2018-10-06 09:07:49

by Hou Tao

Subject: [PATCH] jffs2: free jffs2_sb_info through jffs2_kill_sb()

When an invalid mount option is passed to jffs2, jffs2_parse_options()
will fail and jffs2_sb_info will be freed, but then jffs2_sb_info will
be used (use-after-free) and freeed (double-free) in jffs2_kill_sb().

Fix it by removing the buggy invocation of kfree() when getting invalid
mount options.

Cc: [email protected]
Signed-off-by: Hou Tao <[email protected]>
---
fs/jffs2/super.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index 87bdf0f4cba1..902a7dd10e5c 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -285,10 +285,8 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
sb->s_fs_info = c;

ret = jffs2_parse_options(c, data);
- if (ret) {
- kfree(c);
+ if (ret)
return -EINVAL;
- }

/* Initialize JFFS2 superblock locks, the further initialization will
* be done later */
--
2.16.2.dirty

2018-10-16 05:53:47

by Hou Tao

Subject: Re: [PATCH] jffs2: free jffs2_sb_info through jffs2_kill_sb()

ping ?

On 2018/10/6 17:09, Hou Tao wrote:
> When an invalid mount option is passed to jffs2, jffs2_parse_options()
> will fail and jffs2_sb_info will be freed, but then jffs2_sb_info will
> be used (use-after-free) and freeed (double-free) in jffs2_kill_sb().
>
> Fix it by removing the buggy invocation of kfree() when getting invalid
> mount options.
>
> Cc: [email protected]
> Signed-off-by: Hou Tao <[email protected]>
> ---
> fs/jffs2/super.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
> index 87bdf0f4cba1..902a7dd10e5c 100644
> --- a/fs/jffs2/super.c
> +++ b/fs/jffs2/super.c
> @@ -285,10 +285,8 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
> sb->s_fs_info = c;
>
> ret = jffs2_parse_options(c, data);
> - if (ret) {
> - kfree(c);
> + if (ret)
> return -EINVAL;
> - }
>
> /* Initialize JFFS2 superblock locks, the further initialization will
> * be done later */
>

2018-10-16 06:42:23

by Richard Weinberger

Subject: Re: [PATCH] jffs2: free jffs2_sb_info through jffs2_kill_sb()

On Tue, Oct 16, 2018 at 7:53 AM Hou Tao <[email protected]> wrote:
>
> ping ?
>
> On 2018/10/6 17:09, Hou Tao wrote:
> > When an invalid mount option is passed to jffs2, jffs2_parse_options()
> > will fail and jffs2_sb_info will be freed, but then jffs2_sb_info will
> > be used (use-after-free) and freeed (double-free) in jffs2_kill_sb().
> >
> > Fix it by removing the buggy invocation of kfree() when getting invalid
> > mount options.
> >
> > Cc: [email protected]
> > Signed-off-by: Hou Tao <[email protected]>
> > ---
> > fs/jffs2/super.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
> > index 87bdf0f4cba1..902a7dd10e5c 100644
> > --- a/fs/jffs2/super.c
> > +++ b/fs/jffs2/super.c
> > @@ -285,10 +285,8 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
> > sb->s_fs_info = c;
> >
> > ret = jffs2_parse_options(c, data);
> > - if (ret) {
> > - kfree(c);
> > + if (ret)
> > return -EINVAL;
> > - }

Reviewed-by: Richard Weinberger <[email protected]>

We can carry this via the MTD tree.

--
Thanks,
//richard

2018-10-16 10:28:08

by Hou Tao

Subject: Re: [PATCH] jffs2: free jffs2_sb_info through jffs2_kill_sb()

On 2018/10/16 14:41, Richard Weinberger wrote:
> On Tue, Oct 16, 2018 at 7:53 AM Hou Tao <[email protected]> wrote:
>>
>> ping ?
>>
>> On 2018/10/6 17:09, Hou Tao wrote:
>>> When an invalid mount option is passed to jffs2, jffs2_parse_options()
>>> will fail and jffs2_sb_info will be freed, but then jffs2_sb_info will
>>> be used (use-after-free) and freeed (double-free) in jffs2_kill_sb().
>>>
>>> Fix it by removing the buggy invocation of kfree() when getting invalid
>>> mount options.
>>>
>>> Cc: [email protected]
>>> Signed-off-by: Hou Tao <[email protected]>
>>> ---
>>> fs/jffs2/super.c | 4 +---
>>> 1 file changed, 1 insertion(+), 3 deletions(-)
>>>
>>> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
>>> index 87bdf0f4cba1..902a7dd10e5c 100644
>>> --- a/fs/jffs2/super.c
>>> +++ b/fs/jffs2/super.c
>>> @@ -285,10 +285,8 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
>>> sb->s_fs_info = c;
>>>
>>> ret = jffs2_parse_options(c, data);
>>> - if (ret) {
>>> - kfree(c);
>>> + if (ret)
>>> return -EINVAL;
>>> - }
>
> Reviewed-by: Richard Weinberger <[email protected]>
>
> We can carry this via the MTD tree.
Thanks for that.

Regards,
Tao

2018-10-16 11:50:24

by Boris Brezillon

Subject: Re: [PATCH] jffs2: free jffs2_sb_info through jffs2_kill_sb()

On Tue, 16 Oct 2018 18:26:34 +0800
Hou Tao <[email protected]> wrote:

> On 2018/10/16 14:41, Richard Weinberger wrote:
> > On Tue, Oct 16, 2018 at 7:53 AM Hou Tao <[email protected]> wrote:
> >>
> >> ping ?
> >>
> >> On 2018/10/6 17:09, Hou Tao wrote:
> >>> When an invalid mount option is passed to jffs2, jffs2_parse_options()
> >>> will fail and jffs2_sb_info will be freed, but then jffs2_sb_info will
> >>> be used (use-after-free) and freeed (double-free) in jffs2_kill_sb().
> >>>
> >>> Fix it by removing the buggy invocation of kfree() when getting invalid
> >>> mount options.
> >>>
> >>> Cc: [email protected]
> >>> Signed-off-by: Hou Tao <[email protected]>
> >>> ---
> >>> fs/jffs2/super.c | 4 +---
> >>> 1 file changed, 1 insertion(+), 3 deletions(-)
> >>>
> >>> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
> >>> index 87bdf0f4cba1..902a7dd10e5c 100644
> >>> --- a/fs/jffs2/super.c
> >>> +++ b/fs/jffs2/super.c
> >>> @@ -285,10 +285,8 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
> >>> sb->s_fs_info = c;
> >>>
> >>> ret = jffs2_parse_options(c, data);
> >>> - if (ret) {
> >>> - kfree(c);
> >>> + if (ret)
> >>> return -EINVAL;
> >>> - }
> >
> > Reviewed-by: Richard Weinberger <[email protected]>
> >
> > We can carry this via the MTD tree.
> Thanks for that.

Applied after adding

Fixes: 92abc475d8de ("jffs2: implement mount option parsing and compression overriding")

>
> Regards,
> Tao
>
>
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