EXEC) to convert the memfd to W^X.
4. call exec() on the memfd.
Link: https://lkml.kernel.org/r/20221215001205.51969-5-jeffxu@google.com
Signed-off-by: Jeff Xu <jeffxu@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: kernel test robot <lkp@intel.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/memfd.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/mm/memfd.c~mm-memfd-add-write-seals-when-apply-seal_exec-to-executable-memfd
+++ a/mm/memfd.c
@@ -222,6 +222,12 @@ static int memfd_add_seals(struct file *
}
}
+ /*
+ * SEAL_EXEC implys SEAL_WRITE, making W^X from the start.
+ */
+ if (seals & F_SEAL_EXEC && inode->i_mode & 0111)
+ seals |= F_SEAL_SHRINK|F_SEAL_GROW|F_SEAL_WRITE|F_SEAL_FUTURE_WRITE;
+
*file_seals |= seals;
error = 0;
_
Patches currently in -mm which might be from jeffxu@google.com are
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2023-01-19 1:14 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-01-19 1:13 [merged mm-stable] mm-memfd-add-write-seals-when-apply-seal_exec-to-executable-memfd.patch removed from -mm tree Andrew Morton
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.