shm.c 23.8 KB
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/*
 * linux/ipc/shm.c
 * Copyright (C) 1992, 1993 Krishna Balasubramanian
 *	 Many improvements/fixes by Bruno Haible.
 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
 *
 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
 *
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 * support for audit of ipc object properties and permission changes
 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
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 *
 * namespaces support
 * OpenVZ, SWsoft Inc.
 * Pavel Emelianov <xemul@openvz.org>
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 */

#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/shm.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/mman.h>
#include <linux/shmem_fs.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
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#include <linux/capability.h>
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#include <linux/ptrace.h>
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#include <linux/seq_file.h>
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#include <linux/mutex.h>
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#include <linux/nsproxy.h>
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#include <asm/uaccess.h>

#include "util.h"

static struct file_operations shm_file_operations;
static struct vm_operations_struct shm_vm_ops;

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static struct ipc_ids init_shm_ids;

#define shm_ids(ns)	(*((ns)->ids[IPC_SHM_IDS]))
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#define shm_lock(ns, id)		\
	((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
#define shm_unlock(shp)			\
	ipc_unlock(&(shp)->shm_perm)
#define shm_get(ns, id)			\
	((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
#define shm_buildid(ns, id, seq)	\
	ipc_buildid(&shm_ids(ns), id, seq)
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static int newseg (struct ipc_namespace *ns, key_t key,
		int shmflg, size_t size);
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static void shm_open (struct vm_area_struct *shmd);
static void shm_close (struct vm_area_struct *shmd);
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static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
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#ifdef CONFIG_PROC_FS
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static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
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#endif

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static void __ipc_init __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
{
	ns->ids[IPC_SHM_IDS] = ids;
	ns->shm_ctlmax = SHMMAX;
	ns->shm_ctlall = SHMALL;
	ns->shm_ctlmni = SHMMNI;
	ns->shm_tot = 0;
	ipc_init_ids(ids, 1);
}

static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
{
	if (shp->shm_nattch){
		shp->shm_perm.mode |= SHM_DEST;
		/* Do not find it any more */
		shp->shm_perm.key = IPC_PRIVATE;
		shm_unlock(shp);
	} else
		shm_destroy(ns, shp);
}

#ifdef CONFIG_IPC_NS
int shm_init_ns(struct ipc_namespace *ns)
{
	struct ipc_ids *ids;

	ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
	if (ids == NULL)
		return -ENOMEM;
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	__shm_init_ns(ns, ids);
	return 0;
}

void shm_exit_ns(struct ipc_namespace *ns)
{
	int i;
	struct shmid_kernel *shp;

	mutex_lock(&shm_ids(ns).mutex);
	for (i = 0; i <= shm_ids(ns).max_id; i++) {
		shp = shm_lock(ns, i);
		if (shp == NULL)
			continue;

		do_shm_rmid(ns, shp);
	}
	mutex_unlock(&shm_ids(ns).mutex);

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	ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
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	kfree(ns->ids[IPC_SHM_IDS]);
	ns->ids[IPC_SHM_IDS] = NULL;
}
#endif
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void __init shm_init (void)
{
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	__shm_init_ns(&init_ipc_ns, &init_shm_ids);
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	ipc_init_proc_interface("sysvipc/shm",
				"       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
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				IPC_SHM_IDS, sysvipc_shm_proc_show);
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}

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static inline int shm_checkid(struct ipc_namespace *ns,
		struct shmid_kernel *s, int id)
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{
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	if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
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		return -EIDRM;
	return 0;
}

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static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
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{
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	return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
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}

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static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
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{
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	return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
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}



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static inline void shm_inc(struct ipc_namespace *ns, int id)
{
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	struct shmid_kernel *shp;

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	shp = shm_lock(ns, id);
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	BUG_ON(!shp);
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	shp->shm_atim = get_seconds();
	shp->shm_lprid = current->tgid;
	shp->shm_nattch++;
	shm_unlock(shp);
}

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#define shm_file_ns(file) (*((struct ipc_namespace **)&(file)->private_data))

