* name indicated by the symlink. The old code always complained that the
* name already exists, due to not following the symlink even if its target
* is nonexistent. The new semantics affects also mknod() and link() when
- * the name is a symlink pointing to a non-existant name.
+ * the name is a symlink pointing to a non-existent name.
*
* I don't know which semantics is the right one, since I have no access
* to standards. But I found by trial that HP-UX 9.0 has the full "new"
return retval;
}
-char * getname(const char __user * filename)
+static char *getname_flags(const char __user * filename, int flags)
{
char *tmp, *result;
result = tmp;
if (retval < 0) {
- __putname(tmp);
- result = ERR_PTR(retval);
+ if (retval != -ENOENT || !(flags & LOOKUP_EMPTY)) {
+ __putname(tmp);
+ result = ERR_PTR(retval);
+ }
}
}
audit_getname(result);
return result;
}
+char *getname(const char __user * filename)
+{
+ return getname_flags(filename, 0);
+}
+
#ifdef CONFIG_AUDITSYSCALL
void putname(const char *name)
{
mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
+ if (current_user_ns() != inode_userns(inode))
+ goto other_perms;
+
if (current_fsuid() == inode->i_uid)
mode >>= 6;
else {
mode >>= 3;
}
+other_perms:
/*
* If the DACs are ok we don't need any capability check.
*/
* Executable DACs are overridable if at least one exec bit is set.
*/
if (!(mask & MAY_EXEC) || execute_ok(inode))
- if (capable(CAP_DAC_OVERRIDE))
+ if (ns_capable(inode_userns(inode), CAP_DAC_OVERRIDE))
return 0;
/*
*/
mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
- if (capable(CAP_DAC_READ_SEARCH))
+ if (ns_capable(inode_userns(inode), CAP_DAC_READ_SEARCH))
return 0;
return -EACCES;
{
struct fs_struct *fs = current->fs;
struct dentry *dentry = nd->path.dentry;
+ int want_root = 0;
BUG_ON(!(nd->flags & LOOKUP_RCU));
- if (nd->root.mnt) {
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
+ want_root = 1;
spin_lock(&fs->lock);
if (nd->root.mnt != fs->root.mnt ||
nd->root.dentry != fs->root.dentry)
goto err;
BUG_ON(nd->inode != dentry->d_inode);
spin_unlock(&dentry->d_lock);
- if (nd->root.mnt) {
+ if (want_root) {
path_get(&nd->root);
spin_unlock(&fs->lock);
}
err:
spin_unlock(&dentry->d_lock);
err_root:
- if (nd->root.mnt)
+ if (want_root)
spin_unlock(&fs->lock);
return -ECHILD;
}
{
struct fs_struct *fs = current->fs;
struct dentry *parent = nd->path.dentry;
+ int want_root = 0;
BUG_ON(!(nd->flags & LOOKUP_RCU));
- if (nd->root.mnt) {
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
+ want_root = 1;
spin_lock(&fs->lock);
if (nd->root.mnt != fs->root.mnt ||
nd->root.dentry != fs->root.dentry)
parent->d_count++;
spin_unlock(&dentry->d_lock);
spin_unlock(&parent->d_lock);
- if (nd->root.mnt) {
+ if (want_root) {
path_get(&nd->root);
spin_unlock(&fs->lock);
}
spin_unlock(&dentry->d_lock);
spin_unlock(&parent->d_lock);
err_root:
- if (nd->root.mnt)
+ if (want_root)
spin_unlock(&fs->lock);
return -ECHILD;
}
/* Try to drop out of rcu-walk mode if we were in it, otherwise do nothing. */
static inline int nameidata_dentry_drop_rcu_maybe(struct nameidata *nd, struct dentry *dentry)
{
- if (nd->flags & LOOKUP_RCU)
- return nameidata_dentry_drop_rcu(nd, dentry);
+ if (nd->flags & LOOKUP_RCU) {
+ if (unlikely(nameidata_dentry_drop_rcu(nd, dentry))) {
+ nd->flags &= ~LOOKUP_RCU;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ return -ECHILD;
+ }
+ }
return 0;
}
BUG_ON(!(nd->flags & LOOKUP_RCU));
nd->flags &= ~LOOKUP_RCU;
- nd->root.mnt = NULL;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
spin_lock(&dentry->d_lock);
if (!__d_rcu_to_refcount(dentry, nd->seq))
goto err_unlock;
return -ECHILD;
}
-/* Try to drop out of rcu-walk mode if we were in it, otherwise do nothing. */
-static inline int nameidata_drop_rcu_last_maybe(struct nameidata *nd)
-{
- if (likely(nd->flags & LOOKUP_RCU))
- return nameidata_drop_rcu_last(nd);
- return 0;
-}
-
/**
* release_open_intent - free up open intent resources
* @nd: pointer to nameidata
return dentry;
}
-static inline struct dentry *
-do_revalidate_rcu(struct dentry *dentry, struct nameidata *nd)
-{
- int status = d_revalidate(dentry, nd);
- if (likely(status > 0))
- return dentry;
- if (status == -ECHILD) {
- if (nameidata_dentry_drop_rcu(nd, dentry))
- return ERR_PTR(-ECHILD);
- return do_revalidate(dentry, nd);
- }
- if (status < 0)
- return ERR_PTR(status);
- /* Don't d_invalidate in rcu-walk mode */
- if (nameidata_dentry_drop_rcu(nd, dentry))
- return ERR_PTR(-ECHILD);
- if (!d_invalidate(dentry)) {
- dput(dentry);
- dentry = NULL;
- }
- return dentry;
-}
-
-static inline int need_reval_dot(struct dentry *dentry)
-{
- if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE)))
- return 0;
-
- if (likely(!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)))
- return 0;
-
- return 1;
-}
-
/*
- * force_reval_path - force revalidation of a dentry
+ * handle_reval_path - force revalidation of a dentry
*
* In some situations the path walking code will trust dentries without
* revalidating them. This causes problems for filesystems that depend on
* invalidate the dentry. It's up to the caller to handle putting references
* to the path if necessary.
*/
-static int
-force_reval_path(struct path *path, struct nameidata *nd)
+static inline int handle_reval_path(struct nameidata *nd)
{
+ struct dentry *dentry = nd->path.dentry;
int status;
- struct dentry *dentry = path->dentry;
- /*
- * only check on filesystems where it's possible for the dentry to
- * become stale.
