On Mon, Sep 11, 2023 at 09:09:07PM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > `aoe_iflist` is expected to be NUL-terminated which is evident by its > use with string apis later on like `strspn`: > | p = aoe_iflist + strspn(aoe_iflist, WHITESPACE); > > It also seems `aoe_iflist` does not need to be NUL-padded which means > `strscpy` [2] is a suitable replacement due to the fact that it > guarantees NUL-termination on the destination buffer while not > unnecessarily NUL-padding. > > 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@xxxxxxxxxxxxxxx > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > Cc: Xu Panda <xu.panda@xxxxxxxxxx> > Cc: Yang Yang <yang.yang29@xxxxxxx> > Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> Agreed, truncation is the current behavior, and padding isn't needed. (Or more precisely, it's already zeroed and this function is called once.) Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > Note: This exact same patch exists [3] but seemed to die so I'm > resending. If it was actually picked-up somewhere then we can ignore > this patch. > > [3]: https://lore.kernel.org/all/202212051930256039214@xxxxxxxxxx/ Ah, weird. Well, I think this current one has a more complete commit log, so let's use this one. -Kees > --- > drivers/block/aoe/aoenet.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/block/aoe/aoenet.c b/drivers/block/aoe/aoenet.c > index 63773a90581d..c51ea95bc2ce 100644 > --- a/drivers/block/aoe/aoenet.c > +++ b/drivers/block/aoe/aoenet.c > @@ -39,8 +39,7 @@ static struct ktstate kts; > #ifndef MODULE > static int __init aoe_iflist_setup(char *str) > { > - strncpy(aoe_iflist, str, IFLISTSZ); > - aoe_iflist[IFLISTSZ - 1] = '\0'; > + strscpy(aoe_iflist, str, IFLISTSZ); > return 1; > } > > > --- > base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c > change-id: 20230911-strncpy-drivers-block-aoe-aoenet-c-024debad6105 > > Best regards, > -- > Justin Stitt <justinstitt@xxxxxxxxxx> > -- Kees Cook
