Vaibhav Jain <vaib...@linux.ibm.com> writes:
> A validation check to prevent out of bounds read/write inside
> functions papr_scm_meta_{get,set}() is off-by-one that prevent reads
> and writes to the last byte of the label area.
>
> This bug manifests as a failure to probe a dimm when libnvdimm is
> unable to read the entire config-area as advertised by
> ND_CMD_GET_CONFIG_SIZE. This usually happens when there are large
> number of namespaces created in the region backed by the dimm and the
> label-index spans max possible config-area. An error of the form below
> usually reported in the kernel logs:
>
> [ 255.293912] nvdimm: probe of nmem0 failed with error -22
>
> The patch fixes these validation checks there by letting libnvdimm
> access the entire config-area.
>
Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
> Fixes: 53e80bd042773('powerpc/nvdimm: Add support for multibyte read/write
> for metadata')
> Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com>
> ---
> arch/powerpc/platforms/pseries/papr_scm.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
> b/arch/powerpc/platforms/pseries/papr_scm.c
> index a5ac371a3f06..0d0f4974a301 100644
> --- a/arch/powerpc/platforms/pseries/papr_scm.c
> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
> @@ -124,7 +124,7 @@ static int papr_scm_meta_get(struct papr_scm_priv *p,
> int len, read;
> int64_t ret;
>
> - if ((hdr->in_offset + hdr->in_length) >= p->metadata_size)
> + if ((hdr->in_offset + hdr->in_length) > p->metadata_size)
> return -EINVAL;
>
> for (len = hdr->in_length; len; len -= read) {
> @@ -178,7 +178,7 @@ static int papr_scm_meta_set(struct papr_scm_priv *p,
> __be64 data_be;
> int64_t ret;
>
> - if ((hdr->in_offset + hdr->in_length) >= p->metadata_size)
> + if ((hdr->in_offset + hdr->in_length) > p->metadata_size)
> return -EINVAL;
>
> for (len = hdr->in_length; len; len -= wrote) {
> --
> 2.21.0
