scsi: message: fusion: Replace deprecated strncpy() with strscpy()

strncpy() is deprecated for use on NUL-terminated destination strings [1]
and as such we should prefer more robust and less ambiguous string
interfaces.

The only caller of mptsas_exp_repmanufacture_info() is
mptsas_probe_one_phy() which can allocate rphy in either
sas_end_device_alloc() or sas_expander_alloc(). Both of which
zero-allocate:

|       rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);

... this is supplied to mptsas_exp_repmanufacture_info() as edev meaning
that no future NUL-padding of edev members is needed.

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.

Also use the more idiomatic strscpy() pattern of (dest, src, sizeof(dest)).

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20231003-strncpy-drivers-message-fusion-mptsas-c-v2-1-5ce07e60bd21@google.com
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/message/fusion/mptsas.c b/drivers/message/fusion/mptsas.c
index 86f16f3ea47870b0763c16d1f070e48b4a1adaa5..300f8e955a5319f92361a607a754e36be1a669d8 100644 (file)
--- a/drivers/message/fusion/mptsas.c
+++ b/drivers/message/fusion/mptsas.c
@@ -2964,17 +2964,17 @@ mptsas_exp_repmanufacture_info(MPT_ADAPTER *ioc,
                        goto out_free;
 
                manufacture_reply = data_out + sizeof(struct rep_manu_request);
-               strncpy(edev->vendor_id, manufacture_reply->vendor_id,
-                       SAS_EXPANDER_VENDOR_ID_LEN);
-               strncpy(edev->product_id, manufacture_reply->product_id,
-                       SAS_EXPANDER_PRODUCT_ID_LEN);
-               strncpy(edev->product_rev, manufacture_reply->product_rev,
-                       SAS_EXPANDER_PRODUCT_REV_LEN);
+               strscpy(edev->vendor_id, manufacture_reply->vendor_id,
+                       sizeof(edev->vendor_id));
+               strscpy(edev->product_id, manufacture_reply->product_id,
+                       sizeof(edev->product_id));
+               strscpy(edev->product_rev, manufacture_reply->product_rev,
+                       sizeof(edev->product_rev));
                edev->level = manufacture_reply->sas_format;
                if (manufacture_reply->sas_format) {
-                       strncpy(edev->component_vendor_id,
+                       strscpy(edev->component_vendor_id,
                                manufacture_reply->component_vendor_id,
-                               SAS_EXPANDER_COMPONENT_VENDOR_ID_LEN);
+                               sizeof(edev->component_vendor_id));
                        tmp = (u8 *)&manufacture_reply->component_id;
                        edev->component_id = tmp[0] << 8 | tmp[1];
                        edev->component_revision_id =