From: "Mickaël Salaün" <mic@digikod.net>
To: "Günther Noack" <gnoack3000@gmail.com>,
linux-security-module@vger.kernel.org
Cc: James Morris <jmorris@namei.org>,
Paul Moore <paul@paul-moore.com>,
"Serge E . Hallyn" <serge@hallyn.com>,
linux-fsdevel@vger.kernel.org,
Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Subject: Re: [PATCH v8 8/9] samples/landlock: Extend sample tool to support LANDLOCK_ACCESS_FS_TRUNCATE
Date: Wed, 5 Oct 2022 20:57:23 +0200 [thread overview]
Message-ID: <8c5b8019-f945-417f-3f98-ef5c9317b52d@digikod.net> (raw)
In-Reply-To: <20221001154908.49665-9-gnoack3000@gmail.com>
On 01/10/2022 17:49, Günther Noack wrote:
> Update the sandboxer sample to restrict truncate actions. This is
> automatically enabled by default if the running kernel supports
> LANDLOCK_ACCESS_FS_TRUNCATE, except for the paths listed in the
> LL_FS_RW environment variable.
>
> Signed-off-by: Günther Noack <gnoack3000@gmail.com>
> ---
> samples/landlock/sandboxer.c | 23 ++++++++++++++---------
> 1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
> index 3e404e51ec64..771b6b10d519 100644
> --- a/samples/landlock/sandboxer.c
> +++ b/samples/landlock/sandboxer.c
> @@ -76,7 +76,8 @@ static int parse_path(char *env_path, const char ***const path_list)
> #define ACCESS_FILE ( \
> LANDLOCK_ACCESS_FS_EXECUTE | \
> LANDLOCK_ACCESS_FS_WRITE_FILE | \
> - LANDLOCK_ACCESS_FS_READ_FILE)
> + LANDLOCK_ACCESS_FS_READ_FILE | \
> + LANDLOCK_ACCESS_FS_TRUNCATE)
>
> /* clang-format on */
>
> @@ -160,10 +161,8 @@ static int populate_ruleset(const char *const env_var, const int ruleset_fd,
> LANDLOCK_ACCESS_FS_MAKE_FIFO | \
> LANDLOCK_ACCESS_FS_MAKE_BLOCK | \
> LANDLOCK_ACCESS_FS_MAKE_SYM | \
> - LANDLOCK_ACCESS_FS_REFER)
> -
> -#define ACCESS_ABI_2 ( \
> - LANDLOCK_ACCESS_FS_REFER)
> + LANDLOCK_ACCESS_FS_REFER | \
> + LANDLOCK_ACCESS_FS_TRUNCATE)
>
> /* clang-format on */
>
> @@ -226,11 +225,17 @@ int main(const int argc, char *const argv[], char *const *const envp)
> return 1;
> }
> /* Best-effort security. */
> - if (abi < 2) {
> - ruleset_attr.handled_access_fs &= ~ACCESS_ABI_2;
> - access_fs_ro &= ~ACCESS_ABI_2;
> - access_fs_rw &= ~ACCESS_ABI_2;
You can now base your patches on the current Linus' master branch, these
three commits are now merged:
https://git.kernel.org/mic/c/2fff00c81d4c37a037cf704d2d219fbcb45aea3c
The (inlined) documentation also needs to be updated according to this
commit to align with the double backtick convention.
> + switch (abi) {
> + case 1:
> + /* Removes LANDLOCK_ACCESS_FS_REFER for ABI < 2 */
> + ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_REFER;
> + __attribute__((fallthrough));
> + case 2:
> + /* Removes LANDLOCK_ACCESS_FS_TRUNCATE for ABI < 3 */
> + ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_TRUNCATE;
> }
> + access_fs_ro &= ruleset_attr.handled_access_fs;
> + access_fs_rw &= ruleset_attr.handled_access_fs;
>
> ruleset_fd =
> landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
next prev parent reply other threads:[~2022-10-05 18:57 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-01 15:48 [PATCH v8 0/9] landlock: truncate support Günther Noack
2022-10-01 15:49 ` [PATCH v8 1/9] security: Create file_truncate hook from path_truncate hook Günther Noack
2022-10-05 18:53 ` Mickaël Salaün
2022-10-08 7:45 ` Günther Noack
2022-10-06 1:10 ` Paul Moore
2022-10-01 15:49 ` [PATCH v8 2/9] selftests/landlock: Locally define __maybe_unused Günther Noack
2022-10-05 18:53 ` Mickaël Salaün
2022-10-08 7:47 ` Günther Noack
2022-10-01 15:49 ` [PATCH v8 3/9] landlock: Refactor check_access_path_dual() into is_access_to_paths_allowed() Günther Noack
2022-10-05 18:54 ` Mickaël Salaün
2022-10-08 7:54 ` Günther Noack
2022-10-01 15:49 ` [PATCH v8 4/9] landlock: Support file truncation Günther Noack
2022-10-04 19:56 ` Nathan Chancellor
2022-10-05 18:52 ` Mickaël Salaün
2022-10-06 20:19 ` Günther Noack
2022-10-05 18:55 ` Mickaël Salaün
2022-10-08 8:08 ` Günther Noack
2022-10-01 15:49 ` [PATCH v8 5/9] selftests/landlock: Selftests for file truncation support Günther Noack
2022-10-01 15:49 ` [PATCH v8 6/9] selftests/landlock: Test open() and ftruncate() in multiple scenarios Günther Noack
2022-10-05 18:56 ` Mickaël Salaün
2022-10-01 15:49 ` [PATCH v8 7/9] selftests/landlock: Test FD passing from a Landlock-restricted to an unrestricted process Günther Noack
2022-10-05 18:57 ` Mickaël Salaün
2022-10-08 8:25 ` Günther Noack
2022-10-01 15:49 ` [PATCH v8 8/9] samples/landlock: Extend sample tool to support LANDLOCK_ACCESS_FS_TRUNCATE Günther Noack
2022-10-05 18:57 ` Mickaël Salaün [this message]
2022-10-08 8:47 ` Günther Noack
2022-10-01 15:49 ` [PATCH v8 9/9] landlock: Document Landlock's file truncation support Günther Noack
2022-10-05 18:57 ` Mickaël Salaün
2022-10-08 8:49 ` Günther Noack
2022-10-05 19:18 ` [PATCH v8 0/9] landlock: truncate support Mickaël Salaün
2022-10-08 10:20 ` Günther Noack
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