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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-30 18:32:21 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-30 18:32:21 -0800
commit8b0fdf631cf6a31f60a9ed3e1c0f37a9715de807 (patch)
tree50bab0b8c054df37f397d581251ba7df1484e061
parent168fe32a072a4b8dc81a3aebf0e5e588d38e2955 (diff)
parent36735a6a2b5e042db1af956ce4bcc13f3ff99e21 (diff)
Merge branch 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull mqueue/bpf vfs cleanups from Al Viro: "mqueue and bpf go through rather painful and similar contortions to create objects in their dentry trees. Provide a primitive for doing that without abusing ->mknod(), switch bpf and mqueue to it. Another mqueue-related thing that has ended up in that branch is on-demand creation of internal mount (based upon the work of Giuseppe Scrivano)" * 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: mqueue: switch to on-demand creation of internal mount tidy do_mq_open() up a bit mqueue: clean prepare_open() up do_mq_open(): move all work prior to dentry_open() into a helper mqueue: fold mq_attr_ok() into mqueue_get_inode() move dentry_open() calls up into do_mq_open() mqueue: switch to vfs_mkobj(), quit abusing ->d_fsdata bpf_obj_do_pin(): switch to vfs_mkobj(), quit abusing ->mknod() new primitive: vfs_mkobj()
-rw-r--r--fs/namei.c21
-rw-r--r--include/linux/fs.h4
-rw-r--r--ipc/mqueue.c241
-rw-r--r--kernel/bpf/inode.c50
4 files changed, 158 insertions, 158 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 4e3fc58dae72..7c221fb0836b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2895,6 +2895,27 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
}
EXPORT_SYMBOL(vfs_create);
+int vfs_mkobj(struct dentry *dentry, umode_t mode,
+ int (*f)(struct dentry *, umode_t, void *),
+ void *arg)
+{
+ struct inode *dir = dentry->d_parent->d_inode;
+ int error = may_create(dir, dentry);
+ if (error)
+ return error;
+
+ mode &= S_IALLUGO;
+ mode |= S_IFREG;
+ error = security_inode_create(dir, dentry, mode);
+ if (error)
+ return error;
+ error = f(dentry, mode, arg);
+ if (!error)
+ fsnotify_create(dir, dentry);
+ return error;
+}
+EXPORT_SYMBOL(vfs_mkobj);
+
bool may_open_dev(const struct path *path)
{
return !(path->mnt->mnt_flags & MNT_NODEV) &&
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 569c51d37312..9798a133e718 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1608,6 +1608,10 @@ extern int vfs_whiteout(struct inode *, struct dentry *);
extern struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode,
int open_flag);
+int vfs_mkobj(struct dentry *, umode_t,
+ int (*f)(struct dentry *, umode_t, void *),
+ void *);
+
/*
* VFS file helper functions.
*/
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 3bc5bb7d6827..690ae6665500 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -270,13 +270,30 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
* that means the min(mq_maxmsg, max_priorities) * struct
* posix_msg_tree_node.
*/
+
+ ret = -EINVAL;
+ if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
+ goto out_inode;
+ if (capable(CAP_SYS_RESOURCE)) {
+ if (info->attr.mq_maxmsg > HARD_MSGMAX ||
+ info->attr.mq_msgsize > HARD_MSGSIZEMAX)
+ goto out_inode;
+ } else {
+ if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
+ info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
+ goto out_inode;
+ }
+ ret = -EOVERFLOW;
+ /* check for overflow */
+ if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
+ goto out_inode;
mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
sizeof(struct posix_msg_tree_node);
-
- mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
- info->attr.mq_msgsize);
-
+ mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
+ if (mq_bytes + mq_treesize < mq_bytes)
+ goto out_inode;
+ mq_bytes += mq_treesize;
spin_lock(&mq_lock);
if (u->mq_bytes + mq_bytes < u->mq_bytes ||
u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
@@ -308,8 +325,9 @@ err:
static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode;
- struct ipc_namespace *ns = sb->s_fs_info;
+ struct ipc_namespace *ns = data;
+ sb->s_fs_info = ns;
sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
@@ -326,18 +344,44 @@ static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
return 0;
}
+static struct file_system_type mqueue_fs_type;
+/*
+ * Return value is pinned only by reference in ->mq_mnt; it will
+ * live until ipcns dies. Caller does not need to drop it.
