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Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c324
1 files changed, 195 insertions, 129 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 360a86ca1f02..4bb889fc980b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -125,9 +125,9 @@
#define EMBEDDED_NAME_MAX (PATH_MAX - offsetof(struct filename, iname))
-static inline void initname(struct filename *name)
+static inline void initname(struct filename *name, const char __user *uptr)
{
- name->uptr = NULL;
+ name->uptr = uptr;
name->aname = NULL;
atomic_set(&name->refcnt, 1);
}
@@ -210,7 +210,7 @@ getname_flags(const char __user *filename, int flags)
return ERR_PTR(-ENAMETOOLONG);
}
}
- initname(result);
+ initname(result, filename);
audit_getname(result);
return result;
}
@@ -268,7 +268,7 @@ struct filename *getname_kernel(const char * filename)
return ERR_PTR(-ENAMETOOLONG);
}
memcpy((char *)result->name, filename, len);
- initname(result);
+ initname(result, NULL);
audit_getname(result);
return result;
}
@@ -571,14 +571,14 @@ int inode_permission(struct mnt_idmap *idmap,
int retval;
retval = sb_permission(inode->i_sb, inode, mask);
- if (retval)
+ if (unlikely(retval))
return retval;
if (unlikely(mask & MAY_WRITE)) {
/*
* Nobody gets write access to an immutable file.
*/
- if (IS_IMMUTABLE(inode))
+ if (unlikely(IS_IMMUTABLE(inode)))
return -EPERM;
/*
@@ -586,16 +586,16 @@ int inode_permission(struct mnt_idmap *idmap,
* written back improperly if their true value is unknown
* to the vfs.
*/
- if (HAS_UNMAPPED_ID(idmap, inode))
+ if (unlikely(HAS_UNMAPPED_ID(idmap, inode)))
return -EACCES;
}
retval = do_inode_permission(idmap, inode, mask);
- if (retval)
+ if (unlikely(retval))
return retval;
retval = devcgroup_inode_permission(inode, mask);
- if (retval)
+ if (unlikely(retval))
return retval;
return security_inode_permission(inode, mask);
@@ -1665,27 +1665,20 @@ static struct dentry *lookup_dcache(const struct qstr *name,
return dentry;
}
-/*
- * Parent directory has inode locked exclusive. This is one
- * and only case when ->lookup() gets called on non in-lookup
- * dentries - as the matter of fact, this only gets called
- * when directory is guaranteed to have no in-lookup children
- * at all.
- * Will return -ENOENT if name isn't found and LOOKUP_CREATE wasn't passed.
- * Will return -EEXIST if name is found and LOOKUP_EXCL was passed.
- */
-struct dentry *lookup_one_qstr_excl(const struct qstr *name,
- struct dentry *base,
- unsigned int flags)
+static struct dentry *lookup_one_qstr_excl_raw(const struct qstr *name,
+ struct dentry *base,
+ unsigned int flags)
{
- struct dentry *dentry = lookup_dcache(name, base, flags);
+ struct dentry *dentry;
struct dentry *old;
- struct inode *dir = base->d_inode;
+ struct inode *dir;
+ dentry = lookup_dcache(name, base, flags);
if (dentry)
- goto found;
+ return dentry;
/* Don't create child dentry for a dead directory. */
+ dir = base->d_inode;
if (unlikely(IS_DEADDIR(dir)))
return ERR_PTR(-ENOENT);
@@ -1698,7 +1691,24 @@ struct dentry *lookup_one_qstr_excl(const struct qstr *name,
dput(dentry);
dentry = old;
}
-found:
+ return dentry;
+}
+
+/*
+ * Parent directory has inode locked exclusive. This is one
+ * and only case when ->lookup() gets called on non in-lookup
+ * dentries - as the matter of fact, this only gets called
+ * when directory is guaranteed to have no in-lookup children
+ * at all.
+ * Will return -ENOENT if name isn't found and LOOKUP_CREATE wasn't passed.
+ * Will return -EEXIST if name is found and LOOKUP_EXCL was passed.
