#include <linux/security.h>
#include <linux/mount.h>
#include <linux/audit.h>
+#include <linux/vs_base.h>
+
#include <asm/namei.h>
#include <asm/uaccess.h>
{
umode_t mode = inode->i_mode;
- if (IS_BARRIER(inode) && !vx_check(0, VX_ADMIN|VX_WATCH))
+ /* Prevent vservers from escaping chroot() barriers */
+ if (IS_BARRIER(inode) && !vx_check(0, VX_ADMIN))
return -EACCES;
if (mask & MAY_WRITE) {
return -EACCES;
}
-static inline int xid_permission(struct inode *inode)
-{
- if (inode->i_xid == 0)
- return 0;
- if (vx_check(inode->i_xid, VX_ADMIN|VX_WATCH|VX_IDENT))
- return 0;
- return -EACCES;
-}
-
int permission(struct inode * inode,int mask, struct nameidata *nd)
{
int retval;
int submask;
+ umode_t mode = inode->i_mode;
/* Ordinary permission routines do not understand MAY_APPEND. */
submask = mask & ~MAY_APPEND;
- if ((retval = xid_permission(inode)))
- return retval;
+ if (nd && (mask & MAY_WRITE) && MNT_IS_RDONLY(nd->mnt) &&
+ (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
+ return -EROFS;
+
if (inode->i_op && inode->i_op->permission)
retval = inode->i_op->permission(inode, submask, nd);
else
mntput(nd->mnt);
}
+/*
+ * umount() mustn't call path_release()/mntput() as that would clear
+ * mnt_expiry_mark
+ */
+void path_release_on_umount(struct nameidata *nd)
+{
+ dput(nd->dentry);
+ _mntput(nd->mnt);
+}
+
/*
* Internal lookup() using the new generic dcache.
* SMP-safe
{
umode_t mode = inode->i_mode;
- if ((inode->i_op && inode->i_op->permission))
+ if (inode->i_op && inode->i_op->permission)
return -EAGAIN;
if (current->fsuid == inode->i_uid)
if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE))
goto ok;
+ if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE))
+ goto ok;
+
if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH))
goto ok;
return result;
}
-inline void nd_set_link(struct nameidata *nd, char *path)
-{
- nd->saved_names[current->link_count] = path;
-}
+static int __emul_lookup_dentry(const char *, struct nameidata *);
-inline char *nd_get_link(struct nameidata *nd)
+/* SMP-safe */
+static inline int
+walk_init_root(const char *name, struct nameidata *nd)
{
- return nd->saved_names[current->link_count];
+ read_lock(¤t->fs->lock);
+ if (current->fs->altroot && !(nd->flags & LOOKUP_NOALT)) {
+ nd->mnt = mntget(current->fs->altrootmnt);
+ nd->dentry = dget(current->fs->altroot);
+ read_unlock(¤t->fs->lock);
+ if (__emul_lookup_dentry(name,nd))
+ return 0;
+ read_lock(¤t->fs->lock);
+ }
+ nd->mnt = mntget(current->fs->rootmnt);
+ nd->dentry = dget(current->fs->root);
+ read_unlock(¤t->fs->lock);
+ return 1;
}
-EXPORT_SYMBOL(nd_set_link);
-EXPORT_SYMBOL(nd_get_link);
+static inline int __vfs_follow_link(struct nameidata *nd, const char *link)
+{
+ int res = 0;
+ char *name;
+ if (IS_ERR(link))
+ goto fail;
-static inline int __vfs_follow_link(struct nameidata *, const char *);
+ if (*link == '/') {
+ path_release(nd);
+ if (!walk_init_root(link, nd))
+ /* weird __emul_prefix() stuff did it */
+ goto out;
+ }
+ res = link_path_walk(link, nd);
+out:
+ if (nd->depth || res || nd->last_type!=LAST_NORM)
+ return res;
+ /*
+ * If it is an iterative symlinks resolution in open_namei() we
+ * have to copy the last component. And all that crap because of
+ * bloody create() on broken symlinks. Furrfu...
