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 don't need the NUL-padding behavior that strncpy() provides as vscsi is NUL-allocated in ibmvscsis_probe() which proceeds to call ibmvscsis_adapter_info(): | vscsi = kzalloc(sizeof(*vscsi), GFP_KERNEL); ibmvscsis_probe() -> ibmvscsis_handle_crq() -> ibmvscsis_parse_command() -> ibmvscsis_mad() -> ibmvscsis_process_mad() -> ibmvscsis_adapter_info() Following the same idea, `partition_name` is defiend as: | static char partition_name[PARTITION_NAMELEN] = "UNKNOWN"; ... which is NUL-padded already, meaning strscpy() is the best option. 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. However, for cap->name and info let's use strscpy_pad as they are allocated via dma_alloc_coherent(): | cap = dma_alloc_coherent(&vscsi->dma_dev->dev, olen, &token, | GFP_ATOMIC); & | info = dma_alloc_coherent(&vscsi->dma_dev->dev, sizeof(*info), &token, | GFP_ATOMIC); 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 Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> --- Changes in v2: - use strscpy_pad for info->partition_name (thanks Kees) - rebase onto mainline bee0e7762ad2c602 - Link to v1: https://lore.kernel.org/r/20231030-strncpy-drivers-scsi-ibmvscsi_tgt-ibmvscsi_tgt-c-v1-1-859b5ce257fd@xxxxxxxxxx --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c index 4dc411a58107..6b16020b1f59 100644 --- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c +++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c @@ -1551,18 +1551,18 @@ static long ibmvscsis_adapter_info(struct scsi_info *vscsi, if (vscsi->client_data.partition_number == 0) vscsi->client_data.partition_number = be32_to_cpu(info->partition_number); - strncpy(vscsi->client_data.srp_version, info->srp_version, + strscpy(vscsi->client_data.srp_version, info->srp_version, sizeof(vscsi->client_data.srp_version)); - strncpy(vscsi->client_data.partition_name, info->partition_name, + strscpy(vscsi->client_data.partition_name, info->partition_name, sizeof(vscsi->client_data.partition_name)); vscsi->client_data.mad_version = be32_to_cpu(info->mad_version); vscsi->client_data.os_type = be32_to_cpu(info->os_type); /* Copy our info */ - strncpy(info->srp_version, SRP_VERSION, - sizeof(info->srp_version)); - strncpy(info->partition_name, vscsi->dds.partition_name, - sizeof(info->partition_name)); + strscpy_pad(info->srp_version, SRP_VERSION, + sizeof(info->srp_version)); + strscpy_pad(info->partition_name, vscsi->dds.partition_name, + sizeof(info->partition_name)); info->partition_number = cpu_to_be32(vscsi->dds.partition_num); info->mad_version = cpu_to_be32(MAD_VERSION_1); info->os_type = cpu_to_be32(LINUX); @@ -1645,8 +1645,8 @@ static int ibmvscsis_cap_mad(struct scsi_info *vscsi, struct iu_entry *iue) be64_to_cpu(mad->buffer), vscsi->dds.window[LOCAL].liobn, token); if (rc == H_SUCCESS) { - strncpy(cap->name, dev_name(&vscsi->dma_dev->dev), - SRP_MAX_LOC_LEN); + strscpy_pad(cap->name, dev_name(&vscsi->dma_dev->dev), + sizeof(cap->name)); len = olen - min_len; status = VIOSRP_MAD_SUCCESS; @@ -3650,7 +3650,7 @@ static int ibmvscsis_get_system_info(void) name = of_get_property(rootdn, "ibm,partition-name", NULL); if (name) - strncpy(partition_name, name, sizeof(partition_name)); + strscpy(partition_name, name, sizeof(partition_name)); num = of_get_property(rootdn, "ibm,partition-no", NULL); if (num) --- base-commit: bee0e7762ad2c6025b9f5245c040fcc36ef2bde8 change-id: 20231030-strncpy-drivers-scsi-ibmvscsi_tgt-ibmvscsi_tgt-c-8a9bd0e54666 Best regards, -- Justin Stitt <justinstitt@xxxxxxxxxx>
