| Message ID | 20231023-strncpy-drivers-scsi-elx-libefc-efc_node-h-v1-1-8b66878b6796@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | scsi: elx: libefc: replace deprecated strncpy with strscpy | expand |
On Mon, Oct 23, 2023 at 09:58:32PM +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. > > A suitable replacement is `strscpy` [2] due to the fact that it > guarantees NUL-termination on the destination buffer without > unnecessarily NUL-padding. > > There seems to not be any uses of `current_state_name` other than in > these assignments. Judging from context surrounding these assignments, > especially considering the string literal "invalid" being assigned, we > want both current_state_name and prev_state_name to be NUL-terminated > strings. I'm nervous that "node" may be either passed over the link or in IO memory, so the behavior change of not %NUL-padding these may trip something at run-time. Unless someone says otherwise, let's stay on the safe side and use strscpy_pad() for "invalid" and handler, and memcpy() for the swap. Looking at "handler", it's always less than 64, so we don't need to worry about early truncation -- it's always __func__, and none of them are very long: $ git grep efc_node_evt_set | grep -v __func__ drivers/scsi/elx/libefc/efc_node.h:efc_node_evt_set(struct efc_sm_ctx *ctx, enum efc_sm_event evt, $ git grep efc_node_evt_set | grep __func__ | cut -d: -f1 | sort -u drivers/scsi/elx/libefc/efc_device.c drivers/scsi/elx/libefc/efc_fabric.c drivers/scsi/elx/libefc/efc_node.c $ grep -E '^_?_?efc' drivers/scsi/elx/libefc/efc_{fabric,device,node}.c \ | cut -d'(' -f1 | cut -d: -f2 | wc -L 37 -Kees > > 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. > > Found with: $ rg "strncpy\(" > --- > drivers/scsi/elx/libefc/efc_node.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/scsi/elx/libefc/efc_node.h b/drivers/scsi/elx/libefc/efc_node.h > index e9c600ac45d5..3a16703d0f97 100644 > --- a/drivers/scsi/elx/libefc/efc_node.h > +++ b/drivers/scsi/elx/libefc/efc_node.h > @@ -26,12 +26,12 @@ efc_node_evt_set(struct efc_sm_ctx *ctx, enum efc_sm_event evt, > struct efc_node *node = ctx->app; > > if (evt == EFC_EVT_ENTER) { > - strncpy(node->current_state_name, handler, > + strscpy(node->current_state_name, handler, > sizeof(node->current_state_name)); > } else if (evt == EFC_EVT_EXIT) { > - strncpy(node->prev_state_name, node->current_state_name, > + strscpy(node->prev_state_name, node->current_state_name, > sizeof(node->prev_state_name)); > - strncpy(node->current_state_name, "invalid", > + strscpy(node->current_state_name, "invalid", > sizeof(node->current_state_name)); > } > node->prev_evt = node->current_evt; > > --- > base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c > change-id: 20231023-strncpy-drivers-scsi-elx-libefc-efc_node-h-cbbf753197b7 > > Best regards, > -- > Justin Stitt <justinstitt@google.com> > >
diff --git a/drivers/scsi/elx/libefc/efc_node.h b/drivers/scsi/elx/libefc/efc_node.h index e9c600ac45d5..3a16703d0f97 100644 --- a/drivers/scsi/elx/libefc/efc_node.h +++ b/drivers/scsi/elx/libefc/efc_node.h @@ -26,12 +26,12 @@ efc_node_evt_set(struct efc_sm_ctx *ctx, enum efc_sm_event evt, struct efc_node *node = ctx->app; if (evt == EFC_EVT_ENTER) { - strncpy(node->current_state_name, handler, + strscpy(node->current_state_name, handler, sizeof(node->current_state_name)); } else if (evt == EFC_EVT_EXIT) { - strncpy(node->prev_state_name, node->current_state_name, + strscpy(node->prev_state_name, node->current_state_name, sizeof(node->prev_state_name)); - strncpy(node->current_state_name, "invalid", + strscpy(node->current_state_name, "invalid", sizeof(node->current_state_name)); } node->prev_evt = node->current_evt;
strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. A suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. There seems to not be any uses of `current_state_name` other than in these assignments. Judging from context surrounding these assignments, especially considering the string literal "invalid" being assigned, we want both current_state_name and prev_state_name to be NUL-terminated strings. 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. Found with: $ rg "strncpy\(" --- drivers/scsi/elx/libefc/efc_node.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c change-id: 20231023-strncpy-drivers-scsi-elx-libefc-efc_node-h-cbbf753197b7 Best regards, -- Justin Stitt <justinstitt@google.com>