This is a note to let you know that I've just added the patch titled powerpc/papr_scm: Fix an off-by-one check in papr_scm_meta_{get, set} to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-papr_scm-fix-an-off-by-one-check-in-papr_scm.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a12b7d2f722e7496d02dd9dd0984f10f7ae091e5 Author: Vaibhav Jain <vaibhav@xxxxxxxxxxxxx> Date: Fri Sep 27 11:50:02 2019 +0530 powerpc/papr_scm: Fix an off-by-one check in papr_scm_meta_{get, set} [ 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@xxxxxxxxxxxxx> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20190927062002.3169-1-vaibhav@xxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index 61883291defc..ee07d0718bf1 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) {