From: "Mickaël Salaün" <mic@digikod.net>
To: "Konstantin Meskhidze (A)" <konstantin.meskhidze@huawei.com>
Cc: willemdebruijn.kernel@gmail.com, gnoack3000@gmail.com,
linux-security-module@vger.kernel.org, netdev@vger.kernel.org,
netfilter-devel@vger.kernel.org, yusongping@huawei.com,
artem.kuzin@huawei.com
Subject: Re: [PATCH v10 09/13] landlock: Add network rules and TCP hooks support
Date: Tue, 4 Apr 2023 19:02:01 +0200 [thread overview]
Message-ID: <f126c31b-f0cf-0746-e517-9f3f19c1915f@digikod.net> (raw)
In-Reply-To: <ac4d6244-641b-e1d4-5c34-d9a9bcd10498@digikod.net>
On 04/04/2023 18:42, Mickaël Salaün wrote:
>
> On 04/04/2023 11:31, Konstantin Meskhidze (A) wrote:
>>
>>
>> 3/31/2023 8:24 PM, Mickaël Salaün пишет:
>>>
>>> On 23/03/2023 09:52, Konstantin Meskhidze wrote:
>>>> This commit adds network rules support in the ruleset management
>>>> helpers and the landlock_create_ruleset syscall.
>>>> Refactor user space API to support network actions. Add new network
>>>> access flags, network rule and network attributes. Increment Landlock
>>>> ABI version. Expand access_masks_t to u32 to be sure network access
>>>> rights can be stored. Implement socket_bind() and socket_connect()
>>>> LSM hooks, which enable to restrict TCP socket binding and connection
>>>> to specific ports.
>>>>
>>>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
>>>> ---
>>>>
>>>> Changes since v9:
>>>> * Changes UAPI port field to __u64.
>>>> * Moves shared code into check_socket_access().
>>>> * Adds get_raw_handled_net_accesses() and
>>>> get_current_net_domain() helpers.
>>>> * Minor fixes.
>>>>
>>>> Changes since v8:
>>>> * Squashes commits.
>>>> * Refactors commit message.
>>>> * Changes UAPI port field to __be16.
>>>> * Changes logic of bind/connect hooks with AF_UNSPEC families.
>>>> * Adds address length checking.
>>>> * Minor fixes.
>>>>
>>>> Changes since v7:
>>>> * Squashes commits.
>>>> * Increments ABI version to 4.
>>>> * Refactors commit message.
>>>> * Minor fixes.
>>>>
>>>> Changes since v6:
>>>> * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask()
>>>> because it OR values.
>>>> * Makes landlock_add_net_access_mask() more resilient incorrect values.
>>>> * Refactors landlock_get_net_access_mask().
>>>> * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use
>>>> LANDLOCK_NUM_ACCESS_FS as value.
>>>> * Updates access_masks_t to u32 to support network access actions.
>>>> * Refactors landlock internal functions to support network actions with
>>>> landlock_key/key_type/id types.
>>>>
>>>> Changes since v5:
>>>> * Gets rid of partial revert from landlock_add_rule
>>>> syscall.
>>>> * Formats code with clang-format-14.
>>>>
>>>> Changes since v4:
>>>> * Refactors landlock_create_ruleset() - splits ruleset and
>>>> masks checks.
>>>> * Refactors landlock_create_ruleset() and landlock mask
>>>> setters/getters to support two rule types.
>>>> * Refactors landlock_add_rule syscall add_rule_path_beneath
>>>> function by factoring out get_ruleset_from_fd() and
>>>> landlock_put_ruleset().
>>>>
>>>> Changes since v3:
>>>> * Splits commit.
>>>> * Adds network rule support for internal landlock functions.
>>>> * Adds set_mask and get_mask for network.
>>>> * Adds rb_root root_net_port.
