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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-09 12:48:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-09 12:48:05 -0700
commitfd3b36d275660c905da9900b078eea341847d5e4 (patch)
tree687872bfb4e3dce727d6bab3e8799cd67d4d5108 /fs/namei.c
parent8ea4a5d84e6c44b3508599fe114ea806e63985a4 (diff)
parent30ce4d1903e1d8a7ccd110860a5eef3c638ed8be (diff)
downloadlinux-stericsson-fd3b36d275660c905da9900b078eea341847d5e4.tar.gz
Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs namei updates from Al Viro: - make lookup_one_len() safe with parent locked only shared(incoming afs series wants that) - fix of getname_kernel() regression from 2015 (-stable fodder, that one). * 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: getname_kernel() needs to make sure that ->name != ->iname in long case make lookup_one_len() safe to use with directory locked shared new helper: __lookup_slow() merge common parts of lookup_one_len{,_unlocked} into common helper
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c124
1 files changed, 57 insertions, 67 deletions
diff --git a/fs/namei.c b/fs/namei.c
index a66ed5a1622a..186bd2464fd5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -224,9 +224,10 @@ getname_kernel(const char * filename)
if (len <= EMBEDDED_NAME_MAX) {
result->name = (char *)result->iname;
} else if (len <= PATH_MAX) {
+ const size_t size = offsetof(struct filename, iname[1]);
struct filename *tmp;
- tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+ tmp = kmalloc(size, GFP_KERNEL);
if (unlikely(!tmp)) {
__putname(result);
return ERR_PTR(-ENOMEM);
@@ -1597,22 +1598,21 @@ static int lookup_fast(struct nameidata *nd,
}
/* Fast lookup failed, do it the slow way */
-static struct dentry *lookup_slow(const struct qstr *name,
- struct dentry *dir,
- unsigned int flags)
+static struct dentry *__lookup_slow(const struct qstr *name,
+ struct dentry *dir,
+ unsigned int flags)
{
- struct dentry *dentry = ERR_PTR(-ENOENT), *old;
+ struct dentry *dentry, *old;
struct inode *inode = dir->d_inode;
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
- inode_lock_shared(inode);
/* Don't go there if it's already dead */
if (unlikely(IS_DEADDIR(inode)))
- goto out;
+ return ERR_PTR(-ENOENT);
again:
dentry = d_alloc_parallel(dir, name, &wq);
if (IS_ERR(dentry))
- goto out;
+ return dentry;
if (unlikely(!d_in_lookup(dentry))) {
if (!(flags & LOOKUP_NO_REVAL)) {
int error = d_revalidate(dentry, flags);
@@ -1634,11 +1634,21 @@ again:
dentry = old;
}
}
-out:
- inode_unlock_shared(inode);
return dentry;
}
+static struct dentry *lookup_slow(const struct qstr *name,
+ struct dentry *dir,
+ unsigned int flags)
+{
+ struct inode *inode = dir->d_inode;
+ struct dentry *res;
+ inode_lock_shared(inode);
+ res = __lookup_slow(name, dir, flags);
+ inode_unlock_shared(inode);
+ return res;
+}
+
static inline int may_lookup(struct nameidata *nd)
{
if (nd->flags & LOOKUP_RCU) {
@@ -2421,56 +2431,63 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
}
EXPORT_SYMBOL(vfs_path_lookup);
-/**
- * lookup_one_len - 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.
- *
- * The caller must hold base->i_mutex.
- */
-struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
+static int lookup_one_len_common(const char *name, struct dentry *base,
+ int len, struct qstr *this)
{
- struct qstr this;
- unsigned int c;
- int err;
-
- WARN_ON_ONCE(!inode_is_locked(base->d_inode));
-
- this.name = name;
- this.len = len;
- this.hash = full_name_hash(base, name, len);
+ this->name = name;
+ this->len = len;
+ this->hash = full_name_hash(base, name, len);
if (!len)
- return ERR_PTR(-EACCES);
+ return -EACCES;
if (unlikely(name[0] == '.')) {
if (len < 2 || (len == 2 && name[1] == '.'))
- return ERR_PTR(-EACCES);
+ return -EACCES;
}
while (len--) {
- c = *(const unsigned char *)name++;
+ unsigned int c = *(const unsigned char *)name++;
if (c == '/' || c == '\0')
- return ERR_PTR(-EACCES);
+ return -EACCES;
}
/*
* 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, &this);
+ int err = base->d_op->d_hash(base, this);
if (err < 0)
- return ERR_PTR(err);
+ return err;
}
- err = inode_permission(base->d_inode, MAY_EXEC);
+ return inode_permission(base->d_inode, MAY_EXEC);
+}
+
+/**
+ * lookup_one_len - 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.
+ *
+ * The caller must hold base->i_mutex.
+ */
+struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
+{
+ struct dentry *dentry;
+ struct qstr this;
+ int err;
+
+ WARN_ON_ONCE(!inode_is_locked(base->d_inode));
+
+ err = lookup_one_len_common(name, base, len, &this);
if (err)
return ERR_PTR(err);
- return __lookup_hash(&this, base, 0);
+ dentry = lookup_dcache(&this, base, 0);
+ return dentry ? dentry : __lookup_slow(&this, base, 0);
}
EXPORT_SYMBOL(lookup_one_len);
@@ -2490,37 +2507,10 @@ struct dentry *lookup_one_len_unlocked(const char *name,
struct dentry *base, int len)
{
struct qstr this;
- unsigned int c;
int err;
struct dentry *ret;
- this.name = name;
- this.len = len;
- this.hash = full_name_hash(base, name, len);
- if (!len)
- return ERR_PTR(-EACCES);
-
- if (unlikely(name[0] == '.')) {
- if (len < 2 || (len == 2 && name[1] == '.'))
- return ERR_PTR(-EACCES);
- }
-
- while (len--) {
- c = *(const unsigned char *)name++;
- if (c == '/' || c == '\0')
- return ERR_PTR(-EACCES);
- }
- /*
- * 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, &this);
- if (err < 0)
- return ERR_PTR(err);
- }
-
- err = inode_permission(base->d_inode, MAY_EXEC);
+ err = lookup_one_len_common(name, base, len, &this);
if (err)
return ERR_PTR(err);