From: Waiman Long <longman@redhat.com>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-doc@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
Matthew Wilcox <willy@infradead.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Takashi Iwai <tiwai@suse.de>, Davidlohr Bueso <dbueso@suse.de>,
Waiman Long <longman@redhat.com>
Subject: [PATCH v8 2/5] ipc: IPCMNI limit check for semmni
Date: Mon, 18 Jun 2018 18:28:15 +0800 [thread overview]
Message-ID: <1529317698-16575-3-git-send-email-longman@redhat.com> (raw)
In-Reply-To: <1529317698-16575-1-git-send-email-longman@redhat.com>
For SysV semaphores, the semmni value is the last part of the 4-element
sem number array. To make semmni behave in a similar way to msgmni and
shmmni, we can't directly use the _minmax handler. Instead, a special
sem specific handler is added to check the last argument to make sure
that it is limited to the [0, IPCMNI] range. An error will be returned
if this is not the case.
Signed-off-by: Waiman Long <longman@redhat.com>
---
ipc/ipc_sysctl.c | 23 ++++++++++++++++++++++-
ipc/util.h | 9 +++++++++
2 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index f87cb29..49f9bf4 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -88,12 +88,33 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
}
+static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int ret, semmni;
+ struct ipc_namespace *ns = current->nsproxy->ipc_ns;
+
+ semmni = ns->sem_ctls[3];
+ ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos);
+
+ if (!ret)
+ ret = sem_check_semmni(current->nsproxy->ipc_ns);
+
+ /*
+ * Reset the semmni value if an error happens.
+ */
+ if (ret)
+ ns->sem_ctls[3] = semmni;
+ return ret;
+}
+
#else
#define proc_ipc_doulongvec_minmax NULL
#define proc_ipc_dointvec NULL
#define proc_ipc_dointvec_minmax NULL
#define proc_ipc_dointvec_minmax_orphans NULL
#define proc_ipc_auto_msgmni NULL
+#define proc_ipc_sem_dointvec NULL
#endif
static int zero;
@@ -175,7 +196,7 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
.data = &init_ipc_ns.sem_ctls,
.maxlen = 4*sizeof(int),
.mode = 0644,
- .proc_handler = proc_ipc_dointvec,
+ .proc_handler = proc_ipc_sem_dointvec,
},
#ifdef CONFIG_CHECKPOINT_RESTORE
{
diff --git a/ipc/util.h b/ipc/util.h
index 0aba323..8e9c52c 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -218,6 +218,15 @@ int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
+static inline int sem_check_semmni(struct ipc_namespace *ns) {
+ /*
+ * Check semmni range [0, IPCMNI]
+ * semmni is the last element of sem_ctls[4] array
+ */
+ return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > IPCMNI))
+ ? -ERANGE : 0;
+}
+
#ifdef CONFIG_COMPAT
#include <linux/compat.h>
struct compat_ipc_perm {
--
1.8.3.1
next prev parent reply other threads:[~2018-06-18 10:30 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-18 10:28 [PATCH v8 0/5] ipc: IPCMNI limit check for *mni & increase that limit Waiman Long
2018-06-18 10:28 ` [PATCH v8 1/5] ipc: IPCMNI limit check for msgmni and shmmni Waiman Long
2018-06-28 3:16 ` Luis R. Rodriguez
2018-08-17 16:51 ` Davidlohr Bueso
2018-06-18 10:28 ` Waiman Long [this message]
2018-06-28 22:39 ` [PATCH v8 2/5] ipc: IPCMNI limit check for semmni Luis R. Rodriguez
2018-06-29 7:26 ` Waiman Long
2018-08-17 16:53 ` Davidlohr Bueso
2018-06-18 10:28 ` [PATCH v8 3/5] ipc: Allow boot time extension of IPCMNI from 32k to 2M Waiman Long
2018-08-17 16:45 ` Davidlohr Bueso
2018-08-18 1:15 ` Waiman Long
2018-10-02 16:32 ` Manfred Spraul
2018-10-02 17:43 ` Waiman Long
2018-06-18 10:28 ` [PATCH v8 4/5] ipc: Conserve sequence numbers in extended IPCMNI mode Waiman Long
2018-06-18 10:28 ` [PATCH v8 5/5] ipc: Add a new ipcmni_compat sysctl to fall back to old behavior Waiman Long
2018-06-18 11:36 ` kbuild test robot
2018-06-18 14:27 ` kbuild test robot
2018-08-17 16:50 ` [PATCH v8 0/5] ipc: IPCMNI limit check for *mni & increase that limit Davidlohr Bueso
2018-09-06 22:24 ` Andrew Morton
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