From: Stanislav Kinsbursky <skinsbursky@parallels.com>
To: akpm@linux-foundation.org
Cc: catalin.marinas@arm.com, will.deacon@arm.com,
dhowells@redhat.com, manfred@colorfullife.com, hughd@google.com,
jmorris@namei.org, mtk.manpages@gmail.com,
kosaki.motohiro@jp.fujitsu.com, paulmck@linux.vnet.ibm.com,
sds@tycho.nsa.gov, devel@openvz.org, a.p.zijlstra@chello.nl,
cmetcalf@tilera.com, linux-driver@qlogic.com,
ron.mercer@qlogic.com, viro@zeniv.linux.org.uk,
eparis@parisplace.org, tglx@linutronix.de,
jitendra.kalsaria@qlogic.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org, ebiederm@xmission.com,
casey@schaufler-ca.com
Subject: [PATCH v7 03/10] ipc: segment key change helper introduced
Date: Thu, 18 Oct 2012 14:22:51 +0400 [thread overview]
Message-ID: <20121018102251.16036.51449.stgit@localhost.localdomain> (raw)
In-Reply-To: <20121018101543.16036.12221.stgit@localhost.localdomain>
This patch introduces existent segment key changing infrastructure.
New function ipc_update_key() can be used change segment key, cuid, cgid
values. It checks for that new key is not used (except IPC_PRIVATE) prior to
set it on existent.
To make this possible, added copying of this fields from user-space in
__get_compat_ipc_perm() and __get_compat_ipc64_perm() functions. Also segment
search by key and lock were splitted into different functions, because
ipc_update_key() doesn't need to lock the segment during check that new key is
not used.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
---
ipc/compat.c | 6 ++++++
ipc/util.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++---
ipc/util.h | 2 ++
3 files changed, 54 insertions(+), 3 deletions(-)
diff --git a/ipc/compat.c b/ipc/compat.c
index ad9518e..af30d13 100644
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -144,6 +144,9 @@ static inline int __get_compat_ipc64_perm(struct ipc64_perm *p64,
err = __get_user(p64->uid, &up64->uid);
err |= __get_user(p64->gid, &up64->gid);
err |= __get_user(p64->mode, &up64->mode);
+ err |= __get_user(p64->cuid, &up64->cuid);
+ err |= __get_user(p64->cgid, &up64->cgid);
+ err |= __get_user(p64->key, &up64->key);
return err;
}
@@ -155,6 +158,9 @@ static inline int __get_compat_ipc_perm(struct ipc64_perm *p,
err = __get_user(p->uid, &up->uid);
err |= __get_user(p->gid, &up->gid);
err |= __get_user(p->mode, &up->mode);
+ err |= __get_user(p->cuid, &up->cuid);
+ err |= __get_user(p->cgid, &up->cgid);
+ err |= __get_user(p->key, &up->key);
return err;
}
diff --git a/ipc/util.c b/ipc/util.c
index 503946e..3396ab5 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -173,7 +173,7 @@ void __init ipc_init_proc_interface(const char *path, const char *header,
* @key: The key to find
*
* Requires ipc_ids.rw_mutex locked.
- * Returns the LOCKED pointer to the ipc structure if found or NULL
+ * Returns the UNLOCKED pointer to the ipc structure if found or NULL
* if not.
* If key is found ipc points to the owning ipc structure
*/
@@ -195,7 +195,6 @@ static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
continue;
}
- ipc_lock_by_ptr(ipc);
return ipc;
}
@@ -203,6 +202,27 @@ static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
}
/**
+ * ipc_findkey_locked - find and lock a key in an ipc identifier set
+ * @ids: Identifier set
+ * @key: The key to find
+ *
+ * Requires ipc_ids.rw_mutex locked.
+ * Returns the LOCKED pointer to the ipc structure if found or NULL
+ * if not.
