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-rw-r--r--fs/namei.c135
1 files changed, 81 insertions, 54 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 967c3db92724..527119afb6a5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -552,6 +552,17 @@ static __always_inline int link_path_walk(const char *name, struct nameidata *nd
return result;
}
+static __always_inline void set_root(struct nameidata *nd)
+{
+ if (!nd->root.mnt) {
+ struct fs_struct *fs = current->fs;
+ read_lock(&fs->lock);
+ nd->root = fs->root;
+ path_get(&nd->root);
+ read_unlock(&fs->lock);
+ }
+}
+
static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
{
int res = 0;
@@ -560,14 +571,10 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
goto fail;
if (*link == '/') {
- struct fs_struct *fs = current->fs;
-
+ set_root(nd);
path_put(&nd->path);
-
- read_lock(&fs->lock);
- nd->path = fs->root;
- path_get(&fs->root);
- read_unlock(&fs->lock);
+ nd->path = nd->root;
+ path_get(&nd->root);
}
res = link_path_walk(link, nd);
@@ -668,23 +675,23 @@ loop:
return err;
}
-int follow_up(struct vfsmount **mnt, struct dentry **dentry)
+int follow_up(struct path *path)
{
struct vfsmount *parent;
struct dentry *mountpoint;
spin_lock(&vfsmount_lock);
- parent=(*mnt)->mnt_parent;
- if (parent == *mnt) {
+ parent = path->mnt->mnt_parent;
+ if (parent == path->mnt) {
spin_unlock(&vfsmount_lock);
return 0;
}
mntget(parent);
- mountpoint=dget((*mnt)->mnt_mountpoint);
+ mountpoint = dget(path->mnt->mnt_mountpoint);
spin_unlock(&vfsmount_lock);
- dput(*dentry);
- *dentry = mountpoint;
- mntput(*mnt);
- *mnt = parent;
+ dput(path->dentry);
+ path->dentry = mountpoint;
+ mntput(path->mnt);
+ path->mnt = parent;
return 1;
}
@@ -695,7 +702,7 @@ static int __follow_mount(struct path *path)
{
int res = 0;
while (d_mountpoint(path->dentry)) {
- struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry);
+ struct vfsmount *mounted = lookup_mnt(path);
if (!mounted)
break;
dput(path->dentry);
@@ -708,32 +715,32 @@ static int __follow_mount(struct path *path)
return res;
}
-static void follow_mount(struct vfsmount **mnt, struct dentry **dentry)
+static void follow_mount(struct path *path)
{
- while (d_mountpoint(*dentry)) {
- struct vfsmount *mounted = lookup_mnt(*mnt, *dentry);
+ while (d_mountpoint(path->dentry)) {
+ struct vfsmount *mounted = lookup_mnt(path);
if (!mounted)
break;
- dput(*dentry);
- mntput(*mnt);
- *mnt = mounted;
- *dentry = dget(mounted->mnt_root);
+ dput(path->dentry);
+ mntput(path->mnt);
+ path->mnt = mounted;
+ path->dentry = dget(mounted->mnt_root);
}
}
/* no need for dcache_lock, as serialization is taken care in
* namespace.c
*/
-int follow_down(struct vfsmount **mnt, struct dentry **dentry)
+int follow_down(struct path *path)
{
struct vfsmount *mounted;
- mounted = lookup_mnt(*mnt, *dentry);
+ mounted = lookup_mnt(path);
if (mounted) {
- dput(*dentry);
- mntput(*mnt);
- *mnt = mounted;
- *dentry = dget(mounted->mnt_root);
+ dput(path->dentry);
+ mntput(path->mnt);
+ path->mnt = mounted;
+ path->dentry = dget(mounted->mnt_root);
return 1;
}
return 0;
@@ -741,19 +748,16 @@ int follow_down(struct vfsmount **mnt, struct dentry **dentry)
static __always_inline void follow_dotdot(struct nameidata *nd)
{
- struct fs_struct *fs = current->fs;
+ set_root(nd);
while(1) {
struct vfsmount *parent;
struct dentry *old = nd->path.dentry;
- read_lock(&fs->lock);
- if (nd->path.dentry == fs->root.dentry &&
- nd->path.mnt == fs->root.mnt) {
- read_unlock(&fs->lock);
+ if (nd->path.dentry == nd->root.dentry &&
+ nd->path.mnt == nd->root.mnt) {
break;
}
- read_unlock(&fs->lock);