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/* This is called by fork, once for every shm attach. */
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static void shm_open(struct vm_area_struct *shmd)
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{
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	shm_inc(shm_file_ns(shmd->vm_file),
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			shmd->vm_file->f_path.dentry->d_inode->i_ino);
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}

/*
 * shm_destroy - free the struct shmid_kernel
 *
 * @shp: struct to free
 *
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 * It has to be called with shp and shm_ids.mutex locked,
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 * but returns with shp unlocked and freed.
 */
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static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
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{
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	ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
	shm_rmid(ns, shp->id);
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	shm_unlock(shp);
	if (!is_file_hugepages(shp->shm_file))
		shmem_lock(shp->shm_file, 0, shp->mlock_user);
	else
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		user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
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						shp->mlock_user);
	fput (shp->shm_file);
	security_shm_free(shp);
	ipc_rcu_putref(shp);
}

/*
 * remove the attach descriptor shmd.
 * free memory for segment if it is marked destroyed.
 * The descriptor has already been removed from the current->mm->mmap list
 * and will later be kfree()d.
 */
static void shm_close (struct vm_area_struct *shmd)
{
	struct file * file = shmd->vm_file;
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	int id = file->f_path.dentry->d_inode->i_ino;
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	struct shmid_kernel *shp;
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	struct ipc_namespace *ns;
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	ns = shm_file_ns(file);

	mutex_lock(&shm_ids(ns).mutex);
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	/* remove from the list of attaches of the shm segment */
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	shp = shm_lock(ns, id);
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	BUG_ON(!shp);
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	shp->shm_lprid = current->tgid;
	shp->shm_dtim = get_seconds();
	shp->shm_nattch--;
	if(shp->shm_nattch == 0 &&
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	   shp->shm_perm.mode & SHM_DEST)
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		shm_destroy(ns, shp);
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	else
		shm_unlock(shp);
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	mutex_unlock(&shm_ids(ns).mutex);
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}

static int shm_mmap(struct file * file, struct vm_area_struct * vma)
{
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	int ret;

	ret = shmem_mmap(file, vma);
	if (ret == 0) {
		vma->vm_ops = &shm_vm_ops;
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		if (!(vma->vm_flags & VM_WRITE))
			vma->vm_flags &= ~VM_MAYWRITE;
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		shm_inc(shm_file_ns(file), file->f_path.dentry->d_inode->i_ino);
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	}

	return ret;
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}

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static int shm_release(struct inode *ino, struct file *file)
{
	struct ipc_namespace *ns;

	ns = shm_file_ns(file);
	put_ipc_ns(ns);
	shm_file_ns(file) = NULL;
	return 0;
}

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static struct file_operations shm_file_operations = {
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	.mmap		= shm_mmap,
	.release	= shm_release,
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#ifndef CONFIG_MMU
	.get_unmapped_area = shmem_get_unmapped_area,
#endif
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};

static struct vm_operations_struct shm_vm_ops = {
	.open	= shm_open,	/* callback for a new vm-area open */
	.close	= shm_close,	/* callback for when the vm-area is released */
	.nopage	= shmem_nopage,
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#if defined(CONFIG_NUMA) && defined(CONFIG_SHMEM)
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	.set_policy = shmem_set_policy,
	.get_policy = shmem_get_policy,
#endif
};

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static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
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{
	int error;
	struct shmid_kernel *shp;
	int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
	struct file * file;
	char name[13];
	int id;

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	if (size < SHMMIN || size > ns->shm_ctlmax)
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		return -EINVAL;