+ */
+struct dentry *lookup_one_qstr_excl(const struct qstr *name,
+ struct dentry *base, unsigned int flags)
+{
+ struct dentry *dentry;
+
+ dentry = lookup_one_qstr_excl_raw(name, base, flags);
if (IS_ERR(dentry))
return dentry;
if (d_is_negative(dentry) && !(flags & LOOKUP_CREATE)) {
@@ -1905,13 +1915,13 @@ static const char *pick_link(struct nameidata *nd, struct path *link,
unlikely(link->mnt->mnt_flags & MNT_NOSYMFOLLOW))
return ERR_PTR(-ELOOP);
- if (!(nd->flags & LOOKUP_RCU)) {
+ if (unlikely(atime_needs_update(&last->link, inode))) {
+ if (nd->flags & LOOKUP_RCU) {
+ if (!try_to_unlazy(nd))
+ return ERR_PTR(-ECHILD);
+ }
touch_atime(&last->link);
cond_resched();
- } else if (atime_needs_update(&last->link, inode)) {
- if (!try_to_unlazy(nd))
- return ERR_PTR(-ECHILD);
- touch_atime(&last->link);
}
error = security_inode_follow_link(link->dentry, inode,
@@ -2424,9 +2434,12 @@ static int link_path_walk(const char *name, struct nameidata *nd)
nd->flags |= LOOKUP_PARENT;
if (IS_ERR(name))
return PTR_ERR(name);
- while (*name=='/')
- name++;
- if (!*name) {
+ if (*name == '/') {
+ do {
+ name++;
+ } while (unlikely(*name == '/'));
+ }
+ if (unlikely(!*name)) {
nd->dir_mode = 0; // short-circuit the 'hardening' idiocy
return 0;
}
@@ -2439,7 +2452,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
idmap = mnt_idmap(nd->path.mnt);
err = may_lookup(idmap, nd);
- if (err)
+ if (unlikely(err))
return err;
nd->last.name = name;
@@ -2742,23 +2755,48 @@ static int filename_parentat(int dfd, struct filename *name,
/* does lookup, returns the object with parent locked */
static struct dentry *__kern_path_locked(int dfd, struct filename *name, struct path *path)
{
+ struct path parent_path __free(path_put) = {};
struct dentry *d;
struct qstr last;
int type, error;
- error = filename_parentat(dfd, name, 0, path, &last, &type);
+ error = filename_parentat(dfd, name, 0, &parent_path, &last, &type);
if (error)
return ERR_PTR(error);
- if (unlikely(type != LAST_NORM)) {
- path_put(path);
+ if (unlikely(type != LAST_NORM))
return ERR_PTR(-EINVAL);
+ inode_lock_nested(parent_path.dentry->d_inode, I_MUTEX_PARENT);
+ d = lookup_one_qstr_excl(&last, parent_path.dentry, 0);
+ if (IS_ERR(d)) {
+ inode_unlock(parent_path.dentry->d_inode);
+ return d;
}
- inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
- d = lookup_one_qstr_excl(&last, path->dentry, 0);
+ path->dentry = no_free_ptr(parent_path.dentry);
+ path->mnt = no_free_ptr(parent_path.mnt);
+ return d;
+}
+
+struct dentry *kern_path_locked_negative(const char *name, struct path *path)
+{
+ struct path parent_path __free(path_put) = {};
+ struct filename *filename __free(putname) = getname_kernel(name);
+ struct dentry *d;
+ struct qstr last;
+ int type, error;
+
+ error = filename_parentat(AT_FDCWD, filename, 0, &parent_path, &last, &type);
+ if (error)
+ return ERR_PTR(error);
+ if (unlikely(type != LAST_NORM))
+ return ERR_PTR(-EINVAL);
+ inode_lock_nested(parent_path.dentry->d_inode, I_MUTEX_PARENT);
+ d = lookup_one_qstr_excl_raw(&last, parent_path.dentry, 0);
if (IS_ERR(d)) {
- inode_unlock(path->dentry->d_inode);
- path_put(path);
+ inode_unlock(parent_path.dentry->d_inode);
+ return d;
}
+ path->dentry = no_free_ptr(parent_path.dentry);
+ path->mnt = no_free_ptr(parent_path.mnt);
return d;
}
@@ -2834,13 +2872,12 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
}
EXPORT_SYMBOL(vfs_path_lookup);
-static int lookup_one_common(struct mnt_idmap *idmap,
- const char *name, struct dentry *base, int len,
- struct qstr *this)
+static int lookup_noperm_common(struct qstr *qname, struct dentry *base)
{
- this->name = name;
- this->len = len;
- this->hash = full_name_hash(base, name, len);
+ const char *name = qname->name;
+ u32 len = qname->len;
+
+ qname->hash = full_name_hash(base, name, len);
if (!len)
return -EACCES;
@@ -2857,139 +2894,135 @@ static int lookup_one_common(struct mnt_idmap *idmap,
* to use its own hash..
