On Mon, Oct 07, 2019 at 09:09:16AM -0700, Mark Salyzyn wrote:
> When filtering xattr list for reading, presence of trusted xattr
> results in a security audit log. However, if there is other content
> no errno will be set, and if there isn't, the errno will be -ENODATA
> and not -EPERM as is usually associated with a lack of capability.
> The check does not block the request to list the xattrs present.
>
> Switch to has_capability_noaudit to reflect a more appropriate check.
>
> Signed-off-by: Mark Salyzyn <salyzyn@xxxxxxxxxxx>
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> Cc: kernel-team@xxxxxxxxxxx
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # v3.18
> Fixes: upstream a082c6f680da ("ovl: filter trusted xattr for non-admin")
> Fixes: 3.18 4bcc9b4b3a0a ("ovl: filter trusted xattr for non-admin")
> ---
> Replaced ns_capable_noaudit with 3.18.y tree specific
> has_capability_noaudit present in original submission to kernel.org
> commit 5c2e9f346b815841f9bed6029ebcb06415caf640
> ("ovl: filter of trusted xattr results in audit")
>
> fs/overlayfs/inode.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> index a01ec1836a72..1175efa5e956 100644
> --- a/fs/overlayfs/inode.c
> +++ b/fs/overlayfs/inode.c
> @@ -265,7 +265,8 @@ static bool ovl_can_list(const char *s)
> return true;
>
> /* Never list trusted.overlay, list other trusted for superuser only */
> - return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN);
> + return !ovl_is_private_xattr(s) &&
> + has_capability_noaudit(current, CAP_SYS_ADMIN);
> }
>
> ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
> --
> 2.23.0.581.g78d2f28ef7-goog
>
Thanks for the backport, this one worked!
greg k-h