- */
- if (!need_reval_dot(dentry))
+ if (likely(!(nd->flags & LOOKUP_JUMPED)))
+ return 0;
+
+ if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE)))
+ return 0;
+
+ if (likely(!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)))
return 0;
+ /* Note: we do not d_invalidate() */
status = d_revalidate(dentry, nd);
if (status > 0)
return 0;
- if (!status) {
- d_invalidate(dentry);
+ if (!status)
status = -ESTALE;
- }
+
return status;
}
static inline int exec_permission(struct inode *inode, unsigned int flags)
{
int ret;
+ struct user_namespace *ns = inode_userns(inode);
if (inode->i_op->permission) {
ret = inode->i_op->permission(inode, MAY_EXEC, flags);
if (ret == -ECHILD)
return ret;
- if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH))
+ if (ns_capable(ns, CAP_DAC_OVERRIDE) ||
+ ns_capable(ns, CAP_DAC_READ_SEARCH))
goto ok;
return ret;
do {
seq = read_seqcount_begin(&fs->seq);
nd->root = fs->root;
+ nd->seq = __read_seqcount_begin(&nd->root.dentry->d_seq);
} while (read_seqcount_retry(&fs->seq, seq));
}
}
path_put(&nd->path);
nd->path = nd->root;
path_get(&nd->root);
+ nd->flags |= LOOKUP_JUMPED;
}
nd->inode = nd->path.dentry->d_inode;
nd->path.dentry = path->dentry;
}
+static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)
+{
+ struct inode *inode = link->dentry->d_inode;
+ if (!IS_ERR(cookie) && inode->i_op->put_link)
+ inode->i_op->put_link(link->dentry, nd, cookie);
+ path_put(link);
+}
+
static __always_inline int
-__do_follow_link(const struct path *link, struct nameidata *nd, void **p)
+follow_link(struct path *link, struct nameidata *nd, void **p)
{
int error;
struct dentry *dentry = link->dentry;
BUG_ON(nd->flags & LOOKUP_RCU);
+ if (link->mnt == nd->path.mnt)
+ mntget(link->mnt);
+
+ if (unlikely(current->total_link_count >= 40)) {
+ *p = ERR_PTR(-ELOOP); /* no ->put_link(), please */
+ path_put(&nd->path);
+ return -ELOOP;
+ }
+ cond_resched();
+ current->total_link_count++;
+
touch_atime(link->mnt, dentry);
nd_set_link(nd, NULL);
- if (link->mnt == nd->path.mnt)
- mntget(link->mnt);
+ error = security_inode_follow_link(link->dentry, nd);
+ if (error) {
+ *p = ERR_PTR(error); /* no ->put_link(), please */
+ path_put(&nd->path);
+ return error;
+ }
nd->last_type = LAST_BIND;
*p = dentry->d_inode->i_op->follow_link(dentry, nd);
if (s)
error = __vfs_follow_link(nd, s);
else if (nd->last_type == LAST_BIND) {
- error = force_reval_path(&nd->path, nd);
- if (error)
+ nd->flags |= LOOKUP_JUMPED;
+ nd->inode = nd->path.dentry->d_inode;
+ if (nd->inode->i_op->follow_link) {
+ /* stepped on a _really_ weird one */
path_put(&nd->path);
+ error = -ELOOP;
+ }
}
}
return error;
}
-/*
- * This limits recursive symlink follows to 8, while
- * limiting consecutive symlinks to 40.
- *
- * Without that kind of total limit, nasty chains of consecutive
- * symlinks can cause almost arbitrarily long lookups.
- */
-static inline int do_follow_link(struct inode *inode, struct path *path, struct nameidata *nd)
-{
- void *cookie;
- int err = -ELOOP;
-
- /* We drop rcu-walk here */
- if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry))
- return -ECHILD;
- BUG_ON(inode != path->dentry->d_inode);
-
- if (current->link_count >= MAX_NESTED_LINKS)
- goto loop;
- if (current->total_link_count >= 40)
- goto loop;
- BUG_ON(nd->depth >= MAX_NESTED_LINKS);
- cond_resched();
- err = security_inode_follow_link(path->dentry, nd);
- if (err)
- goto loop;
- current->link_count++;
- current->total_link_count++;
- nd->depth++;
- err = __do_follow_link(path, nd, &cookie);
- if (!IS_ERR(cookie) && path->dentry->d_inode->i_op->put_link)
- path->dentry->d_inode->i_op->put_link(path->dentry, nd, cookie);
- path_put(path);
- current->link_count--;
- nd->depth--;
- return err;
-loop:
- path_put_conditional(path, nd);
- path_put(&nd->path);
- return err;
-}
-
static int follow_up_rcu(struct path *path)
{
struct vfsmount *parent;
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
- ret = path->dentry->d_op->d_manage(path->dentry,
- false, false);
+ ret = path->dentry->d_op->d_manage(path->dentry, false);
if (ret < 0)
return ret == -EISDIR ? 0 : ret;
}
return 0;
}
+static inline bool managed_dentry_might_block(struct dentry *dentry)
+{
+ return (dentry->d_flags & DCACHE_MANAGE_TRANSIT &&
+ dentry->d_op->d_manage(dentry, true) < 0);
+}
+
/*
* Skip to top of mountpoint pile in rcuwalk mode. We abort the rcu-walk if we
* meet a managed dentry and we're not walking to "..". True is returned to
static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
struct inode **inode, bool reverse_transit)
{
- while (d_mountpoint(path->dentry)) {
+ for (;;) {
struct vfsmount *mounted;
- if (unlikely(path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) &&
- !reverse_transit &&
- path->dentry->d_op->d_manage(path->dentry, false, true) < 0)
+ /*
+ * Don't forget we might have a non-mountpoint managed dentry
+ * that wants to block transit.
+ */
+ *inode = path->dentry->d_inode;
+ if (!reverse_transit &&
+ unlikely(managed_dentry_might_block(path->dentry)))
return false;
+
+ if (!d_mountpoint(path->dentry))
+ break;
+
mounted = __lookup_mnt(path->mnt, path->dentry, 1);
if (!mounted)
break;
path->mnt = mounted;
path->dentry = mounted->mnt_root;
nd->seq = read_seqcount_begin(&path->dentry->d_seq);
- *inode = path->dentry->d_inode;
}
if (unlikely(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT))
seq = read_seqcount_begin(&parent->d_seq);
if (read_seqcount_retry(&old->d_seq, nd->seq))
- return -ECHILD;
+ goto failed;
inode = parent->d_inode;
nd->path.dentry = parent;
nd->seq = seq;
}
__follow_mount_rcu(nd, &nd->path, &inode, true);
nd->inode = inode;
-
return 0;
+
+failed:
+ nd->flags &= ~LOOKUP_RCU;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ return -ECHILD;
}
/*
* Care must be taken as namespace_sem may be held (indicated by mounting_here
* being true).
*/
-int follow_down(struct path *path, bool mounting_here)
+int follow_down(struct path *path)
{
unsigned managed;
int ret;
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
ret = path->dentry->d_op->d_manage(
- path->dentry, mounting_here, false);
+ path->dentry, false);
if (ret < 0)
return ret == -EISDIR ? 0 : ret;
}
{
struct vfsmount *mnt = nd->path.mnt;
struct dentry *dentry, *parent = nd->path.dentry;
- struct inode *dir;
+ int need_reval = 1;
+ int status = 1;
int err;
- /*
- * See if the low-level filesystem might want
- * to use its own hash..
