On Tue, Oct 10, 2023 at 09:38:11PM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings > [1] and as such we should prefer more robust and less ambiguous string > interfaces. > > We can see that linfo->lmac_type is expected to be NUL-terminated based > on the `... - 1`'s present in the current code. Presumably making room > for a NUL-byte at the end of the buffer. > > Considering the above, a suitable replacement is `strscpy` [2] due to > the fact that it guarantees NUL-termination on the destination buffer > without unnecessarily NUL-padding. > > Let's also prefer the more idiomatic strscpy usage of (dest, src, > sizeof(dest)) rather than (dest, src, SOME_LEN). > > 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 <justinst...@google.com> > --- > Note: build-tested only. > --- > drivers/net/ethernet/marvell/octeontx2/af/cgx.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c > b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c > index e06f77ad6106..6c70c8498690 100644 > --- a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c > +++ b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c > @@ -1218,8 +1218,6 @@ static inline void link_status_user_format(u64 lstat, > struct cgx_link_user_info *linfo, > struct cgx *cgx, u8 lmac_id) > { > - const char *lmac_string; > - > linfo->link_up = FIELD_GET(RESP_LINKSTAT_UP, lstat); > linfo->full_duplex = FIELD_GET(RESP_LINKSTAT_FDUPLEX, lstat); > linfo->speed = cgx_speed_mbps[FIELD_GET(RESP_LINKSTAT_SPEED, lstat)]; > @@ -1230,12 +1228,12 @@ static inline void link_status_user_format(u64 lstat, > if (linfo->lmac_type_id >= LMAC_MODE_MAX) { > dev_err(&cgx->pdev->dev, "Unknown lmac_type_id %d reported by > firmware on cgx port%d:%d", > linfo->lmac_type_id, cgx->cgx_id, lmac_id); > - strncpy(linfo->lmac_type, "Unknown", LMACTYPE_STR_LEN - 1); > + strscpy(linfo->lmac_type, "Unknown", sizeof(linfo->lmac_type)); > return; > } > > - lmac_string = cgx_lmactype_string[linfo->lmac_type_id]; > - strncpy(linfo->lmac_type, lmac_string, LMACTYPE_STR_LEN - 1); > + strscpy(linfo->lmac_type, cgx_lmactype_string[linfo->lmac_type_id], > + sizeof(linfo->lmac_type));
Yup, sizes match. Good replacement and simplification. drivers/net/ethernet/marvell/octeontx2/af/mbox.h:565:#define LMACTYPE_STR_LEN 16 drivers/net/ethernet/marvell/octeontx2/af/mbox.h:566: char lmac_type[LMACTYPE_STR_LEN]; Reviewed-by: Kees Cook <keesc...@chromium.org> -- Kees Cook
