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858ee3784e
Commit b231cca438 ("message queues: increase range limits") changed
how we create a queue that does not include an attr struct passed to
open so that it creates the queue with whatever the maximum values are.
However, if the admin has set the maximums to allow flexibility in
creating a queue (aka, both a large size and large queue are allowed,
but combined they create a queue too large for the RLIMIT_MSGQUEUE of
the user), then attempts to create a queue without an attr struct will
fail. Switch back to using acceptable defaults regardless of what the
maximums are.
Note: so far, we only know of a few applications that rely on this
behavior (specifically, set the maximums in /proc, then run the
application which calls mq_open() without passing in an attr struct, and
the application expects the newly created message queue to have the
maximum sizes that were set in /proc used on the mq_open() call, and all
of those applications that we know of are actually part of regression
test suites that were coded to do something like this:
for size in 4096 65536 $((1024 * 1024)) $((16 * 1024 * 1024)); do
echo $size > /proc/sys/fs/mqueue/msgsize_max
mq_open || echo "Error opening mq with size $size"
done
These test suites that depend on any behavior like this are broken. The
concept that programs should rely upon the system wide maximum in order
to get their desired results instead of simply using a attr struct to
specify what they want is fundamentally unfriendly programming practice
for any multi-tasking OS.
Fixing this will break those few apps that we know of (and those app
authors recognize the brokenness of their code and the need to fix it).
However, the following patch "mqueue: separate mqueue default value"
allows a workaround in the form of new knobs for the default msg queue
creation parameters for any software out there that we don't already
know about that might rely on this behavior at the moment.
Signed-off-by: Doug Ledford <dledford@redhat.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Amerigo Wang <amwang@redhat.com>
Cc: Joe Korty <joe.korty@ccur.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
153 lines
3.9 KiB
C
153 lines
3.9 KiB
C
#ifndef __IPC_NAMESPACE_H__
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#define __IPC_NAMESPACE_H__
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#include <linux/err.h>
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#include <linux/idr.h>
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#include <linux/rwsem.h>
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#include <linux/notifier.h>
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#include <linux/nsproxy.h>
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/*
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* ipc namespace events
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*/
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#define IPCNS_MEMCHANGED 0x00000001 /* Notify lowmem size changed */
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#define IPCNS_CREATED 0x00000002 /* Notify new ipc namespace created */
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#define IPCNS_REMOVED 0x00000003 /* Notify ipc namespace removed */
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#define IPCNS_CALLBACK_PRI 0
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struct user_namespace;
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struct ipc_ids {
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int in_use;
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unsigned short seq;
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unsigned short seq_max;
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struct rw_semaphore rw_mutex;
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struct idr ipcs_idr;
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};
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struct ipc_namespace {
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atomic_t count;
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struct ipc_ids ids[3];
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int sem_ctls[4];
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int used_sems;
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int msg_ctlmax;
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int msg_ctlmnb;
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int msg_ctlmni;
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atomic_t msg_bytes;
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atomic_t msg_hdrs;
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int auto_msgmni;
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size_t shm_ctlmax;
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size_t shm_ctlall;
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int shm_ctlmni;
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int shm_tot;
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/*
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* Defines whether IPC_RMID is forced for _all_ shm segments regardless
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* of shmctl()
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*/
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int shm_rmid_forced;
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struct notifier_block ipcns_nb;
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/* The kern_mount of the mqueuefs sb. We take a ref on it */
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struct vfsmount *mq_mnt;
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/* # queues in this ns, protected by mq_lock */
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unsigned int mq_queues_count;
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/* next fields are set through sysctl */
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unsigned int mq_queues_max; /* initialized to DFLT_QUEUESMAX */
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unsigned int mq_msg_max; /* initialized to DFLT_MSGMAX */
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unsigned int mq_msgsize_max; /* initialized to DFLT_MSGSIZEMAX */
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/* user_ns which owns the ipc ns */
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struct user_namespace *user_ns;
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};
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extern struct ipc_namespace init_ipc_ns;
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extern atomic_t nr_ipc_ns;
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extern spinlock_t mq_lock;
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#ifdef CONFIG_SYSVIPC
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extern int register_ipcns_notifier(struct ipc_namespace *);
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extern int cond_register_ipcns_notifier(struct ipc_namespace *);
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extern void unregister_ipcns_notifier(struct ipc_namespace *);
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extern int ipcns_notify(unsigned long);
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extern void shm_destroy_orphaned(struct ipc_namespace *ns);
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#else /* CONFIG_SYSVIPC */
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static inline int register_ipcns_notifier(struct ipc_namespace *ns)
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{ return 0; }
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static inline int cond_register_ipcns_notifier(struct ipc_namespace *ns)
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{ return 0; }
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static inline void unregister_ipcns_notifier(struct ipc_namespace *ns) { }
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static inline int ipcns_notify(unsigned long l) { return 0; }
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static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
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#endif /* CONFIG_SYSVIPC */
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#ifdef CONFIG_POSIX_MQUEUE
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extern int mq_init_ns(struct ipc_namespace *ns);
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/* default values */
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#define MIN_QUEUESMAX 1
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#define DFLT_QUEUESMAX 256 /* max number of message queues */
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#define HARD_QUEUESMAX 1024
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#define MIN_MSGMAX 1
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#define DFLT_MSG 10U
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#define DFLT_MSGMAX 10 /* max number of messages in each queue */
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#define HARD_MSGMAX (32768*sizeof(void *)/4)
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#define MIN_MSGSIZEMAX 128
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#define DFLT_MSGSIZE 8192U
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#define DFLT_MSGSIZEMAX 8192 /* max message size */
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#define HARD_MSGSIZEMAX (8192*128)
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#else
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static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
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#endif
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#if defined(CONFIG_IPC_NS)
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extern struct ipc_namespace *copy_ipcs(unsigned long flags,
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struct task_struct *tsk);
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static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
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{
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if (ns)
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atomic_inc(&ns->count);
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return ns;
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}
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extern void put_ipc_ns(struct ipc_namespace *ns);
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#else
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static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
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struct task_struct *tsk)
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{
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if (flags & CLONE_NEWIPC)
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return ERR_PTR(-EINVAL);
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return tsk->nsproxy->ipc_ns;
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}
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static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
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{
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return ns;
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}
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static inline void put_ipc_ns(struct ipc_namespace *ns)
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{
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}
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#endif
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#ifdef CONFIG_POSIX_MQUEUE_SYSCTL
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struct ctl_table_header;
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extern struct ctl_table_header *mq_register_sysctl_table(void);
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#else /* CONFIG_POSIX_MQUEUE_SYSCTL */
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static inline struct ctl_table_header *mq_register_sysctl_table(void)
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{
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return NULL;
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}
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#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
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#endif
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