+ */
+static struct vfsmount *mq_internal_mount(void)
+{
+ struct ipc_namespace *ns = current->nsproxy->ipc_ns;
+ struct vfsmount *m = ns->mq_mnt;
+ if (m)
+ return m;
+ m = kern_mount_data(&mqueue_fs_type, ns);
+ spin_lock(&mq_lock);
+ if (unlikely(ns->mq_mnt)) {
+ spin_unlock(&mq_lock);
+ if (!IS_ERR(m))
+ kern_unmount(m);
+ return ns->mq_mnt;
+ }
+ if (!IS_ERR(m))
+ ns->mq_mnt = m;
+ spin_unlock(&mq_lock);
+ return m;
+}
+
static struct dentry *mqueue_mount(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data)
{
- struct ipc_namespace *ns;
- if (flags & SB_KERNMOUNT) {
- ns = data;
- data = NULL;
- } else {
- ns = current->nsproxy->ipc_ns;
- }
- return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
+ struct vfsmount *m;
+ if (flags & SB_KERNMOUNT)
+ return mount_nodev(fs_type, flags, data, mqueue_fill_super);
+ m = mq_internal_mount();
+ if (IS_ERR(m))
+ return ERR_CAST(m);
+ atomic_inc(&m->mnt_sb->s_active);
+ down_write(&m->mnt_sb->s_umount);
+ return dget(m->mnt_root);
}
static void init_once(void *foo)
@@ -416,11 +460,11 @@ static void mqueue_evict_inode(struct inode *inode)
put_ipc_ns(ipc_ns);
}
-static int mqueue_create(struct inode *dir, struct dentry *dentry,
- umode_t mode, bool excl)
+static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
{
+ struct inode *dir = dentry->d_parent->d_inode;
struct inode *inode;
- struct mq_attr *attr = dentry->d_fsdata;
+ struct mq_attr *attr = arg;
int error;
struct ipc_namespace *ipc_ns;
@@ -461,6 +505,12 @@ out_unlock:
return error;
}
+static int mqueue_create(struct inode *dir, struct dentry *dentry,
+ umode_t mode, bool excl)
+{
+ return mqueue_create_attr(dentry, mode, NULL);
+}
+
static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
@@ -691,96 +741,46 @@ static void remove_notification(struct mqueue_inode_info *info)
info->notify_user_ns = NULL;
}
-static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
-{
- int mq_treesize;
- unsigned long total_size;
-
- if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
- return -EINVAL;
- if (capable(CAP_SYS_RESOURCE)) {
- if (attr->mq_maxmsg > HARD_MSGMAX ||
- attr->mq_msgsize > HARD_MSGSIZEMAX)
- return -EINVAL;
- } else {
- if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
- attr->mq_msgsize > ipc_ns->mq_msgsize_max)
- return -EINVAL;
- }
- /* check for overflow */
- if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
- return -EOVERFLOW;
- mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
- min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
- sizeof(struct posix_msg_tree_node);
- total_size = attr->mq_maxmsg * attr->mq_msgsize;
- if (total_size + mq_treesize < total_size)
- return -EOVERFLOW;
- return 0;
-}
-
-/*
- * Invoked when creating a new queue via sys_mq_open
- */
-static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
- struct path *path, int oflag, umode_t mode,
+static int prepare_open(struct dentry *dentry, int oflag, int ro,
+ umode_t mode, struct filename *name,
struct mq_attr *attr)
{
- const struct cred *cred = current_cred();
- int ret;
-
- if (attr) {
- ret = mq_attr_ok(ipc_ns, attr);
- if (ret)
- return ERR_PTR(ret);
- /* store for use during create */
- path->dentry->d_fsdata = attr;
- } else {
- struct mq_attr def_attr;
-
- def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
- ipc_ns->mq_msg_default);
- def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
- ipc_ns->mq_msgsize_default);
- ret = mq_attr_ok(ipc_ns, &def_attr);
- if (ret)
- return ERR_PTR(ret);
- }
-
