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-rw-r--r--fs/namei.c374
1 files changed, 187 insertions, 187 deletions
diff --git a/fs/namei.c b/fs/namei.c
index c75ea03ca147..186bd2464fd5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/namei.c
*
@@ -38,6 +39,7 @@
#include <linux/bitops.h>
#include <linux/init_task.h>
#include <linux/uaccess.h>
+#include <linux/build_bug.h>
#include "internal.h"
#include "mount.h"
@@ -129,6 +131,7 @@ getname_flags(const char __user *filename, int flags, int *empty)
struct filename *result;
char *kname;
int len;
+ BUILD_BUG_ON(offsetof(struct filename, iname) % sizeof(long) != 0);
result = audit_reusename(filename);
if (result)
@@ -221,9 +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);
@@ -390,50 +394,6 @@ static inline int do_inode_permission(struct inode *inode, int mask)
}
/**
- * __inode_permission - Check for access rights to a given inode
- * @inode: Inode to check permission on
- * @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
- *
- * Check for read/write/execute permissions on an inode.
- *
- * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
- *
- * This does not check for a read-only file system. You probably want
- * inode_permission().
- */
-int __inode_permission(struct inode *inode, int mask)
-{
- int retval;
-
- if (unlikely(mask & MAY_WRITE)) {
- /*
- * Nobody gets write access to an immutable file.
- */
- if (IS_IMMUTABLE(inode))
- return -EPERM;
-
- /*
- * Updating mtime will likely cause i_uid and i_gid to be
- * written back improperly if their true value is unknown
- * to the vfs.
- */
- if (HAS_UNMAPPED_ID(inode))
- return -EACCES;
- }
-
- retval = do_inode_permission(inode, mask);
- if (retval)
- return retval;
-
- retval = devcgroup_inode_permission(inode, mask);
- if (retval)
- return retval;
-
- return security_inode_permission(inode, mask);
-}
-EXPORT_SYMBOL(__inode_permission);
-
-/**
* sb_permission - Check superblock-level permissions
* @sb: Superblock of inode to check permission on
* @inode: Inode to check permission on
@@ -471,7 +431,32 @@ int inode_permission(struct inode *inode, int mask)
retval = sb_permission(inode->i_sb, inode, mask);
if (retval)
return retval;
- return __inode_permission(inode, mask);
+
+ if (unlikely(mask & MAY_WRITE)) {
+ /*
+ * Nobody gets write access to an immutable file.
+ */
+ if (IS_IMMUTABLE(inode))
+ return -EPERM;
+
+ /*
+ * Updating mtime will likely cause i_uid and i_gid to be
+ * written back improperly if their true value is unknown
+ * to the vfs.
+ */
+ if (HAS_UNMAPPED_ID(inode))
+ return -EACCES;
+ }
+
+ retval = do_inode_permission(inode, mask);
+ if (retval)
+ return retval;
+
+ retval = devcgroup_inode_permission(inode, mask);
+ if (retval)
+ return retval;
+
+ return security_inode_permission(inode, mask);
}
EXPORT_SYMBOL(inode_permission);
@@ -577,9 +562,10 @@ static int __nd_alloc_stack(struct nameidata *nd)
static bool path_connected(const struct path *path)
{
struct vfsmount *mnt = path->mnt;
+ struct super_block *sb = mnt->mnt_sb;
- /* Only bind mounts can have disconnected paths */
- if (mnt->mnt_root == mnt->mnt_sb->s_root)
+ /* Bind mounts and multi-root filesystems can have disconnected paths */
+ if (!(sb->s_iflags & SB_I_MULTIROOT) && (mnt->mnt_root == sb->s_root))
return true;
return is_subdir(path->dentry, mnt->mnt_root);
@@ -944,7 +930,8 @@ static inline int may_follow_link(struct nameidata *nd)
if (nd->flags & LOOKUP_RCU)
return -ECHILD;
- audit_log_link_denied("follow_link", &nd->stack[0].link);
+ audit_inode(nd->name, nd->stack[0].link.dentry, 0);
+ audit_log_link_denied("follow_link");
return -EACCES;
}
@@ -1010,7 +997,7 @@ static int may_linkat(struct path *link)
if (safe_hardlink_source(inode) || inode_owner_or_capable(inode))
return 0;
- audit_log_link_denied("linkat", link);
+ audit_log_link_denied("linkat");
return -EPERM;
}
@@ -1128,21 +1115,9 @@ static int follow_automount(struct path *path, struct nameidata *nd,
* of the daemon to instantiate them before they can be used.
*/
if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
- LOOKUP_OPEN | LOOKUP_CREATE |
- LOOKUP_AUTOMOUNT))) {
- /* Positive dentry that isn't meant to trigger an
- * automount, EISDIR will allow it to be used,
- * otherwise there's no mount here "now" so return
- * ENOENT.
