On Mon, Oct 16, 2023 at 09:50:26AM +0800, 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 enables to restrict TCP socket binding and connection > to specific ports. > 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]. > 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). > > [1] > https://lore.kernel.org/r/278ab07f-7583-a4e0-3d37-1bacd091531d@xxxxxxxxxxx > [2] > https://lore.kernel.org/all/263c1eb3-602f-57fe-8450-3f138581bee7@xxxxxxxxxxx > > 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, > }; > > /** > @@ -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. > + */ > + __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. > + * > + * 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, > + 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(); > + > + 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 > + 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); > 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); > 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 > + * 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; > + /** > + * @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; > /** > * @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. */ > 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). > + */ You can replace this comment block with that: + /* Checks that allowed_access matches the @ruleset constraints. */ > + 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. */ > + 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); > +}