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	if (ns->shm_tot + numpages >= ns->shm_ctlall)
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		return -ENOSPC;

	shp = ipc_rcu_alloc(sizeof(*shp));
	if (!shp)
		return -ENOMEM;

	shp->shm_perm.key = key;
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	shp->shm_perm.mode = (shmflg & S_IRWXUGO);
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	shp->mlock_user = NULL;

	shp->shm_perm.security = NULL;
	error = security_shm_alloc(shp);
	if (error) {
		ipc_rcu_putref(shp);
		return error;
	}

	if (shmflg & SHM_HUGETLB) {
		/* hugetlb_zero_setup takes care of mlock user accounting */
		file = hugetlb_zero_setup(size);
		shp->mlock_user = current->user;
	} else {
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		int acctflag = VM_ACCOUNT;
		/*
		 * Do not allow no accounting for OVERCOMMIT_NEVER, even
	 	 * if it's asked for.
		 */
		if  ((shmflg & SHM_NORESERVE) &&
				sysctl_overcommit_memory != OVERCOMMIT_NEVER)
			acctflag = 0;
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		sprintf (name, "SYSV%08x", key);
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		file = shmem_file_setup(name, size, acctflag);
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	}
	error = PTR_ERR(file);
	if (IS_ERR(file))
		goto no_file;

	error = -ENOSPC;
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	id = shm_addid(ns, shp);
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	if(id == -1) 
		goto no_id;

	shp->shm_cprid = current->tgid;
	shp->shm_lprid = 0;
	shp->shm_atim = shp->shm_dtim = 0;
	shp->shm_ctim = get_seconds();
	shp->shm_segsz = size;
	shp->shm_nattch = 0;
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	shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
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	shp->shm_file = file;
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	file->f_path.dentry->d_inode->i_ino = shp->id;
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	shm_file_ns(file) = get_ipc_ns(ns);

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	/* Hugetlb ops would have already been assigned. */
	if (!(shmflg & SHM_HUGETLB))
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		file->f_op = &shm_file_operations;
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	ns->shm_tot += numpages;
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	shm_unlock(shp);
	return shp->id;

no_id:
	fput(file);
no_file:
	security_shm_free(shp);
	ipc_rcu_putref(shp);
	return error;
}

asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
{
	struct shmid_kernel *shp;
	int err, id = 0;
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	struct ipc_namespace *ns;

	ns = current->nsproxy->ipc_ns;
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	mutex_lock(&shm_ids(ns).mutex);
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	if (key == IPC_PRIVATE) {
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		err = newseg(ns, key, shmflg, size);
	} else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
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		if (!(shmflg & IPC_CREAT))
			err = -ENOENT;
		else
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			err = newseg(ns, key, shmflg, size);
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	} else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
		err = -EEXIST;
	} else {
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		shp = shm_lock(ns, id);
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		BUG_ON(shp==NULL);
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		if (shp->shm_segsz < size)
			err = -EINVAL;
		else if (ipcperms(&shp->shm_perm, shmflg))
			err = -EACCES;
		else {
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			int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
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			err = security_shm_associate(shp, shmflg);
			if (!err)
				err = shmid;
		}
		shm_unlock(shp);
	}
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	mutex_unlock(&shm_ids(ns).mutex);
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	return err;
}

static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
{
	switch(version) {
	case IPC_64:
		return copy_to_user(buf, in, sizeof(*in));
	case IPC_OLD:
	    {
		struct shmid_ds out;

		ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
		out.shm_segsz	= in->shm_segsz;
		out.shm_atime	= in->shm_atime;
		out.shm_dtime	= in->shm_dtime;
		out.shm_ctime	= in->shm_ctime;
		out.shm_cpid	= in->shm_cpid;
		out.shm_lpid	= in->shm_lpid;
		out.shm_nattch	= in->shm_nattch;

		return copy_to_user(buf, &out, sizeof(out));
	    }
	default:
		return -EINVAL;
	}
}

struct shm_setbuf {
	uid_t	uid;
	gid_t	gid;
	mode_t	mode;
};	

static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
{
	switch(version) {
	case IPC_64:
	    {
		struct shmid64_ds tbuf;

		if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
			return -EFAULT;

		out->uid	= tbuf.shm_perm.uid;
		out->gid	= tbuf.shm_perm.gid;
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		out->mode	= tbuf.shm_perm.mode;
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		return 0;
	    }
	case IPC_OLD:
	    {
		struct shmid_ds tbuf_old;

		if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
			return -EFAULT;

