2023-09-05 20:09:16

by Konstantin Meskhidze

Subject: [PATCH] ubifs: fix possible dereference after free

'old_idx' could be dereferenced after free via 'rb_link_node' function
call.

Fixes: b5fda08ef213 ("ubifs: Fix memleak when insert_old_idx() failed")
Co-developed-by: Ivanov Mikhail <[email protected]>
Signed-off-by: Konstantin Meskhidze <[email protected]>
---
fs/ubifs/tnc.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index 6b7d95b65f4b..f4728e65d1bd 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -64,8 +64,9 @@ static void do_insert_old_idx(struct ubifs_info *c,
p = &(*p)->rb_right;
else {
ubifs_err(c, "old idx added twice!");
kfree(old_idx);
+ return;
}
}
rb_link_node(&old_idx->rb, parent, p);
rb_insert_color(&old_idx->rb, &c->old_idx);
--
2.34.1

2023-09-06 10:44:54

by Zhihao Cheng

Subject: Re: [PATCH] ubifs: fix possible dereference after free

?? 2023/9/5 18:12, Konstantin Meskhidze д??:
> 'old_idx' could be dereferenced after free via 'rb_link_node' function
> call.
>
> Fixes: b5fda08ef213 ("ubifs: Fix memleak when insert_old_idx() failed")
> Co-developed-by: Ivanov Mikhail <[email protected]>
> Signed-off-by: Konstantin Meskhidze <[email protected]>
> ---
> fs/ubifs/tnc.c | 1 +
> 1 file changed, 1 insertion(+)
>

Only for static alarms??although it couldn't happen in theory.

Reviewed-by: Zhihao Cheng <[email protected]>

> diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
> index 6b7d95b65f4b..f4728e65d1bd 100644
> --- a/fs/ubifs/tnc.c
> +++ b/fs/ubifs/tnc.c
> @@ -64,8 +64,9 @@ static void do_insert_old_idx(struct ubifs_info *c,
> p = &(*p)->rb_right;
> else {
> ubifs_err(c, "old idx added twice!");
> kfree(old_idx);
> + return;
> }
> }
> rb_link_node(&old_idx->rb, parent, p);
> rb_insert_color(&old_idx->rb, &c->old_idx);
>