Merge tag 'v6.5/vfs.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fix from Christian Brauner:
 "A fix for the backing file work from this cycle.

  When init_file() failed it would call file_free_rcu() on the file
  allocated by the caller of init_file(). It naively assumed that the
  correct cleanup operation would be called depending on whether it is a
  regular file or a backing file. However, that presupposes that the
  FMODE_BACKING flag would already be set which it won't be as that is
  done in the caller of init_file().

  Fix that bug by moving the cleanup of the allocated file into the
  caller where it belongs in the first place. There's no good reason for
  init_file() to consume resources it didn't allocate. This is a
  mainline only fix and was reported by syzbot. The fix was validated by
  syzbot against the provided reproducer"

* tag 'v6.5/vfs.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: move cleanup from init_file() into its callers

1 files changed, 10 insertions, 4 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index e06c68e2d7574a..fc7d677ff5ad58 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -160,7 +160,7 @@ static int init_file(struct file *f, int flags, const struct cred *cred)
 	f->f_cred = get_cred(cred);
 	error = security_file_alloc(f);
 	if (unlikely(error)) {
-		file_free_rcu(&f->f_rcuhead);
+		put_cred(f->f_cred);
 		return error;
 	}
 
@@ -208,8 +208,10 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
 		return ERR_PTR(-ENOMEM);
 
 	error = init_file(f, flags, cred);
-	if (unlikely(error))
+	if (unlikely(error)) {
+		kmem_cache_free(filp_cachep, f);
 		return ERR_PTR(error);
+	}
 
 	percpu_counter_inc(&nr_files);
 
@@ -240,8 +242,10 @@ struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred)
 		return ERR_PTR(-ENOMEM);
 
 	error = init_file(f, flags, cred);
-	if (unlikely(error))
+	if (unlikely(error)) {
+		kmem_cache_free(filp_cachep, f);
 		return ERR_PTR(error);
+	}
 
 	f->f_mode |= FMODE_NOACCOUNT;
 
@@ -265,8 +269,10 @@ struct file *alloc_empty_backing_file(int flags, const struct cred *cred)
 		return ERR_PTR(-ENOMEM);
 
 	error = init_file(&ff->file, flags, cred);
-	if (unlikely(error))
+	if (unlikely(error)) {
+		kfree(ff);
 		return ERR_PTR(error);
+	}
 
 	ff->file.f_mode |= FMODE_BACKING | FMODE_NOACCOUNT;
 	return &ff->file;