		out->uid	= tbuf_old.shm_perm.uid;
		out->gid	= tbuf_old.shm_perm.gid;
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		out->mode	= tbuf_old.shm_perm.mode;
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		return 0;
	    }
	default:
		return -EINVAL;
	}
}

static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
{
	switch(version) {
	case IPC_64:
		return copy_to_user(buf, in, sizeof(*in));
	case IPC_OLD:
	    {
		struct shminfo out;

		if(in->shmmax > INT_MAX)
			out.shmmax = INT_MAX;
		else
			out.shmmax = (int)in->shmmax;

		out.shmmin	= in->shmmin;
		out.shmmni	= in->shmmni;
		out.shmseg	= in->shmseg;
		out.shmall	= in->shmall; 

		return copy_to_user(buf, &out, sizeof(out));
	    }
	default:
		return -EINVAL;
	}
}

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static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
		unsigned long *swp)
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{
	int i;

	*rss = 0;
	*swp = 0;

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	for (i = 0; i <= shm_ids(ns).max_id; i++) {
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		struct shmid_kernel *shp;
		struct inode *inode;

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		shp = shm_get(ns, i);
L
Linus Torvalds 已提交
495 496 497
		if(!shp)
			continue;

J
Josef Sipek 已提交
498
		inode = shp->shm_file->f_path.dentry->d_inode;
L
Linus Torvalds 已提交
499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517

		if (is_file_hugepages(shp->shm_file)) {
			struct address_space *mapping = inode->i_mapping;
			*rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
		} else {
			struct shmem_inode_info *info = SHMEM_I(inode);
			spin_lock(&info->lock);
			*rss += inode->i_mapping->nrpages;
			*swp += info->swapped;
			spin_unlock(&info->lock);
		}
	}
}

asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
{
	struct shm_setbuf setbuf;
	struct shmid_kernel *shp;
	int err, version;
K
Kirill Korotaev 已提交
518
	struct ipc_namespace *ns;
L
Linus Torvalds 已提交
519 520 521 522 523 524 525

	if (cmd < 0 || shmid < 0) {
		err = -EINVAL;
		goto out;
	}

	version = ipc_parse_version(&cmd);
K
Kirill Korotaev 已提交
526
	ns = current->nsproxy->ipc_ns;
L
Linus Torvalds 已提交
527 528 529 530 531 532 533 534 535 536 537

	switch (cmd) { /* replace with proc interface ? */
	case IPC_INFO:
	{
		struct shminfo64 shminfo;

		err = security_shm_shmctl(NULL, cmd);
		if (err)
			return err;

		memset(&shminfo,0,sizeof(shminfo));
K
Kirill Korotaev 已提交
538 539 540
		shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
		shminfo.shmmax = ns->shm_ctlmax;
		shminfo.shmall = ns->shm_ctlall;
L
Linus Torvalds 已提交
541 542 543 544 545

		shminfo.shmmin = SHMMIN;
		if(copy_shminfo_to_user (buf, &shminfo, version))
			return -EFAULT;
		/* reading a integer is always atomic */
K
Kirill Korotaev 已提交
546
		err= shm_ids(ns).max_id;
L
Linus Torvalds 已提交
547 548 549 550 551 552 553 554 555 556 557 558 559
		if(err<0)
			err = 0;
		goto out;
	}
	case SHM_INFO:
	{
		struct shm_info shm_info;

		err = security_shm_shmctl(NULL, cmd);
		if (err)
			return err;

		memset(&shm_info,0,sizeof(shm_info));
K
Kirill Korotaev 已提交
560 561 562 563
		mutex_lock(&shm_ids(ns).mutex);
		shm_info.used_ids = shm_ids(ns).in_use;
		shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
		shm_info.shm_tot = ns->shm_tot;
L
Linus Torvalds 已提交
564 565
		shm_info.swap_attempts = 0;
		shm_info.swap_successes = 0;
K
Kirill Korotaev 已提交
566 567
		err = shm_ids(ns).max_id;
		mutex_unlock(&shm_ids(ns).mutex);
L
Linus Torvalds 已提交
568 569 570 571 572 573 574 575 576 577 578 579 580 581
		if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
			err = -EFAULT;
			goto out;
		}