*/
if (base->d_flags & DCACHE_OP_HASH) {
- int err = base->d_op->d_hash(base, this);
+ int err = base->d_op->d_hash(base, qname);
if (err < 0)
return err;
}
+ return 0;
+}
+static int lookup_one_common(struct mnt_idmap *idmap,
+ struct qstr *qname, struct dentry *base)
+{
+ int err;
+ err = lookup_noperm_common(qname, base);
+ if (err < 0)
+ return err;
return inode_permission(idmap, base->d_inode, MAY_EXEC);
}
/**
- * try_lookup_one_len - filesystem helper to lookup single pathname component
- * @name: pathname component to lookup
+ * try_lookup_noperm - filesystem helper to lookup single pathname component
+ * @name: qstr storing pathname component to lookup
* @base: base directory to lookup from
- * @len: maximum length @len should be interpreted to
*
* Look up a dentry by name in the dcache, returning NULL if it does not
* currently exist. The function does not try to create a dentry.
*
* Note that this routine is purely a helper for filesystem usage and should
- * not be called by generic code.
+ * not be called by generic code. It does no permission checking.
*
* No locks need be held - only a counted reference to @base is needed.
*
*/
-struct dentry *try_lookup_one_len(const char *name, struct dentry *base, int len)
+struct dentry *try_lookup_noperm(struct qstr *name, struct dentry *base)
{
- struct qstr this;
int err;
- err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this);
+ err = lookup_noperm_common(name, base);
if (err)
return ERR_PTR(err);
- return lookup_dcache(&this, base, 0);
+ return lookup_dcache(name, base, 0);
}
-EXPORT_SYMBOL(try_lookup_one_len);
+EXPORT_SYMBOL(try_lookup_noperm);
/**
- * lookup_one_len - filesystem helper to lookup single pathname component
- * @name: pathname component to lookup
+ * lookup_noperm - filesystem helper to lookup single pathname component
+ * @name: qstr storing pathname component to lookup
* @base: base directory to lookup from
- * @len: maximum length @len should be interpreted to
*
* Note that this routine is purely a helper for filesystem usage and should
- * not be called by generic code.
+ * not be called by generic code. It does no permission checking.
*
* The caller must hold base->i_mutex.
*/
-struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
+struct dentry *lookup_noperm(struct qstr *name, struct dentry *base)
{
struct dentry *dentry;
- struct qstr this;
int err;
WARN_ON_ONCE(!inode_is_locked(base->d_inode));
- err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this);
+ err = lookup_noperm_common(name, base);
if (err)
return ERR_PTR(err);
- dentry = lookup_dcache(&this, base, 0);
- return dentry ? dentry : __lookup_slow(&this, base, 0);
+ dentry = lookup_dcache(name, base, 0);
+ return dentry ? dentry : __lookup_slow(name, base, 0);
}
-EXPORT_SYMBOL(lookup_one_len);
+EXPORT_SYMBOL(lookup_noperm);
/**
- * lookup_one - filesystem helper to lookup single pathname component
+ * lookup_one - lookup single pathname component
* @idmap: idmap of the mount the lookup is performed from
- * @name: pathname component to lookup
+ * @name: qstr holding pathname component to lookup
* @base: base directory to lookup from
- * @len: maximum length @len should be interpreted to
*
- * Note that this routine is purely a helper for filesystem usage and should
- * not be called by generic code.
+ * This can be used for in-kernel filesystem clients such as file servers.
*
* The caller must hold base->i_mutex.
*/
-struct dentry *lookup_one(struct mnt_idmap *idmap, const char *name,
- struct dentry *base, int len)
+struct dentry *lookup_one(struct mnt_idmap *idmap, struct qstr *name,
+ struct dentry *base)
{
struct dentry *dentry;
- struct qstr this;
int err;
WARN_ON_ONCE(!inode_is_locked(base->d_inode));
- err = lookup_one_common(idmap, name, base, len, &this);
+ err = lookup_one_common(idmap, name, base);
if (err)
return ERR_PTR(err);
- dentry = lookup_dcache(&this, base, 0);
- return dentry ? dentry : __lookup_slow(&this, base, 0);
+ dentry = lookup_dcache(name, base, 0);
+ return dentry ? dentry : __lookup_slow(name, base, 0);
}
EXPORT_SYMBOL(lookup_one);
/**
- * lookup_one_unlocked - filesystem helper to lookup single pathname component
+ * lookup_one_unlocked - lookup single pathname component
* @idmap: idmap of the mount the lookup is performed from
- * @name: pathname component to lookup
+ * @name: qstr olding pathname component to lookup
* @base: base directory to lookup from
- * @len: maximum length @len should be interpreted to
*
- * Note that this routine is purely a helper for filesystem usage and should
- * not be called by generic code.