spin_lock(&dcache_lock);
if (nd->path.dentry != nd->path.mnt->mnt_root) {
nd->path.dentry = dget(nd->path.dentry->d_parent);
@@ -775,7 +779,7 @@ static __always_inline void follow_dotdot(struct nameidata *nd)
mntput(nd->path.mnt);
nd->path.mnt = parent;
}
- follow_mount(&nd->path.mnt, &nd->path.dentry);
+ follow_mount(&nd->path);
}
/*
@@ -853,7 +857,8 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
err = inode_permission(nd->path.dentry->d_inode,
MAY_EXEC);
if (!err)
- err = ima_path_check(&nd->path, MAY_EXEC);
+ err = ima_path_check(&nd->path, MAY_EXEC,
+ IMA_COUNT_UPDATE);
if (err)
break;
@@ -1016,25 +1021,23 @@ static int path_walk(const char *name, struct nameidata *nd)
return link_path_walk(name, nd);
}
-/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int do_path_lookup(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)
{
int retval = 0;
int fput_needed;
struct file *file;
- struct fs_struct *fs = current->fs;
nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags;
nd->depth = 0;
+ nd->root.mnt = NULL;
if (*name=='/') {
- read_lock(&fs->lock);
- nd->path = fs->root;
- path_get(&fs->root);
- read_unlock(&fs->lock);
+ set_root(nd);
+ nd->path = nd->root;
+ path_get(&nd->root);
} else if (dfd == AT_FDCWD) {
+ struct fs_struct *fs = current->fs;
read_lock(&fs->lock);
nd->path = fs->pwd;
path_get(&fs->pwd);
@@ -1062,17 +1065,29 @@ static int do_path_lookup(int dfd, const char *name,
fput_light(file, fput_needed);
}
+ return 0;
- retval = path_walk(name, nd);
+fput_fail:
+ fput_light(file, fput_needed);
+out_fail:
+ return retval;
+}
+
+/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
+static int do_path_lookup(int dfd, const char *name,
+ unsigned int flags, struct nameidata *nd)
+{
+ int retval = path_init(dfd, name, flags, nd);
+ if (!retval)
+ retval = path_walk(name, nd);
if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
nd->path.dentry->d_inode))
audit_inode(name, nd->path.dentry);
-out_fail:
+ if (nd->root.mnt) {
+ path_put(&nd->root);
+ nd->root.mnt = NULL;
+ }
return retval;
-
-fput_fail:
- fput_light(file, fput_needed);
- goto out_fail;
}
int path_lookup(const char *name, unsigned int flags,
@@ -1112,14 +1127,18 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
nd->path.dentry = dentry;
nd->path.mnt = mnt;
path_get(&nd->path);
+ nd->root = nd->path;
+ path_get(&nd->root);
retval = path_walk(name, nd);
if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
nd->path.dentry->d_inode))
audit_inode(name, nd->path.dentry);
- return retval;
+ path_put(&nd->root);
+ nd->root.mnt = NULL;
+ return retval;
}
/**
@@ -1515,7 +1534,8 @@ int may_open(struct path *path, int acc_mode, int flag)
return error;
error = ima_path_check(path,
- acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC));
+ acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC),
+ IMA_COUNT_UPDATE);
if (error)
return error;
/*
@@ -1674,9 +1694,14 @@ struct file *do_filp_open(int dfd, const char *pathname,
/*
* Create - we need to know the parent.
*/
- error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd);
+ error = path_init(dfd, pathname, LOOKUP_PARENT, &nd);
if (error)
return ERR_PTR(error);
+ error = path_walk(pathname, &nd);
+ if (error)
+ return ERR_PTR(error);
+ if (unlikely(!audit_dummy_context()))
+ audit_inode(pathname, nd.path.dentry);
/*
* We have the parent and last component. First of all, check
@@ -1804,6 +1829,8 @@ exit:
if (!IS_ERR(nd.intent.open.file))
release_open_intent(&nd);
exit_parent:
+ if (nd.root.mnt)
+ path_put(&nd.root);
path_put(&nd.path);
return ERR_PTR(error);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.