+ */
+ name = __getname();
+ if (unlikely(!name)) {
+ path_release(nd);
+ return -ENOMEM;
+ }
+ strcpy(name, nd->last.name);
+ nd->last.name = name;
+ return 0;
+fail:
+ path_release(nd);
+ return PTR_ERR(link);
+}
/*
* This limits recursive symlink follows to 8, while
goto loop;
if (current->total_link_count >= 40)
goto loop;
+ BUG_ON(nd->depth >= MAX_NESTED_LINKS);
cond_resched();
err = security_inode_follow_link(dentry, nd);
if (err)
goto loop;
current->link_count++;
current->total_link_count++;
+ nd->depth++;
touch_atime(nd->mnt, dentry);
nd_set_link(nd, NULL);
err = dentry->d_inode->i_op->follow_link(dentry, nd);
dentry->d_inode->i_op->put_link(dentry, nd);
}
current->link_count--;
+ nd->depth--;
return err;
loop:
path_release(nd);
goto return_reval;
inode = nd->dentry->d_inode;
- if (current->link_count)
+ if (nd->depth)
lookup_flags = LOOKUP_FOLLOW;
/* At this point we know we have a real path component. */
return 0; /* something went wrong... */
if (!nd->dentry->d_inode || S_ISDIR(nd->dentry->d_inode->i_mode)) {
- struct nameidata nd_root;
+ struct dentry *old_dentry = nd->dentry;
+ struct vfsmount *old_mnt = nd->mnt;
+ struct qstr last = nd->last;
+ int last_type = nd->last_type;
/*
* NAME was not found in alternate root or it's a directory. Try to find
* it in the normal root:
*/
- nd_root.last_type = LAST_ROOT;
- nd_root.flags = nd->flags;
- memcpy(&nd_root.intent, &nd->intent, sizeof(nd_root.intent));
+ nd->last_type = LAST_ROOT;
read_lock(¤t->fs->lock);
- nd_root.mnt = mntget(current->fs->rootmnt);
- nd_root.dentry = dget(current->fs->root);
+ nd->mnt = mntget(current->fs->rootmnt);
+ nd->dentry = dget(current->fs->root);
read_unlock(¤t->fs->lock);
- if (path_walk(name, &nd_root))
- return 1;
- if (nd_root.dentry->d_inode) {
+ if (path_walk(name, nd) == 0) {
+ if (nd->dentry->d_inode) {
+ dput(old_dentry);
+ mntput(old_mnt);
+ return 1;
+ }
path_release(nd);
- nd->dentry = nd_root.dentry;
- nd->mnt = nd_root.mnt;
- nd->last = nd_root.last;
- return 1;
}
- path_release(&nd_root);
+ nd->dentry = old_dentry;
+ nd->mnt = old_mnt;
+ nd->last = last;
+ nd->last_type = last_type;
}
return 1;
}
}
}
-/* SMP-safe */
-static inline int
-walk_init_root(const char *name, struct nameidata *nd)
-{
- read_lock(¤t->fs->lock);
- if (current->fs->altroot && !(nd->flags & LOOKUP_NOALT)) {
- nd->mnt = mntget(current->fs->altrootmnt);
- nd->dentry = dget(current->fs->altroot);
- read_unlock(¤t->fs->lock);
- if (__emul_lookup_dentry(name,nd))
- return 0;
- read_lock(¤t->fs->lock);
- }
- nd->mnt = mntget(current->fs->rootmnt);
- nd->dentry = dget(current->fs->root);
- read_unlock(¤t->fs->lock);
- return 1;
-}
-
int fastcall path_lookup(const char *name, unsigned int flags, struct nameidata *nd)
{
int retval;
nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags;
+ nd->depth = 0;
read_lock(¤t->fs->lock);
if (*name=='/') {
}
nd->mnt = mntget(current->fs->rootmnt);
nd->dentry = dget(current->fs->root);
- }
- else{
+ } else {
nd->mnt = mntget(current->fs->pwdmnt);
nd->dentry = dget(current->fs->pwd);
}
return permission(dir,MAY_WRITE | MAY_EXEC, nd);
}
+static inline int mnt_may_create(struct vfsmount *mnt, struct inode *dir, struct dentry *child) {
+ if (child->d_inode)
+ return -EEXIST;
+ if (IS_DEADDIR(dir))
+ return -ENOENT;
+ if (mnt->mnt_flags & MNT_RDONLY)
+ return -EROFS;
+ return 0;
+}
+
+static inline int mnt_may_unlink(struct vfsmount *mnt, struct inode *dir, struct dentry *child) {
+ if (!child->d_inode)
+ return -ENOENT;
+ if (mnt->mnt_flags & MNT_RDONLY)
+ return -EROFS;
+ return 0;
+}
+
/*
* Special case: O_CREAT|O_EXCL implies O_NOFOLLOW for security
* reasons.
return -EACCES;
flag &= ~O_TRUNC;
- } else if (IS_RDONLY(inode) && (flag & FMODE_WRITE))
+ } else if ((IS_RDONLY(inode) || (nd && MNT_IS_RDONLY(nd->mnt)))
+ && (flag & FMODE_WRITE))
return -EROFS;
/*
* An append-only file must be opened in append mode for writing.
return -EPERM;
}
+ /* O_NOATIME can only be set by the owner or superuser */
+ if (flag & O_NOATIME)
+ if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
+ return -EPERM;
+
/*
* Ensure there are no outstanding leases on the file.