+ * This can be used for in-kernel filesystem clients such as file servers.
*
- * Unlike lookup_one_len, it should be called without the parent
- * i_mutex held, and will take the i_mutex itself if necessary.
+ * Unlike lookup_one, it should be called without the parent
+ * i_rwsem held, and will take the i_rwsem itself if necessary.
*/
-struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap,
- const char *name, struct dentry *base,
- int len)
+struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap, struct qstr *name,
+ struct dentry *base)
{
- struct qstr this;
int err;
struct dentry *ret;
- err = lookup_one_common(idmap, name, base, len, &this);
+ err = lookup_one_common(idmap, name, base);
if (err)
return ERR_PTR(err);
- ret = lookup_dcache(&this, base, 0);
+ ret = lookup_dcache(name, base, 0);
if (!ret)
- ret = lookup_slow(&this, base, 0);
+ ret = lookup_slow(name, base, 0);
return ret;
}
EXPORT_SYMBOL(lookup_one_unlocked);
/**
- * lookup_one_positive_unlocked - filesystem helper to lookup single
- * pathname component
+ * lookup_one_positive_unlocked - lookup single pathname component
* @idmap: idmap of the mount the lookup is performed from
- * @name: pathname component to lookup
+ * @name: qstr holding pathname component to lookup
* @base: base directory to lookup from
- * @len: maximum length @len should be interpreted to
*
* This helper will yield ERR_PTR(-ENOENT) on negatives. The helper returns
* known positive or ERR_PTR(). This is what most of the users want.
@@ -2998,16 +3031,15 @@ EXPORT_SYMBOL(lookup_one_unlocked);
* time, so callers of lookup_one_unlocked() need to be very careful; pinned
* positives have >d_inode stable, so this one avoids such problems.
*
- * Note that this routine is purely a helper for filesystem usage and should
- * not be called by generic code.
+ * This can be used for in-kernel filesystem clients such as file servers.
*
- * The helper should be called without i_mutex held.
+ * The helper should be called without i_rwsem held.
*/
struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap,
- const char *name,
- struct dentry *base, int len)
+ struct qstr *name,
+ struct dentry *base)
{
- struct dentry *ret = lookup_one_unlocked(idmap, name, base, len);
+ struct dentry *ret = lookup_one_unlocked(idmap, name, base);
if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
dput(ret);
@@ -3018,38 +3050,48 @@ struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap,
EXPORT_SYMBOL(lookup_one_positive_unlocked);
/**
- * lookup_one_len_unlocked - filesystem helper to lookup single pathname component
+ * lookup_noperm_unlocked - filesystem helper to lookup single pathname component
* @name: pathname component to lookup
* @base: base directory to lookup from
- * @len: maximum length @len should be interpreted to
*
* Note that this routine is purely a helper for filesystem usage and should
- * not be called by generic code.
+ * not be called by generic code. It does no permission checking.
*
- * Unlike lookup_one_len, it should be called without the parent
- * i_mutex held, and will take the i_mutex itself if necessary.
+ * Unlike lookup_noperm, it should be called without the parent
+ * i_rwsem held, and will take the i_rwsem itself if necessary.
*/
-struct dentry *lookup_one_len_unlocked(const char *name,
- struct dentry *base, int len)
+struct dentry *lookup_noperm_unlocked(struct qstr *name, struct dentry *base)
{
- return lookup_one_unlocked(&nop_mnt_idmap, name, base, len);
+ struct dentry *ret;
+
+ ret = try_lookup_noperm(name, base);
+ if (!ret)
+ ret = lookup_slow(name, base, 0);
+ return ret;
}
-EXPORT_SYMBOL(lookup_one_len_unlocked);
+EXPORT_SYMBOL(lookup_noperm_unlocked);
/*
- * Like lookup_one_len_unlocked(), except that it yields ERR_PTR(-ENOENT)
+ * Like lookup_noperm_unlocked(), except that it yields ERR_PTR(-ENOENT)
* on negatives. Returns known positive or ERR_PTR(); that's what
* most of the users want. Note that pinned negative with unlocked parent
- * _can_ become positive at any time, so callers of lookup_one_len_unlocked()
+ * _can_ become positive at any time, so callers of lookup_noperm_unlocked()
* need to be very careful; pinned positives have ->d_inode stable, so
* this one avoids such problems.
