From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= Date: Wed, 14 Sep 2016 09:24:12 +0200 Message-Id: <20160914072415.26021-20-mic@digikod.net> In-Reply-To: <20160914072415.26021-1-mic@digikod.net> References: <20160914072415.26021-1-mic@digikod.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [kernel-hardening] [RFC v3 19/22] landlock: Add interrupted origin To: linux-kernel@vger.kernel.org Cc: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= , Alexei Starovoitov , Andy Lutomirski , Arnd Bergmann , Casey Schaufler , Daniel Borkmann , Daniel Mack , David Drysdale , "David S . Miller" , Elena Reshetova , "Eric W . Biederman" , James Morris , Kees Cook , Paul Moore , Sargun Dhillon , "Serge E . Hallyn" , Tejun Heo , Will Drewry , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-security-module@vger.kernel.org, netdev@vger.kernel.org, cgroups@vger.kernel.org List-ID: This third origin of hook call should cover all possible trigger paths (e.g. page fault). Landlock eBPF programs can then take decisions accordingly. Signed-off-by: Mickaël Salaün Cc: Alexei Starovoitov Cc: Andy Lutomirski Cc: Daniel Borkmann Cc: Kees Cook --- include/uapi/linux/bpf.h | 3 ++- security/landlock/lsm.c | 17 +++++++++++++++-- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 12e61508f879..3cc52e51357f 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -580,7 +580,8 @@ enum landlock_hook_id { /* Trigger type */ #define LANDLOCK_FLAG_ORIGIN_SYSCALL (1 << 0) #define LANDLOCK_FLAG_ORIGIN_SECCOMP (1 << 1) -#define _LANDLOCK_FLAG_ORIGIN_MASK ((1 << 2) - 1) +#define LANDLOCK_FLAG_ORIGIN_INTERRUPT (1 << 2) +#define _LANDLOCK_FLAG_ORIGIN_MASK ((1 << 3) - 1) /* context of function access flags */ #define _LANDLOCK_FLAG_ACCESS_MASK ((1ULL << 0) - 1) diff --git a/security/landlock/lsm.c b/security/landlock/lsm.c index 000dd0c7ec3d..2a15839a08c8 100644 --- a/security/landlock/lsm.c +++ b/security/landlock/lsm.c @@ -17,6 +17,7 @@ #include /* FIELD_SIZEOF() */ #include #include +#include /* in_interrupt() */ #include /* struct seccomp_* */ #include /* uintptr_t */ @@ -109,6 +110,7 @@ static int landlock_run_prog(enum landlock_hook_id hook_id, __u64 args[6]) #endif /* CONFIG_CGROUP_BPF */ struct landlock_rule *rule; u32 hook_idx = get_index(hook_id); + u16 current_call; struct landlock_data ctx = { .hook = hook_id, @@ -128,6 +130,16 @@ static int landlock_run_prog(enum landlock_hook_id hook_id, __u64 args[6]) * prioritize fine-grained policies (i.e. per thread), and return early. */ + if (unlikely(in_interrupt())) { + current_call = LANDLOCK_FLAG_ORIGIN_INTERRUPT; +#ifdef CONFIG_SECCOMP_FILTER + /* bypass landlock_ret evaluation */ + goto seccomp_int; +#endif /* CONFIG_SECCOMP_FILTER */ + } else { + current_call = LANDLOCK_FLAG_ORIGIN_SYSCALL; + } + #ifdef CONFIG_SECCOMP_FILTER /* seccomp triggers and landlock_ret cleanup */ ctx.origin = LANDLOCK_FLAG_ORIGIN_SECCOMP; @@ -164,8 +176,9 @@ static int landlock_run_prog(enum landlock_hook_id hook_id, __u64 args[6]) return -ret; ctx.cookie = 0; +seccomp_int: /* syscall trigger */ - ctx.origin = LANDLOCK_FLAG_ORIGIN_SYSCALL; + ctx.origin = current_call; ret = landlock_run_prog_for_syscall(hook_idx, &ctx, current->seccomp.landlock_hooks); if (ret) @@ -175,7 +188,7 @@ static int landlock_run_prog(enum landlock_hook_id hook_id, __u64 args[6]) #ifdef CONFIG_CGROUP_BPF /* syscall trigger */ if (cgroup_bpf_enabled) { - ctx.origin = LANDLOCK_FLAG_ORIGIN_SYSCALL; + ctx.origin = current_call; /* get the default cgroup associated with the current thread */ cgrp = task_css_set(current)->dfl_cgrp; ret = landlock_run_prog_for_syscall(hook_idx, &ctx, -- 2.9.3