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Merge branch 'misc.namei' of git://git.kernel.org/pub/scm/linux/kerne…
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…l/git/viro/vfs

Pull namei updates from Al Viro:
 "Clearing fallout from mkdirat in io_uring series. The fix in the
  kern_path_locked() patch plus associated cleanups"

* 'misc.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  putname(): IS_ERR_OR_NULL() is wrong here
  namei: Standardize callers of filename_create()
  namei: Standardize callers of filename_lookup()
  rename __filename_parentat() to filename_parentat()
  namei: Fix use after free in kern_path_locked
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@torvalds
torvalds committed Sep 12, 2021
2 parents 8d4a0b5 + ea47ab1 commit fdfc346
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Showing 2 changed files with 58 additions and 59 deletions.
1 change: 0 additions & 1 deletion fs/fs_parser.c
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Original file line number Diff line number Diff line change
Expand Up @@ -165,7 +165,6 @@ int fs_lookup_param(struct fs_context *fc,
return invalf(fc, "%s: not usable as path", param->key);
}

f->refcnt++; /* filename_lookup() drops our ref. */
ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
if (ret < 0) {
errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);
Expand Down
116 changes: 58 additions & 58 deletions fs/namei.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -255,7 +255,7 @@ getname_kernel(const char * filename)

void putname(struct filename *name)
{
if (IS_ERR_OR_NULL(name))
if (IS_ERR(name))
return;

BUG_ON(name->refcnt <= 0);
Expand Down Expand Up @@ -2467,7 +2467,7 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path
return err;
}

static int __filename_lookup(int dfd, struct filename *name, unsigned flags,
int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root)
{
int retval;
Expand All @@ -2488,15 +2488,6 @@ static int __filename_lookup(int dfd, struct filename *name, unsigned flags,
return retval;
}

int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root)
{
int retval = __filename_lookup(dfd, name, flags, path, root);

putname(name);
return retval;
}

/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
static int path_parentat(struct nameidata *nd, unsigned flags,
struct path *parent)
Expand All @@ -2514,9 +2505,10 @@ static int path_parentat(struct nameidata *nd, unsigned flags,
return err;
}

static int __filename_parentat(int dfd, struct filename *name,
unsigned int flags, struct path *parent,
struct qstr *last, int *type)
/* Note: this does not consume "name" */
static int filename_parentat(int dfd, struct filename *name,
unsigned int flags, struct path *parent,
struct qstr *last, int *type)
{
int retval;
struct nameidata nd;
Expand All @@ -2538,25 +2530,14 @@ static int __filename_parentat(int dfd, struct filename *name,
return retval;
}

static int filename_parentat(int dfd, struct filename *name,
unsigned int flags, struct path *parent,
struct qstr *last, int *type)
{
int retval = __filename_parentat(dfd, name, flags, parent, last, type);

putname(name);
return retval;
}

/* does lookup, returns the object with parent locked */
struct dentry *kern_path_locked(const char *name, struct path *path)
static struct dentry *__kern_path_locked(struct filename *name, struct path *path)
{
struct dentry *d;
struct qstr last;
int type, error;

error = filename_parentat(AT_FDCWD, getname_kernel(name), 0, path,
&last, &type);
error = filename_parentat(AT_FDCWD, name, 0, path, &last, &type);
if (error)
return ERR_PTR(error);
if (unlikely(type != LAST_NORM)) {
Expand All @@ -2572,10 +2553,23 @@ struct dentry *kern_path_locked(const char *name, struct path *path)
return d;
}

struct dentry *kern_path_locked(const char *name, struct path *path)
{
struct filename *filename = getname_kernel(name);
struct dentry *res = __kern_path_locked(filename, path);

putname(filename);
return res;
}

int kern_path(const char *name, unsigned int flags, struct path *path)
{
return filename_lookup(AT_FDCWD, getname_kernel(name),
flags, path, NULL);
struct filename *filename = getname_kernel(name);
int ret = filename_lookup(AT_FDCWD, filename, flags, path, NULL);

putname(filename);
return ret;

}
EXPORT_SYMBOL(kern_path);

Expand All @@ -2591,10 +2585,15 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
const char *name, unsigned int flags,
struct path *path)
{
struct filename *filename;
struct path root = {.mnt = mnt, .dentry = dentry};
int ret;

filename = getname_kernel(name);
/* the first argument of filename_lookup() is ignored with root */
return filename_lookup(AT_FDCWD, getname_kernel(name),
flags , path, &root);
ret = filename_lookup(AT_FDCWD, filename, flags, path, &root);
putname(filename);
return ret;
}
EXPORT_SYMBOL(vfs_path_lookup);

Expand Down Expand Up @@ -2798,8 +2797,11 @@ int path_pts(struct path *path)
int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
struct path *path, int *empty)
{
return filename_lookup(dfd, getname_flags(name, flags, empty),
flags, path, NULL);
struct filename *filename = getname_flags(name, flags, empty);
int ret = filename_lookup(dfd, filename, flags, path, NULL);

putname(filename);
return ret;
}
EXPORT_SYMBOL(user_path_at_empty);