- */
- if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
- err = parent->d_op->d_hash(parent, nd->inode, name);
- if (err < 0)
- return err;
- }
-
/*
* Rename seqlock is not required here because in the off chance
* of a false negative due to a concurrent rename, we're going to
*/
if (nd->flags & LOOKUP_RCU) {
unsigned seq;
-
*inode = nd->inode;
dentry = __d_lookup_rcu(parent, name, &seq, inode);
- if (!dentry) {
- if (nameidata_drop_rcu(nd))
- return -ECHILD;
- goto need_lookup;
- }
+ if (!dentry)
+ goto unlazy;
+
/* Memory barrier in read_seqcount_begin of child is enough */
if (__read_seqcount_retry(&parent->d_seq, nd->seq))
return -ECHILD;
-
nd->seq = seq;
+
if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
- dentry = do_revalidate_rcu(dentry, nd);
- if (!dentry)
- goto need_lookup;
- if (IS_ERR(dentry))
- goto fail;
- if (!(nd->flags & LOOKUP_RCU))
- goto done;
+ status = d_revalidate(dentry, nd);
+ if (unlikely(status <= 0)) {
+ if (status != -ECHILD)
+ need_reval = 0;
+ goto unlazy;
+ }
}
path->mnt = mnt;
path->dentry = dentry;
if (likely(__follow_mount_rcu(nd, path, inode, false)))
return 0;
- if (nameidata_drop_rcu(nd))
- return -ECHILD;
- /* fallthru */
+unlazy:
+ if (dentry) {
+ if (nameidata_dentry_drop_rcu(nd, dentry))
+ return -ECHILD;
+ } else {
+ if (nameidata_drop_rcu(nd))
+ return -ECHILD;
+ }
+ } else {
+ dentry = __d_lookup(parent, name);
}
- dentry = __d_lookup(parent, name);
- if (!dentry)
- goto need_lookup;
-found:
- if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
- dentry = do_revalidate(dentry, nd);
- if (!dentry)
- goto need_lookup;
- if (IS_ERR(dentry))
- goto fail;
+
+retry:
+ if (unlikely(!dentry)) {
+ struct inode *dir = parent->d_inode;
+ BUG_ON(nd->inode != dir);
+
+ mutex_lock(&dir->i_mutex);
+ dentry = d_lookup(parent, name);
+ if (likely(!dentry)) {
+ dentry = d_alloc_and_lookup(parent, name, nd);
+ if (IS_ERR(dentry)) {
+ mutex_unlock(&dir->i_mutex);
+ return PTR_ERR(dentry);
+ }
+ /* known good */
+ need_reval = 0;
+ status = 1;
+ }
+ mutex_unlock(&dir->i_mutex);
}
-done:
+ if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval)
+ status = d_revalidate(dentry, nd);
+ if (unlikely(status <= 0)) {
+ if (status < 0) {
+ dput(dentry);
+ return status;
+ }
+ if (!d_invalidate(dentry)) {
+ dput(dentry);
+ dentry = NULL;
+ need_reval = 1;
+ goto retry;
+ }
+ }
+
path->mnt = mnt;
path->dentry = dentry;
err = follow_managed(path, nd->flags);
}
*inode = path->dentry->d_inode;
return 0;
+}
+
+static inline int may_lookup(struct nameidata *nd)
+{
+ if (nd->flags & LOOKUP_RCU) {
+ int err = exec_permission(nd->inode, IPERM_FLAG_RCU);
+ if (err != -ECHILD)
+ return err;
+ if (nameidata_drop_rcu(nd))
+ return -ECHILD;
+ }
+ return exec_permission(nd->inode, 0);
+}
+
+static inline int handle_dots(struct nameidata *nd, int type)
+{
+ if (type == LAST_DOTDOT) {
+ if (nd->flags & LOOKUP_RCU) {
+ if (follow_dotdot_rcu(nd))
+ return -ECHILD;
+ } else
+ follow_dotdot(nd);
+ }
+ return 0;
+}
-need_lookup:
- dir = parent->d_inode;
- BUG_ON(nd->inode != dir);
+static void terminate_walk(struct nameidata *nd)
+{
+ if (!(nd->flags & LOOKUP_RCU)) {
+ path_put(&nd->path);
+ } else {
+ nd->flags &= ~LOOKUP_RCU;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ }
+}
- mutex_lock(&dir->i_mutex);
+static inline int walk_component(struct nameidata *nd, struct path *path,
+ struct qstr *name, int type, int follow)
+{
+ struct inode *inode;
+ int err;
/*
- * First re-do the cached lookup just in case it was created
- * while we waited for the directory semaphore, or the first
- * lookup failed due to an unrelated rename.
- *
- * This could use version numbering or similar to avoid unnecessary
- * cache lookups, but then we'd have to do the first lookup in the
- * non-racy way. However in the common case here, everything should
- * be hot in cache, so would it be a big win?
+ * "." and ".." are special - ".." especially so because it has
+ * to be able to know about the current root directory and
+ * parent relationships.
*/
- dentry = d_lookup(parent, name);
- if (likely(!dentry)) {
- dentry = d_alloc_and_lookup(parent, name, nd);
- mutex_unlock(&dir->i_mutex);
- if (IS_ERR(dentry))
- goto fail;
- goto done;
+ if (unlikely(type != LAST_NORM))
+ return handle_dots(nd, type);
+ err = do_lookup(nd, name, path, &inode);
+ if (unlikely(err)) {
+ terminate_walk(nd);
+ return err;
}
- /*
- * Uhhuh! Nasty case: the cache was re-populated while
- * we waited on the semaphore. Need to revalidate.
- */
- mutex_unlock(&dir->i_mutex);
- goto found;
+ if (!inode) {
+ path_to_nameidata(path, nd);
+ terminate_walk(nd);
+ return -ENOENT;
+ }
+ if (unlikely(inode->i_op->follow_link) && follow) {
+ if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry))
+ return -ECHILD;
+ BUG_ON(inode != path->dentry->d_inode);
+ return 1;
+ }
+ path_to_nameidata(path, nd);
+ nd->inode = inode;
+ return 0;
+}
-fail:
- return PTR_ERR(dentry);
+/*
+ * This limits recursive symlink follows to 8, while
+ * limiting consecutive symlinks to 40.
+ *
+ * Without that kind of total limit, nasty chains of consecutive
+ * symlinks can cause almost arbitrarily long lookups.
+ */
+static inline int nested_symlink(struct path *path, struct nameidata *nd)
+{
+ int res;
+
+ BUG_ON(nd->depth >= MAX_NESTED_LINKS);
+ if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
+ path_put_conditional(path, nd);
+ path_put(&nd->path);
+ return -ELOOP;
+ }
+
+ nd->depth++;
+ current->link_count++;
+
+ do {
+ struct path link = *path;
+ void *cookie;
+
+ res = follow_link(&link, nd, &cookie);
+ if (!res)
+ res = walk_component(nd, path, &nd->last,
+ nd->last_type, LOOKUP_FOLLOW);
+ put_link(nd, &link, cookie);
+ } while (res > 0);
+
+ current->link_count--;
+ nd->depth--;
+ return res;
}
/*
while (*name=='/')
name++;
if (!*name)
- goto return_reval;
-
- if (nd->depth)
- lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE);
+ return 0;
/* At this point we know we have a real path component. */
for(;;) {
- struct inode *inode;
unsigned long hash;
struct qstr this;
unsigned int c;
+ int type;
nd->flags |= LOOKUP_CONTINUE;
- if (nd->flags & LOOKUP_RCU) {
- err = exec_permission(nd->inode, IPERM_FLAG_RCU);
- if (err == -ECHILD) {
- if (nameidata_drop_rcu(nd))
- return -ECHILD;
- goto exec_again;
- }
- } else {
-exec_again:
- err = exec_permission(nd->inode, 0);
- }
+
+ err = may_lookup(nd);
if (err)
break;
this.len = name - (const char *) this.name;
this.hash = end_name_hash(hash);
+ type = LAST_NORM;
+ if (this.name[0] == '.') switch (this.len) {
+ case 2:
+ if (this.name[1] == '.') {
+ type = LAST_DOTDOT;
+ nd->flags |= LOOKUP_JUMPED;
+ }
+ break;
+ case 1:
+ type = LAST_DOT;
+ }
+ if (likely(type == LAST_NORM)) {
+ struct dentry *parent = nd->path.dentry;
+ nd->flags &= ~LOOKUP_JUMPED;
+ if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
+ err = parent->d_op->d_hash(parent, nd->inode,
+ &this);
+ if (err < 0)
+ break;
+ }
+ }
+
/* remove trailing slashes? */
if (!c)
goto last_component;
while (*++name == '/');
if (!*name)
- goto last_with_slashes;
+ goto last_component;
- /*
- * "." and ".." are special - ".." especially so because it has
- * to be able to know about the current root directory and
- * parent relationships.
- */
- if (this.name[0] == '.') switch (this.len) {
- default:
- break;
- case 2:
- if (this.name[1] != '.')