>>>>
>>>> ---
>>>> include/uapi/linux/landlock.h | 49 +++++
>>>> security/landlock/Kconfig | 1 +
>>>> security/landlock/Makefile | 2 +
>>>> security/landlock/limits.h | 6 +-
>>>> security/landlock/net.c | 198 +++++++++++++++++++
>>>> security/landlock/net.h | 26 +++
>>>> security/landlock/ruleset.c | 52 ++++-
>>>> security/landlock/ruleset.h | 63 +++++-
>>>> security/landlock/setup.c | 2 +
>>>> security/landlock/syscalls.c | 72 ++++++-
>>>> tools/testing/selftests/landlock/base_test.c | 2 +-
>>>> 11 files changed, 450 insertions(+), 23 deletions(-)
>>>> create mode 100644 security/landlock/net.c
>>>> create mode 100644 security/landlock/net.h
>>>
>>> [...]
>>>
>>>> diff --git a/security/landlock/net.c b/security/landlock/net.c
>>>
>>> [...]
>>>> +static int check_socket_access(struct socket *sock, struct sockaddr *address, int addrlen, u16 port,
>>>> + access_mask_t access_request)
>>>> +{
>>>> + int ret;
>>>> + bool allowed = false;
>>>> + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {};
>>>> + const struct landlock_rule *rule;
>>>> + access_mask_t handled_access;
>>>> + const struct landlock_id id = {
>>>> + .key.data = port,
>>>> + .type = LANDLOCK_KEY_NET_PORT,
>>>> + };
>>>> + const struct landlock_ruleset *const domain = get_current_net_domain();
>>>> +
>>>> + if (WARN_ON_ONCE(!domain))
>>>> + return 0;
>>>> + if (WARN_ON_ONCE(domain->num_layers < 1))
>>>> + return -EACCES;
>>>> + /* Check if it's a TCP socket. */
>>>> + if (sock->type != SOCK_STREAM)
>>>> + return 0;
>>>> +
>>>> + ret = check_addrlen(address, addrlen);
>>>> + if (ret)
>>>> + return ret;
>>>> +
>>>> + switch (address->sa_family) {
>>>> + case AF_UNSPEC:
>>>> + /*
>>>> + * Connecting to an address with AF_UNSPEC dissolves the TCP
>>>> + * association, which have the same effect as closing the
>>>> + * connection while retaining the socket object (i.e., the file
>>>> + * descriptor). As for dropping privileges, closing
>>>> + * connections is always allowed.
>>>> + */
>>>> + if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP)
>>>> + return 0;
>>>> +
>>>> + /*
>>>> + * For compatibility reason, accept AF_UNSPEC for bind
>>>> + * accesses (mapped to AF_INET) only if the address is
>>>> + * INADDR_ANY (cf. __inet_bind). Checking the address is
>>>> + * required to not wrongfully return -EACCES instead of
>>>> + * -EAFNOSUPPORT.
>>>> + */
>>>> + if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP) {
>>>> + const struct sockaddr_in *const sockaddr =
>>>> + (struct sockaddr_in *)address;
>>>> +
>>>> + if (sockaddr->sin_addr.s_addr != htonl(INADDR_ANY))
>>>> + return -EAFNOSUPPORT;
>>>> + }
>>>> +
>>>> + fallthrough;
>>>> + case AF_INET:
>>>> +#if IS_ENABLED(CONFIG_IPV6)
>>>> + case AF_INET6:
>>>> +#endif
Some more fixes:
You can move the port/id.key.data block from my patch here, where it is
actually used.
>>>> + rule = landlock_find_rule(domain, id);
>>>> + handled_access = landlock_init_layer_masks(
>>>> + domain, access_request, &layer_masks,
>>>> + LANDLOCK_KEY_NET_PORT);
>>>> + allowed = landlock_unmask_layers(rule, handled_access,
>>>> + &layer_masks,
>>>> + ARRAY_SIZE(layer_masks));
The `return allowed ? 0 : -EACCES;` should be here.
>>>> + }
>>>> + return allowed ? 0 : -EACCES;
We should have `return 0;` here.
We need a test for an sa_family different than AF_UNSPEC, AF_INET, and
AF_INET6 to make sure everything else is allowed (e.g. AF_UNIX with
SOCK_STREAM and another test with SOCK_DGRAM). Please make sure this new
test will not pass with SOCK_STREAM and the current patch series, but of
course it should pass with the next one.