Expand Down Expand Up @@ -3618,8 +3620,8 @@ struct file *do_file_open_root(const struct path *root,
return file;
}

static struct dentry *__filename_create(int dfd, struct filename *name,
struct path *path, unsigned int lookup_flags)
static struct dentry *filename_create(int dfd, struct filename *name,
struct path *path, unsigned int lookup_flags)
{
struct dentry *dentry = ERR_PTR(-EEXIST);
struct qstr last;
Expand All @@ -3634,7 +3636,7 @@ static struct dentry *__filename_create(int dfd, struct filename *name,
*/
lookup_flags &= LOOKUP_REVAL;

error = __filename_parentat(dfd, name, lookup_flags, path, &last, &type);
error = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
if (error)
return ERR_PTR(error);

Expand Down Expand Up @@ -3687,21 +3689,15 @@ static struct dentry *__filename_create(int dfd, struct filename *name,
return dentry;
}

static inline struct dentry *filename_create(int dfd, struct filename *name,
struct dentry *kern_path_create(int dfd, const char *pathname,
struct path *path, unsigned int lookup_flags)
{
struct dentry *res = __filename_create(dfd, name, path, lookup_flags);
struct filename *filename = getname_kernel(pathname);
struct dentry *res = filename_create(dfd, filename, path, lookup_flags);

putname(name);
putname(filename);
return res;
}

struct dentry *kern_path_create(int dfd, const char *pathname,
struct path *path, unsigned int lookup_flags)
{
return filename_create(dfd, getname_kernel(pathname),
path, lookup_flags);
}
EXPORT_SYMBOL(kern_path_create);

void done_path_create(struct path *path, struct dentry *dentry)
Expand All @@ -3716,7 +3712,11 @@ EXPORT_SYMBOL(done_path_create);
inline struct dentry *user_path_create(int dfd, const char __user *pathname,
struct path *path, unsigned int lookup_flags)
{
return filename_create(dfd, getname(pathname), path, lookup_flags);
struct filename *filename = getname(pathname);
struct dentry *res = filename_create(dfd, filename, path, lookup_flags);

putname(filename);
return res;
}
EXPORT_SYMBOL(user_path_create);

Expand Down Expand Up @@ -3797,7 +3797,7 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode,
if (error)
goto out1;
retry:
dentry = __filename_create(dfd, name, &path, lookup_flags);
dentry = filename_create(dfd, name, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out1;
Expand Down Expand Up @@ -3897,7 +3897,7 @@ int do_mkdirat(int dfd, struct filename *name, umode_t mode)
unsigned int lookup_flags = LOOKUP_DIRECTORY;

retry:
dentry = __filename_create(dfd, name, &path, lookup_flags);
dentry = filename_create(dfd, name, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_putname;
Expand Down Expand Up @@ -3996,7 +3996,7 @@ int do_rmdir(int dfd, struct filename *name)
int type;
unsigned int lookup_flags = 0;
retry:
error = __filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
error = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
if (error)
goto exit1;

Expand Down Expand Up @@ -4137,7 +4137,7 @@ int do_unlinkat(int dfd, struct filename *name)
struct inode *delegated_inode = NULL;
unsigned int lookup_flags = 0;
retry:
error = __filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
error = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
if (error)
goto exit1;

Expand Down Expand Up @@ -4266,7 +4266,7 @@ int do_symlinkat(struct filename *from, int newdfd, struct filename *to)
goto out_putnames;
}
retry:
dentry = __filename_create(newdfd, to, &path, lookup_flags);
dentry = filename_create(newdfd, to, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_putnames;
Expand Down Expand Up @@ -4426,11 +4426,11 @@ int do_linkat(int olddfd, struct filename *old, int newdfd,
if (flags & AT_SYMLINK_FOLLOW)
how |= LOOKUP_FOLLOW;
retry:
error = __filename_lookup(olddfd, old, how, &old_path, NULL);
error = filename_lookup(olddfd, old, how, &old_path, NULL);
if (error)
goto out_putnames;

new_dentry = __filename_create(newdfd, new, &new_path,
new_dentry = filename_create(newdfd, new, &new_path,
(how & LOOKUP_REVAL));
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
Expand Down Expand Up @@ -4689,13 +4689,13 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd,
target_flags = 0;

retry:
error = __filename_parentat(olddfd, from, lookup_flags, &old_path,
&old_last, &old_type);
error = filename_parentat(olddfd, from, lookup_flags, &old_path,
&old_last, &old_type);
if (error)
goto put_names;

error = __filename_parentat(newdfd, to, lookup_flags, &new_path, &new_last,
&new_type);
error = filename_parentat(newdfd, to, lookup_flags, &new_path, &new_last,
&new_type);
if (error)
goto exit1;

Expand Down

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