- break;
- if (nd->flags & LOOKUP_RCU) {
- if (follow_dotdot_rcu(nd))
- return -ECHILD;
- } else
- follow_dotdot(nd);
- /* fallthrough */
- case 1:
- continue;
- }
- /* This does the actual lookups.. */
- err = do_lookup(nd, &this, &next, &inode);
- if (err)
- break;
- err = -ENOENT;
- if (!inode)
- goto out_dput;
+ err = walk_component(nd, &next, &this, type, LOOKUP_FOLLOW);
+ if (err < 0)
+ return err;
- if (inode->i_op->follow_link) {
- err = do_follow_link(inode, &next, nd);
+ if (err) {
+ err = nested_symlink(&next, nd);
if (err)
- goto return_err;
- nd->inode = nd->path.dentry->d_inode;
- err = -ENOENT;
- if (!nd->inode)
- break;
- } else {
- path_to_nameidata(&next, nd);
- nd->inode = inode;
+ return err;
}
err = -ENOTDIR;
if (!nd->inode->i_op->lookup)
continue;
/* here ends the main loop */
-last_with_slashes:
- lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
last_component:
/* Clear LOOKUP_CONTINUE iff it was previously unset */
nd->flags &= lookup_flags | ~LOOKUP_CONTINUE;
- if (lookup_flags & LOOKUP_PARENT)
- goto lookup_parent;
- if (this.name[0] == '.') switch (this.len) {
- default:
- break;
- case 2:
- if (this.name[1] != '.')
- break;
- if (nd->flags & LOOKUP_RCU) {
- if (follow_dotdot_rcu(nd))
- return -ECHILD;
- } else
- follow_dotdot(nd);
- /* fallthrough */
- case 1:
- goto return_reval;
- }
- err = do_lookup(nd, &this, &next, &inode);
- if (err)
- break;
- if (inode && unlikely(inode->i_op->follow_link) &&
- (lookup_flags & LOOKUP_FOLLOW)) {
- err = do_follow_link(inode, &next, nd);
- if (err)
- goto return_err;
- nd->inode = nd->path.dentry->d_inode;
- } else {
- path_to_nameidata(&next, nd);
- nd->inode = inode;
- }
- err = -ENOENT;
- if (!nd->inode)
- break;
- if (lookup_flags & LOOKUP_DIRECTORY) {
- err = -ENOTDIR;
- if (!nd->inode->i_op->lookup)
- break;
- }
- goto return_base;
-lookup_parent:
nd->last = this;
- nd->last_type = LAST_NORM;
- if (this.name[0] != '.')
- goto return_base;
- if (this.len == 1)
- nd->last_type = LAST_DOT;
- else if (this.len == 2 && this.name[1] == '.')
- nd->last_type = LAST_DOTDOT;
- else
- goto return_base;
-return_reval:
- /*
- * We bypassed the ordinary revalidation routines.
- * We may need to check the cached dentry for staleness.
- */
- if (need_reval_dot(nd->path.dentry)) {
- if (nameidata_drop_rcu_last_maybe(nd))
- return -ECHILD;
- /* Note: we do not d_invalidate() */
- err = d_revalidate(nd->path.dentry, nd);
- if (!err)
- err = -ESTALE;
- if (err < 0)
- break;
- return 0;
- }
-return_base:
- if (nameidata_drop_rcu_last_maybe(nd))
- return -ECHILD;
+ nd->last_type = type;
return 0;
-out_dput:
- if (!(nd->flags & LOOKUP_RCU))
- path_put_conditional(&next, nd);
- break;
}
- if (!(nd->flags & LOOKUP_RCU))
- path_put(&nd->path);
-return_err:
+ terminate_walk(nd);
return err;
}
-static inline int path_walk_rcu(const char *name, struct nameidata *nd)
-{
- current->total_link_count = 0;
-
- return link_path_walk(name, nd);
-}
-
-static inline int path_walk_simple(const char *name, struct nameidata *nd)
-{
- current->total_link_count = 0;
-
- return link_path_walk(name, nd);
-}
-
-static int path_walk(const char *name, struct nameidata *nd)
-{
- struct path save = nd->path;
- int result;
-
- current->total_link_count = 0;
-
- /* make sure the stuff we saved doesn't go away */
- path_get(&save);
-
- result = link_path_walk(name, nd);
- if (result == -ESTALE) {
- /* nd->path had been dropped */
- current->total_link_count = 0;
- nd->path = save;
- nd->inode = save.dentry->d_inode;
- path_get(&nd->path);
- nd->flags |= LOOKUP_REVAL;
- result = link_path_walk(name, nd);
- }
-
- path_put(&save);
-
- return result;
-}
-
-static void path_finish_rcu(struct nameidata *nd)
-{
- if (nd->flags & LOOKUP_RCU) {
- /* RCU dangling. Cancel it. */
- nd->flags &= ~LOOKUP_RCU;
- nd->root.mnt = NULL;
- rcu_read_unlock();
- br_read_unlock(vfsmount_lock);
- }
- if (nd->file)
- fput(nd->file);
-}
-
-static int path_init_rcu(int dfd, const char *name, unsigned int flags, struct nameidata *nd)
+static int path_init(int dfd, const char *name, unsigned int flags,
+ struct nameidata *nd, struct file **fp)
{
int retval = 0;
int fput_needed;
struct file *file;
nd->last_type = LAST_ROOT; /* if there are only slashes... */
- nd->flags = flags | LOOKUP_RCU;
+ nd->flags = flags | LOOKUP_JUMPED;
nd->depth = 0;
+ if (flags & LOOKUP_ROOT) {
+ struct inode *inode = nd->root.dentry->d_inode;
+ if (*name) {
+ if (!inode->i_op->lookup)
+ return -ENOTDIR;
+ retval = inode_permission(inode, MAY_EXEC);
+ if (retval)
+ return retval;
+ }
+ nd->path = nd->root;
+ nd->inode = inode;
+ if (flags & LOOKUP_RCU) {
+ br_read_lock(vfsmount_lock);
+ rcu_read_lock();
+ nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ } else {
+ path_get(&nd->path);
+ }
+ return 0;
+ }
+
nd->root.mnt = NULL;
- nd->file = NULL;
if (*name=='/') {
- struct fs_struct *fs = current->fs;
- unsigned seq;
-
- br_read_lock(vfsmount_lock);
- rcu_read_lock();
-
- do {
- seq = read_seqcount_begin(&fs->seq);
- nd->root = fs->root;
- nd->path = nd->root;
- nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
- } while (read_seqcount_retry(&fs->seq, seq));
-
+ if (flags & LOOKUP_RCU) {
+ br_read_lock(vfsmount_lock);
+ rcu_read_lock();
+ set_root_rcu(nd);
+ } else {
+ set_root(nd);
+ path_get(&nd->root);
+ }
+ nd->path = nd->root;
} else if (dfd == AT_FDCWD) {
- struct fs_struct *fs = current->fs;
- unsigned seq;
-
- br_read_lock(vfsmount_lock);
- rcu_read_lock();
+ if (flags & LOOKUP_RCU) {
+ struct fs_struct *fs = current->fs;
+ unsigned seq;
- do {
- seq = read_seqcount_begin(&fs->seq);
- nd->path = fs->pwd;
- nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
- } while (read_seqcount_retry(&fs->seq, seq));
+ br_read_lock(vfsmount_lock);
+ rcu_read_lock();
+ do {
+ seq = read_seqcount_begin(&fs->seq);
+ nd->path = fs->pwd;
+ nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ } while (read_seqcount_retry(&fs->seq, seq));
+ } else {
+ get_fs_pwd(current->fs, &nd->path);
