On 07.12.2022 13:46, Peng Zhang wrote:
> From: ZhangPeng <[email protected]>
>
> Syzbot reported a OOB read bug:
>
> BUG: KASAN: slab-out-of-bounds in indx_insert_into_buffer+0xaa3/0x13b0
> fs/ntfs3/index.c:1755
> Read of size 17168 at addr ffff8880255e06c0 by task syz-executor308/3630
>
> Call Trace:
> <TASK>
> memmove+0x25/0x60 mm/kasan/shadow.c:54
> indx_insert_into_buffer+0xaa3/0x13b0 fs/ntfs3/index.c:1755
> indx_insert_entry+0x446/0x6b0 fs/ntfs3/index.c:1863
> ntfs_create_inode+0x1d3f/0x35c0 fs/ntfs3/inode.c:1548
> ntfs_create+0x3e/0x60 fs/ntfs3/namei.c:100
> lookup_open fs/namei.c:3413 [inline]
>
> If the member struct INDEX_BUFFER *index of struct indx_node is
> incorrect, that is, the value of __le32 used is greater than the value
> of __le32 total in struct INDEX_HDR. Therefore, OOB read occurs when
> memmove is called in indx_insert_into_buffer().
> Fix this by adding a check in hdr_find_e().
>
> Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
> Reported-by: [email protected]
> Signed-off-by: ZhangPeng <[email protected]>
> ---
> fs/ntfs3/index.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
> index 440328147e7e..28af0a5afbf2 100644
> --- a/fs/ntfs3/index.c
> +++ b/fs/ntfs3/index.c
> @@ -679,9 +679,13 @@ static struct NTFS_DE *hdr_find_e(const struct ntfs_index *indx,
> u32 e_size, e_key_len;
> u32 end = le32_to_cpu(hdr->used);
> u32 off = le32_to_cpu(hdr->de_off);
> + u32 total = le32_to_cpu(hdr->total);
> u16 offs[128];
>
> fill_table:
> + if (end > total)
> + return NULL;
> +
> if (off + sizeof(struct NTFS_DE) > end)
> return NULL;
>
Applied, thanks for the patch!