| Message ID | 20231005-strncpy-drivers-net-ethernet-brocade-bna-bfa_ioc-c-v1-1-8dfd30123afc@google.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | bna: replace deprecated strncpy with strscpy | expand |
On Thu, Oct 05, 2023 at 09:05:42PM +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. > > bfa_ioc_get_adapter_manufacturer() simply copies a string literal into > `manufacturer`. > > NUL-padding is not needed because bfa_ioc_get_adapter_manufacturer()'s > only caller passes `ad_attr` (which is from ioc_attr) which is then > memset to 0. > bfa_nw_ioc_get_attr() -> > bfa_ioc_get_adapter_attr() -> > bfa_nw_ioc_get_attr() -> > memset((void *)ioc_attr, 0, sizeof(struct bfa_ioc_attr)); > > 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. > > 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/net/ethernet/brocade/bna/bfa_ioc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/brocade/bna/bfa_ioc.c b/drivers/net/ethernet/brocade/bna/bfa_ioc.c > index b07522ac3e74..497cb65f2d06 100644 > --- a/drivers/net/ethernet/brocade/bna/bfa_ioc.c > +++ b/drivers/net/ethernet/brocade/bna/bfa_ioc.c > @@ -2839,7 +2839,7 @@ bfa_ioc_get_adapter_optrom_ver(struct bfa_ioc *ioc, char *optrom_ver) > static void > bfa_ioc_get_adapter_manufacturer(struct bfa_ioc *ioc, char *manufacturer) > { > - strncpy(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN); > + strscpy(manufacturer, BFA_MFG_NAME, sizeof(manufacturer)); > } tl;dr: please use: strscpy_pad(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN); sizeof() will not work correctly here -- manufacturer is a char *, so this will always be sizeof(unsigned long). Which begs the question, why is an unbounded string being passed here? Yay fragile API. I notice bfa_ioc_get_adapter_manufacturer() in drivers/scsi/bfa/bfa_ioc.c does this: memset((void *)manufacturer, 0, BFA_ADAPTER_MFG_NAME_LEN); strscpy(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN); So, I think we should follow suit (but use strscpy_pad() instead to avoid the partially redundant memset). I also note that the "manufacturer" argument comes from many possible structs, not just struct bfa_adapter_attr: drivers/net/ethernet/brocade/bna/bfa_ioc.c:2761: bfa_ioc_get_adapter_manufacturer(ioc, ad_attr->manufacturer); struct bfa_adapter_attr { char manufacturer[BFA_ADAPTER_MFG_NAME_LEN]; drivers/scsi/bfa/bfa_ioc.c:2698: bfa_ioc_get_adapter_manufacturer(ioc, ad_attr->manufacturer); struct bfa_adapter_attr_s { char manufacturer[BFA_ADAPTER_MFG_NAME_LEN]; drivers/scsi/bfa/bfa_fcs_lport.c:2630: bfa_ioc_get_adapter_manufacturer(&port->fcs->bfa->ioc, struct bfa_fcs_fdmi_hba_attr_s { ... u8 manufacturer[64]; This is unexpectedly large... I was expecting either 8 or BFA_ADAPTER_MFG_NAME_LEN: drivers/net/ethernet/brocade/bna/bfa_defs.h:31: BFA_ADAPTER_MFG_NAME_LEN = 8, /*!< manufacturer name length */ drivers/scsi/bfa/bfa_defs.h:259: BFA_ADAPTER_MFG_NAME_LEN = 8, /* manufacturer name length */ (But it seems not a problem, since it's memset() before...) And there are more that I've check, since I also found this macro: #define bfa_get_adapter_manufacturer(__bfa, __manufacturer) \ bfa_ioc_get_adapter_manufacturer(&(__bfa)->ioc, __manufacturer) And there are multiple implementations of bfa_ioc_get_adapter_manufacturer(), it seems.
diff --git a/drivers/net/ethernet/brocade/bna/bfa_ioc.c b/drivers/net/ethernet/brocade/bna/bfa_ioc.c index b07522ac3e74..497cb65f2d06 100644 --- a/drivers/net/ethernet/brocade/bna/bfa_ioc.c +++ b/drivers/net/ethernet/brocade/bna/bfa_ioc.c @@ -2839,7 +2839,7 @@ bfa_ioc_get_adapter_optrom_ver(struct bfa_ioc *ioc, char *optrom_ver) static void bfa_ioc_get_adapter_manufacturer(struct bfa_ioc *ioc, char *manufacturer) { - strncpy(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN); + strscpy(manufacturer, BFA_MFG_NAME, sizeof(manufacturer)); } static void
`strncpy` is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. bfa_ioc_get_adapter_manufacturer() simply copies a string literal into `manufacturer`. NUL-padding is not needed because bfa_ioc_get_adapter_manufacturer()'s only caller passes `ad_attr` (which is from ioc_attr) which is then memset to 0. bfa_nw_ioc_get_attr() -> bfa_ioc_get_adapter_attr() -> bfa_nw_ioc_get_attr() -> memset((void *)ioc_attr, 0, sizeof(struct bfa_ioc_attr)); 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. 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/net/ethernet/brocade/bna/bfa_ioc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 change-id: 20231005-strncpy-drivers-net-ethernet-brocade-bna-bfa_ioc-c-68f13966f388 Best regards, -- Justin Stitt <justinstitt@google.com>