- */
- if (path->dentry->d_inode)
- return -EISDIR;
- else
- return -ENOENT;
- }
-
- if (path->dentry->d_sb->s_user_ns != &init_user_ns)
- return -EACCES;
+ LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
+ path->dentry->d_inode)
+ return -EISDIR;
nd->total_link_count++;
if (nd->total_link_count >= 40)
@@ -1209,7 +1184,7 @@ static int follow_managed(struct path *path, struct nameidata *nd)
/* Given that we're not holding a lock here, we retain the value in a
* local variable for each dentry as we look at it so that we don't see
* the components of that value change under us */
- while (managed = ACCESS_ONCE(path->dentry->d_flags),
+ while (managed = READ_ONCE(path->dentry->d_flags),
managed &= DCACHE_MANAGED_DENTRY,
unlikely(managed != 0)) {
/* Allow the filesystem to manage the transit without i_mutex
@@ -1394,7 +1369,7 @@ int follow_down(struct path *path)
unsigned managed;
int ret;
- while (managed = ACCESS_ONCE(path->dentry->d_flags),
+ while (managed = READ_ONCE(path->dentry->d_flags),
unlikely(managed & DCACHE_MANAGED_DENTRY)) {
/* Allow the filesystem to manage the transit without i_mutex
* being held.
@@ -1503,43 +1478,36 @@ static struct dentry *lookup_dcache(const struct qstr *name,
}
/*
- * Call i_op->lookup on the dentry. The dentry must be negative and
- * unhashed.
- *
- * dir->d_inode->i_mutex must be held
+ * 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.
*/
-static struct dentry *lookup_real(struct inode *dir, struct dentry *dentry,
- unsigned int flags)
-{
- struct dentry *old;
-
- /* Don't create child dentry for a dead directory. */
- if (unlikely(IS_DEADDIR(dir))) {
- dput(dentry);
- return ERR_PTR(-ENOENT);
- }
-
- old = dir->i_op->lookup(dir, dentry, flags);
- if (unlikely(old)) {
- dput(dentry);
- dentry = old;
- }
- return dentry;
-}
-
static struct dentry *__lookup_hash(const struct qstr *name,
struct dentry *base, unsigned int flags)
{
struct dentry *dentry = lookup_dcache(name, base, flags);
+ struct dentry *old;
+ struct inode *dir = base->d_inode;
if (dentry)
return dentry;
+ /* Don't create child dentry for a dead directory. */
+ if (unlikely(IS_DEADDIR(dir)))
+ return ERR_PTR(-ENOENT);
+
dentry = d_alloc(base, name);
if (unlikely(!dentry))
return ERR_PTR(-ENOMEM);
- return lookup_real(base->d_inode, dentry, flags);
+ old = dir->i_op->lookup(dir, dentry, flags);
+ if (unlikely(old)) {
+ dput(dentry);
+ dentry = old;
+ }
+ return dentry;
}
static int lookup_fast(struct nameidata *nd,
@@ -1630,22 +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);
@@ -1667,11 +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) {
@@ -2454,56 +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);
@@ -2523,37 +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);
@@ -2906,6 +2863,27 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
}
EXPORT_SYMBOL(vfs_create);
+int vfs_mkobj(struct dentry *dentry, umode_t mode,
+ int (*f)(struct dentry *, umode_t, void *),
+ void *arg)
+{
+ struct inode *dir = dentry->d_parent->d_inode;
+ int error = may_create(dir, dentry);
+ if (error)
+ return error;
+
+ mode &= S_IALLUGO;
+ mode |= S_IFREG;
+ error = security_inode_create(dir, dentry, mode);
+ if (error)
+ return error;
+ error = f(dentry, mode, arg);
+ if (!error)
+ fsnotify_create(dir, dentry);
+ return error;
+}
+EXPORT_SYMBOL(vfs_mkobj);
+
bool may_open_dev(const struct path *path)
{
return !(path->mnt->mnt_flags & MNT_NODEV) &&
@@ -3389,9 +3367,7 @@ finish_open_created:
goto out;
*opened |= FILE_OPENED;
opened:
- error = open_check_o_direct(file);
- if (!error)
- error = ima_file_check(file, op->acc_mode, *opened);
+ error = ima_file_check(file, op->acc_mode, *opened);
if (!error && will_truncate)
error = handle_truncate(file);
out:
@@ -3458,7 +3434,7 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags,
goto out;
child = vfs_tmpfile(path.dentry, op->mode, op->open_flag);
error = PTR_ERR(child);
- if (unlikely(IS_ERR(child)))
+ if (IS_ERR(child))
goto out2;
dput(path.dentry);
path.dentry = child;
@@ -3471,9 +3447,6 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags,
error = finish_open(file, child, NULL, opened);
if (error)
goto out2;
- error = open_check_o_direct(file);
- if (error)
- fput(file);
out2:
mnt_drop_write(path.mnt);
out:
@@ -3737,8 +3710,8 @@ static int may_mknod(umode_t mode)
}
}
-SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
- unsigned, dev)
+long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+ unsigned int dev)
{
struct dentry *dentry;
struct path path;
@@ -3781,9 +3754,15 @@ out:
return error;
}
+SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
+ unsigned int, dev)
+{
+ return do_mknodat(dfd, filename, mode, dev);
+}
+
SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev)
{
- return sys_mknodat(AT_FDCWD, filename, mode, dev);
+ return do_mknodat(AT_FDCWD, filename, mode, dev);
}
int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
@@ -3812,7 +3791,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
}
EXPORT_SYMBOL(vfs_mkdir);
-SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
+long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
{
struct dentry *dentry;
struct path path;
@@ -3837,9 +3816,14 @@ retry:
return error;
}
+SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
+{
+ return do_mkdirat(dfd, pathname, mode);
+}
+
SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
{
- return sys_mkdirat(AT_FDCWD, pathname, mode);
+ return do_mkdirat(AT_FDCWD, pathname, mode);
}
int vfs_rmdir(struct inode *dir, struct dentry *dentry)
@@ -3881,7 +3865,7 @@ out:
}
EXPORT_SYMBOL(vfs_rmdir);
-static long do_rmdir(int dfd, const char __user *pathname)
+long do_rmdir(int dfd, const char __user *pathname)
{
int error = 0;
struct filename *name;
@@ -4009,10 +3993,9 @@ EXPORT_SYMBOL(vfs_unlink);
* writeout happening, and we don't want to prevent access to the directory
* while waiting on the I/O.