+ }
} else {
struct dentry *dentry;
- file = fget_light(dfd, &fput_needed);
+ file = fget_raw_light(dfd, &fput_needed);
retval = -EBADF;
if (!file)
goto out_fail;
dentry = file->f_path.dentry;
- retval = -ENOTDIR;
- if (!S_ISDIR(dentry->d_inode->i_mode))
- goto fput_fail;
+ if (*name) {
+ retval = -ENOTDIR;
+ if (!S_ISDIR(dentry->d_inode->i_mode))
+ goto fput_fail;
- retval = file_permission(file, MAY_EXEC);
- if (retval)
- goto fput_fail;
+ retval = file_permission(file, MAY_EXEC);
+ if (retval)
+ goto fput_fail;
+ }
nd->path = file->f_path;
- if (fput_needed)
- nd->file = file;
-
- nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
- br_read_lock(vfsmount_lock);
- rcu_read_lock();
+ if (flags & LOOKUP_RCU) {
+ if (fput_needed)
+ *fp = file;
+ nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ br_read_lock(vfsmount_lock);
+ rcu_read_lock();
+ } else {
+ path_get(&file->f_path);
+ fput_light(file, fput_needed);
+ }
}
+
nd->inode = nd->path.dentry->d_inode;
return 0;
return retval;
}
-static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd)
+static inline int lookup_last(struct nameidata *nd, struct path *path)
{
- int retval = 0;
- int fput_needed;
- struct file *file;
-
- nd->last_type = LAST_ROOT; /* if there are only slashes... */
- nd->flags = flags;
- nd->depth = 0;
- nd->root.mnt = NULL;
-
- if (*name=='/') {
- set_root(nd);
- nd->path = nd->root;
- path_get(&nd->root);
- } else if (dfd == AT_FDCWD) {
- get_fs_pwd(current->fs, &nd->path);
- } else {
- struct dentry *dentry;
-
- file = fget_light(dfd, &fput_needed);
- retval = -EBADF;
- if (!file)
- goto out_fail;
-
- dentry = file->f_path.dentry;
-
- retval = -ENOTDIR;
- if (!S_ISDIR(dentry->d_inode->i_mode))
- goto fput_fail;
-
- retval = file_permission(file, MAY_EXEC);
- if (retval)
- goto fput_fail;
+ if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len])
+ nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
- nd->path = file->f_path;
- path_get(&file->f_path);
-
- fput_light(file, fput_needed);
- }
- nd->inode = nd->path.dentry->d_inode;
- return 0;
-
-fput_fail:
- fput_light(file, fput_needed);
-out_fail:
- return retval;
+ nd->flags &= ~LOOKUP_PARENT;
+ return walk_component(nd, path, &nd->last, nd->last_type,
+ nd->flags & LOOKUP_FOLLOW);
}
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int do_path_lookup(int dfd, const char *name,
+static int path_lookupat(int dfd, const char *name,
unsigned int flags, struct nameidata *nd)
{
- int retval;
+ struct file *base = NULL;
+ struct path path;
+ int err;
/*
* Path walking is largely split up into 2 different synchronisation
* be handled by restarting a traditional ref-walk (which will always
* be able to complete).
*/
- retval = path_init_rcu(dfd, name, flags, nd);
- if (unlikely(retval))
- return retval;
- retval = path_walk_rcu(name, nd);
- path_finish_rcu(nd);
- if (nd->root.mnt) {
- path_put(&nd->root);
- nd->root.mnt = NULL;
+ err = path_init(dfd, name, flags | LOOKUP_PARENT, nd, &base);
+
+ if (unlikely(err))
+ return err;
+
+ current->total_link_count = 0;
+ err = link_path_walk(name, nd);
+
+ if (!err && !(flags & LOOKUP_PARENT)) {
+ err = lookup_last(nd, &path);
+ while (err > 0) {
+ void *cookie;
+ struct path link = path;
+ nd->flags |= LOOKUP_PARENT;
+ err = follow_link(&link, nd, &cookie);
+ if (!err)
+ err = lookup_last(nd, &path);
+ put_link(nd, &link, cookie);
+ }
}
- if (unlikely(retval == -ECHILD || retval == -ESTALE)) {
- /* slower, locked walk */
- if (retval == -ESTALE)
- flags |= LOOKUP_REVAL;
- retval = path_init(dfd, name, flags, nd);
- if (unlikely(retval))
- return retval;
- retval = path_walk(name, nd);
- if (nd->root.mnt) {
- path_put(&nd->root);
- nd->root.mnt = NULL;
+ if (nd->flags & LOOKUP_RCU) {
+ /* went all way through without dropping RCU */
+ BUG_ON(err);
+ if (nameidata_drop_rcu_last(nd))
+ err = -ECHILD;
+ }
+
+ if (!err) {
+ err = handle_reval_path(nd);
+ if (err)
+ path_put(&nd->path);
+ }
+
+ if (!err && nd->flags & LOOKUP_DIRECTORY) {
+ if (!nd->inode->i_op->lookup) {
+ path_put(&nd->path);
+ err = -ENOTDIR;
}
}
+ if (base)
+ fput(base);
+
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
+ path_put(&nd->root);
+ nd->root.mnt = NULL;
+ }
+ return err;
+}
+
+static int do_path_lookup(int dfd, const char *name,
+ unsigned int flags, struct nameidata *nd)
+{
+ int retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd);
+ if (unlikely(retval == -ECHILD))
+ retval = path_lookupat(dfd, name, flags, nd);
+ if (unlikely(retval == -ESTALE))
+ retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd);
+
if (likely(!retval)) {
if (unlikely(!audit_dummy_context())) {
if (nd->path.dentry && nd->inode)
audit_inode(name, nd->path.dentry);
}
}
-
return retval;
}
-int path_lookup(const char *name, unsigned int flags,
- struct nameidata *nd)
+int kern_path_parent(const char *name, struct nameidata *nd)
{
- return do_path_lookup(AT_FDCWD, name, flags, nd);
+ return do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, nd);
}
int kern_path(const char *name, unsigned int flags, struct path *path)
const char *name, unsigned int flags,
struct nameidata *nd)
{
- int retval;
-
- /* same as do_path_lookup */
- nd->last_type = LAST_ROOT;
- nd->flags = flags;
- nd->depth = 0;
-
- nd->path.dentry = dentry;
- nd->path.mnt = mnt;
- path_get(&nd->path);
- nd->root = nd->path;
- path_get(&nd->root);
- nd->inode = nd->path.dentry->d_inode;
-
- retval = path_walk(name, nd);
- if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
- nd->inode))
- audit_inode(name, nd->path.dentry);
-
- path_put(&nd->root);
- nd->root.mnt = NULL;
-
- return retval;
+ nd->root.dentry = dentry;
+ nd->root.mnt = mnt;
+ /* the first argument of do_path_lookup() is ignored with LOOKUP_ROOT */
+ return do_path_lookup(AT_FDCWD, name, flags | LOOKUP_ROOT, nd);
}
static struct dentry *__lookup_hash(struct qstr *name,
if (err)
return ERR_PTR(err);
- /*
- * See if the low-level filesystem might want
- * to use its own hash..
