From: Christian Brauner <brauner@kernel.org>
To: Dongliang Mu <dzm91@hust.edu.cn>
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Arve Hjønnevåg" <arve@android.com>,
"Todd Kjos" <tkjos@android.com>,
"Martijn Coenen" <maco@android.com>,
"Joel Fernandes" <joel@joelfernandes.org>,
"Carlos Llamas" <cmllamas@google.com>,
"Suren Baghdasaryan" <surenb@google.com>,
"Kees Cook" <keescook@chromium.org>,
"Dongliang Mu" <mudongliangabcd@gmail.com>,
syzkaller <syzkaller@googlegroups.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drivers: binderfs: fix memory leak in binderfs_fill_super
Date: Fri, 12 Aug 2022 15:41:38 +0200 [thread overview]
Message-ID: <20220812134138.gpu7274yahlvr6hr@wittgenstein> (raw)
In-Reply-To: <20220812132124.2053673-1-dzm91@hust.edu.cn>
On Fri, Aug 12, 2022 at 09:21:24PM +0800, Dongliang Mu wrote:
> From: Dongliang Mu <mudongliangabcd@gmail.com>
>
> In binderfs_fill_super, if s_root is not successfully initialized by
> d_make_root, the previous allocated s_sb_info will not be freed since
> generic_shutdown_super first checks if sb->s_root and then does
> put_super operation. The put_super operation calls binderfs_put_super
> to deallocate s_sb_info and put ipc_ns. This will lead to memory leak
> in binderfs_fill_super.
>
> Fix this by invoking binderfs_put_super at error sites before s_root
> is successfully initialized.
>
> Fixes: 095cf502b31e ("binderfs: port to new mount api")
> Reported-by: syzkaller <syzkaller@googlegroups.com>
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
Seems right but where's the full syzbot link to the issue?
Also, wouldn't (untested) sm like the below be better?:
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index 588d753a7a19..4582b043d21e 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -692,6 +692,15 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
sb->s_magic = BINDERFS_SUPER_MAGIC;
sb->s_op = &binderfs_super_ops;
sb->s_time_gran = 1;
+ sb->s_fs_info = NULL;
+
+ inode = new_inode(sb);
+ if (!inode)
+ return -ENOMEM;
+
+ sb->s_root = d_make_root(inode);
+ if (!sb->s_root)
+ return -ENOMEM;
sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL);
if (!sb->s_fs_info)
@@ -709,10 +718,6 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
info->mount_opts.max = ctx->max;
info->mount_opts.stats_mode = ctx->stats_mode;
- inode = new_inode(sb);
- if (!inode)
- return -ENOMEM;
-
inode->i_ino = FIRST_INODE;
inode->i_fop = &simple_dir_operations;
inode->i_mode = S_IFDIR | 0755;
@@ -720,10 +725,6 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
inode->i_op = &binderfs_dir_inode_operations;
set_nlink(inode, 2);
- sb->s_root = d_make_root(inode);
- if (!sb->s_root)
- return -ENOMEM;
-
ret = binderfs_binder_ctl_create(sb);
if (ret)
return ret;
> drivers/android/binderfs.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
> index 588d753a7a19..20f5bc77495f 100644
> --- a/drivers/android/binderfs.c
> +++ b/drivers/android/binderfs.c
> @@ -710,8 +710,10 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
> info->mount_opts.stats_mode = ctx->stats_mode;
>
> inode = new_inode(sb);
> - if (!inode)
> + if (!inode) {
> + binderfs_put_super(sb);
> return -ENOMEM;
> + }
>
> inode->i_ino = FIRST_INODE;
> inode->i_fop = &simple_dir_operations;
> @@ -721,8 +723,10 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
> set_nlink(inode, 2);
>
> sb->s_root = d_make_root(inode);
> - if (!sb->s_root)
> + if (!sb->s_root) {
> + binderfs_put_super(sb);
> return -ENOMEM;
> + }
>
> ret = binderfs_binder_ctl_create(sb);
> if (ret)
> --
> 2.25.1
>
next prev parent reply other threads:[~2022-08-12 13:41 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-12 13:21 [PATCH] drivers: binderfs: fix memory leak in binderfs_fill_super Dongliang Mu
2022-08-12 13:41 ` Christian Brauner [this message]
2022-08-12 13:48 ` Dongliang Mu
2022-08-12 14:18 ` Christian Brauner
2022-08-15 0:59 ` Dongliang Mu
2022-08-12 13:41 ` Greg Kroah-Hartman
2022-08-12 13:56 ` Dongliang Mu
2022-08-12 14:02 ` Dongliang Mu
2022-08-12 14:09 ` Greg Kroah-Hartman
2022-08-12 14:24 ` Christian Brauner
2022-08-12 14:32 ` Greg Kroah-Hartman
2022-08-15 1:46 ` Al Viro
2022-08-15 1:48 ` Al Viro
2022-08-15 8:47 ` Christian Brauner
2022-08-17 11:43 ` Greg Kroah-Hartman
2022-08-17 13:03 ` [PATCH] binderfs: rework superblock destruction Christian Brauner
2022-08-17 13:59 ` Al Viro
2022-08-17 14:01 ` Christian Brauner
2022-08-17 14:19 ` Al Viro
2022-08-17 14:32 ` Al Viro
2022-08-17 15:05 ` Christian Brauner
2022-08-17 14:51 ` Christian Brauner
2022-08-17 15:21 ` Al Viro
2022-08-17 15:24 ` Christian Brauner
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