2018-11-15 07:53:49

by Jaegeuk Kim

Subject: [PATCH] f2fs: check memory boundary by insane namelen

If namelen is corrupted to have very long value, fill_dentries can copy
wrong memory area.

Signed-off-by: Jaegeuk Kim <[email protected]>
---
fs/f2fs/dir.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index bacc667950b6..c0c845da12fa 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -808,6 +808,17 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
de_name.name = d->filename[bit_pos];
de_name.len = le16_to_cpu(de->name_len);

+ /* check memory boundary before moving forward */
+ bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
+ if (unlikely(bit_pos > d->max)) {
+ f2fs_msg(sbi->sb, KERN_WARNING,
+ "%s: corrupted namelen=%d, run fsck to fix.",
+ __func__, le16_to_cpu(de->name_len));
+ set_sbi_flag(sbi, SBI_NEED_FSCK);
+ err = -EINVAL;
+ goto out;
+ }
+
if (f2fs_encrypted_inode(d->inode)) {
int save_len = fstr->len;

@@ -830,7 +841,6 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
if (readdir_ra)
f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));

- bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
ctx->pos = start_pos + bit_pos;
}
out:
--
2.19.0.605.g01d371f741-goog

2018-11-17 02:29:05

by Chao Yu

Subject: Re: [f2fs-dev] [PATCH] f2fs: check memory boundary by insane namelen

On 2018-11-15 15:50, Jaegeuk Kim wrote:
> If namelen is corrupted to have very long value, fill_dentries can copy
> wrong memory area.
>
> Signed-off-by: Jaegeuk Kim <[email protected]>

Reviewed-by: Chao Yu <[email protected]>

Thanks,

2018-11-24 08:31:09

by Sheng Yong

Subject: Re: [f2fs-dev] [PATCH] f2fs: check memory boundary by insane namelen

Hi, Jaegeuk and Chao,

On 2018/11/15 15:50, Jaegeuk Kim wrote:
> If namelen is corrupted to have very long value, fill_dentries can copy
> wrong memory area.
>
Is there any scenario that could hit this corruption? Or this is triggered
by fuzzing injection?

thanks,
Sheng Yong

> Signed-off-by: Jaegeuk Kim <[email protected]>
> ---
> fs/f2fs/dir.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index bacc667950b6..c0c845da12fa 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -808,6 +808,17 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
> de_name.name = d->filename[bit_pos];
> de_name.len = le16_to_cpu(de->name_len);
>
> + /* check memory boundary before moving forward */
> + bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
> + if (unlikely(bit_pos > d->max)) {
> + f2fs_msg(sbi->sb, KERN_WARNING,
> + "%s: corrupted namelen=%d, run fsck to fix.",
> + __func__, le16_to_cpu(de->name_len));
> + set_sbi_flag(sbi, SBI_NEED_FSCK);
> + err = -EINVAL;
> + goto out;
> + }
> +
> if (f2fs_encrypted_inode(d->inode)) {
> int save_len = fstr->len;
>
> @@ -830,7 +841,6 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
> if (readdir_ra)
> f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));
>
> - bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
> ctx->pos = start_pos + bit_pos;
> }
> out:
>

2018-11-24 10:00:28

by Chao Yu

Subject: Re: [f2fs-dev] [PATCH] f2fs: check memory boundary by insane namelen

Hi Sheng,

On 2018/11/23 20:11, Sheng Yong wrote:
> Hi, Jaegeuk and Chao,
>
> On 2018/11/15 15:50, Jaegeuk Kim wrote:
>> If namelen is corrupted to have very long value, fill_dentries can copy
>> wrong memory area.
>>
> Is there any scenario that could hit this corruption? Or this is triggered

I didn't see such issue in my test, I guess it may be caused by fuzzing test.

Thanks,

> by fuzzing injection?
>
> thanks,
> Sheng Yong
>
>> Signed-off-by: Jaegeuk Kim <[email protected]>
>> ---
>> fs/f2fs/dir.c | 12 +++++++++++-
>> 1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
>> index bacc667950b6..c0c845da12fa 100644
>> --- a/fs/f2fs/dir.c
>> +++ b/fs/f2fs/dir.c
>> @@ -808,6 +808,17 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
>> de_name.name = d->filename[bit_pos];
>> de_name.len = le16_to_cpu(de->name_len);
>>
>> + /* check memory boundary before moving forward */
>> + bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
>> + if (unlikely(bit_pos > d->max)) {
>> + f2fs_msg(sbi->sb, KERN_WARNING,
>> + "%s: corrupted namelen=%d, run fsck to fix.",
>> + __func__, le16_to_cpu(de->name_len));
>> + set_sbi_flag(sbi, SBI_NEED_FSCK);
>> + err = -EINVAL;
>> + goto out;
>> + }
>> +
>> if (f2fs_encrypted_inode(d->inode)) {
>> int save_len = fstr->len;
>>
>> @@ -830,7 +841,6 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
>> if (readdir_ra)
>> f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));
>>
>> - bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
>> ctx->pos = start_pos + bit_pos;
>> }
>> out:
>>
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>
>

2018-11-26 23:26:40

by Jaegeuk Kim

Subject: Re: [f2fs-dev] [PATCH] f2fs: check memory boundary by insane namelen

On 11/23, Sheng Yong wrote:
> Hi, Jaegeuk and Chao,
>
> On 2018/11/15 15:50, Jaegeuk Kim wrote:
> > If namelen is corrupted to have very long value, fill_dentries can copy
> > wrong memory area.
> >
> Is there any scenario that could hit this corruption? Or this is triggered
> by fuzzing injection?

Hi Sheng,

It's from a fuzzing test.

Thanks,

>
> thanks,
> Sheng Yong
>
> > Signed-off-by: Jaegeuk Kim <[email protected]>
> > ---
> > fs/f2fs/dir.c | 12 +++++++++++-
> > 1 file changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> > index bacc667950b6..c0c845da12fa 100644
> > --- a/fs/f2fs/dir.c
> > +++ b/fs/f2fs/dir.c
> > @@ -808,6 +808,17 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
> > de_name.name = d->filename[bit_pos];
> > de_name.len = le16_to_cpu(de->name_len);
> > + /* check memory boundary before moving forward */
> > + bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
> > + if (unlikely(bit_pos > d->max)) {
> > + f2fs_msg(sbi->sb, KERN_WARNING,
> > + "%s: corrupted namelen=%d, run fsck to fix.",
> > + __func__, le16_to_cpu(de->name_len));
> > + set_sbi_flag(sbi, SBI_NEED_FSCK);
> > + err = -EINVAL;
> > + goto out;
> > + }
> > +
> > if (f2fs_encrypted_inode(d->inode)) {
> > int save_len = fstr->len;
> > @@ -830,7 +841,6 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
> > if (readdir_ra)
> > f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));
> > - bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
> > ctx->pos = start_pos + bit_pos;
> > }
> > out:
> >