[PATCH 1/2] erofs: fix missing unmap if z_erofs_get_extent_compressedlen() fails

[PATCH 1/2] erofs: fix missing unmap if z_erofs_get_extent_compressedlen() fails

[Gao Xiang]

Otherwise, meta buffers could be leaked.

Fixes: cec6e93beadf ("erofs: support parsing big pcluster compress indexes")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
 fs/erofs/zmap.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 749a5ac943f4..98eff1259de4 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -694,7 +694,7 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 		map->m_pa = blknr_to_addr(m.pblk);
 		err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
 		if (err)
-			goto out;
+			goto unmap_out;
 	}
 
 	if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN) {
@@ -718,14 +718,12 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 		if (!err)
 			map->m_flags |= EROFS_MAP_FULL_MAPPED;
 	}
+
 unmap_out:
 	erofs_unmap_metabuf(&m.map->buf);
-
-out:
 	erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
 		  __func__, map->m_la, map->m_pa,
 		  map->m_llen, map->m_plen, map->m_flags);
-
 	return err;
 }
 
-- 
2.24.4

[PATCH 2/2] erofs: validate the extent length for uncompressed pclusters

[Gao Xiang]

syzkaller reported a KASAN use-after-free:
https://syzkaller.appspot.com/bug?extid=2ae90e873e97f1faf6f2

The referenced fuzzed image actually has two issues:
 - m_pa == 0 as a non-inlined pcluster;
 - The logical length is longer than its physical length.

The first issue has already been addressed.  This patch addresses
the second issue by checking the extent length validity.

Reported-by: syzbot+2ae90e873e97f1faf6f2@syzkaller.appspotmail.com
Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
 fs/erofs/zmap.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 98eff1259de4..0150570c33aa 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -698,6 +698,11 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 	}
 
 	if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN) {
+		if (map->m_llen > map->m_plen) {
+			DBG_BUGON(1);
+			err = -EFSCORRUPTED;
+			goto unmap_out;
+		}
 		if (vi->z_advise & Z_EROFS_ADVISE_INTERLACED_PCLUSTER)
 			map->m_algorithmformat =
 				Z_EROFS_COMPRESSION_INTERLACED;
-- 
2.24.4

Re: [PATCH 1/2] erofs: fix missing unmap if z_erofs_get_extent_compressedlen() fails

[Yue Hu]

On Mon,  5 Dec 2022 23:00:49 +0800
Gao Xiang <hsiangkao@linux.alibaba.com> wrote:

> Otherwise, meta buffers could be leaked.
> 
> Fixes: cec6e93beadf ("erofs: support parsing big pcluster compress indexes")
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Reviewed-by: Yue Hu <huyue2@coolpad.com>

> ---
>  fs/erofs/zmap.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
> index 749a5ac943f4..98eff1259de4 100644
> --- a/fs/erofs/zmap.c
> +++ b/fs/erofs/zmap.c
> @@ -694,7 +694,7 @@ static int z_erofs_do_map_blocks(struct inode *inode,
>  		map->m_pa = blknr_to_addr(m.pblk);
>  		err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
>  		if (err)
> -			goto out;
> +			goto unmap_out;
>  	}
>  
>  	if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN) {
> @@ -718,14 +718,12 @@ static int z_erofs_do_map_blocks(struct inode *inode,
>  		if (!err)
>  			map->m_flags |= EROFS_MAP_FULL_MAPPED;
>  	}
> +
>  unmap_out:
>  	erofs_unmap_metabuf(&m.map->buf);
> -
> -out:
>  	erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
>  		  __func__, map->m_la, map->m_pa,
>  		  map->m_llen, map->m_plen, map->m_flags);
> -
>  	return err;
>  }
>  

Re: [PATCH 1/2] erofs: fix missing unmap if z_erofs_get_extent_compressedlen() fails

[Chao Yu]

On 2022/12/5 23:00, Gao Xiang wrote:
> Otherwise, meta buffers could be leaked.
> 
> Fixes: cec6e93beadf ("erofs: support parsing big pcluster compress indexes")
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,

Re: [PATCH 2/2] erofs: validate the extent length for uncompressed pclusters

[Chao Yu]

On 2022/12/5 23:00, Gao Xiang wrote:
> syzkaller reported a KASAN use-after-free:
> https://syzkaller.appspot.com/bug?extid=2ae90e873e97f1faf6f2
> 
> The referenced fuzzed image actually has two issues:
>   - m_pa == 0 as a non-inlined pcluster;
>   - The logical length is longer than its physical length.
> 
> The first issue has already been addressed.  This patch addresses
> the second issue by checking the extent length validity.
> 
> Reported-by: syzbot+2ae90e873e97f1faf6f2@syzkaller.appspotmail.com
> Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter")
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,