On Mon, Aug 21, 2017 at 02:09:26AM +0200, Mickaël Salaün wrote: > Add a new type of eBPF program used by Landlock rules. > > This new BPF program type will be registered with the Landlock LSM > initialization. > > Add an initial Landlock Kconfig. > > Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx> > Cc: Alexei Starovoitov <ast@xxxxxxxxxx> > Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> > Cc: David S. Miller <davem@xxxxxxxxxxxxx> > Cc: James Morris <james.l.morris@xxxxxxxxxx> > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > Cc: Serge E. Hallyn <serge@xxxxxxxxxx> > --- > > Changes since v6: > * add 3 more sub-events: IOCTL, LOCK, FCNTL > https://lkml.kernel.org/r/2fbc99a6-f190-f335-bd14-04bdeed35571@xxxxxxxxxxx > * rename LANDLOCK_VERSION to LANDLOCK_ABI to better reflect its purpose, > and move it from landlock.h to common.h > * rename BPF_PROG_TYPE_LANDLOCK to BPF_PROG_TYPE_LANDLOCK_RULE: an eBPF > program could be used for something else than a rule > * simplify struct landlock_context by removing the arch and syscall_nr fields > * remove all eBPF map functions call, remove ABILITY_WRITE > * refactor bpf_landlock_func_proto() (suggested by Kees Cook) > * constify pointers > * fix doc inclusion > > Changes since v5: > * rename file hooks.c to init.c > * fix spelling > > Changes since v4: > * merge a minimal (not enabled) LSM code and Kconfig in this commit > > Changes since v3: > * split commit > * revamp the landlock_context: > * add arch, syscall_nr and syscall_cmd (ioctl, fcntl…) to be able to > cross-check action with the event type > * replace args array with dedicated fields to ease the addition of new > fields > --- > include/linux/bpf_types.h | 3 ++ > include/uapi/linux/bpf.h | 97 +++++++++++++++++++++++++++++++++++++++++ > security/Kconfig | 1 + > security/Makefile | 2 + > security/landlock/Kconfig | 18 ++++++++ > security/landlock/Makefile | 3 ++ > security/landlock/common.h | 21 +++++++++ > security/landlock/init.c | 98 ++++++++++++++++++++++++++++++++++++++++++ > tools/include/uapi/linux/bpf.h | 97 +++++++++++++++++++++++++++++++++++++++++ > 9 files changed, 340 insertions(+) > create mode 100644 security/landlock/Kconfig > create mode 100644 security/landlock/Makefile > create mode 100644 security/landlock/common.h > create mode 100644 security/landlock/init.c > > diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h > index 6f1a567667b8..8bac93970a47 100644 > --- a/include/linux/bpf_types.h > +++ b/include/linux/bpf_types.h > @@ -18,6 +18,9 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_KPROBE, kprobe_prog_ops) > BPF_PROG_TYPE(BPF_PROG_TYPE_TRACEPOINT, tracepoint_prog_ops) > BPF_PROG_TYPE(BPF_PROG_TYPE_PERF_EVENT, perf_event_prog_ops) > #endif > +#ifdef CONFIG_SECURITY_LANDLOCK > +BPF_PROG_TYPE(BPF_PROG_TYPE_LANDLOCK_RULE, bpf_landlock_ops) > +#endif > > BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops) > BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops) > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index 8541ab85e432..20da634da941 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -129,6 +129,7 @@ enum bpf_prog_type { > BPF_PROG_TYPE_LWT_XMIT, > BPF_PROG_TYPE_SOCK_OPS, > BPF_PROG_TYPE_SK_SKB, > + BPF_PROG_TYPE_LANDLOCK_RULE, > }; > > enum bpf_attach_type { > @@ -879,4 +880,100 @@ enum { > #define TCP_BPF_IW 1001 /* Set TCP initial congestion window */ > #define TCP_BPF_SNDCWND_CLAMP 1002 /* Set sndcwnd_clamp */ > > +/** > + * enum landlock_subtype_event - event occurring when an action is performed on > + * a particular kernel object > + * > + * An event is a policy decision point which exposes the same context type > + * (especially the same arg[0-9] field types) for each rule execution. > + * > + * @LANDLOCK_SUBTYPE_EVENT_UNSPEC: invalid value > + * @LANDLOCK_SUBTYPE_EVENT_FS: generic filesystem event > + * @LANDLOCK_SUBTYPE_EVENT_FS_IOCTL: custom IOCTL sub-event > + * @LANDLOCK_SUBTYPE_EVENT_FS_LOCK: custom LOCK sub-event > + * @LANDLOCK_SUBTYPE_EVENT_FS_FCNTL: custom FCNTL sub-event > + */ > +enum landlock_subtype_event { > + LANDLOCK_SUBTYPE_EVENT_UNSPEC, > + LANDLOCK_SUBTYPE_EVENT_FS, > + LANDLOCK_SUBTYPE_EVENT_FS_IOCTL, > + LANDLOCK_SUBTYPE_EVENT_FS_LOCK, > + LANDLOCK_SUBTYPE_EVENT_FS_FCNTL, > +}; > +#define _LANDLOCK_SUBTYPE_EVENT_LAST LANDLOCK_SUBTYPE_EVENT_FS_FCNTL > + > +/** > + * DOC: landlock_subtype_ability > + * > + * eBPF context and functions allowed for a rule > + * > + * - LANDLOCK_SUBTYPE_ABILITY_DEBUG: allows to do debug actions (e.g. writing > + * logs), which may be dangerous and should only be used for rule testing > + */ > +#define LANDLOCK_SUBTYPE_ABILITY_DEBUG (1ULL << 0) > +#define _LANDLOCK_SUBTYPE_ABILITY_NB 1 > +#define _LANDLOCK_SUBTYPE_ABILITY_MASK ((1ULL << _LANDLOCK_SUBTYPE_ABILITY_NB) - 1) can you move the last two macros out of uapi? There is really no need for the implementation details to leak into uapi. > + > +/* > + * Future options for a Landlock rule (e.g. run even if a previous rule denied > + * an action). > + */ > +#define _LANDLOCK_SUBTYPE_OPTION_NB 0 > +#define _LANDLOCK_SUBTYPE_OPTION_MASK ((1ULL << _LANDLOCK_SUBTYPE_OPTION_NB) - 1) same here > + > +/* > + * Status visible in the @status field of a context (e.g. already called in > + * this syscall session, with same args...). > + * > + * The @status field exposed to a rule shall depend on the rule version. > + */ > +#define _LANDLOCK_SUBTYPE_STATUS_NB 0 > +#define _LANDLOCK_SUBTYPE_STATUS_MASK ((1ULL << _LANDLOCK_SUBTYPE_STATUS_NB) - 1) and here > + > +/** > + * DOC: landlock_action_fs > + * > + * - %LANDLOCK_ACTION_FS_EXEC: execute a file or walk through a directory > + * - %LANDLOCK_ACTION_FS_WRITE: modify a file or a directory view (which > + * include mount actions) > + * - %LANDLOCK_ACTION_FS_READ: read a file or a directory > + * - %LANDLOCK_ACTION_FS_NEW: create a file or a directory > + * - %LANDLOCK_ACTION_FS_GET: open or receive a file > + * - %LANDLOCK_ACTION_FS_REMOVE: unlink a file or remove a directory > + * > + * Each of the following actions are specific to syscall multiplexers. Each of > + * them trigger a dedicated Landlock event where their command can be read. > + * > + * - %LANDLOCK_ACTION_FS_IOCTL: ioctl command > + * - %LANDLOCK_ACTION_FS_LOCK: flock or fcntl lock command > + * - %LANDLOCK_ACTION_FS_FCNTL: fcntl command > + */ > +#define LANDLOCK_ACTION_FS_EXEC (1ULL << 0) > +#define LANDLOCK_ACTION_FS_WRITE (1ULL << 1) > +#define LANDLOCK_ACTION_FS_READ (1ULL << 2) > +#define LANDLOCK_ACTION_FS_NEW (1ULL << 3) > +#define LANDLOCK_ACTION_FS_GET (1ULL << 4) > +#define LANDLOCK_ACTION_FS_REMOVE (1ULL << 5) > +#define LANDLOCK_ACTION_FS_IOCTL (1ULL << 6) > +#define LANDLOCK_ACTION_FS_LOCK (1ULL << 7) > +#define LANDLOCK_ACTION_FS_FCNTL (1ULL << 8) > +#define _LANDLOCK_ACTION_FS_NB 9 > +#define _LANDLOCK_ACTION_FS_MASK ((1ULL << _LANDLOCK_ACTION_FS_NB) - 1) and here > + > + > +/** > + * struct landlock_context - context accessible to a Landlock rule > + * > + * @status: bitfield for future use (LANDLOCK_SUBTYPE_STATUS_*) > + * @event: event type (&enum landlock_subtype_event) > + * @arg1: event's first optional argument > + * @arg2: event's second optional argument > + */ > +struct landlock_context { > + __u64 status; > + __u64 event; > + __u64 arg1; > + __u64 arg2; > +}; looking at all the uapi additions.. probably worth moving them into separate .h like we did with bpf_perf_event.h How about include/uapi/linux/landlock.h ? It can include bpf.h first thing and then the rest of landlock related bits. so all, but BPF_PROG_TYPE_LANDLOCK_RULE will go there. > +++ b/security/landlock/Kconfig > @@ -0,0 +1,18 @@ > +config SECURITY_LANDLOCK > + bool "Landlock sandbox support" > + depends on SECURITY > + depends on BPF_SYSCALL > + depends on SECCOMP_FILTER > + default y all new features need to start with default n > +static inline const struct bpf_func_proto *bpf_landlock_func_proto( > + enum bpf_func_id func_id, > + const union bpf_prog_subtype *prog_subtype) > +{ > + /* generic functions */ > + if (prog_subtype->landlock_rule.ability & > + LANDLOCK_SUBTYPE_ABILITY_DEBUG) { > + switch (func_id) { > + case BPF_FUNC_get_current_comm: > + return &bpf_get_current_comm_proto; > + case BPF_FUNC_get_current_pid_tgid: > + return &bpf_get_current_pid_tgid_proto; > + case BPF_FUNC_get_current_uid_gid: > + return &bpf_get_current_uid_gid_proto; why current_*() helpers are 'debug' only? -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
