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Message-Id: <20170328234650.19695-6-mic@digikod.net> Date: Wed, 29 Mar 2017 01:46:44 +0200 From: Mickaël Salaün <mic@...ikod.net> To: linux-kernel@...r.kernel.org Cc: Mickaël Salaün <mic@...ikod.net>, Alexei Starovoitov <ast@...nel.org>, Andy Lutomirski <luto@...capital.net>, Arnaldo Carvalho de Melo <acme@...nel.org>, Casey Schaufler <casey@...aufler-ca.com>, Daniel Borkmann <daniel@...earbox.net>, David Drysdale <drysdale@...gle.com>, "David S . Miller" <davem@...emloft.net>, "Eric W . Biederman" <ebiederm@...ssion.com>, James Morris <james.l.morris@...cle.com>, Jann Horn <jann@...jh.net>, Jonathan Corbet <corbet@....net>, Matthew Garrett <mjg59@...f.ucam.org>, Michael Kerrisk <mtk.manpages@...il.com>, Kees Cook <keescook@...omium.org>, Paul Moore <paul@...l-moore.com>, Sargun Dhillon <sargun@...gun.me>, "Serge E . Hallyn" <serge@...lyn.com>, Shuah Khan <shuah@...nel.org>, Tejun Heo <tj@...nel.org>, Thomas Graf <tgraf@...g.ch>, Will Drewry <wad@...omium.org>, kernel-hardening@...ts.openwall.com, linux-api@...r.kernel.org, linux-security-module@...r.kernel.org, netdev@...r.kernel.org Subject: [PATCH net-next v6 05/11] seccomp: Split put_seccomp_filter() with put_seccomp() The semantic is unchanged. This will be useful for the Landlock integration with seccomp (next commit). Signed-off-by: Mickaël Salaün <mic@...ikod.net> Cc: Kees Cook <keescook@...omium.org> Cc: Andy Lutomirski <luto@...capital.net> Cc: Will Drewry <wad@...omium.org> --- include/linux/seccomp.h | 4 ++-- kernel/fork.c | 2 +- kernel/seccomp.c | 18 +++++++++++++----- 3 files changed, 16 insertions(+), 8 deletions(-) diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index ecc296c137cd..e25aee2cdfc0 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -77,10 +77,10 @@ static inline int seccomp_mode(struct seccomp *s) #endif /* CONFIG_SECCOMP */ #ifdef CONFIG_SECCOMP_FILTER -extern void put_seccomp_filter(struct task_struct *tsk); +extern void put_seccomp(struct task_struct *tsk); extern void get_seccomp_filter(struct task_struct *tsk); #else /* CONFIG_SECCOMP_FILTER */ -static inline void put_seccomp_filter(struct task_struct *tsk) +static inline void put_seccomp(struct task_struct *tsk) { return; } diff --git a/kernel/fork.c b/kernel/fork.c index 6c463c80e93d..a27d8e67ce33 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -363,7 +363,7 @@ void free_task(struct task_struct *tsk) #endif rt_mutex_debug_task_free(tsk); ftrace_graph_exit_task(tsk); - put_seccomp_filter(tsk); + put_seccomp(tsk); arch_release_task_struct(tsk); if (tsk->flags & PF_KTHREAD) free_kthread_struct(tsk); diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 65f61077ad50..326f79e32127 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -64,6 +64,8 @@ struct seccomp_filter { /* Limit any path through the tree to 256KB worth of instructions. */ #define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter)) +static void put_seccomp_filter(struct seccomp_filter *filter); + /* * Endianness is explicitly ignored and left for BPF program authors to manage * as per the specific architecture. @@ -314,7 +316,7 @@ static inline void seccomp_sync_threads(void) * current's path will hold a reference. (This also * allows a put before the assignment.) */ - put_seccomp_filter(thread); + put_seccomp_filter(thread->seccomp.filter); smp_store_release(&thread->seccomp.filter, caller->seccomp.filter); @@ -476,10 +478,11 @@ static inline void seccomp_filter_free(struct seccomp_filter *filter) } } -/* put_seccomp_filter - decrements the ref count of tsk->seccomp.filter */ -void put_seccomp_filter(struct task_struct *tsk) +/* put_seccomp_filter - decrements the ref count of a filter */ +static void put_seccomp_filter(struct seccomp_filter *filter) { - struct seccomp_filter *orig = tsk->seccomp.filter; + struct seccomp_filter *orig = filter; + /* Clean up single-reference branches iteratively. */ while (orig && atomic_dec_and_test(&orig->usage)) { struct seccomp_filter *freeme = orig; @@ -488,6 +491,11 @@ void put_seccomp_filter(struct task_struct *tsk) } } +void put_seccomp(struct task_struct *tsk) +{ + put_seccomp_filter(tsk->seccomp.filter); +} + static void seccomp_init_siginfo(siginfo_t *info, int syscall, int reason) { memset(info, 0, sizeof(*info)); @@ -914,7 +922,7 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog))) ret = -EFAULT; - put_seccomp_filter(task); + put_seccomp_filter(task->seccomp.filter); return ret; out: -- 2.11.0
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