*/
-static long do_unlinkat(int dfd, const char __user *pathname)
+long do_unlinkat(int dfd, struct filename *name)
{
int error;
- struct filename *name;
struct dentry *dentry;
struct path path;
struct qstr last;
@@ -4021,8 +4004,7 @@ static long do_unlinkat(int dfd, const char __user *pathname)
struct inode *delegated_inode = NULL;
unsigned int lookup_flags = 0;
retry:
- name = filename_parentat(dfd, getname(pathname), lookup_flags,
- &path, &last, &type);
+ name = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
if (IS_ERR(name))
return PTR_ERR(name);
@@ -4064,12 +4046,12 @@ exit2:
mnt_drop_write(path.mnt);
exit1:
path_put(&path);
- putname(name);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
inode = NULL;
goto retry;
}
+ putname(name);
return error;
slashes:
@@ -4090,12 +4072,12 @@ SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)
if (flag & AT_REMOVEDIR)
return do_rmdir(dfd, pathname);
- return do_unlinkat(dfd, pathname);
+ return do_unlinkat(dfd, getname(pathname));
}
SYSCALL_DEFINE1(unlink, const char __user *, pathname)
{
- return do_unlinkat(AT_FDCWD, pathname);
+ return do_unlinkat(AT_FDCWD, getname(pathname));
}
int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
@@ -4119,8 +4101,8 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
}
EXPORT_SYMBOL(vfs_symlink);
-SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
- int, newdfd, const char __user *, newname)
+long do_symlinkat(const char __user *oldname, int newdfd,
+ const char __user *newname)
{
int error;
struct filename *from;
@@ -4150,9 +4132,15 @@ out_putname:
return error;
}
+SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
+ int, newdfd, const char __user *, newname)
+{
+ return do_symlinkat(oldname, newdfd, newname);
+}
+
SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname)
{
- return sys_symlinkat(oldname, AT_FDCWD, newname);
+ return do_symlinkat(oldname, AT_FDCWD, newname);
}
/**
@@ -4244,8 +4232,8 @@ EXPORT_SYMBOL(vfs_link);
* with linux 2.0, and to avoid hard-linking to directories
* and other special files. --ADM
*/
-SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
- int, newdfd, const char __user *, newname, int, flags)
+int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+ const char __user *newname, int flags)
{
struct dentry *new_dentry;
struct path old_path, new_path;
@@ -4309,9 +4297,15 @@ out:
return error;
}
+SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
+ int, newdfd, const char __user *, newname, int, flags)
+{
+ return do_linkat(olddfd, oldname, newdfd, newname, flags);
+}
+
SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname)
{
- return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+ return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
}
/**
@@ -4489,8 +4483,8 @@ out:
}
EXPORT_SYMBOL(vfs_rename);
-SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
- int, newdfd, const char __user *, newname, unsigned int, flags)
+static int do_renameat2(int olddfd, const char __user *oldname, int newdfd,
+ const char __user *newname, unsigned int flags)
{
struct dentry *old_dentry, *new_dentry;
struct dentry *trap;
@@ -4632,15 +4626,21 @@ exit:
return error;
}
+SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
+ int, newdfd, const char __user *, newname, unsigned int, flags)
+{
+ return do_renameat2(olddfd, oldname, newdfd, newname, flags);
+}
+
SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname)
{
- return sys_renameat2(olddfd, oldname, newdfd, newname, 0);
+ return do_renameat2(olddfd, oldname, newdfd, newname, 0);
}
SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
{
- return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+ return do_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
}
int vfs_whiteout(struct inode *dir, struct dentry *dentry)