All of lore.kernel.org
 help / color / mirror / Atom feed
From: jeffxu@chromium.org
To: skhan@linuxfoundation.org, keescook@chromium.org
Cc: akpm@linux-foundation.org, dmitry.torokhov@gmail.com,
	dverkamp@chromium.org, hughd@google.com, jeffxu@google.com,
	jorgelo@chromium.org, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-mm@kvack.org,
	mnissler@chromium.org, jannh@google.com,
	linux-hardening@vger.kernel.org, Jeff Xu <jeffxu@chromium.org>
Subject: [PATCH v3] mm/memfd: Add write seals when apply SEAL_EXEC to executable memfd
Date: Fri,  2 Dec 2022 01:34:04 +0000	[thread overview]
Message-ID: <20221202013404.163143-7-jeffxu@google.com> (raw)
In-Reply-To: <20221202013404.163143-1-jeffxu@google.com>

From: Jeff Xu <jeffxu@chromium.org>

When apply F_SEAL_EXEC to an executable memfd, add write seals also to
prevent modification of memfd.

Signed-off-by: Jeff Xu <jeffxu@chromium.org>
---
 mm/memfd.c                                 |  3 +++
 tools/testing/selftests/memfd/memfd_test.c | 25 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/mm/memfd.c b/mm/memfd.c
index 96dcfbfed09e..3a04c0698957 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -222,6 +222,9 @@ static int memfd_add_seals(struct file *file, unsigned int seals)
 		}
 	}
 
+	if (seals & F_SEAL_EXEC && inode->i_mode & 0111)
+		seals |= F_ALL_SEALS;
+
 	*file_seals |= seals;
 	error = 0;
 
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index 775c9e6c061e..0731e5b3cdce 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -32,6 +32,13 @@
 #define F_SEAL_EXEC	0x0020
 #endif
 
+#define F_ALL_SEALS (F_SEAL_SEAL | \
+		     F_SEAL_SHRINK | \
+		     F_SEAL_GROW | \
+		     F_SEAL_WRITE | \
+		     F_SEAL_FUTURE_WRITE | \
+		     F_SEAL_EXEC)
+
 #ifndef MAX_PATH
 #define MAX_PATH 256
 #endif
@@ -1006,6 +1013,7 @@ static void test_exec_seal(void)
 
 	printf("%s SEAL-EXEC\n", memfd_str);
 
+	printf("%s	Apply SEAL_EXEC\n", memfd_str);
 	fd = mfd_assert_new("kern_memfd_seal_exec",
 			    mfd_def_size,
 			    MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
@@ -1024,7 +1032,24 @@ static void test_exec_seal(void)
 	mfd_fail_chmod(fd, 0700);
 	mfd_fail_chmod(fd, 0100);
 	mfd_assert_chmod(fd, 0666);
+	mfd_assert_write(fd);
+	close(fd);
+
+	printf("%s	Apply ALL_SEALS\n", memfd_str);
+	fd = mfd_assert_new("kern_memfd_seal_exec",
+			    mfd_def_size,
+			    MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
 
+	mfd_assert_mode(fd, 0777);
+	mfd_assert_chmod(fd, 0700);
+
+	mfd_assert_has_seals(fd, 0);
+	mfd_assert_add_seals(fd, F_SEAL_EXEC);
+	mfd_assert_has_seals(fd, F_ALL_SEALS);
+
+	mfd_fail_chmod(fd, 0711);
+	mfd_fail_chmod(fd, 0600);
+	mfd_fail_write(fd);
 	close(fd);
 }
 
-- 
2.39.0.rc0.267.gcb52ba06e7-goog


  parent reply	other threads:[~2022-12-02  1:36 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-02  1:33 [PATCH v3] mm/memfd: MFD_NOEXEC_SEAL and MFD_EXEC jeffxu
2022-12-02  1:33 ` [PATCH v3] mm/memfd: add F_SEAL_EXEC jeffxu
2022-12-02 22:43   ` Kees Cook
2022-12-02 22:45   ` Kees Cook
2022-12-02  1:34 ` [PATCH v3] mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC jeffxu
2022-12-02 11:32   ` kernel test robot
2022-12-02 13:33   ` kernel test robot
2022-12-02 13:43   ` kernel test robot
2022-12-02 22:56   ` Kees Cook
2022-12-02 23:32     ` Jeff Xu
2022-12-02  1:34 ` [PATCH v3] selftests/memfd: add tests for F_SEAL_EXEC jeffxu
2022-12-02  1:34 ` [PATCH v3] selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC jeffxu
2022-12-02  1:34 ` [PATCH v3] mm/memfd: security hook for memfd_create jeffxu
2022-12-02 10:11   ` kernel test robot
2022-12-02 12:33   ` kernel test robot
2022-12-02 22:58   ` Kees Cook
2022-12-02 23:23     ` Jeff Xu
2022-12-02  1:34 ` jeffxu [this message]
2022-12-02 23:23   ` [PATCH v3] mm/memfd: Add write seals when apply SEAL_EXEC to executable memfd Daniel Verkamp
2022-12-03  2:29     ` Jeff Xu
2022-12-02 22:41 ` [PATCH v3] mm/memfd: MFD_NOEXEC_SEAL and MFD_EXEC Kees Cook

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20221202013404.163143-7-jeffxu@google.com \
    --to=jeffxu@chromium.org \
    --cc=akpm@linux-foundation.org \
    --cc=dmitry.torokhov@gmail.com \
    --cc=dverkamp@chromium.org \
    --cc=hughd@google.com \
    --cc=jannh@google.com \
    --cc=jeffxu@google.com \
    --cc=jorgelo@chromium.org \
    --cc=keescook@chromium.org \
    --cc=linux-hardening@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mnissler@chromium.org \
    --cc=skhan@linuxfoundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
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.