*/
-struct dentry *lookup_positive_unlocked(const char *name,
- struct dentry *base, int len)
+struct dentry *lookup_noperm_positive_unlocked(struct qstr *name,
+ struct dentry *base)
{
- return lookup_one_positive_unlocked(&nop_mnt_idmap, name, base, len);
+ struct dentry *ret;
+
+ ret = lookup_noperm_unlocked(name, base);
+ if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
+ dput(ret);
+ ret = ERR_PTR(-ENOENT);
+ }
+ return ret;
}
-EXPORT_SYMBOL(lookup_positive_unlocked);
+EXPORT_SYMBOL(lookup_noperm_positive_unlocked);
#ifdef CONFIG_UNIX98_PTYS
int path_pts(struct path *path)
@@ -5368,25 +5410,25 @@ EXPORT_SYMBOL(vfs_get_link);
static char *__page_get_link(struct dentry *dentry, struct inode *inode,
struct delayed_call *callback)
{
- struct page *page;
+ struct folio *folio;
struct address_space *mapping = inode->i_mapping;
if (!dentry) {
- page = find_get_page(mapping, 0);
- if (!page)
+ folio = filemap_get_folio(mapping, 0);
+ if (IS_ERR(folio))
return ERR_PTR(-ECHILD);
- if (!PageUptodate(page)) {
- put_page(page);
+ if (!folio_test_uptodate(folio)) {
+ folio_put(folio);
return ERR_PTR(-ECHILD);
}
} else {
- page = read_mapping_page(mapping, 0, NULL);
- if (IS_ERR(page))
- return (char*)page;
+ folio = read_mapping_folio(mapping, 0, NULL);
+ if (IS_ERR(folio))
+ return ERR_CAST(folio);
}
- set_delayed_call(callback, page_put_link, page);
+ set_delayed_call(callback, page_put_link, folio);
BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
- return page_address(page);
+ return folio_address(folio);
}
const char *page_get_link_raw(struct dentry *dentry, struct inode *inode,
@@ -5396,6 +5438,17 @@ const char *page_get_link_raw(struct dentry *dentry, struct inode *inode,
}
EXPORT_SYMBOL_GPL(page_get_link_raw);
+/**
+ * page_get_link() - An implementation of the get_link inode_operation.
+ * @dentry: The directory entry which is the symlink.
+ * @inode: The inode for the symlink.
+ * @callback: Used to drop the reference to the symlink.
+ *
+ * Filesystems which store their symlinks in the page cache should use
+ * this to implement the get_link() member of their inode_operations.
+ *
+ * Return: A pointer to the NUL-terminated symlink.
+ */
const char *page_get_link(struct dentry *dentry, struct inode *inode,
struct delayed_call *callback)
{
@@ -5405,12 +5458,25 @@ const char *page_get_link(struct dentry *dentry, struct inode *inode,
nd_terminate_link(kaddr, inode->i_size, PAGE_SIZE - 1);
return kaddr;
}
-
EXPORT_SYMBOL(page_get_link);
+/**
+ * page_put_link() - Drop the reference to the symlink.
+ * @arg: The folio which contains the symlink.
+ *
+ * This is used internally by page_get_link(). It is exported for use
+ * by filesystems which need to implement a variant of page_get_link()
+ * themselves. Despite the apparent symmetry, filesystems which use
+ * page_get_link() do not need to call page_put_link().
+ *
+ * The argument, while it has a void pointer type, must be a pointer to
+ * the folio which was retrieved from the page cache. The delayed_call
+ * infrastructure is used to drop the reference count once the caller
+ * is done with the symlink.
+ */
void page_put_link(void *arg)
{
- put_page(arg);
+ folio_put(arg);
}
EXPORT_SYMBOL(page_put_link);
generated by cgit (git 2.34.1) at 2025-05-31 10:26:39 +0000