| Message ID | 20231212-strncpy-drivers-scsi-ibmvscsi_tgt-ibmvscsi_tgt-c-v2-1-bdb9a7cd96c8@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] scsi: ibmvscsi_tgt: replace deprecated strncpy with strscpy | expand |
On Tue, Dec 12, 2023 at 01:20:20AM +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 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@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> This looks good to me. The only question that I haven't seen an answer to from the maintainers is whether this is a __nonstring or not. It really looks like it should be a C String, so with that assumption: Reviewed-by: Kees Cook <keescook@chromium.org> -Kees
On 12/12/23 13:23, Kees Cook wrote: > On Tue, Dec 12, 2023 at 01:20:20AM +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 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@vger.kernel.org >> Signed-off-by: Justin Stitt <justinstitt@google.com> > > This looks good to me. The only question that I haven't seen an answer > to from the maintainers is whether this is a __nonstring or not. It > really looks like it should be a C String, so with that assumption: To reaffirm the assumption, as I mentioned in my response to v1 these are intended to be handled as C strings. Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com> > > Reviewed-by: Kees Cook <keescook@chromium.org> > > -Kees >
On Thu, Jan 18, 2024 at 12:21:04PM -0800, Tyrel Datwyler wrote: > On 12/12/23 13:23, Kees Cook wrote: > > On Tue, Dec 12, 2023 at 01:20:20AM +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 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@vger.kernel.org > >> Signed-off-by: Justin Stitt <justinstitt@google.com> > > > > This looks good to me. The only question that I haven't seen an answer > > to from the maintainers is whether this is a __nonstring or not. It > > really looks like it should be a C String, so with that assumption: > > To reaffirm the assumption, as I mentioned in my response to v1 these are > intended to be handled as C strings. Great; thanks! Are you taking this, or should I carry it in the hardening tree? -Kees > > Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com> > > > > > Reviewed-by: Kees Cook <keescook@chromium.org> > > > > -Kees > > >
Kees, > Great; thanks! Are you taking this, or should I carry it in the > hardening tree? I'll pick it up now that Tyrel has reviewed it.
Tyrel, > To reaffirm the assumption, as I mentioned in my response to v1 these are > intended to be handled as C strings. > > Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com> Applied to 6.9/scsi-staging, thanks!
On Tue, 12 Dec 2023 01:20:20 +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 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); > > [...] Applied to 6.9/scsi-queue, thanks! [1/1] scsi: ibmvscsi_tgt: replace deprecated strncpy with strscpy https://git.kernel.org/mkp/scsi/c/165470fb2600
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)
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@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- 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@google.com --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) --- base-commit: bee0e7762ad2c6025b9f5245c040fcc36ef2bde8 change-id: 20231030-strncpy-drivers-scsi-ibmvscsi_tgt-ibmvscsi_tgt-c-8a9bd0e54666 Best regards, -- Justin Stitt <justinstitt@google.com>