- mode &= ~current_umask();
- ret = vfs_create(dir, path->dentry, mode, true);
- path->dentry->d_fsdata = NULL;
- if (ret)
- return ERR_PTR(ret);
- return dentry_open(path, oflag, cred);
-}
-
-/* Opens existing queue */
-static struct file *do_open(struct path *path, int oflag)
-{
static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
MAY_READ | MAY_WRITE };
int acc;
+
+ if (d_really_is_negative(dentry)) {
+ if (!(oflag & O_CREAT))
+ return -ENOENT;
+ if (ro)
+ return ro;
+ audit_inode_parent_hidden(name, dentry->d_parent);
+ return vfs_mkobj(dentry, mode & ~current_umask(),
+ mqueue_create_attr, attr);
+ }
+ /* it already existed */
+ audit_inode(name, dentry, 0);
+ if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
+ return -EEXIST;
if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
- return ERR_PTR(-EINVAL);
+ return -EINVAL;
acc = oflag2acc[oflag & O_ACCMODE];
- if (inode_permission(d_inode(path->dentry), acc))
- return ERR_PTR(-EACCES);
- return dentry_open(path, oflag, current_cred());
+ return inode_permission(d_inode(dentry), acc);
}
static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
struct mq_attr *attr)
{
- struct path path;
- struct file *filp;
+ struct vfsmount *mnt = mq_internal_mount();
+ struct dentry *root;
struct filename *name;
+ struct path path;
int fd, error;
- struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
- struct vfsmount *mnt = ipc_ns->mq_mnt;
- struct dentry *root = mnt->mnt_root;
int ro;
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+
audit_mq_open(oflag, mode, attr);
if (IS_ERR(name = getname(u_name)))
@@ -791,7 +791,7 @@ static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
goto out_putname;
ro = mnt_want_write(mnt); /* we'll drop it in any case */
- error = 0;
+ root = mnt->mnt_root;
inode_lock(d_inode(root));
path.dentry = lookup_one_len(name->name, root, strlen(name->name));
if (IS_ERR(path.dentry)) {
@@ -799,38 +799,14 @@ static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
goto out_putfd;
}
path.mnt = mntget(mnt);
-
- if (oflag & O_CREAT) {
- if (d_really_is_positive(path.dentry)) { /* entry already exists */
- audit_inode(name, path.dentry, 0);
- if (oflag & O_EXCL) {
- error = -EEXIST;
- goto out;
- }
- filp = do_open(&path, oflag);
- } else {
- if (ro) {
- error = ro;
- goto out;
- }
- audit_inode_parent_hidden(name, root);
- filp = do_create(ipc_ns, d_inode(root), &path,
- oflag, mode, attr);
- }
- } else {
- if (d_really_is_negative(path.dentry)) {
- error = -ENOENT;
- goto out;
- }
- audit_inode(name, path.dentry, 0);
- filp = do_open(&path, oflag);
+ error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
+ if (!error) {
+ struct file *file = dentry_open(&path, oflag, current_cred());
+ if (!IS_ERR(file))
+ fd_install(fd, file);
+ else
+ error = PTR_ERR(file);
}
-
- if (!IS_ERR(filp))
- fd_install(fd, filp);
- else
- error = PTR_ERR(filp);
-out:
path_put(&path);
out_putfd:
if (error) {
@@ -864,6 +840,9 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
struct vfsmount *mnt = ipc_ns->mq_mnt;
+ if (!mnt)
+ return -ENOENT;
+
name = getname(u_name);
if (IS_ERR(name))
return PTR_ERR(name);
@@ -1590,28 +1569,26 @@ int mq_init_ns(struct ipc_namespace *ns)
ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
ns->mq_msg_default = DFLT_MSG;
ns->mq_msgsize_default = DFLT_MSGSIZE;
+ ns->mq_mnt = NULL;
- ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
- if (IS_ERR(ns->mq_mnt)) {
- int err = PTR_ERR(ns->mq_mnt);
- ns->mq_mnt = NULL;
- return err;
