On Fri, Oct 20, 2023 at 07:08:33AM +0300, Konstantin Meskhidze (A) wrote: > > > 10/18/2023 3:29 PM, Mickaël Salaün пишет: > > On Mon, Oct 16, 2023 at 09:50:26AM +0800, Konstantin Meskhidze wrote: > > > This commit adds network rules support in the ruleset management > > > > Here are some advices to better write commit messages: > > https://docs.kernel.org/process/submitting-patches.html#describe-your-changes > > The "Describe your changes in imperative mood" part is important for > > this commit and others. Most of this patch series' commit messages need > > small updates. > > Ok. I will refactor commit messages with "imperative mood". Thanks. > > > > > 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 > > > > Please explain the "why" (when it makes sense) instead of just listing > > the "what". > > Ok. > > > > > > rights can be stored. Implement socket_bind() and socket_connect() > > > LSM hooks, which enables to restrict TCP socket binding and connection > > > to specific ports. > > > > I reworded and moved this part in last: > > > For the file system, a file descriptor is a direct access to a file/data. > > > But for the network, it's impossible to identify for which data/peer a > > > newly created socket will give access to, it's needed to wait for a > > > connect or bind request to identify the use case for this socket. > > > That's why the access rights (related to ports) are tied to an opened > > > socket, but this would not align with the way Landlock access control > > > works for the filesystem [2]. > > Thanks. > > > > Please add empty line to split paragraphs. > > Got it. > > > > > The new landlock_net_port_attr structure has two fields. The allowed_access > > > field contains the LANDLOCK_ACCESS_NET_* rights. The port field contains > > > the port value according to the allowed protocol. This field can > > > take up to a 64-bit value [1] but the maximum value depends on the related > > > protocol (e.g. 16-bit for TCP). > > > > For the file system, a file descriptor is a direct access to a file/data. > > However, for network sockets, we cannot identify for which data or peer a newly > > created socket will give access to. Indeed, we need to wait for a connect or > > bind request to identify the use case for this socket. > > > > Access rights are not tied to socket file descriptors. Instead, bind and > > connect actions are controlled by the task's domain. As for the filesystem, a > > directory file descriptor may enable to open another file (i.e. a new data > > item), but this opening is restricted by the task's domain, not the file > > descriptor's access rights [2]. > > > > > > > > [1] > > > https://lore.kernel.org/r/278ab07f-7583-a4e0-3d37-1bacd091531d@xxxxxxxxxxx > > > [2] > > > https://lore.kernel.org/all/263c1eb3-602f-57fe-8450-3f138581bee7@xxxxxxxxxxx > > > > [1] https://lore.kernel.org/r/278ab07f-7583-a4e0-3d37-1bacd091531d@xxxxxxxxxxx > > [2] https://lore.kernel.org/r/263c1eb3-602f-57fe-8450-3f138581bee7@xxxxxxxxxxx > Thanks. > > > > > > > > Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx> > > > Link: https://lore.kernel.org/r/20230920092641.832134-9-konstantin.meskhidze@xxxxxxxxxx > > > [mic: Remove !ARCH_EPHEMERAL_INODES in Kconfig, and add landlock_ prefix > > > to add_rule_net_service()] > > > Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx> > > > --- > > > > > > Changes since v12: > > > * Moves add_rule_net_port() back in syscalls.c and makes it static. > > > * Deletes bind_access_mask allowing bind action rule on port 0. > > > * Adds comment about port 0 in landlock_net_port_attr structure. > > > * Removes !ARCH_EPHEMERAL_INODES from Kconfig. > > > * Minor fixes. > > > * Refactors commit message. > > > > > > Changes since v11: > > > * Replaces dates with "2022-2023" in net.c/h files headers. > > > * Removes WARN_ON_ONCE(!domain) in check_socket_access(). > > > * Using "typeof(*address)" instead of offsetofend(struct sockaddr, sa_family). > > > * Renames LANDLOCK_RULE_NET_SERVICE to LANDLOCK_RULE_NET_PORT. > > > * Renames landlock_net_service_attr to landlock_net_port_attr. > > > * Defines two add_rule_net_service() functions according to > > > IS_ENABLED(CONFIG_INET) instead of changing the body of the only > > > function. > > > * Adds af_family consistency check while handling AF_UNSPEC specifically. > > > * Adds bind_access_mask in add_rule_net_service() to deny all rules with bind > > > action on port zero. > > > * Minor fixes. > > > * Refactors commit message. > > > > > > Changes since v10: > > > * Removes "packed" attribute. > > > * Applies Mickaёl's patch with some refactoring. > > > * Deletes get_port() and check_addrlen() helpers. > > > * Refactors check_socket_access() by squashing get_port() and > > > check_addrlen() helpers into it. > > > * Fixes commit message. > > > > > > 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 | 56 ++++++ > > > security/landlock/Kconfig | 1 + > > > security/landlock/Makefile | 2 + > > > security/landlock/limits.h | 5 + > > > security/landlock/net.c | 198 +++++++++++++++++++ > > > security/landlock/net.h | 33 ++++ > > > security/landlock/ruleset.c | 62 +++++- > > > security/landlock/ruleset.h | 59 +++++- > > > security/landlock/setup.c | 2 + > > > security/landlock/syscalls.c | 69 ++++++- > > > tools/testing/selftests/landlock/base_test.c | 2 +- > > > 11 files changed, 466 insertions(+), 23 deletions(-) > > > create mode 100644 security/landlock/net.c > > > create mode 100644 security/landlock/net.h > > > > > > diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h > > > index 81d09ef9aa50..25349666b19e 100644 > > > --- a/include/uapi/linux/landlock.h > > > +++ b/include/uapi/linux/landlock.h > > > @@ -31,6 +31,12 @@ struct landlock_ruleset_attr { > > > * this access right. > > > */ > > > __u64 handled_access_fs; > > > + /** > > > + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) > > > + * that is handled by this ruleset and should then be forbidden if no > > > + * rule explicitly allow them. > > > + */ > > > + __u64 handled_access_net; > > > }; > > > > > > /* > > > @@ -54,6 +60,11 @@ enum landlock_rule_type { > > > * landlock_path_beneath_attr . > > > */ > > > LANDLOCK_RULE_PATH_BENEATH = 1, > > > + /** > > > + * @LANDLOCK_RULE_NET_PORT: Type of a &struct > > > + * landlock_net_port_attr . > > > + */ > > > + LANDLOCK_RULE_NET_PORT = 2, > > > > We don't need the explicit " = 2". > > Fixed. Thanks. > > > > > }; > > > > > > /** > > > @@ -79,6 +90,32 @@ struct landlock_path_beneath_attr { > > > */ > > > } __attribute__((packed)); > > > > > > +/** > > > + * struct landlock_net_port_attr - Network port definition > > > + * > > > + * Argument of sys_landlock_add_rule(). > > > + */ > > > +struct landlock_net_port_attr { > > > + /** > > > + * @allowed_access: Bitmask of allowed access network for a port > > > + * (cf. `Network flags`_). > > > + */ > > > + __u64 allowed_access; > > > + /** > > > + * @port: Network port. Landlock does not forbid rules with port 0, > > > + * since some network services use it. Port 0 is a reserved one in > > > + * TCP/IP networking, meaning that it should not be used in TCP or > > > + * UDP messages. To allocate its source port number, services call > > > + * TCP/IP network functions like bind() to request one. With port 0 > > > + * it triggers the operating system to automatically search for > > > + * and return a suitable available port in the TCP/IP dynamic > > > + * port number range. This port range can be controlled by a > > > + * sysadmin with /proc/sys/net/ipv4/ip_local_port_range sysctl, > > > + * which is also used by IPv6. > > > > This looks too inspired from > > https://www.lifewire.com/port-0-in-tcp-and-udp-818145 > > Yep. You are right. > > > > Let's make it simpler: > > > > * @port: Network port. > > * > > * It should be noted that port 0 passed to :manpage:`bind(2)` will > > * bind to an available port from a specific port range. This can be > > * configured thanks to the ``/proc/sys/net/ipv4/ip_local_port_range`` > > * sysctl (also used for IPv6). A Landlock rule with port 0 and the > > * ``LANDLOCK_ACCESS_NET_BIND_TCP`` right means that requesting to bind > > * on port 0 is allowed and it will automatically translate to binding > > * on the related port range. > Thanks. > > > > > + */ > > > + __u64 port; > > > +}; > > > + > > > /** > > > * DOC: fs_access > > > * > > > @@ -189,4 +226,23 @@ struct landlock_path_beneath_attr { > > > #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) > > > /* clang-format on */ > > > > > > +/** > > > + * DOC: net_access > > > + * > > > + * Network flags > > > + * ~~~~~~~~~~~~~~~~ > > > + * > > > + * These flags enable to restrict a sandboxed process to a set of network > > > + * actions. > > > > You can add: > > "This is supported since ABI 4." > > Updated. > > > > > + * > > > + * TCP sockets with allowed actions: > > > + * > > > + * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. > > > + * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to > > > + * a remote port. > > > + */ > > > +/* clang-format off */ > > > +#define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) > > > +#define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) > > > +/* clang-format on */ > > > #endif /* _UAPI_LINUX_LANDLOCK_H */ > > > diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig > > > index c1e862a38410..c4bf0d5eff39 100644 > > > --- a/security/landlock/Kconfig > > > +++ b/security/landlock/Kconfig > > > @@ -3,6 +3,7 @@ > > > config SECURITY_LANDLOCK > > > bool "Landlock support" > > > depends on SECURITY > > > + select SECURITY_NETWORK > > > select SECURITY_PATH > > > help > > > Landlock is a sandboxing mechanism that enables processes to restrict > > > diff --git