From: Elena Reshetova <elena.reshetova@intel.com>
To: linux-kernel@vger.kernel.org
Cc: cgroups@vger.kernel.org, linux-audit@redhat.com,
linux-fsdevel@vger.kernel.org, peterz@infradead.org,
gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk,
tj@kernel.org, mingo@redhat.com, hannes@cmpxchg.org,
lizefan@huawei.com, acme@kernel.org,
alexander.shishkin@linux.intel.com, paul@paul-moore.com,
eparis@redhat.com, akpm@linux-foundation.org, arnd@arndb.de,
luto@kernel.org, Elena Reshetova <elena.reshetova@intel.com>,
Hans Liljestrand <ishkamiel@gmail.com>,
Kees Cook <keescook@chromium.org>,
David Windsor <dwindsor@gmail.com>
Subject: [PATCH 01/19] kernel: convert sighand_struct.count from atomic_t to refcount_t
Date: Mon, 20 Feb 2017 12:18:50 +0200 [thread overview]
Message-ID: <1487585948-6401-2-git-send-email-elena.reshetova@intel.com> (raw)
In-Reply-To: <1487585948-6401-1-git-send-email-elena.reshetova@intel.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
---
fs/exec.c | 4 ++--
include/linux/init_task.h | 2 +-
include/linux/sched.h | 3 ++-
kernel/fork.c | 8 ++++----
4 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 698a860..3f78ff2 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1174,7 +1174,7 @@ static int de_thread(struct task_struct *tsk)
flush_itimer_signals();
#endif
- if (atomic_read(&oldsighand->count) != 1) {
+ if (refcount_read(&oldsighand->count) != 1) {
struct sighand_struct *newsighand;
/*
* This ->sighand is shared with the CLONE_SIGHAND
@@ -1184,7 +1184,7 @@ static int de_thread(struct task_struct *tsk)
if (!newsighand)
return -ENOMEM;
- atomic_set(&newsighand->count, 1);
+ refcount_set(&newsighand->count, 1);
memcpy(newsighand->action, oldsighand->action,
sizeof(newsighand->action));
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 3a85d61..1f160b2 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -82,7 +82,7 @@ extern struct fs_struct init_fs;
extern struct nsproxy init_nsproxy;
#define INIT_SIGHAND(sighand) { \
- .count = ATOMIC_INIT(1), \
+ .count = REFCOUNT_INIT(1), \
.action = { { { .sa_handler = SIG_DFL, } }, }, \
.siglock = __SPIN_LOCK_UNLOCKED(sighand.siglock), \
.signalfd_wqh = __WAIT_QUEUE_HEAD_INITIALIZER(sighand.signalfd_wqh), \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0f0d497..a0430aa 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -42,6 +42,7 @@ struct sched_param {
#include <linux/seccomp.h>
#include <linux/rcupdate.h>
#include <linux/rculist.h>
+#include <linux/refcount.h>
#include <linux/rtmutex.h>
#include <linux/time.h>
@@ -527,7 +528,7 @@ static inline int get_dumpable(struct mm_struct *mm)
#define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK)
struct sighand_struct {
- atomic_t count;
+ refcount_t count;
struct k_sigaction action[_NSIG];
spinlock_t siglock;
wait_queue_head_t signalfd_wqh;
diff --git a/kernel/fork.c b/kernel/fork.c
index e96e256..9488f01 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1285,7 +1285,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
struct sighand_struct *sig;
if (clone_flags & CLONE_SIGHAND) {
- atomic_inc(¤t->sighand->count);
+ refcount_inc(¤t->sighand->count);
return 0;
}
sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