		err = err < 0 ? 0 : err;
		goto out;
	}
	case SHM_STAT:
	case IPC_STAT:
	{
		struct shmid64_ds tbuf;
		int result;
		memset(&tbuf, 0, sizeof(tbuf));
K
Kirill Korotaev 已提交
582
		shp = shm_lock(ns, shmid);
L
Linus Torvalds 已提交
583 584 585 586 587
		if(shp==NULL) {
			err = -EINVAL;
			goto out;
		} else if(cmd==SHM_STAT) {
			err = -EINVAL;
K
Kirill Korotaev 已提交
588
			if (shmid > shm_ids(ns).max_id)
L
Linus Torvalds 已提交
589
				goto out_unlock;
K
Kirill Korotaev 已提交
590
			result = shm_buildid(ns, shmid, shp->shm_perm.seq);
L
Linus Torvalds 已提交
591
		} else {
K
Kirill Korotaev 已提交
592
			err = shm_checkid(ns, shp,shmid);
L
Linus Torvalds 已提交
593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623
			if(err)
				goto out_unlock;
			result = 0;
		}
		err=-EACCES;
		if (ipcperms (&shp->shm_perm, S_IRUGO))
			goto out_unlock;
		err = security_shm_shmctl(shp, cmd);
		if (err)
			goto out_unlock;
		kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
		tbuf.shm_segsz	= shp->shm_segsz;
		tbuf.shm_atime	= shp->shm_atim;
		tbuf.shm_dtime	= shp->shm_dtim;
		tbuf.shm_ctime	= shp->shm_ctim;
		tbuf.shm_cpid	= shp->shm_cprid;
		tbuf.shm_lpid	= shp->shm_lprid;
		if (!is_file_hugepages(shp->shm_file))
			tbuf.shm_nattch	= shp->shm_nattch;
		else
			tbuf.shm_nattch = file_count(shp->shm_file) - 1;
		shm_unlock(shp);
		if(copy_shmid_to_user (buf, &tbuf, version))
			err = -EFAULT;
		else
			err = result;
		goto out;
	}
	case SHM_LOCK:
	case SHM_UNLOCK:
	{
K
Kirill Korotaev 已提交
624
		shp = shm_lock(ns, shmid);
L
Linus Torvalds 已提交
625 626 627 628
		if(shp==NULL) {
			err = -EINVAL;
			goto out;
		}
K
Kirill Korotaev 已提交
629
		err = shm_checkid(ns, shp,shmid);
L
Linus Torvalds 已提交
630 631 632
		if(err)
			goto out_unlock;

S
Steve Grubb 已提交
633 634 635 636
		err = audit_ipc_obj(&(shp->shm_perm));
		if (err)
			goto out_unlock;

L
Linus Torvalds 已提交
637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655
		if (!capable(CAP_IPC_LOCK)) {
			err = -EPERM;
			if (current->euid != shp->shm_perm.uid &&
			    current->euid != shp->shm_perm.cuid)
				goto out_unlock;
			if (cmd == SHM_LOCK &&
			    !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
				goto out_unlock;
		}

		err = security_shm_shmctl(shp, cmd);
		if (err)
			goto out_unlock;
		