a/security/landlock/Makefile b/security/landlock/Makefile > > > index 7bbd2f413b3e..53d3c92ae22e 100644 > > > --- a/security/landlock/Makefile > > > +++ b/security/landlock/Makefile > > > @@ -2,3 +2,5 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o > > > > > > landlock-y := setup.o syscalls.o object.o ruleset.o \ > > > cred.o ptrace.o fs.o > > > + > > > +landlock-$(CONFIG_INET) += net.o > > > \ No newline at end of file > > > diff --git a/security/landlock/limits.h b/security/landlock/limits.h > > > index bafb3b8dc677..93c9c6f91556 100644 > > > --- a/security/landlock/limits.h > > > +++ b/security/landlock/limits.h > > > @@ -23,6 +23,11 @@ > > > #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) > > > #define LANDLOCK_SHIFT_ACCESS_FS 0 > > > > > > +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP > > > +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1) > > > +#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET) > > > +#define LANDLOCK_SHIFT_ACCESS_NET LANDLOCK_NUM_ACCESS_FS > > > + > > > /* clang-format on */ > > > > > > #endif /* _SECURITY_LANDLOCK_LIMITS_H */ > > > diff --git a/security/landlock/net.c b/security/landlock/net.c > > > new file mode 100644 > > > index 000000000000..1bf26cf3c41b > > > --- /dev/null > > > +++ b/security/landlock/net.c > > > @@ -0,0 +1,198 @@ > > > +// SPDX-License-Identifier: GPL-2.0-only > > > +/* > > > + * Landlock LSM - Network management and hooks > > > + * > > > + * Copyright © 2022-2023 Huawei Tech. Co., Ltd. > > > + * Copyright © 2022-2023 Microsoft Corporation > > > + */ > > > + > > > +#include <linux/in.h> > > > +#include <linux/net.h> > > > +#include <linux/socket.h> > > > +#include <net/ipv6.h> > > > + > > > +#include "common.h" > > > +#include "cred.h" > > > +#include "limits.h" > > > +#include "net.h" > > > +#include "ruleset.h" > > > + > > > +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, > > > + const u16 port, access_mask_t access_rights) > > > +{ > > > + int err; > > > + const struct landlock_id id = { > > > + .key.data = (__force uintptr_t)htons(port), > > > + .type = LANDLOCK_KEY_NET_PORT, > > > + }; > > > + > > > + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); > > > + > > > + /* Transforms relative access rights to absolute ones. */ > > > + access_rights |= LANDLOCK_MASK_ACCESS_NET & > > > + ~landlock_get_net_access_mask(ruleset, 0); > > > + > > > + mutex_lock(&ruleset->lock); > > > + err = landlock_insert_rule(ruleset, id, access_rights); > > > + mutex_unlock(&ruleset->lock); > > > + > > > + return err; > > > +} > > > + > > > +static access_mask_t > > > +get_raw_handled_net_accesses(const struct landlock_ruleset *const domain) > > > +{ > > > + access_mask_t access_dom = 0; > > > + size_t layer_level; > > > + > > > + for (layer_level = 0; layer_level < domain->num_layers; layer_level++) > > > + access_dom |= landlock_get_net_access_mask(domain, layer_level); > > > + return access_dom; > > > +} > > > + > > > +static const struct landlock_ruleset *get_current_net_domain(void) > > > +{ > > > + const struct landlock_ruleset *const dom = > > > + landlock_get_current_domain(); > > > + > > > + if (!dom || !get_raw_handled_net_accesses(dom)) > > > + return NULL; > > > + > > > + return dom; > > > +} > > > + > > > +static int check_socket_access(struct socket *const sock, > > > > To be consistent with current_check_access_path(), please rename to > > current_check_access_socket(). > > Done. Thanks. > > > > > + struct sockaddr *const address, > > > + const int addrlen, > > > + const access_mask_t access_request) > > > +{ > > > + __be16 port; > > > + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; > > > + const struct landlock_rule *rule; > > > + access_mask_t handled_access; > > > + struct landlock_id id = { > > > + .type = LANDLOCK_KEY_NET_PORT, > > > + }; > > > + const struct landlock_ruleset *const domain = get_current_net_domain(); > > > > For consistency with other functions, s/domain/dom/g > > Ok. Fixed. > > > > > + > > > + if (!domain) > > > + return 0; > > > + if (WARN_ON_ONCE(domain->num_layers < 1)) > > > + return -EACCES; > > > + > > > + /* Checks if it's a (potential) TCP socket. */ > > > + if (sock->type != SOCK_STREAM) > > > + return 0; > > > + > > > + /* Checks for minimal header length to safely read sa_family. */ > > > + if (addrlen < offsetofend(typeof(*address), sa_family)) > > > + return -EINVAL; > > > + > > > + switch (address->sa_family) { > > > + case AF_UNSPEC: > > > + case AF_INET: > > > + if (addrlen < sizeof(struct sockaddr_in)) > > > + return -EINVAL; > > > + port = ((struct sockaddr_in *)address)->sin_port; > > > + break; > > > +#if IS_ENABLED(CONFIG_IPV6) > > > + case AF_INET6: > > > + if (addrlen < SIN6_LEN_RFC2133) > > > + return -EINVAL; > > > + port = ((struct sockaddr_in6 *)address)->sin6_port; > > > + break; > > > +#endif > > > > #endif /* IS_ENABLED(CONFIG_INET) */ > > #endif /* IS_ENABLED(CONFIG_IPV6) */ I suppose. Indeed > > > > > + default: > > > + return 0; > > > + } > > > + > > > + /* Specific AF_UNSPEC handling. */ > > > + if (address->sa_family == 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. > > > + * > > > + * For a TCP access control system, this request is legitimate. > > > + * Let the network stack handle potential inconsistencies and > > > + * return -EINVAL if needed. > > > + */ > > > + 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. > > > + * > > > + * We could return 0 and let the network stack handle these > > > + * checks, but it is safer to return a proper error and test > > > + * consistency thanks to kselftest. > > > + */ > > > + if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP) { > > > + /* addrlen has already been checked for AF_UNSPEC. */ > > > + const struct sockaddr_in *const sockaddr = > > > + (struct sockaddr_in *)address; > > > + > > > + if (sock->sk->__sk_common.skc_family != AF_INET) > > > + return -EINVAL; > > > + > > > + if (sockaddr->sin_addr.s_addr != htonl(INADDR_ANY)) > > > + return -EAFNOSUPPORT; > > > + } > > > + } else { > > > + /* > > > + * Checks sa_family consistency to not wrongfully return > > > + * -EACCES instead of -EINVAL. Valid sa_family changes are > > > + * only (from AF_INET or AF_INET6) to AF_UNSPEC. > > > + * > > > + * We could return 0 and let the network stack handle this > > > + * check, but it is safer to return a proper error and test > > > + * consistency thanks to kselftest. > > > + */ > > > + if (address->sa_family != sock->sk->__sk_common.skc_family) > > > + return -EINVAL; > > > + } > > > + > > > + id.key.data = (__force uintptr_t)port; > > > + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); > > > + > > > + rule = landlock_find_rule(domain, id); > > > + handled_access = landlock_init_layer_masks( > > > + domain, access_request, &layer_masks, LANDLOCK_KEY_NET_PORT); > > > + if (landlock_unmask_layers(rule, handled_access, &layer_masks, > > > + ARRAY_SIZE(layer_masks))) > > > + return 0; > > > + > > > + return -EACCES; > > > +} > > > + > > > +static int hook_socket_bind(struct socket *const sock, > > > + struct sockaddr *const address, const int addrlen) > > > +{ > > > + return check_socket_access(sock, address, addrlen, > > > + LANDLOCK_ACCESS_NET_BIND_TCP); > > > +} > > > + > > > +static int hook_socket_connect(struct socket *const sock, > > > + struct sockaddr *const address, > > > + const int addrlen) > > > +{ > > > + return check_socket_access(sock, address, addrlen, > > > + LANDLOCK_ACCESS_NET_CONNECT_TCP); > > > +} > > > + > > > +static struct security_hook_list landlock_hooks[] __ro_after_init = { > > > + LSM_HOOK_INIT(socket_bind, hook_socket_bind), > > > + LSM_HOOK_INIT(socket_connect, hook_socket_connect), > > > +}; > > > + > > > +__init void landlock_add_net_hooks(void) > > > +{ > > > + security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks), > > > + LANDLOCK_NAME); > > > +} > > > diff --git a/security/landlock/net.h b/security/landlock/net.h > > > new file mode 100644 > > > index 000000000000..588a49fd6907 > > > --- /dev/null > > > +++ b/security/landlock/net.h > > > @@ -0,0 +1,33 @@ > > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > > +/* > > > + * Landlock LSM - Network management and hooks > > > + * > > > + * Copyright © 2022-2023 Huawei Tech. Co., Ltd. > > > + */ > > > + > > > +#ifndef _SECURITY_LANDLOCK_NET_H > > > +#define _SECURITY_LANDLOCK_NET_H > > > + > > > +#include "common.h" > > > +#include "ruleset.h" > > > +#include "setup.h" > > > + > > > +#if IS_ENABLED(CONFIG_INET) > > > +__init void landlock_add_net_hooks(void); > > > + > > > +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, > > > + const u16 port, access_mask_t access_rights); > > > +#else /* IS_ENABLED(CONFIG_INET) */ > > > +static inline void landlock_add_net_hooks(void) > > > +{ > > > +} > > > + > > > +static inline int > > > +landlock_append_net_rule(struct landlock_ruleset *const ruleset, const u16 port, > > > + access_mask_t access_rights); > > > +{ > > > + return -EAFNOSUPPORT; > > > +} > > > +#endif /* IS_ENABLED(CONFIG_INET) */ > > > + > > > +#endif /* _SECURITY_LANDLOCK_NET_H */ > > > diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c > > > index 4c209acee01e..1fe4298ff4a7 100644 > > > --- a/security/landlock/ruleset.c > > > +++ b/security/landlock/ruleset.c > > > @@ -36,6 +36,11 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) > > > refcount_set(&new_ruleset->usage, 1); > > > mutex_init(&new_ruleset->lock); > > > new_ruleset->root_inode = RB_ROOT; > > > + > > > +#if IS_ENABLED(CONFIG_INET) > > > + new_ruleset->root_net_port = RB_ROOT; > > > +#endif /* IS_ENABLED(CONFIG_INET) */ > > > + > > > new_ruleset->num_layers = num_layers; > > > /* > > > * hierarchy = NULL > > > @@ -46,16 +51,21 