- */
- if (base->d_flags & DCACHE_OP_HASH) {
- err = base->d_op->d_hash(base, inode, name);
- dentry = ERR_PTR(err);
- if (err < 0)
- goto out;
- }
-
/*
* Don't bother with __d_lookup: callers are for creat as
* well as unlink, so a lot of the time it would cost
if (!dentry)
dentry = d_alloc_and_lookup(base, name, nd);
-out:
+
return dentry;
}
return __lookup_hash(&nd->last, nd->path.dentry, nd);
}
-static int __lookup_one_len(const char *name, struct qstr *this,
- struct dentry *base, int len)
-{
- unsigned long hash;
- unsigned int c;
-
- this->name = name;
- this->len = len;
- if (!len)
- return -EACCES;
-
- hash = init_name_hash();
- while (len--) {
- c = *(const unsigned char *)name++;
- if (c == '/' || c == '\0')
- return -EACCES;
- hash = partial_name_hash(c, hash);
- }
- this->hash = end_name_hash(hash);
- return 0;
-}
-
/**
* lookup_one_len - filesystem helper to lookup single pathname component
* @name: pathname component to lookup
*/
struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
{
- int err;
struct qstr this;
+ unsigned long hash;
+ unsigned int c;
WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex));
- err = __lookup_one_len(name, &this, base, len);
- if (err)
- return ERR_PTR(err);
+ this.name = name;
+ this.len = len;
+ if (!len)
+ return ERR_PTR(-EACCES);
+
+ hash = init_name_hash();
+ while (len--) {
+ c = *(const unsigned char *)name++;
+ if (c == '/' || c == '\0')
+ return ERR_PTR(-EACCES);
+ hash = partial_name_hash(c, hash);
+ }
+ this.hash = end_name_hash(hash);
+ /*
+ * See if the low-level filesystem might want
+ * to use its own hash..
+ */
+ if (base->d_flags & DCACHE_OP_HASH) {
+ int err = base->d_op->d_hash(base, base->d_inode, &this);
+ if (err < 0)
+ return ERR_PTR(err);
+ }
return __lookup_hash(&this, base, NULL);
}
struct path *path)
{
struct nameidata nd;
- char *tmp = getname(name);
+ char *tmp = getname_flags(name, flags);
int err = PTR_ERR(tmp);
if (!IS_ERR(tmp)) {
if (!(dir->i_mode & S_ISVTX))
return 0;
+ if (current_user_ns() != inode_userns(inode))
+ goto other_userns;
if (inode->i_uid == fsuid)
return 0;
if (dir->i_uid == fsuid)
return 0;
- return !capable(CAP_FOWNER);
+
+other_userns:
+ return !ns_capable(inode_userns(inode), CAP_FOWNER);
}
/*
return error;
}
-int may_open(struct path *path, int acc_mode, int flag)
+static int may_open(struct path *path, int acc_mode, int flag)
{
struct dentry *dentry = path->dentry;
struct inode *inode = dentry->d_inode;
int error;
+ /* O_PATH? */
+ if (!acc_mode)
+ return 0;
+
if (!inode)
return -ENOENT;
}
/* O_NOATIME can only be set by the owner or superuser */
- if (flag & O_NOATIME && !is_owner_or_cap(inode))
+ if (flag & O_NOATIME && !inode_owner_or_capable(inode))
return -EPERM;
/*
return error;
}
-/*
- * Be careful about ever adding any more callers of this
- * function. Its flags must be in the namei format, not
- * what get passed to sys_open().
- */
-static int __open_namei_create(struct nameidata *nd, struct path *path,
- int open_flag, int mode)
-{
- int error;
- struct dentry *dir = nd->path.dentry;
-
- if (!IS_POSIXACL(dir->d_inode))
- mode &= ~current_umask();
- error = security_path_mknod(&nd->path, path->dentry, mode, 0);
- if (error)
- goto out_unlock;
- error = vfs_create(dir->d_inode, path->dentry, mode, nd);
-out_unlock:
- mutex_unlock(&dir->d_inode->i_mutex);
- dput(nd->path.dentry);
- nd->path.dentry = path->dentry;
-
- if (error)
- return error;
- /* Don't check for write permission, don't truncate */
- return may_open(&nd->path, 0, open_flag & ~O_TRUNC);
-}
-
/*
* Note that while the flag value (low two bits) for sys_open means:
* 00 - read-only
return flag;
}
-static int open_will_truncate(int flag, struct inode *inode)
-{
- /*
- * We'll never write to the fs underlying
- * a device file.
- */
- if (special_file(inode->i_mode))
- return 0;
- return (flag & O_TRUNC);
-}
-
-static struct file *finish_open(struct nameidata *nd,
- int open_flag, int acc_mode)
-{
- struct file *filp;
- int will_truncate;
- int error;
-
- will_truncate = open_will_truncate(open_flag, nd->path.dentry->d_inode);
- if (will_truncate) {
- error = mnt_want_write(nd->path.mnt);
- if (error)
- goto exit;
- }
- error = may_open(&nd->path, acc_mode, open_flag);
- if (error) {
- if (will_truncate)
- mnt_drop_write(nd->path.mnt);
- goto exit;
- }
- filp = nameidata_to_filp(nd);
- if (!IS_ERR(filp)) {
- error = ima_file_check(filp, acc_mode);
- if (error) {
- fput(filp);
- filp = ERR_PTR(error);
- }
- }
- if (!IS_ERR(filp)) {
- if (will_truncate) {
- error = handle_truncate(filp);
- if (error) {
- fput(filp);
- filp = ERR_PTR(error);
- }
- }
- }
- /*
- * It is now safe to drop the mnt write
- * because the filp has had a write taken
- * on its behalf.
- */
- if (will_truncate)
- mnt_drop_write(nd->path.mnt);
- path_put(&nd->path);
- return filp;
-
-exit:
- path_put(&nd->path);
- return ERR_PTR(error);
-}
-
/*
- * Handle O_CREAT case for do_filp_open
+ * Handle the last step of open()
*/
static struct file *do_last(struct nameidata *nd, struct path *path,
- int open_flag, int acc_mode,
- int mode, const char *pathname)
+ const struct open_flags *op, const char *pathname)
{
struct dentry *dir = nd->path.dentry;
+ struct dentry *dentry;
+ int open_flag = op->open_flag;
+ int will_truncate = open_flag & O_TRUNC;
+ int want_write = 0;
+ int acc_mode = op->acc_mode;
struct file *filp;
- int error = -EISDIR;
+ int error;
+
+ nd->flags &= ~LOOKUP_PARENT;
+ nd->flags |= op->intent;
switch (nd->last_type) {
case LAST_DOTDOT:
- follow_dotdot(nd);
- dir = nd->path.dentry;
case LAST_DOT:
- if (need_reval_dot(dir)) {
- int status = d_revalidate(nd->path.dentry, nd);
- if (!status)
- status = -ESTALE;
- if (status < 0) {
- error = status;
- goto exit;
- }
- }
+ error = handle_dots(nd, nd->last_type);
+ if (error)
+ return ERR_PTR(error);
/* fallthrough */
case LAST_ROOT:
- goto exit;
+ if (nd->flags & LOOKUP_RCU) {
+ if (nameidata_drop_rcu_last(nd))
+ return ERR_PTR(-ECHILD);
+ }
+ error = handle_reval_path(nd);
+ if (error)
+ goto exit;
+ audit_inode(pathname, nd->path.dentry);
+ if (open_flag & O_CREAT) {
+ error = -EISDIR;
+ goto exit;
+ }
+ goto ok;
case LAST_BIND:
+ /* can't be RCU mode here */
+ error = handle_reval_path(nd);
+ if (error)
+ goto exit;
audit_inode(pathname, dir);
goto ok;
}
+ if (!(open_flag & O_CREAT)) {
+ int symlink_ok = 0;
+ if (nd->last.name[nd->last.len])
+ nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+ if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW))
+ symlink_ok = 1;
+ /* we _can_ be in RCU mode here */
+ error = walk_component(nd, path, &nd->last, LAST_NORM,
+ !symlink_ok);
+ if (error < 0)
+ return ERR_PTR(error);
+ if (error) /* symlink */
+ return NULL;
+ /* sayonara */
+ if (nd->flags & LOOKUP_RCU) {
+ if (nameidata_drop_rcu_last(nd))
+ return ERR_PTR(-ECHILD);
+ }
+
+ error = -ENOTDIR;
+ if (nd->flags & LOOKUP_DIRECTORY) {
+ if (!nd->inode->i_op->lookup)
+ goto exit;
+ }
+ audit_inode(pathname, nd->path.dentry);
+ goto ok;
+ }
+
+ /* create side of things */
+
+ if (nd->flags & LOOKUP_RCU) {
+ if (nameidata_drop_rcu_last(nd))
+ return ERR_PTR(-ECHILD);
+ }
+
+ audit_inode(pathname, dir);
+ error = -EISDIR;
/* trailing slashes? */
if (nd->last.name[nd->last.len])
goto exit;
mutex_lock(&dir->d_inode->i_mutex);
- path->dentry = lookup_hash(nd);
- path->mnt = nd->path.mnt;
-
- error = PTR_ERR(path->dentry);
- if (IS_ERR(path->dentry)) {
+ dentry = lookup_hash(nd);
+ error = PTR_ERR(dentry);
+ if (IS_ERR(dentry)) {
mutex_unlock(&dir->d_inode->i_mutex);
goto exit;
}
- if (IS_ERR(nd->intent.open.file)) {
- error = PTR_ERR(nd->intent.open.file);
- goto exit_mutex_unlock;
- }
+ path->dentry = dentry;
+ path->mnt = nd->path.mnt;
/* Negative dentry, just create the file */
- if (!path->dentry->d_inode) {
+ if (!dentry->d_inode) {
+ int mode = op->mode;
+ if (!IS_POSIXACL(dir->d_inode))
+ mode &= ~current_umask();
/*
* This write is needed to ensure that a
- * ro->rw transition does not occur between
+ * rw->ro transition does not occur between
* the time when the file is created and when
* a permanent write count is taken through
* the 'struct file' in nameidata_to_filp().