		if(cmd==SHM_LOCK) {
			struct user_struct * user = current->user;
			if (!is_file_hugepages(shp->shm_file)) {
				err = shmem_lock(shp->shm_file, 1, user);
				if (!err) {
A
Andrew Morton 已提交
656
					shp->shm_perm.mode |= SHM_LOCKED;
L
Linus Torvalds 已提交
657 658 659 660 661
					shp->mlock_user = user;
				}
			}
		} else if (!is_file_hugepages(shp->shm_file)) {
			shmem_lock(shp->shm_file, 0, shp->mlock_user);
A
Andrew Morton 已提交
662
			shp->shm_perm.mode &= ~SHM_LOCKED;
L
Linus Torvalds 已提交
663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679
			shp->mlock_user = NULL;
		}
		shm_unlock(shp);
		goto out;
	}
	case IPC_RMID:
	{
		/*
		 *	We cannot simply remove the file. The SVID states
		 *	that the block remains until the last person
		 *	detaches from it, then is deleted. A shmat() on
		 *	an RMID segment is legal in older Linux and if 
		 *	we change it apps break...
		 *
		 *	Instead we set a destroyed flag, and then blow
		 *	the name away when the usage hits zero.
		 */
K
Kirill Korotaev 已提交
680 681
		mutex_lock(&shm_ids(ns).mutex);
		shp = shm_lock(ns, shmid);
L
Linus Torvalds 已提交
682 683 684
		err = -EINVAL;
		if (shp == NULL) 
			goto out_up;
K
Kirill Korotaev 已提交
685
		err = shm_checkid(ns, shp, shmid);
L
Linus Torvalds 已提交
686 687 688
		if(err)
			goto out_unlock_up;

S
Steve Grubb 已提交
689 690 691 692
		err = audit_ipc_obj(&(shp->shm_perm));
		if (err)
			goto out_unlock_up;

L
Linus Torvalds 已提交
693 694 695 696 697 698 699 700 701 702 703
		if (current->euid != shp->shm_perm.uid &&
		    current->euid != shp->shm_perm.cuid && 
		    !capable(CAP_SYS_ADMIN)) {
			err=-EPERM;
			goto out_unlock_up;
		}

		err = security_shm_shmctl(shp, cmd);
		if (err)
			goto out_unlock_up;

K
Kirill Korotaev 已提交
704 705
		do_shm_rmid(ns, shp);
		mutex_unlock(&shm_ids(ns).mutex);
L
Linus Torvalds 已提交
706 707 708 709 710 711 712 713 714
		goto out;
	}

	case IPC_SET:
	{
		if (copy_shmid_from_user (&setbuf, buf, version)) {
			err = -EFAULT;
			goto out;
		}
K
Kirill Korotaev 已提交
715 716
		mutex_lock(&shm_ids(ns).mutex);
		shp = shm_lock(ns, shmid);
L
Linus Torvalds 已提交
717 718 719
		err=-EINVAL;
		if(shp==NULL)
			goto out_up;
K
Kirill Korotaev 已提交
720
		err = shm_checkid(ns, shp,shmid);
L
Linus Torvalds 已提交
721 722
		if(err)
			goto out_unlock_up;
S
Steve Grubb 已提交
723 724 725
		err = audit_ipc_obj(&(shp->shm_perm));
		if (err)
			goto out_unlock_up;
726
		err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
S
Steve Grubb 已提交
727 728
		if (err)
			goto out_unlock_up;
L
Linus Torvalds 已提交
729 730 731 732 733 734 735 736 737 738 739 740 741
		err=-EPERM;
		if (current->euid != shp->shm_perm.uid &&
		    current->euid != shp->shm_perm.cuid && 
		    !capable(CAP_SYS_ADMIN)) {
			goto out_unlock_up;
		}

		err = security_shm_shmctl(shp, cmd);
		if (err)
			goto out_unlock_up;
		
		shp->shm_perm.uid = setbuf.uid;
		shp->shm_perm.gid = setbuf.gid;
A
Andrew Morton 已提交
742
		shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
L
Linus Torvalds 已提交
743 744 745 746 747 748 749 750 751 752 753 754 755 756
			| (setbuf.mode & S_IRWXUGO);
		shp->shm_ctim = get_seconds();
		break;
	}

	default:
		err = -EINVAL;
		goto out;
	}

	err = 0;
out_unlock_up:
	shm_unlock(shp);
out_up:
K
Kirill Korotaev 已提交
757
	mutex_unlock(&shm_ids(ns).mutex);
L
Linus Torvalds 已提交
758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782
	goto out;
out_unlock:
	shm_unlock(shp);
out:
	return err;
}

