From: Vaibhav Jain vaibhav@linux.ibm.com
[ Upstream commit 612ee81b9461475b5a5612c2e8d71559dd3c7920 ]
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.
Fixes: 53e80bd042773('powerpc/nvdimm: Add support for multibyte read/write for metadata') Signed-off-by: Vaibhav Jain vaibhav@linux.ibm.com Reviewed-by: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20190927062002.3169-1-vaibhav@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 61883291defc3..ee07d0718bf1a 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -152,7 +152,7 @@ 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) { @@ -206,7 +206,7 @@ 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) {