2023-01-09 11:51:25

by Yang Yang

Subject: [PATCH linux-next] xfs: use strscpy() to instead of strncpy()

From: Xu Panda <[email protected]>

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL-terminated strings.

Signed-off-by: Xu Panda <[email protected]>
Signed-off-by: Yang Yang <[email protected]>
---
fs/xfs/xfs_xattr.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index 10aa1fd39d2b..913c1794bc2f 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -212,9 +212,7 @@ __xfs_xattr_put_listent(
offset = context->buffer + context->count;
memcpy(offset, prefix, prefix_len);
offset += prefix_len;
- strncpy(offset, (char *)name, namelen); /* real name */
- offset += namelen;
- *offset = '\0';
+ strscpy(offset, (char *)name, namelen + 1); /* real name */

compute_size:
context->count += prefix_len + namelen + 1;
--
2.15.2

2023-02-02 00:57:09

by Darrick J. Wong

Subject: Re: [PATCH linux-next] xfs: use strscpy() to instead of strncpy()

On Mon, Jan 09, 2023 at 07:40:43PM +0800, [email protected] wrote:
> From: Xu Panda <[email protected]>
>
> The implementation of strscpy() is more robust and safer.
> That's now the recommended way to copy NUL-terminated strings.
>
> Signed-off-by: Xu Panda <[email protected]>
> Signed-off-by: Yang Yang <[email protected]>

Looks fine,
Reviewed-by: Darrick J. Wong <[email protected]>

--D

> ---
> fs/xfs/xfs_xattr.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
> index 10aa1fd39d2b..913c1794bc2f 100644
> --- a/fs/xfs/xfs_xattr.c
> +++ b/fs/xfs/xfs_xattr.c
> @@ -212,9 +212,7 @@ __xfs_xattr_put_listent(
> offset = context->buffer + context->count;
> memcpy(offset, prefix, prefix_len);
> offset += prefix_len;
> - strncpy(offset, (char *)name, namelen); /* real name */
> - offset += namelen;
> - *offset = '\0';
> + strscpy(offset, (char *)name, namelen + 1); /* real name */
>
> compute_size:
> context->count += prefix_len + namelen + 1;
> --
> 2.15.2

2023-02-11 04:43:08

by Long Li

Subject: Re: [PATCH linux-next] xfs: use strscpy() to instead of strncpy()

On Wed, Feb 01, 2023 at 04:57:02PM -0800, Darrick J. Wong wrote:
> On Mon, Jan 09, 2023 at 07:40:43PM +0800, [email protected] wrote:
> > From: Xu Panda <[email protected]>
> >
> > The implementation of strscpy() is more robust and safer.
> > That's now the recommended way to copy NUL-terminated strings.
> >
> > Signed-off-by: Xu Panda <[email protected]>
> > Signed-off-by: Yang Yang <[email protected]>
>
> Looks fine,
> Reviewed-by: Darrick J. Wong <[email protected]>
>
> --D
>
> > ---
> > fs/xfs/xfs_xattr.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
> > index 10aa1fd39d2b..913c1794bc2f 100644
> > --- a/fs/xfs/xfs_xattr.c
> > +++ b/fs/xfs/xfs_xattr.c
> > @@ -212,9 +212,7 @@ __xfs_xattr_put_listent(
> > offset = context->buffer + context->count;
> > memcpy(offset, prefix, prefix_len);
> > offset += prefix_len;
> > - strncpy(offset, (char *)name, namelen); /* real name */
> > - offset += namelen;
> > - *offset = '\0';
> > + strscpy(offset, (char *)name, namelen + 1); /* real name */

The name is not null terminated, it will result slab-out-of-bounds in strscpy().

[1] https://lore.kernel.org/linux-xfs/[email protected]/T/#u

> >
> > compute_size:
> > context->count += prefix_len + namelen + 1;
> > --
> > 2.15.2