2024-02-01 13:22:22

by Zhipeng Lu

Subject: [PATCH] [v2] hfs: fix a memleak in hfs_find_init

In every caller of hfs_find_init, `ptr` won't be freed when hfs_find_init
fails, but will be freed when somewhere after hfs_find_init fails.
This suggests that hfs_find_init should proberly free `ptr` in its own
error-handling to prevent `ptr` from leaking.

In particular, When the switch statment goes to default and return an error,
`ptr` should be freed.

Fixes: b3b2177a2d79 ("hfs: add lock nesting notation to hfs_find_init")
Signed-off-by: Zhipeng Lu <[email protected]>
---
Changelog:

v2: Improve commit message to be more clear.
---
fs/hfs/bfind.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/hfs/bfind.c b/fs/hfs/bfind.c
index ef9498a6e88a..7aa3b9aba4d1 100644
--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -36,6 +36,7 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX);
break;
default:
+ kfree(fd->search_key);
return -EINVAL;
}
return 0;
--
2.34.1

2024-02-02 13:18:21

by Viacheslav Dubeyko

Subject: Re: [PATCH] [v2] hfs: fix a memleak in hfs_find_init

> On 1 Feb 2024, at 16:00, Zhipeng Lu <[email protected]> wrote:
>
> In every caller of hfs_find_init, `ptr` won't be freed when hfs_find_init
> fails, but will be freed when somewhere after hfs_find_init fails.

Current statement sounds confusing for my taste. I don’t follow it.
What do you mean here?

> This suggests that hfs_find_init should proberly free `ptr` in its own
> error-handling to prevent `ptr` from leaking.

I assume you meant properly here?

>
> In particular, When the switch statment goes to default and return an error,
> `ptr` should be freed.

I assume you meant statement here?

Also, you mentioning `ptr` but we freed fd->search_key here. It sounds confusing too.

>
> Fixes: b3b2177a2d79 ("hfs: add lock nesting notation to hfs_find_init")
> Signed-off-by: Zhipeng Lu <[email protected]>
> ---
> Changelog:
>
> v2: Improve commit message to be more clear.

Currently, it sounds slightly more confusing. :)

Thanks,
Slava.

> ---
> fs/hfs/bfind.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/hfs/bfind.c b/fs/hfs/bfind.c
> index ef9498a6e88a..7aa3b9aba4d1 100644
> --- a/fs/hfs/bfind.c
> +++ b/fs/hfs/bfind.c
> @@ -36,6 +36,7 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
> mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX);
> break;
> default:
> + kfree(fd->search_key);
> return -EINVAL;
> }
> return 0;
> --
> 2.34.1
>