| Message ID | 20230913-strncpy-drivers-dax-bus-c-v1-1-bee91f20825b@google.com |
|---|---|
| State | Accepted |
| Commit | 75b3d5dc0846cfa54ea52d7d84215b761ecbf569 |
| Headers | show |
| Series | dax: refactor deprecated strncpy | expand |
On 9/12/23 18:10, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We should prefer more robust and less ambiguous string interfaces. > > `dax_id->dev_name` is expected to be NUL-terminated and has been zero-allocated. > > A suitable replacement is `strscpy` [2] due to the fact that it > guarantees NUL-termination on the destination buffer. Moreover, due to > `dax_id` being zero-allocated the padding behavior of `strncpy` is not > needed and a simple 1:1 replacement of strncpy -> strscpy should > suffice. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] > Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> > --- > Note: build-tested only. > --- > drivers/dax/bus.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index 0ee96e6fc426..1659b787b65f 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -103,7 +103,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf, > if (action == ID_ADD) { > dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL); > if (dax_id) { > - strncpy(dax_id->dev_name, buf, DAX_NAME_LEN); > + strscpy(dax_id->dev_name, buf, DAX_NAME_LEN); > list_add(&dax_id->list, &dax_drv->ids); > } else > rc = -ENOMEM; > > --- > base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c > change-id: 20230913-strncpy-drivers-dax-bus-c-f12e3153e44b > > Best regards, > -- > Justin Stitt <justinstitt@google.com> >
On Wed, Sep 13, 2023 at 01:10:24AM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We should prefer more robust and less ambiguous string interfaces. > > `dax_id->dev_name` is expected to be NUL-terminated and has been zero-allocated. > > A suitable replacement is `strscpy` [2] due to the fact that it > guarantees NUL-termination on the destination buffer. Moreover, due to > `dax_id` being zero-allocated the padding behavior of `strncpy` is not > needed and a simple 1:1 replacement of strncpy -> strscpy should > suffice. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] > Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> Looks correct to me. Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 0ee96e6fc426..1659b787b65f 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -103,7 +103,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf, if (action == ID_ADD) { dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL); if (dax_id) { - strncpy(dax_id->dev_name, buf, DAX_NAME_LEN); + strscpy(dax_id->dev_name, buf, DAX_NAME_LEN); list_add(&dax_id->list, &dax_drv->ids); } else rc = -ENOMEM;
`strncpy` is deprecated for use on NUL-terminated destination strings [1]. We should prefer more robust and less ambiguous string interfaces. `dax_id->dev_name` is expected to be NUL-terminated and has been zero-allocated. A suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer. Moreover, due to `dax_id` being zero-allocated the padding behavior of `strncpy` is not needed and a simple 1:1 replacement of strncpy -> strscpy should suffice. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: build-tested only. --- drivers/dax/bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c change-id: 20230913-strncpy-drivers-dax-bus-c-f12e3153e44b Best regards, -- Justin Stitt <justinstitt@google.com>