+ * If key is found ipc points to the owning ipc structure
+ */
+
+static struct kern_ipc_perm *ipc_findkey_locked(struct ipc_ids *ids, key_t key)
+{
+ struct kern_ipc_perm *ipc;
+
+ ipc = ipc_findkey(ids, key);
+ if (ipc)
+ ipc_lock_by_ptr(ipc);
+ return ipc;
+}
+
+/**
* ipc_get_maxid - get the last assigned id
* @ids: IPC identifier set
*
@@ -388,7 +408,7 @@ retry:
* a new entry + read locks are not "upgradable"
*/
down_write(&ids->rw_mutex);
- ipcp = ipc_findkey(ids, params->key);
+ ipcp = ipc_findkey_locked(ids, params->key);
if (ipcp == NULL) {
/* key not used */
if (!(flg & IPC_CREAT))
@@ -755,6 +775,29 @@ int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
}
/**
+ * ipc_update_key - update the key of an IPC.
+ * @in: the permission given as input.
+ * @out: the permission of the ipc to set.
+ *
+ * Common routine called by sys_shmctl(), sys_semctl(). sys_msgctl().
+ */
+int ipc_update_key(struct ipc_ids *ids, struct ipc64_perm *in,
+ struct kern_ipc_perm *out)
+{
+
+ if (in->key && out->key != in->key) {
+ /*
+ * Check for existent segment with the same key.
+ * Note: ipc_ids.rw_mutex is taken for write already.
+ */
+ if (ipc_findkey(ids, in->key))
+ return -EEXIST;
+ out->key = in->key;
+ }
+ return 0;
+}
+
+/**
* ipc_update_perm - update the permissions of an IPC.
* @in: the permission given as input.
* @out: the permission of the ipc to set.
diff --git a/ipc/util.h b/ipc/util.h
index 3a9e558..271bded 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -126,6 +126,8 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
+int ipc_update_key(struct ipc_ids *ids, struct ipc64_perm *in,
+ struct kern_ipc_perm *out);
int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
struct ipc_ids *ids, int id, int cmd,
next prev parent reply other threads:[~2012-10-18 10:23 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-18 10:22 [PATCH v7 00/10] IPC: checkpoint/restore in userspace enhancements Stanislav Kinsbursky
2012-10-18 10:22 ` [PATCH v7 01/10] ipc: remove forced assignment of selected message Stanislav Kinsbursky
2012-10-18 10:22 ` [PATCH v7 02/10] ipc: "use key as id" functionality for resource get system call introduced Stanislav Kinsbursky
2012-10-18 10:22 ` Stanislav Kinsbursky [this message]
2012-10-18 10:22 ` [PATCH v7 04/10] ipc: add new SHM_SET command for sys_shmctl() call Stanislav Kinsbursky
2012-10-18 10:23 ` [PATCH v7 05/10] ipc: add new MSG_SET command for sys_msgctl() call Stanislav Kinsbursky
2012-10-18 10:23 ` [PATCH v7 06/10] qlge driver: rename internal SEM_SET macro to SEM_INIT Stanislav Kinsbursky
2012-10-18 10:23 ` [PATCH v7 07/10] ipc: add new SEM_SET command for sys_semctl() call Stanislav Kinsbursky
2012-10-18 10:23 ` [PATCH v7 08/10] IPC: message queue receive cleanup Stanislav Kinsbursky
2012-10-18 10:23 ` [PATCH v7 09/10] IPC: message queue copy feature introduced Stanislav Kinsbursky
2012-10-18 10:39 ` Michael Kerrisk (man-pages)
2012-10-18 10:23 ` [PATCH v7 10/10] test: IPC message queue copy feture test Stanislav Kinsbursky
2012-10-18 10:41 ` [PATCH v7 00/10] IPC: checkpoint/restore in userspace enhancements Michael Kerrisk (man-pages)
2012-10-18 12:11 ` Eric W. Biederman
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