/*
 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 *
 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 * "raddr" thing points to kernel space, and there has to be a wrapper around
 * this.
 */
long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
{
	struct shmid_kernel *shp;
	unsigned long addr;
	unsigned long size;
	struct file * file;
	int    err;
	unsigned long flags;
	unsigned long prot;
	int acc_mode;
	void *user_addr;
K
Kirill Korotaev 已提交
783
	struct ipc_namespace *ns;
L
Linus Torvalds 已提交
784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821

	if (shmid < 0) {
		err = -EINVAL;
		goto out;
	} else if ((addr = (ulong)shmaddr)) {
		if (addr & (SHMLBA-1)) {
			if (shmflg & SHM_RND)
				addr &= ~(SHMLBA-1);	   /* round down */
			else
#ifndef __ARCH_FORCE_SHMLBA
				if (addr & ~PAGE_MASK)
#endif
					return -EINVAL;
		}
		flags = MAP_SHARED | MAP_FIXED;
	} else {
		if ((shmflg & SHM_REMAP))
			return -EINVAL;

		flags = MAP_SHARED;
	}

	if (shmflg & SHM_RDONLY) {
		prot = PROT_READ;
		acc_mode = S_IRUGO;
	} else {
		prot = PROT_READ | PROT_WRITE;
		acc_mode = S_IRUGO | S_IWUGO;
	}
	if (shmflg & SHM_EXEC) {
		prot |= PROT_EXEC;
		acc_mode |= S_IXUGO;
	}

	/*
	 * We cannot rely on the fs check since SYSV IPC does have an
	 * additional creator id...
	 */
K
Kirill Korotaev 已提交
822 823
	ns = current->nsproxy->ipc_ns;
	shp = shm_lock(ns, shmid);
L
Linus Torvalds 已提交
824 825 826 827
	if(shp == NULL) {
		err = -EINVAL;
		goto out;
	}
K
Kirill Korotaev 已提交
828
	err = shm_checkid(ns, shp,shmid);
L
Linus Torvalds 已提交
829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845
	if (err) {
		shm_unlock(shp);
		goto out;
	}
	if (ipcperms(&shp->shm_perm, acc_mode)) {
		shm_unlock(shp);
		err = -EACCES;
		goto out;
	}

	err = security_shm_shmat(shp, shmaddr, shmflg);
	if (err) {
		shm_unlock(shp);
		return err;
	}
		
	file = shp->shm_file;
J
Josef Sipek 已提交
846
	size = i_size_read(file->f_path.dentry->d_inode);
L
Linus Torvalds 已提交
847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868
	shp->shm_nattch++;
	shm_unlock(shp);

	down_write(&current->mm->mmap_sem);
	if (addr && !(shmflg & SHM_REMAP)) {
		user_addr = ERR_PTR(-EINVAL);
		if (find_vma_intersection(current->mm, addr, addr + size))
			goto invalid;
		/*
		 * If shm segment goes below stack, make sure there is some
		 * space left for the stack to grow (at least 4 pages).
		 */
		if (addr < current->mm->start_stack &&
		    addr > current->mm->start_stack - size - PAGE_SIZE * 5)
			goto invalid;
	}
		
	user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);

invalid:
	up_write(&current->mm->mmap_sem);

K
Kirill Korotaev 已提交
869 870
	mutex_lock(&shm_ids(ns).mutex);
	shp = shm_lock(ns, shmid);
871
	BUG_ON(!shp);
L
Linus Torvalds 已提交
872 873
	shp->shm_nattch--;
	if(shp->shm_nattch == 0 &&
A
Andrew Morton 已提交
874
	   shp->shm_perm.mode & SHM_DEST)
K
Kirill Korotaev 已提交
875
		shm_destroy(ns, shp);
L
Linus Torvalds 已提交
876 877
	else
		shm_unlock(shp);
K
Kirill Korotaev 已提交
878
	mutex_unlock(&shm_ids(ns).mutex);
L
Linus Torvalds 已提交
879 880 881 882 883 884 885 886 887

	*raddr = (unsigned long) user_addr;
	err = 0;
	if (IS_ERR(user_addr))
		err = PTR_ERR(user_addr);
out:
	return err;
}