>>>> +}
>>>> +
next prev parent reply other threads:[~2023-04-04 17:02 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-23 8:52 [PATCH v10 00/13] Network support for Landlock Konstantin Meskhidze
2023-03-23 8:52 ` [PATCH v10 01/13] landlock: Make ruleset's access masks more generic Konstantin Meskhidze
2023-03-23 8:52 ` [PATCH v10 02/13] landlock: Allow filesystem layout changes for domains without such rule type Konstantin Meskhidze
2023-04-16 16:09 ` Mickaël Salaün
2023-04-20 11:42 ` Konstantin Meskhidze (A)
2023-04-20 17:32 ` Mickaël Salaün
2023-04-21 7:54 ` Konstantin Meskhidze (A)
2023-03-23 8:52 ` [PATCH v10 03/13] landlock: Remove unnecessary inlining Konstantin Meskhidze
2023-04-16 16:09 ` Mickaël Salaün
2023-04-20 11:45 ` Konstantin Meskhidze (A)
2023-03-23 8:52 ` [PATCH v10 04/13] landlock: Refactor landlock_find_rule/insert_rule Konstantin Meskhidze
2023-03-23 8:52 ` [PATCH v10 05/13] landlock: Refactor merge/inherit_ruleset functions Konstantin Meskhidze
2023-04-16 16:09 ` Mickaël Salaün
2023-04-20 11:46 ` Konstantin Meskhidze (A)
2023-03-23 8:52 ` [PATCH v10 06/13] landlock: Move and rename layer helpers Konstantin Meskhidze
2023-03-23 8:52 ` [PATCH v10 07/13] landlock: Refactor " Konstantin Meskhidze
2023-04-16 16:11 ` Mickaël Salaün
2023-04-20 16:05 ` Konstantin Meskhidze (A)
2023-03-23 8:52 ` [PATCH v10 08/13] landlock: Refactor landlock_add_rule() syscall Konstantin Meskhidze
2023-03-23 8:52 ` [PATCH v10 09/13] landlock: Add network rules and TCP hooks support Konstantin Meskhidze
2023-03-31 17:24 ` Mickaël Salaün
2023-03-31 17:30 ` Mickaël Salaün
2023-04-04 9:33 ` Konstantin Meskhidze (A)
2023-04-04 9:31 ` Konstantin Meskhidze (A)
2023-04-04 16:42 ` Mickaël Salaün
2023-04-04 17:02 ` Mickaël Salaün [this message]
2023-04-05 19:19 ` Konstantin Meskhidze (A)
2023-04-06 10:31 ` Mickaël Salaün
2023-04-06 10:37 ` Konstantin Meskhidze (A)
2023-04-05 17:42 ` Konstantin Meskhidze (A)
2023-04-06 10:28 ` Mickaël Salaün
2023-04-06 10:30 ` Konstantin Meskhidze (A)
2023-04-16 16:11 ` Mickaël Salaün
2023-04-21 9:39 ` Konstantin Meskhidze (A)
2023-04-26 14:15 ` Mickaël Salaün
2023-03-23 8:52 ` [PATCH v10 10/13] selftests/landlock: Share enforce_ruleset() Konstantin Meskhidze
2023-04-16 16:12 ` Mickaël Salaün
2023-04-20 16:06 ` Konstantin Meskhidze (A)
2023-03-23 8:52 ` [PATCH v10 11/13] selftests/landlock: Add 10 new test suites dedicated to network Konstantin Meskhidze
2023-04-16 16:13 ` Mickaël Salaün
2023-04-21 10:02 ` Konstantin Meskhidze (A)
2023-04-26 19:10 ` Mickaël Salaün
2023-03-23 8:52 ` [PATCH v10 12/13] samples/landlock: Add network demo Konstantin Meskhidze
2023-04-16 16:13 ` Mickaël Salaün
2023-04-21 10:04 ` Konstantin Meskhidze (A)
2023-03-23 8:52 ` [PATCH v10 13/13] landlock: Document Landlock's network support Konstantin Meskhidze
2023-04-16 16:13 ` Mickaël Salaün
2023-04-21 10:07 ` Konstantin Meskhidze (A)
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