*/
struct dentry *lookup_create(struct nameidata *nd, int is_dir)
{
struct dentry *dentry;
+ int error;
down(&nd->dentry->d_inode->i_sem);
- dentry = ERR_PTR(-EEXIST);
+ error = -EEXIST;
if (nd->last_type != LAST_NORM)
- goto fail;
+ goto out;
nd->flags &= ~LOOKUP_PARENT;
dentry = lookup_hash(&nd->last, nd->dentry);
if (IS_ERR(dentry))
+ goto ret;
+ error = mnt_may_create(nd->mnt, nd->dentry->d_inode, dentry);
+ if (error)
goto fail;
+ error = -ENOENT;
if (!is_dir && nd->last.name[nd->last.len] && !dentry->d_inode)
- goto enoent;
+ goto fail;
+ret:
return dentry;
-enoent:
- dput(dentry);
- dentry = ERR_PTR(-ENOENT);
fail:
- return dentry;
+ dput(dentry);
+out:
+ return ERR_PTR(error);
}
int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
dentry = lookup_hash(&nd.last, nd.dentry);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
+ error = mnt_may_unlink(nd.mnt, nd.dentry->d_inode, dentry);
+ if (error)
+ goto exit2;
error = vfs_rmdir(nd.dentry->d_inode, dentry);
+ exit2:
dput(dentry);
}
up(&nd.dentry->d_inode->i_sem);
/* Why not before? Because we want correct error value */
if (nd.last.name[nd.last.len])
goto slashes;
+ error = mnt_may_unlink(nd.mnt, nd.dentry->d_inode, dentry);
+ if (error)
+ goto exit2;
inode = dentry->d_inode;
if (inode)
atomic_inc(&inode->i_count);
error = path_lookup(to, LOOKUP_PARENT, &nd);
if (error)
goto out;
- error = -EXDEV;
- if (old_nd.mnt != nd.mnt)
+ /*
+ * We allow hard-links to be created to a bind-mount as long
+ * as the bind-mount is not read-only. Checking for cross-dev
+ * links is subsumed by the superblock check in vfs_link().
+ */
+ error = -EROFS;
+ if (MNT_IS_RDONLY(old_nd.mnt))
goto out_release;
new_dentry = lookup_create(&nd, 0);
error = PTR_ERR(new_dentry);
error = -EINVAL;
if (old_dentry == trap)
goto exit4;
+ error = -EROFS;
+ if (MNT_IS_RDONLY(newnd.mnt))
+ goto exit4;
new_dentry = lookup_hash(&newnd.last, new_dir);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
struct nameidata nd;
- int res = dentry->d_inode->i_op->follow_link(dentry, &nd);
+ int res;
+ nd.depth = 0;
+ res = dentry->d_inode->i_op->follow_link(dentry, &nd);
if (!res) {
res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));
if (dentry->d_inode->i_op->put_link)
return res;
}
-static inline int
-__vfs_follow_link(struct nameidata *nd, const char *link)
-{
- int res = 0;
- char *name;
- if (IS_ERR(link))
- goto fail;
-
- if (*link == '/') {
- path_release(nd);
- if (!walk_init_root(link, nd))
- /* weird __emul_prefix() stuff did it */
- goto out;
- }
- res = link_path_walk(link, nd);
-out:
- if (current->link_count || res || nd->last_type!=LAST_NORM)
- return res;
- /*
- * If it is an iterative symlinks resolution in open_namei() we
- * have to copy the last component. And all that crap because of
- * bloody create() on broken symlinks. Furrfu...
- */
- name = __getname();
- if (unlikely(!name)) {
- path_release(nd);
- return -ENOMEM;
- }
- strcpy(name, nd->last.name);
- nd->last.name = name;
- return 0;
-fail:
- path_release(nd);
- return PTR_ERR(link);
-}
-
int vfs_follow_link(struct nameidata *nd, const char *link)
{
return __vfs_follow_link(nd, link);
int page_follow_link_light(struct dentry *dentry, struct nameidata *nd)
{
struct page *page;
- char *s = page_getlink(dentry, &page);
- if (!IS_ERR(s)) {
- nd_set_link(nd, s);
- s = NULL;
- }
- return PTR_ERR(s);
+ nd_set_link(nd, page_getlink(dentry, &page));
+ return 0;
}
void page_put_link(struct dentry *dentry, struct nameidata *nd)
git://git.onelab.eu / linux-2.6.git / blobdiff