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Message-Id: <1472121165-29071-5-git-send-email-mic@digikod.net>
Date: Thu, 25 Aug 2016 12:32:39 +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>, Arnd Bergmann <arnd@...db.de>,
Casey Schaufler <casey@...aufler-ca.com>,
Daniel Borkmann <daniel@...earbox.net>,
Daniel Mack <daniel@...que.org>, David Drysdale <drysdale@...gle.com>,
"David S . Miller" <davem@...emloft.net>,
Elena Reshetova <elena.reshetova@...el.com>,
James Morris <james.l.morris@...cle.com>,
Kees Cook <keescook@...omium.org>, Paul Moore <pmoore@...hat.com>,
Sargun Dhillon <sargun@...gun.me>,
"Serge E . Hallyn" <serge@...lyn.com>, 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: [RFC v2 04/10] 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 | 5 +++--
kernel/fork.c | 2 +-
kernel/seccomp.c | 18 +++++++++++++-----
3 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index 2296e6b2f690..29b20fe8fd4d 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h
@@ -83,13 +83,14 @@ 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;
}
+
static inline void get_seccomp_filter(struct task_struct *tsk)
{
return;
diff --git a/kernel/fork.c b/kernel/fork.c
index 4a7ec0c6c88c..b23a71ec8003 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -235,7 +235,7 @@ void free_task(struct task_struct *tsk)
free_thread_stack(tsk->stack);
rt_mutex_debug_task_free(tsk);
ftrace_graph_exit_task(tsk);
- put_seccomp_filter(tsk);
+ put_seccomp(tsk);
arch_release_task_struct(tsk);
free_task_struct(tsk);
}
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 7002796f14a4..f1f475691c27 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -60,6 +60,8 @@ struct seccomp_filter {
struct bpf_prog *prog;
};
+static void put_seccomp_filter(struct seccomp_filter *filter);
+
/* Limit any path through the tree to 256KB worth of instructions. */
#define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter))
@@ -313,7 +315,7 @@ 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);
@@ -475,10 +477,11 @@ 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;
@@ -487,6 +490,11 @@ void put_seccomp_filter(struct task_struct *tsk)
}
}
+void put_seccomp(struct task_struct *tsk)
+{
+ put_seccomp_filter(tsk->seccomp.filter);
+}
+
/**
* seccomp_send_sigsys - signals the task to allow in-process syscall emulation
* @syscall: syscall number to send to userland
@@ -926,7 +934,7 @@ 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:
--
2.8.1
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