error = mnt_want_write(nd->path.mnt);
if (error)
goto exit_mutex_unlock;
- error = __open_namei_create(nd, path, open_flag, mode);
- if (error) {
- mnt_drop_write(nd->path.mnt);
- goto exit;
- }
- filp = nameidata_to_filp(nd);
- mnt_drop_write(nd->path.mnt);
- path_put(&nd->path);
- if (!IS_ERR(filp)) {
- error = ima_file_check(filp, acc_mode);
- if (error) {
- fput(filp);
- filp = ERR_PTR(error);
- }
- }
- return filp;
+ want_write = 1;
+ /* Don't check for write permission, don't truncate */
+ open_flag &= ~O_TRUNC;
+ will_truncate = 0;
+ acc_mode = MAY_OPEN;
+ error = security_path_mknod(&nd->path, dentry, mode, 0);
+ if (error)
+ goto exit_mutex_unlock;
+ error = vfs_create(dir->d_inode, dentry, mode, nd);
+ if (error)
+ goto exit_mutex_unlock;
+ mutex_unlock(&dir->d_inode->i_mutex);
+ dput(nd->path.dentry);
+ nd->path.dentry = dentry;
+ goto common;
}
/*
if (S_ISDIR(nd->inode->i_mode))
goto exit;
ok:
- filp = finish_open(nd, open_flag, acc_mode);
+ if (!S_ISREG(nd->inode->i_mode))
+ will_truncate = 0;
+
+ if (will_truncate) {
+ error = mnt_want_write(nd->path.mnt);
+ if (error)
+ goto exit;
+ want_write = 1;
+ }
+common:
+ error = may_open(&nd->path, acc_mode, open_flag);
+ if (error)
+ goto exit;
+ filp = nameidata_to_filp(nd);
+ if (!IS_ERR(filp)) {
+ error = ima_file_check(filp, op->acc_mode);
+ if (error) {
+ fput(filp);
+ filp = ERR_PTR(error);
+ }
+ }
+ if (!IS_ERR(filp)) {
+ if (will_truncate) {
+ error = handle_truncate(filp);
+ if (error) {
+ fput(filp);
+ filp = ERR_PTR(error);
+ }
+ }
+ }
+out:
+ if (want_write)
+ mnt_drop_write(nd->path.mnt);
+ path_put(&nd->path);
return filp;
exit_mutex_unlock:
exit_dput:
path_put_conditional(path, nd);
exit:
- path_put(&nd->path);
- return ERR_PTR(error);
+ filp = ERR_PTR(error);
+ goto out;
}
-/*
- * Note that the low bits of the passed in "open_flag"
- * are not the same as in the local variable "flag". See
- * open_to_namei_flags() for more details.
- */
-struct file *do_filp_open(int dfd, const char *pathname,
- int open_flag, int mode, int acc_mode)
+static struct file *path_openat(int dfd, const char *pathname,
+ struct nameidata *nd, const struct open_flags *op, int flags)
{
+ struct file *base = NULL;
struct file *filp;
- struct nameidata nd;
- int error;
struct path path;
- int count = 0;
- int flag = open_to_namei_flags(open_flag);
- int flags;
-
- if (!(open_flag & O_CREAT))
- mode = 0;
-
- /* Must never be set by userspace */
- open_flag &= ~FMODE_NONOTIFY;
-
- /*
- * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
- * check for O_DSYNC if the need any syncing at all we enforce it's
- * always set instead of having to deal with possibly weird behaviour
- * for malicious applications setting only __O_SYNC.
- */
- if (open_flag & __O_SYNC)
- open_flag |= O_DSYNC;
-
- if (!acc_mode)
- acc_mode = MAY_OPEN | ACC_MODE(open_flag);
-
- /* O_TRUNC implies we need access checks for write permissions */
- if (open_flag & O_TRUNC)
- acc_mode |= MAY_WRITE;
-
- /* Allow the LSM permission hook to distinguish append
- access from general write access. */
- if (open_flag & O_APPEND)
- acc_mode |= MAY_APPEND;
-
- flags = LOOKUP_OPEN;
- if (open_flag & O_CREAT) {
- flags |= LOOKUP_CREATE;
- if (open_flag & O_EXCL)
- flags |= LOOKUP_EXCL;
- }
- if (open_flag & O_DIRECTORY)
- flags |= LOOKUP_DIRECTORY;
- if (!(open_flag & O_NOFOLLOW))
- flags |= LOOKUP_FOLLOW;
+ int error;
filp = get_empty_filp();
if (!filp)
return ERR_PTR(-ENFILE);
- filp->f_flags = open_flag;
- nd.intent.open.file = filp;
- nd.intent.open.flags = flag;
- nd.intent.open.create_mode = mode;
-
- if (open_flag & O_CREAT)
- goto creat;
+ filp->f_flags = op->open_flag;
+ nd->intent.open.file = filp;
+ nd->intent.open.flags = open_to_namei_flags(op->open_flag);
+ nd->intent.open.create_mode = op->mode;
- /* !O_CREAT, simple open */
- error = do_path_lookup(dfd, pathname, flags, &nd);
+ error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base);
if (unlikely(error))
- goto out_filp2;
- error = -ELOOP;
- if (!(nd.flags & LOOKUP_FOLLOW)) {
- if (nd.inode->i_op->follow_link)
- goto out_path2;
- }
- error = -ENOTDIR;
- if (nd.flags & LOOKUP_DIRECTORY) {
- if (!nd.inode->i_op->lookup)
- goto out_path2;
- }
- audit_inode(pathname, nd.path.dentry);
- filp = finish_open(&nd, open_flag, acc_mode);
-out2:
- release_open_intent(&nd);
- return filp;
-
-out_path2:
- path_put(&nd.path);
-out_filp2:
- filp = ERR_PTR(error);
- goto out2;
-
-creat:
- /* OK, have to create the file. Find the parent. */
- error = path_init_rcu(dfd, pathname,
- LOOKUP_PARENT | (flags & LOOKUP_REVAL), &nd);
- if (error)
goto out_filp;
- error = path_walk_rcu(pathname, &nd);
- path_finish_rcu(&nd);
- if (unlikely(error == -ECHILD || error == -ESTALE)) {
- /* slower, locked walk */
- if (error == -ESTALE) {
-reval:
- flags |= LOOKUP_REVAL;
- }
- error = path_init(dfd, pathname,
- LOOKUP_PARENT | (flags & LOOKUP_REVAL), &nd);
- if (error)
- goto out_filp;
- error = path_walk_simple(pathname, &nd);
- }
+ current->total_link_count = 0;
+ error = link_path_walk(pathname, nd);
if (unlikely(error))
goto out_filp;
- if (unlikely(!audit_dummy_context()))
- audit_inode(pathname, nd.path.dentry);
- /*
- * We have the parent and last component.
