On Tue, Jan 08, 2019 at 12:36:35PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Check extended attribute entry names for invalid characters.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> fs/xfs/libxfs/xfs_attr.c | 17 +++++++++++++++++
> fs/xfs/libxfs/xfs_attr.h | 2 +-
> fs/xfs/scrub/attr.c | 6 ++++++
> 3 files changed, 24 insertions(+), 1 deletion(-)
>
>
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 844ed87b1900..2dd9ee2a2e08 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -1336,3 +1336,20 @@ xfs_attr_node_get(xfs_da_args_t *args)
> xfs_da_state_free(state);
> return retval;
> }
> +
> +/* Returns true if the attribute entry name is valid. */
> +bool
> +xfs_attr_namecheck(
> + const void *name,
> + size_t length)
> +{
> + /*
> + * MAXNAMELEN includes the trailing null, but (name/length) leave it
> + * out, so use >= for the length check.
> + */
> + if (length >= MAXNAMELEN)
> + return false;
> +
> + /* There shouldn't be any nulls here */
> + return !memchr(name, 0, length);
> +}
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index bdf52a333f3f..2297d8467666 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -145,6 +145,6 @@ int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags);
> int xfs_attr_remove_args(struct xfs_da_args *args);
> int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
> int flags, struct attrlist_cursor_kern *cursor);
> -
> +bool xfs_attr_namecheck(const void *name, size_t length);
>
> #endif /* __XFS_ATTR_H__ */
> diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
> index 9960bc5b5d76..dce74ec57038 100644
> --- a/fs/xfs/scrub/attr.c
> +++ b/fs/xfs/scrub/attr.c
> @@ -93,6 +93,12 @@ xchk_xattr_listent(
> return;
> }
>
> + /* Does this name make sense? */
> + if (!xfs_attr_namecheck(name, namelen)) {
> + xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, args.blkno);
> + return;
> + }
> +
> args.flags = ATTR_KERNOTIME;
> if (flags & XFS_ATTR_ROOT)
> args.flags |= ATTR_ROOT;
>