@@ -1293,14 +1293,14 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
if (!sig)
return -ENOMEM;
- atomic_set(&sig->count, 1);
+ refcount_set(&sig->count, 1);
memcpy(sig->action, current->sighand->action, sizeof(sig->action));
return 0;
}
void __cleanup_sighand(struct sighand_struct *sighand)
{
- if (atomic_dec_and_test(&sighand->count)) {
+ if (refcount_dec_and_test(&sighand->count)) {
signalfd_cleanup(sighand);
/*
* sighand_cachep is SLAB_DESTROY_BY_RCU so we can free it
@@ -2170,7 +2170,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
return -EINVAL;
}
if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
- if (atomic_read(¤t->sighand->count) > 1)
+ if (refcount_read(¤t->sighand->count) > 1)
return -EINVAL;
}
if (unshare_flags & CLONE_VM) {
--
2.7.4
next prev parent reply other threads:[~2017-02-20 10:28 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-20 10:18 [PATCH 00/19] Kernel subsystem refcounter conversions Elena Reshetova
2017-02-20 10:18 ` Elena Reshetova [this message]
2017-02-20 12:30 ` [PATCH 01/19] kernel: convert sighand_struct.count from atomic_t to refcount_t kbuild test robot
2017-02-20 12:42 ` kbuild test robot
2017-02-20 10:18 ` [PATCH 02/19] kernel: convert signal_struct.sigcnt " Elena Reshetova
2017-02-20 10:18 ` [PATCH 03/19] kernel: convert user_struct.__count " Elena Reshetova
2017-02-20 10:18 ` [PATCH 04/19] kernel: convert task_struct.usage " Elena Reshetova
2017-02-20 10:18 ` [PATCH 05/19] kernel: convert task_struct.stack_refcount " Elena Reshetova
2017-02-20 10:18 ` [PATCH 06/19] kernel: convert perf_event_context.refcount " Elena Reshetova
2017-02-20 10:28 ` Peter Zijlstra
2017-02-20 12:14 ` Reshetova, Elena
2017-02-20 10:18 ` [PATCH 07/19] kernel: convert ring_buffer.refcount " Elena Reshetova
2017-02-20 10:18 ` [PATCH 08/19] kernel: convert ring_buffer.aux_refcount " Elena Reshetova
2017-02-20 10:18 ` [PATCH 09/19] kernel: convert uprobe.ref " Elena Reshetova
2017-02-20 10:18 ` [PATCH 10/19] kernel: convert nsproxy.count " Elena Reshetova
2017-02-20 10:19 ` [PATCH 11/19] kernel: convert cgroup_namespace.count " Elena Reshetova
2017-03-06 19:55 ` Tejun Heo
2017-02-20 10:19 ` [PATCH 12/19] kernel: convert css_set.refcount " Elena Reshetova
2017-03-06 19:54 ` Tejun Heo
2017-03-07 19:12 ` Reshetova, Elena
2017-03-07 19:21 ` Tejun Heo
2017-02-20 10:19 ` [PATCH 13/19] kernel: convert group_info.usage " Elena Reshetova
2017-02-20 10:19 ` [PATCH 14/19] kernel: convert cred.usage " Elena Reshetova
2017-02-20 10:19 ` [PATCH 15/19] kernel: convert audit_tree.count " Elena Reshetova
2017-02-20 22:07 ` Paul Moore
2017-02-21 7:15 ` Reshetova, Elena
2017-02-28 22:11 ` Paul Moore
2017-03-01 0:16 ` Kees Cook
2017-03-01 19:35 ` Paul Moore
2017-03-01 23:04 ` Kees Cook
2017-04-11 19:01 ` Paul Moore
2017-04-18 6:33 ` Reshetova, Elena
2017-02-20 10:19 ` [PATCH 16/19] kernel: convert audit_watch.count " Elena Reshetova
2017-02-20 10:19 ` [PATCH 17/19] kernel: convert numa_group.refcount " Elena Reshetova
2017-02-20 10:19 ` [PATCH 18/19] kernel: convert futex_pi_state.refcount " Elena Reshetova
2017-02-20 10:19 ` [PATCH 19/19] kernel: convert kcov.refcount " Elena Reshetova
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