S
Stephen Rothwell 已提交
888 889 890 891 892 893 894 895 896 897 898 899
asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
{
	unsigned long ret;
	long err;

	err = do_shmat(shmid, shmaddr, shmflg, &ret);
	if (err)
		return err;
	force_successful_syscall_return();
	return (long)ret;
}

L
Linus Torvalds 已提交
900 901 902 903 904 905 906 907 908 909 910 911
/*
 * detach and kill segment if marked destroyed.
 * The work is done in shm_close.
 */
asmlinkage long sys_shmdt(char __user *shmaddr)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma, *next;
	unsigned long addr = (unsigned long)shmaddr;
	loff_t size = 0;
	int retval = -EINVAL;

912 913 914
	if (addr & ~PAGE_MASK)
		return retval;

L
Linus Torvalds 已提交
915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950
	down_write(&mm->mmap_sem);

	/*
	 * This function tries to be smart and unmap shm segments that
	 * were modified by partial mlock or munmap calls:
	 * - It first determines the size of the shm segment that should be
	 *   unmapped: It searches for a vma that is backed by shm and that
	 *   started at address shmaddr. It records it's size and then unmaps
	 *   it.
	 * - Then it unmaps all shm vmas that started at shmaddr and that
	 *   are within the initially determined size.
	 * Errors from do_munmap are ignored: the function only fails if
	 * it's called with invalid parameters or if it's called to unmap
	 * a part of a vma. Both calls in this function are for full vmas,
	 * the parameters are directly copied from the vma itself and always
	 * valid - therefore do_munmap cannot fail. (famous last words?)
	 */
	/*
	 * If it had been mremap()'d, the starting address would not
	 * match the usual checks anyway. So assume all vma's are
	 * above the starting address given.
	 */
	vma = find_vma(mm, addr);

	while (vma) {
		next = vma->vm_next;

		/*
		 * Check if the starting address would match, i.e. it's
		 * a fragment created by mprotect() and/or munmap(), or it
		 * otherwise it starts at this address with no hassles.
		 */
		if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
			(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {


J
Josef Sipek 已提交
951
			size = vma->vm_file->f_path.dentry->d_inode->i_size;
L
Linus Torvalds 已提交
952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970
			do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
			/*
			 * We discovered the size of the shm segment, so
			 * break out of here and fall through to the next
			 * loop that uses the size information to stop
			 * searching for matching vma's.
			 */
			retval = 0;
			vma = next;
			break;
		}
		vma = next;
	}

	/*
	 * We need look no further than the maximum address a fragment
	 * could possibly have landed at. Also cast things to loff_t to
	 * prevent overflows and make comparisions vs. equal-width types.
	 */
971
	size = PAGE_ALIGN(size);
L
Linus Torvalds 已提交
972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987
	while (vma && (loff_t)(vma->vm_end - addr) <= size) {
		next = vma->vm_next;

		/* finding a matching vma now does not alter retval */
		if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
			(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)

			do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
		vma = next;
	}

	up_write(&mm->mmap_sem);
	return retval;
}

#ifdef CONFIG_PROC_FS
988
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
L
Linus Torvalds 已提交
989
{
990 991
	struct shmid_kernel *shp = it;
	char *format;
L
Linus Torvalds 已提交
992 993 994 995

#define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
#define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"

996 997 998 999 1000 1001 1002
	if (sizeof(size_t) <= sizeof(int))
		format = SMALL_STRING;
	else
		format = BIG_STRING;
	return seq_printf(s, format,
			  shp->shm_perm.key,
			  shp->id,
A
Andrew Morton 已提交
1003
			  shp->shm_perm.mode,
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014
			  shp->shm_segsz,
			  shp->shm_cprid,
			  shp->shm_lprid,
			  is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
			  shp->shm_perm.uid,
			  shp->shm_perm.gid,
			  shp->shm_perm.cuid,
			  shp->shm_perm.cgid,
			  shp->shm_atim,
			  shp->shm_dtim,
			  shp->shm_ctim);
L
Linus Torvalds 已提交
1015 1016
}
#endif