2023-04-14 06:19:21

by Jingbo Xu

Subject: [PATCH] erofs: fix potential overflow calculating xattr_isize

Given on-disk i_xattr_icount is 16 bits and xattr_isize is calculated
from i_xattr_icount multiplying 4, xattr_isize has a theoretical maximum
of 256K (64K * 4).

Thus declare xattr_isize as unsigned int to avoid the potential overflow.

Fixes: bfb8674dc044 ("staging: erofs: add erofs in-memory stuffs")
Signed-off-by: Jingbo Xu <[email protected]>
---
fs/erofs/internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 8a563374b518..c86241a32ab3 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -306,7 +306,7 @@ struct erofs_inode {

unsigned char datalayout;
unsigned char inode_isize;
- unsigned short xattr_isize;
+ unsigned int xattr_isize;

unsigned int xattr_shared_count;
unsigned int *xattr_shared_xattrs;
--
2.19.1.6.gb485710b

2023-04-14 06:29:33

by Gao Xiang

Subject: Re: [PATCH] erofs: fix potential overflow calculating xattr_isize

On 2023/4/14 14:18, Jingbo Xu wrote:
> Given on-disk i_xattr_icount is 16 bits and xattr_isize is calculated
> from i_xattr_icount multiplying 4, xattr_isize has a theoretical maximum
> of 256K (64K * 4).
>
> Thus declare xattr_isize as unsigned int to avoid the potential overflow.
>
> Fixes: bfb8674dc044 ("staging: erofs: add erofs in-memory stuffs")
> Signed-off-by: Jingbo Xu <[email protected]>

Thanks for catching this!
Reviewed-by: Gao Xiang <[email protected]>

Thanks,
Gao Xiang

> ---
> fs/erofs/internal.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 8a563374b518..c86241a32ab3 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -306,7 +306,7 @@ struct erofs_inode {
>
> unsigned char datalayout;
> unsigned char inode_isize;
> - unsigned short xattr_isize;
> + unsigned int xattr_isize;
>
> unsigned int xattr_shared_count;
> unsigned int *xattr_shared_xattrs;

2023-04-16 15:12:22

by Chao Yu

Subject: Re: [PATCH] erofs: fix potential overflow calculating xattr_isize

On 2023/4/14 14:18, Jingbo Xu wrote:
> Given on-disk i_xattr_icount is 16 bits and xattr_isize is calculated
> from i_xattr_icount multiplying 4, xattr_isize has a theoretical maximum
> of 256K (64K * 4).
>
> Thus declare xattr_isize as unsigned int to avoid the potential overflow.
>
> Fixes: bfb8674dc044 ("staging: erofs: add erofs in-memory stuffs")
> Signed-off-by: Jingbo Xu <[email protected]>

Good catch!

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

Thanks,