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) > > > } > > > > > > struct landlock_ruleset * > > > -landlock_create_ruleset(const access_mask_t fs_access_mask) > > > +landlock_create_ruleset(const access_mask_t fs_access_mask, > > > + const access_mask_t net_access_mask) > > > { > > > struct landlock_ruleset *new_ruleset; > > > > > > /* Informs about useless ruleset. */ > > > - if (!fs_access_mask) > > > + if (!fs_access_mask && !net_access_mask) > > > return ERR_PTR(-ENOMSG); > > > new_ruleset = create_ruleset(1); > > > - if (!IS_ERR(new_ruleset)) > > > + if (IS_ERR(new_ruleset)) > > > + return new_ruleset; > > > + if (fs_access_mask) > > > landlock_add_fs_access_mask(new_ruleset, fs_access_mask, 0); > > > + if (net_access_mask) > > > + landlock_add_net_access_mask(new_ruleset, net_access_mask, 0); > > > > This is good, but it is not tested: we need to add a test that both > > handle FS and net restrictions. You can add one in net.c, just handling > > LANDLOCK_ACCESS_FS_READ_DIR and LANDLOCK_ACCESS_NET_BIND_TCP, add one > > rule with path_beneath (e.g. /dev) and another with net_port, and check > > that open("/") is denied, open("/dev") is allowed, and and only the > > allowed port is allowed with bind(). This test should be simple and can > > only check against an IPv4 socket, i.e. using ipv4_tcp fixture, just > > after port_endianness. fcntl.h should then be included by net.c > > Ok. > > > > I guess that was the purpose of layout1.with_net (in fs_test.c) but it > > Yep. I added this kind of nest in fs_test.c to test both fs and network > rules together. > > is not complete. You can revamp this test and move it to net.c > > following the above suggestions, keeping it consistent with other tests > > in net.c . You don't need the test_open() nor create_ruleset() helpers. > > > > This test must failed if we change "ruleset->access_masks[layer_level] |=" > > to "ruleset->access_masks[layer_level] =" in > > landlock_add_fs_access_mask() or landlock_add_net_access_mask(). > > Do you want to change it? Why? The kernel code is correct and must not be changed. However, if by mistake we change it and remove the OR, a test should catch that. We need a test to assert this assumption. > Fs and network masks are ORed to not intersect with each other. Yes, they are ORed, and we need a test to check that. Noting is currently testing this OR (and the different rule type consistency). I'm suggesting to revamp the layout1.with_net test into ipv4_tcp.with_fs and make it check ruleset->access_masks[] and rule addition of different types. > > > > > return new_ruleset; > > > } > > > > > > @@ -74,6 +84,11 @@ static bool is_object_pointer(const enum landlock_key_type key_type) > > > case LANDLOCK_KEY_INODE: > > > return true; > > > > > > +#if IS_ENABLED(CONFIG_INET) > > > + case LANDLOCK_KEY_NET_PORT: > > > + return false; > > > +#endif /* IS_ENABLED(CONFIG_INET) */ > > > + > > > default: > > > WARN_ON_ONCE(1); > > > return false; > > > @@ -126,7 +141,13 @@ static struct rb_root *get_root(struct landlock_ruleset *const ruleset, > > > case LANDLOCK_KEY_INODE: > > > return &ruleset->root_inode; > > > > > > +#if IS_ENABLED(CONFIG_INET) > > > + case LANDLOCK_KEY_NET_PORT: > > > + return &ruleset->root_net_port; > > > +#endif /* IS_ENABLED(CONFIG_INET) */ > > > + > > > default: > > > + WARN_ON_ONCE(1); > > > > Please move this WARN to the patch that added the previous and next > > lines. > > OK. Will be moved. > > > > > return ERR_PTR(-EINVAL); > > > } > > > } > > > @@ -153,7 +174,8 @@ static void build_check_ruleset(void) > > > BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES); > > > BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS); > > > BUILD_BUG_ON(access_masks < > > > - (LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS)); > > > + ((LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS) | > > > + (LANDLOCK_MASK_ACCESS_NET << LANDLOCK_SHIFT_ACCESS_NET))); > > > } > > > > > > /** > > > @@ -370,6 +392,13 @@ static int merge_ruleset(struct landlock_ruleset *const dst, > > > if (err) > > > goto out_unlock; > > > > > > +#if IS_ENABLED(CONFIG_INET) > > > + /* Merges the @src network port tree. */ > > > + err = merge_tree(dst, src, LANDLOCK_KEY_NET_PORT); > > > + if (err) > > > + goto out_unlock; > > > +#endif /* IS_ENABLED(CONFIG_INET) */ > > > + > > > out_unlock: > > > mutex_unlock(&src->lock); > > > mutex_unlock(&dst->lock); > > > @@ -426,6 +455,13 @@ static int inherit_ruleset(struct landlock_ruleset *const parent, > > > if (err) > > > goto out_unlock; > > > > > > +#if IS_ENABLED(CONFIG_INET) > > > + /* Copies the @parent network port tree. */ > > > + err = inherit_tree(parent, child, LANDLOCK_KEY_NET_PORT); > > > + if (err) > > > + goto out_unlock; > > > +#endif /* IS_ENABLED(CONFIG_INET) */ > > > + > > > if (WARN_ON_ONCE(child->num_layers <= parent->num_layers)) { > > > err = -EINVAL; > > > goto