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: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
---
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(-)
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 <[email protected]>
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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
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 <[email protected]>
-Kees
--
Kees Cook
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: [email protected]
>> Signed-off-by: Justin Stitt <[email protected]>
>
> 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 <[email protected]>
>
> Reviewed-by: Kees Cook <[email protected]>
>
> -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: [email protected]
> >> Signed-off-by: Justin Stitt <[email protected]>
> >
> > 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 <[email protected]>
>
> >
> > Reviewed-by: Kees Cook <[email protected]>
> >
> > -Kees
> >
>
--
Kees Cook
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.
--
Martin K. Petersen Oracle Linux Engineering
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 <[email protected]>
Applied to 6.9/scsi-staging, thanks!
--
Martin K. Petersen Oracle Linux Engineering
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
--
Martin K. Petersen Oracle Linux Engineering