Several potential vulnerabilities in the filesystem

[jianqiang wang]

Hi Xiang,

I just checked the second crash, the patch can solve this issue. Did
you also look into the other two issues?

Best
Jianqiang

Gao Xiang <hsiangkao at linux.alibaba.com> 于2024年6月5日周三 13:18写道：
>
> Hi Jianqiang,
>
> On 2024/6/5 19:00, jianqiang wang wrote:
> > Hi,
> >
> > I do have the crafted image.
> >
> > payload_00500, payload_00763, payload_00846 can be used to reproduce
> > 1,2,3 vulnerabilities respectively.
> >
> > Each image is a hard drive file and the vulnerabilities can be
> > triggered by performing the following operations:
> >
> >      struct udevice *dev;
> >      uclass_first_device_err(UCLASS_IDE, &dev);  //detect the block device
> >
> >      fs_set_blk_dev("ide","0:1", 0);
> >      fs_ls("/");   //mount the first partition and list the root directory files
> >
> >      fs_set_blk_dev("ide","0:1", 0);
> >      char buf[10];
> >      buf[0] = 0;
> >      buf[1] = 0;
> >      buf[2] = 0;
> >      buf[3] = 0;
> >      loff_t actread = 0;
> >      fs_read("/a.txt", (ulong)buf, 0, 5, &actread);
> >      printf("fd actread %lld %x %x %x\n",actread,buf[0],buf[1],buf[2]);
> >   read the /a.txt file
> >
> >
> >      fs_set_blk_dev("ide","0:1", 0);
> >      fs_read("/a.txt.ln", (ulong)buf, 0, 5, &actread);
> >      printf("fd actread %lld %x %x %x\n",actread,buf[0],buf[1],buf[2]);
> >   read the /a.txt.ln symbol file
> >
> >      fs_set_blk_dev("ide","0:1", 0);
> >      fs_unlink("/a.txt.ln");  //unlink it
> >
> > The second and third may not trigger a crash however, can be observed
> > by inserting logging before the memset/memcpy function.
>
> Sorry, I just found that this issue was already fixed in erofs-utils:
> https://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git/commit/?id=884866ca07817e97c59605a2fa858a0b732d3f3c
>
> Would you mind checking if the patch above fixes the issue?
>
> Hi Jianan,
> Would you mind backporting this patch for u-boot?
>
> Thanks,
> Gao Xiang
>
> >
> > Best regards
> >
> > Gao Xiang <hsiangkao at linux.alibaba.com> 于2024年6月5日周三 05:10写道：
> >>
> >>
> >>
> >> On 2024/6/5 06:53, jianqiang wang wrote:
> >>> Hi Das U-Boot developers,
> >>>
> >>
> >> ...
> >>
> >>>
> >>> 2. in file fs/erofs/data.c, function z_erofs_read_one_data, the node
> >>> data is read from the storage, however, without a proper check, the
> >>> data can be corrupted. For example, the inode data is used in function
> >>> z_erofs_read_data, map.m_llen will be calculated to a very large
> >>> value, which means the length variable will be very large. It will
> >>> cause a large memory clear with memset(buffer + end - offset, 0,
> >>> length);
> >>
> >> Would you mind giving a reproducer or a crafted image to trigger
> >> this?  Or it's your pure observation.
> >>
> >> Thanks,
> >> Gao XIang
> >>