- }
return 0;
}
void mq_clear_sbinfo(struct ipc_namespace *ns)
{
- ns->mq_mnt->mnt_sb->s_fs_info = NULL;
+ if (ns->mq_mnt)
+ ns->mq_mnt->mnt_sb->s_fs_info = NULL;
}
void mq_put_mnt(struct ipc_namespace *ns)
{
- kern_unmount(ns->mq_mnt);
+ if (ns->mq_mnt)
+ kern_unmount(ns->mq_mnt);
}
static int __init init_mqueue_fs(void)
{
+ struct vfsmount *m;
int error;
mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
@@ -1633,6 +1610,10 @@ static int __init init_mqueue_fs(void)
if (error)
goto out_filesystem;
+ m = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
+ if (IS_ERR(m))
+ goto out_filesystem;
+ init_ipc_ns.mq_mnt = m;
return 0;
out_filesystem:
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 5bb5e49ef4c3..81e2f6995adb 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -150,39 +150,29 @@ static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
return 0;
}
-static int bpf_mkobj_ops(struct inode *dir, struct dentry *dentry,
- umode_t mode, const struct inode_operations *iops)
+static int bpf_mkobj_ops(struct dentry *dentry, umode_t mode, void *raw,
+ const struct inode_operations *iops)
{
- struct inode *inode;
-
- inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG);
+ struct inode *dir = dentry->d_parent->d_inode;
+ struct inode *inode = bpf_get_inode(dir->i_sb, dir, mode);
if (IS_ERR(inode))
return PTR_ERR(inode);
inode->i_op = iops;
- inode->i_private = dentry->d_fsdata;
+ inode->i_private = raw;
bpf_dentry_finalize(dentry, inode, dir);
return 0;
}
-static int bpf_mkobj(struct inode *dir, struct dentry *dentry, umode_t mode,
- dev_t devt)
+static int bpf_mkprog(struct dentry *dentry, umode_t mode, void *arg)
{
- enum bpf_type type = MINOR(devt);
-
- if (MAJOR(devt) != UNNAMED_MAJOR || !S_ISREG(mode) ||
- dentry->d_fsdata == NULL)
- return -EPERM;
+ return bpf_mkobj_ops(dentry, mode, arg, &bpf_prog_iops);
+}
- switch (type) {
- case BPF_TYPE_PROG:
- return bpf_mkobj_ops(dir, dentry, mode, &bpf_prog_iops);
- case BPF_TYPE_MAP:
- return bpf_mkobj_ops(dir, dentry, mode, &bpf_map_iops);
- default:
- return -EPERM;
- }
+static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg)
+{
+ return bpf_mkobj_ops(dentry, mode, arg, &bpf_map_iops);
}
static struct dentry *
@@ -218,7 +208,6 @@ static int bpf_symlink(struct inode *dir, struct dentry *dentry,
static const struct inode_operations bpf_dir_iops = {
.lookup = bpf_lookup,
- .mknod = bpf_mkobj,
.mkdir = bpf_mkdir,
.symlink = bpf_symlink,
.rmdir = simple_rmdir,
@@ -234,7 +223,6 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw,
struct inode *dir;
struct path path;
umode_t mode;
- dev_t devt;
int ret;
dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0);
@@ -242,9 +230,8 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw,
return PTR_ERR(dentry);
mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());
- devt = MKDEV(UNNAMED_MAJOR, type);
- ret = security_path_mknod(&path, dentry, mode, devt);
+ ret = security_path_mknod(&path, dentry, mode, 0);
if (ret)
goto out;
@@ -254,9 +241,16 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw,
goto out;
}
- dentry->d_fsdata = raw;
- ret = vfs_mknod(dir, dentry, mode, devt);
- dentry->d_fsdata = NULL;
+ switch (type) {
+ case BPF_TYPE_PROG:
+ ret = vfs_mkobj(dentry, mode, bpf_mkprog, raw);
+ break;
+ case BPF_TYPE_MAP:
+ ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw);
+ break;
+ default:
+ ret = -EPERM;
+ }
out:
done_path_create(&path, dentry);
return ret;

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