2021-08-25 21:05:14

by Kari Argillander

Subject: [PATCH] fs/ntfs3: Fix integer overflow in ni_fiemap with fiemap_prep()

Use fiemap_prep() to check valid flags. It also shrink request scope
(@len) to what the fs can actually handle.

This address following Smatch static checker warning:
fs/ntfs3/frecord.c:1894 ni_fiemap()
warn: potential integer overflow from user 'vbo + len'

Because fiemap_prep() shrinks @len this cannot happened anymore.

Reported-by Dan Carpenter <[email protected]>
Link: lore.kernel.org/ntfs3/20210825080440.GA17407@kili/

Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation")
Signed-off-by: Kari Argillander <[email protected]>
---
fs/ntfs3/file.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index 59344985c2e8..cb736701f2cc 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -1210,8 +1210,9 @@ int ntfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
int err;
struct ntfs_inode *ni = ntfs_i(inode);

- if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR)
- return -EOPNOTSUPP;
+ err = fiemap_prep(inode, fieinfo, start, &len, ~FIEMAP_FLAG_XATTR);
+ if (err)
+ return err;

ni_lock(ni);

--
2.30.2

2021-09-02 20:08:58

by Konstantin Komarov

Subject: Re: [PATCH] fs/ntfs3: Fix integer overflow in ni_fiemap with fiemap_prep()

On 25.08.2021 21:24, Kari Argillander wrote:
> Use fiemap_prep() to check valid flags. It also shrink request scope
> (@len) to what the fs can actually handle.
>
> This address following Smatch static checker warning:
> fs/ntfs3/frecord.c:1894 ni_fiemap()
> warn: potential integer overflow from user 'vbo + len'
>
> Because fiemap_prep() shrinks @len this cannot happened anymore.
>
> Reported-by Dan Carpenter <[email protected]>
> Link: lore.kernel.org/ntfs3/20210825080440.GA17407@kili/
>
> Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation")
> Signed-off-by: Kari Argillander <[email protected]>
> ---
> fs/ntfs3/file.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
> index 59344985c2e8..cb736701f2cc 100644
> --- a/fs/ntfs3/file.c
> +++ b/fs/ntfs3/file.c
> @@ -1210,8 +1210,9 @@ int ntfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> int err;
> struct ntfs_inode *ni = ntfs_i(inode);
>
> - if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR)
> - return -EOPNOTSUPP;
> + err = fiemap_prep(inode, fieinfo, start, &len, ~FIEMAP_FLAG_XATTR);
> + if (err)
> + return err;
>
> ni_lock(ni);
>
>

Hello, Dan, Kari!

Thanks for finding and fixing this issue. Applied patch.