out_unlock; > > > @@ -455,6 +491,13 @@ static void free_ruleset(struct landlock_ruleset *const ruleset) > > > rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root_inode, > > > node) > > > free_rule(freeme, LANDLOCK_KEY_INODE); > > > + > > > +#if IS_ENABLED(CONFIG_INET) > > > + rbtree_postorder_for_each_entry_safe(freeme, next, > > > + &ruleset->root_net_port, node) > > > + free_rule(freeme, LANDLOCK_KEY_NET_PORT); > > > +#endif /* IS_ENABLED(CONFIG_INET) */ > > > + > > > put_hierarchy(ruleset->hierarchy); > > > kfree(ruleset); > > > } > > > @@ -635,7 +678,8 @@ get_access_mask_t(const struct landlock_ruleset *const ruleset, > > > * > > > * @domain: The domain that defines the current restrictions. > > > * @access_request: The requested access rights to check. > > > - * @layer_masks: The layer masks to populate. > > > + * @layer_masks: It must contain LANDLOCK_NUM_ACCESS_FS or LANDLOCK_NUM_ACCESS_NET > > > > "%LANDLOCK_NUM_ACCESS_FS or %LANDLOCK_NUM_ACCESS_NET" > > Done. > > > > > + * elements according to @key_type. > > > * @key_type: The key type to switch between access masks of different types. > > > * > > > * Returns: An access mask where each access right bit is set which is handled > > > @@ -656,6 +700,14 @@ landlock_init_layer_masks(const struct landlock_ruleset *const domain, > > > get_access_mask = landlock_get_fs_access_mask; > > > num_access = LANDLOCK_NUM_ACCESS_FS; > > > break; > > > + > > > +#if IS_ENABLED(CONFIG_INET) > > > + case LANDLOCK_KEY_NET_PORT: > > > + get_access_mask = landlock_get_net_access_mask; > > > + num_access = LANDLOCK_NUM_ACCESS_NET; > > > + break; > > > +#endif /* IS_ENABLED(CONFIG_INET) */ > > > + > > > default: > > > WARN_ON_ONCE(1); > > > return 0; > > > diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h > > > index 1ede2b9a79b7..ba4a06035599 100644 > > > --- a/security/landlock/ruleset.h > > > +++ b/security/landlock/ruleset.h > > > @@ -33,13 +33,16 @@ > > > typedef u16 access_mask_t; > > > /* Makes sure all filesystem access rights can be stored. */ > > > static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); > > > +/* Makes sure all network access rights can be stored. */ > > > +static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_NET); > > > /* Makes sure for_each_set_bit() and for_each_clear_bit() calls are OK. */ > > > static_assert(sizeof(unsigned long) >= sizeof(access_mask_t)); > > > > > > /* Ruleset access masks. */ > > > -typedef u16 access_masks_t; > > > +typedef u32 access_masks_t; > > > /* Makes sure all ruleset access rights can be stored. */ > > > -static_assert(BITS_PER_TYPE(access_masks_t) >= LANDLOCK_NUM_ACCESS_FS); > > > +static_assert(BITS_PER_TYPE(access_masks_t) >= > > > + LANDLOCK_NUM_ACCESS_FS + LANDLOCK_NUM_ACCESS_NET); > > > > > > typedef u16 layer_mask_t; > > > /* Makes sure all layers can be checked. */ > > > @@ -84,6 +87,11 @@ enum landlock_key_type { > > > * keys. > > > */ > > > LANDLOCK_KEY_INODE = 1, > > > + /** > > > + * @LANDLOCK_KEY_NET_PORT: Type of &landlock_ruleset.root_net_port's > > > + * node keys. > > > + */ > > > + LANDLOCK_KEY_NET_PORT, > > > }; > > > > > > /** > > > @@ -158,6 +166,13 @@ struct landlock_ruleset { > > > * reaches zero. > > > */ > > > struct rb_root root_inode; > > > > #if IS_ENABLED(CONFIG_INET) > OK. Done. > > > + /** > > > + * @root_net_port: Root of a red-black tree containing &struct > > > + * landlock_rule nodes with network port. Once a ruleset is tied to a > > > + * process (i.e. as a domain), this tree is immutable until @usage > > > + * reaches zero. > > > + */ > > > + struct rb_root root_net_port; > > > > #endif /* IS_ENABLED(CONFIG_INET) */ > > Done. > > > > > /** > > > * @hierarchy: Enables hierarchy identification even when a parent > > > * domain vanishes. This is needed for the ptrace protection. > > > @@ -196,13 +211,13 @@ struct landlock_ruleset { > > > */ > > > u32 num_layers; > > > /** > > > - * @access_masks: Contains the subset of filesystem > > > - * actions that are restricted by a ruleset. A domain > > > - * saves all layers of merged rulesets in a stack > > > - * (FAM), starting from the first layer to the last > > > - * one. These layers are used when merging rulesets, > > > - * for user space backward compatibility (i.e. > > > - * future-proof), and to properly handle merged > > > + * @access_masks: Contains the subset of filesystem and > > > + * network actions that are restricted by a ruleset. > > > + * A domain saves all layers of merged rulesets in a > > > + * stack (FAM), starting from the first layer to the > > > + * last one. These layers are used when merging > > > + * rulesets, for user space backward compatibility > > > + * (i.e. future-proof), and to properly handle merged > > > * rulesets without overlapping access rights. These > > > * layers are set once and never changed for the > > > * lifetime of the ruleset. > > > @@ -213,7 +228,8 @@ struct landlock_ruleset { > > > }; > > > > > > struct landlock_ruleset * > > > -landlock_create_ruleset(const access_mask_t access_mask); > > > +landlock_create_ruleset(const access_mask_t access_mask_fs, > > > + const access_mask_t access_mask_net); > > > > > > void landlock_put_ruleset(struct landlock_ruleset *const ruleset); > > > void landlock_put_ruleset_deferred(struct landlock_ruleset *const ruleset); > > > @@ -249,6 +265,19 @@ landlock_add_fs_access_mask(struct landlock_ruleset *const ruleset, > > > (fs_mask << LANDLOCK_SHIFT_ACCESS_FS); > > > } > > > > > > +static inline void > > > +landlock_add_net_access_mask(struct landlock_ruleset *const ruleset, > > > + const access_mask_t net_access_mask, > > > + const u16 layer_level) > > > +{ > > > + access_mask_t net_mask = net_access_mask & LANDLOCK_MASK_ACCESS_NET; > > > + > > > + /* Should already be checked in sys_landlock_create_ruleset(). */ > > > + WARN_ON_ONCE(net_access_mask != net_mask); > > > + ruleset->access_masks[layer_level] |= > > > + (net_mask << LANDLOCK_SHIFT_ACCESS_NET); > > > +} > > > + > > > static inline access_mask_t > > > landlock_get_raw_fs_access_mask(const struct landlock_ruleset *const ruleset, > > > const u16 layer_level) > > > @@ -266,6 +295,16 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, > > > return landlock_get_raw_fs_access_mask(ruleset, layer_level) | > > > LANDLOCK_ACCESS_FS_INITIALLY_DENIED; > > > } > > > + > > > +static inline access_mask_t > > > +landlock_get_net_access_mask(const struct landlock_ruleset *const ruleset, > > > + const u16 layer_level) > > > +{ > > > + return (ruleset->access_masks[layer_level] >> > > > + LANDLOCK_SHIFT_ACCESS_NET) & > > > + LANDLOCK_MASK_ACCESS_NET; > > > +} > > > + > > > bool landlock_unmask_layers(const struct landlock_rule *const rule, > > > const access_mask_t access_request, > > > layer_mask_t (*const layer_masks)[], > > > diff --git a/security/landlock/setup.c b/security/landlock/setup.c > > > index 0f6113528fa4..df81612811bf 100644 > > > --- a/security/landlock/setup.c > > > +++ b/security/landlock/setup.c > > > @@ -14,6 +14,7 @@ > > > #include "fs.h" > > > #include "ptrace.h" > > > #include "setup.h" > > > +#include "net.h" > > > > > > bool landlock_initialized __ro_after_init = false; > > > > > > @@ -29,6 +30,7 @@ static int __init landlock_init(void) > > > landlock_add_cred_hooks(); > > > landlock_add_ptrace_hooks(); > > > landlock_add_fs_hooks(); > > > + landlock_add_net_hooks(); > > > landlock_initialized = true; > > > pr_info("Up and running.\n"); > > > return 0; > > > diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c > > > index 8a54e87dbb17..3ad652d9a146 100644 > > > --- a/security/landlock/syscalls.c > > > +++ b/security/landlock/syscalls.c > > > @@ -29,6 +29,7 @@ > > > #include "cred.h" > > > #include "fs.h" > > > #include "limits.h" > > > +#include "net.h" > > > #include "ruleset.h" > > > #include "setup.h" > > > > > > @@ -74,7 +75,8 @@ static void build_check_abi(void) > > > { > > > struct landlock_ruleset_attr ruleset_attr; > > > struct landlock_path_beneath_attr path_beneath_attr; > > > - size_t ruleset_size, path_beneath_size; > > > + struct landlock_net_port_attr net_port_attr; > > > + size_t ruleset_size, path_beneath_size, net_port_size; > > > > > > /* > > > * For each user space ABI structures, first checks that there is no > > > @@ -82,13 +84,19 @@ static void build_check_abi(void) > > > * struct size. > > > */ > > > ruleset_size = sizeof(ruleset_attr.handled_access_fs); > > > + ruleset_size += sizeof(ruleset_attr.handled_access_net); > > > BUILD_BUG_ON(sizeof(ruleset_attr) != ruleset_size); > > > - BUILD_BUG_ON(sizeof(ruleset_attr) != 8); > > > + BUILD_BUG_ON(sizeof(ruleset_attr) != 16); > > > > > > path_beneath_size = sizeof(path_beneath_attr.allowed_access); > > > path_beneath_size += sizeof(path_beneath_attr.parent_fd); > > > BUILD_BUG_ON(sizeof(path_beneath_attr) != path_beneath_size); > > > BUILD_BUG_ON(sizeof(path_beneath_attr) != 12); > > > + > > > + net_port_size = sizeof(net_port_attr.allowed_access); > > > + net_port_size += sizeof(net_port_attr.port); > > > + BUILD_BUG_ON(sizeof(net_port_attr) != net_port_size); > > > + BUILD_BUG_ON(sizeof(net_port_attr) != 16); > > > } > > > > > > /* Ruleset handling */ > > > @@ -129,7 +137,7 @@ static const struct file_operations ruleset_fops = { > > > .write = fop_dummy_write, > > > }; > > > > > > -#define LANDLOCK_ABI_VERSION 3 > > > +#define LANDLOCK_ABI_VERSION 4 > > > > > > /** > > > * sys_landlock_create_ruleset - Create a new ruleset > > > @@ -188,8 +196,14 @@ SYSCALL_DEFINE3(landlock_create_ruleset, > > > LANDLOCK_MASK_ACCESS_FS) > > > return -EINVAL; > > > > > > + /* Checks network content (and 32-bits cast). */ > > > + if ((ruleset_attr.handled_access_net | LANDLOCK_MASK_ACCESS_NET) != > > > + LANDLOCK_MASK_ACCESS_NET) > > > + return -EINVAL; > > > + > > > /* Checks arguments and transforms to kernel struct. */ > > > - ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs); > > > + ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs, > > > + ruleset_attr.handled_access_net); > > > if (IS_ERR(ruleset)) > > > return PTR_ERR(ruleset); > > > > > > @@ -282,7 +296,7 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, > > > int res, err; > > > access_mask_t mask; > > > > > > - /* Copies raw user space buffer, only one type for now. */ > > > + /* Copies raw user space buffer. */ > > > > Shouldn't this be part of a previous patch? > > I did it according Gunter's suggestion > https://lore.kernel.org/netdev/20230627.82cde73b1efe@xxxxxxxxxx/ Ok, that indeed makes more sense in this patch, please keep it. > > > > > res = copy_from_user(&path_beneath_attr, rule_attr, > > > sizeof(path_beneath_attr)); > > > if (res) > > > @@ -315,13 +329,49 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, > > > return err; > > > } > > > > > > +static int add_rule_net_port(struct landlock_ruleset *ruleset, > > > + const void __user *const rule_attr) > > > +{ > > > + struct landlock_net_port_attr net_port_attr; > > > + int res; > > > + access_mask_t mask; > > > + > > > + /* Copies raw user space buffer. */ > > > + res = copy_from_user(&net_port_attr, rule_attr, sizeof(net_port_attr)); > > > + if (res) > > > + return -EFAULT; > > > + > > > + /* > > > + * Informs about useless rule: empty allowed_access (i.e. deny rules) > > > + * are ignored by network actions. > > > + */ > > > + if (!net_port_attr.allowed_access) > > > + return -ENOMSG; > > > + > > > + /* > > > + * Checks that allowed_access matches the @ruleset constraints > > > + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). > > > + */ > > > + mask = landlock_get_net_access_mask(ruleset, 0); > > > + if ((net_port_attr.allowed_access | mask) != mask) > > > + return -EINVAL; > > > + > > > + /* Denies inserting a rule with port higher than 65535. */ > > > > For consistency with the following comment: > > "Denies inserting a rule with port greater than 65535." > > > Done. Thanks. > > > > > + if (net_port_attr.port > U16_MAX) > > > + return -EINVAL; > > > + > > > + /* Imports the new rule. */ > > > + return landlock_append_net_rule(ruleset, net_port_attr.port, > > > + net_port_attr.allowed_access); > > > +} > > > + > > > /** > > > * sys_landlock_add_rule - Add a new rule to a ruleset > > > * > > > * @ruleset_fd: File descriptor tied to the ruleset that should be extended > > > * with the new rule. > > > - * @rule_type: Identify the structure type pointed to by @rule_attr (only > > > - * %LANDLOCK_RULE_PATH_BENEATH for now). > > > + * @rule_type: Identify the structure type pointed to by @rule_attr: > > > + * %LANDLOCK_RULE_PATH_BENEATH or %LANDLOCK_RULE_NET_PORT. > > > * @rule_attr: Pointer to a rule (only of type &struct > > > * landlock_path_beneath_attr for now). > > > * @flags: Must be 0. > > > @@ -332,6 +382,8 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, > > > * Possible returned errors are: > > > * > > > * - %EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; > > > + * - %EAFNOSUPPORT: @rule_type is LANDLOCK_RULE_NET_PORT but TCP/IP is not > > > > %LANDLOCK_RULE_NET_PORT > > Done. > > > > > + * supported by the running kernel; > > > * - %EINVAL: @flags is not 0, or inconsistent access in the rule (i.e. > > > * &landlock_path_beneath_attr.allowed_access is not a subset of the > > > > &landlock_path_beneath_attr.allowed_access or > > &landlock_net_port_attr.allowed_access is not a subset of the > > Fixed. Thanks. > > > > > * ruleset handled accesses); > > > > EINVAL description needs to be updated, especially for port > U16_MAX: > > - * ruleset handled accesses); > > + * ruleset handled accesses), or &landlock_net_port_attr.port is > > + greater than 65535; > > Done. Thanks. > > > > > > > @@ -366,6 +418,9 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, > > > case LANDLOCK_RULE_PATH_BENEATH: > > > err = add_rule_path_beneath(ruleset, rule_attr); > > > break; > > > + case LANDLOCK_RULE_NET_PORT: > > > + err = add_rule_net_port(ruleset, rule_attr); > > > + break; > > > default: > > > err = -EINVAL; > > > break; > > > diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c > > > index 792c3f0a59b4..646f778dfb1e 100644 > > > --- a/tools/testing/selftests/landlock/base_test.c > > > +++ b/tools/testing/selftests/landlock/base_test.c > > > @@ -75,7 +75,7 @@ TEST(abi_version) > > > const struct landlock_ruleset_attr ruleset_attr = { > > > .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE, > > > }; > > > - ASSERT_EQ(3, landlock_create_ruleset(NULL, 0, > > > + ASSERT_EQ(4, landlock_create_ruleset(NULL, 0, > > > LANDLOCK_CREATE_RULESET_VERSION)); > > > > > > ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0, > > > -- > > > 2.25.1 > > > > > .