- */
- nd.flags = flags;
- filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
+ filp = do_last(nd, &path, op, pathname);
while (unlikely(!filp)) { /* trailing symlink */
struct path link = path;
- struct inode *linki = link.dentry->d_inode;
void *cookie;
- error = -ELOOP;
- if (!(nd.flags & LOOKUP_FOLLOW))
- goto exit_dput;
- if (count++ == 32)
- goto exit_dput;
- /*
- * This is subtle. Instead of calling do_follow_link() we do
- * the thing by hands. The reason is that this way we have zero
- * link_count and path_walk() (called from ->follow_link)
- * honoring LOOKUP_PARENT. After that we have the parent and
- * last component, i.e. we are in the same situation as after
- * the first path_walk(). Well, almost - if the last component
- * is normal we get its copy stored in nd->last.name and we will
- * have to putname() it when we are done. Procfs-like symlinks
- * just set LAST_BIND.
- */
- nd.flags |= LOOKUP_PARENT;
- error = security_inode_follow_link(link.dentry, &nd);
- if (error)
- goto exit_dput;
- error = __do_follow_link(&link, &nd, &cookie);
- if (unlikely(error)) {
- if (!IS_ERR(cookie) && linki->i_op->put_link)
- linki->i_op->put_link(link.dentry, &nd, cookie);
- /* nd.path had been dropped */
- nd.path = link;
- goto out_path;
+ if (!(nd->flags & LOOKUP_FOLLOW)) {
+ path_put_conditional(&path, nd);
+ path_put(&nd->path);
+ filp = ERR_PTR(-ELOOP);
+ break;
}
- nd.flags &= ~LOOKUP_PARENT;
- filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
- if (linki->i_op->put_link)
- linki->i_op->put_link(link.dentry, &nd, cookie);
- path_put(&link);
+ nd->flags |= LOOKUP_PARENT;
+ nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
+ error = follow_link(&link, nd, &cookie);
+ if (unlikely(error))
+ filp = ERR_PTR(error);
+ else
+ filp = do_last(nd, &path, op, pathname);
+ put_link(nd, &link, cookie);
}
out:
- if (nd.root.mnt)
- path_put(&nd.root);
- if (filp == ERR_PTR(-ESTALE) && !(flags & LOOKUP_REVAL))
- goto reval;
- release_open_intent(&nd);
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT))
+ path_put(&nd->root);
+ if (base)
+ fput(base);
+ release_open_intent(nd);
return filp;
-exit_dput:
- path_put_conditional(&path, &nd);
-out_path:
- path_put(&nd.path);
out_filp:
filp = ERR_PTR(error);
goto out;
}
-/**
- * filp_open - open file and return file pointer
- *
- * @filename: path to open
- * @flags: open flags as per the open(2) second argument
- * @mode: mode for the new file if O_CREAT is set, else ignored
- *
- * This is the helper to open a file from kernelspace if you really
- * have to. But in generally you should not do this, so please move
- * along, nothing to see here..
- */
-struct file *filp_open(const char *filename, int flags, int mode)
+struct file *do_filp_open(int dfd, const char *pathname,
+ const struct open_flags *op, int flags)
{
- return do_filp_open(AT_FDCWD, filename, flags, mode, 0);
+ struct nameidata nd;
+ struct file *filp;
+
+ filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU);
+ if (unlikely(filp == ERR_PTR(-ECHILD)))
+ filp = path_openat(dfd, pathname, &nd, op, flags);
+ if (unlikely(filp == ERR_PTR(-ESTALE)))
+ filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_REVAL);
+ return filp;
+}
+
+struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
+ const char *name, const struct open_flags *op, int flags)
+{
+ struct nameidata nd;
+ struct file *file;
+
+ nd.root.mnt = mnt;
+ nd.root.dentry = dentry;
+
+ flags |= LOOKUP_ROOT;
+
+ if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN)
+ return ERR_PTR(-ELOOP);
+
+ file = path_openat(-1, name, &nd, op, flags | LOOKUP_RCU);
+ if (unlikely(file == ERR_PTR(-ECHILD)))
+ file = path_openat(-1, name, &nd, op, flags);
+ if (unlikely(file == ERR_PTR(-ESTALE)))
+ file = path_openat(-1, name, &nd, op, flags | LOOKUP_REVAL);
+ return file;
}
-EXPORT_SYMBOL(filp_open);
/**
* lookup_create - lookup a dentry, creating it if it doesn't exist
if (error)
return error;
- if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD))
+ if ((S_ISCHR(mode) || S_ISBLK(mode)) &&
+ !ns_capable(inode_userns(dir), CAP_MKNOD))
return -EPERM;
if (!dir->i_op->mknod)
return error;
mutex_lock(&inode->i_mutex);
- error = dir->i_op->link(old_dentry, dir, new_dentry);
+ /* Make sure we don't allow creating hardlink to an unlinked file */
+ if (inode->i_nlink == 0)
+ error = -ENOENT;
+ else
+ error = dir->i_op->link(old_dentry, dir, new_dentry);
mutex_unlock(&inode->i_mutex);
if (!error)
fsnotify_link(dir, inode, new_dentry);
struct dentry *new_dentry;
struct nameidata nd;
struct path old_path;
+ int how = 0;
int error;
char *to;
- if ((flags & ~AT_SYMLINK_FOLLOW) != 0)
+ if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0)
return -EINVAL;
+ /*
+ * To use null names we require CAP_DAC_READ_SEARCH
+ * This ensures that not everyone will be able to create
+ * handlink using the passed filedescriptor.
+ */
+ if (flags & AT_EMPTY_PATH) {
+ if (!capable(CAP_DAC_READ_SEARCH))
+ return -ENOENT;
+ how = LOOKUP_EMPTY;
+ }
+
+ if (flags & AT_SYMLINK_FOLLOW)
+ how |= LOOKUP_FOLLOW;
- error = user_path_at(olddfd, oldname,
- flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
- &old_path);
+ error = user_path_at(olddfd, oldname, how, &old_path);
if (error)
return error;
EXPORT_SYMBOL(__page_symlink);
EXPORT_SYMBOL(page_symlink);
EXPORT_SYMBOL(page_symlink_inode_operations);
-EXPORT_SYMBOL(path_lookup);
+EXPORT_SYMBOL(kern_path_parent);
EXPORT_SYMBOL(kern_path);
EXPORT_SYMBOL(vfs_path_lookup);
EXPORT_SYMBOL(inode_permission);
git.openpandora.org / pandora-kernel.git / blobdiff