nfit, libnvdimm: fix interleave set cookie calculation

The interleave-set cookie is a sum that sanity checks the composition of
an interleave set has not changed from when the namespace was initially
created.  The checksum is calculated by sorting the DIMMs by their
location in the interleave-set. The comparison for the sort must be
64-bit wide, not byte-by-byte as performed by memcmp() in the broken
case.

Fix the implementation to accept correct cookie values in addition to
the Linux "memcmp" order cookies, but only allow correct cookies to be
generated going forward. It does mean that namespaces created by
third-party-tooling, or created by newer kernels with this fix, will not
validate on older kernels. However, there are a couple mitigating
conditions:

    1/ platforms with namespace-label capable NVDIMMs are not widely
       available.

    2/ interleave-sets with a single-dimm are by definition not affected
       (nothing to sort). This covers the QEMU-KVM NVDIMM emulation case.

The cookie stored in the namespace label will be fixed by any write the
namespace label, the most straightforward way to achieve this is to
write to the "alt_name" attribute of a namespace in sysfs.

Cc: <stable@vger.kernel.org>
Fixes: edfe40c75f75 ("libnvdimm, nfit: add interleave-set state-tracking infrastructure")
Reported-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com>
Tested-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 7361d00818e2bb61f5d280c6817db2a2e8d01fc4..662036bdc65eca8d531886cc658fd9829cc60c00 100644 (file)
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -1603,7 +1603,7 @@ static size_t sizeof_nfit_set_info(int num_mappings)
                + num_mappings * sizeof(struct nfit_set_info_map);
 }
 
-static int cmp_map(const void *m0, const void *m1)
+static int cmp_map_compat(const void *m0, const void *m1)
 {
        const struct nfit_set_info_map *map0 = m0;
        const struct nfit_set_info_map *map1 = m1;
@@ -1612,6 +1612,14 @@ static int cmp_map(const void *m0, const void *m1)
                        sizeof(u64));
 }
 
+static int cmp_map(const void *m0, const void *m1)
+{
+       const struct nfit_set_info_map *map0 = m0;
+       const struct nfit_set_info_map *map1 = m1;
+
+       return map0->region_offset - map1->region_offset;
+}
+
 /* Retrieve the nth entry referencing this spa */
 static struct acpi_nfit_memory_map *memdev_from_spa(
                struct acpi_nfit_desc *acpi_desc, u16 range_index, int n)
@@ -1667,6 +1675,12 @@ static int acpi_nfit_init_interleave_set(struct acpi_nfit_desc *acpi_desc,
        sort(&info->mapping[0], nr, sizeof(struct nfit_set_info_map),
                        cmp_map, NULL);
        nd_set->cookie = nd_fletcher64(info, sizeof_nfit_set_info(nr), 0);
+
+       /* support namespaces created with the wrong sort order */
+       sort(&info->mapping[0], nr, sizeof(struct nfit_set_info_map),
+                       cmp_map_compat, NULL);
+       nd_set->altcookie = nd_fletcher64(info, sizeof_nfit_set_info(nr), 0);
+
        ndr_desc->nd_set = nd_set;
        devm_kfree(dev, info);
 

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index ce3e8dfa10ad5ccc5285621e5c5b27b5c557e16b..1b481a5fb9667da9731c4a536dd16ef73f5e1ead 100644 (file)
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1700,6 +1700,7 @@ static int select_pmem_id(struct nd_region *nd_region, u8 *pmem_id)
 struct device *create_namespace_pmem(struct nd_region *nd_region,
                struct nd_namespace_label *nd_label)
 {
+       u64 altcookie = nd_region_interleave_set_altcookie(nd_region);
        u64 cookie = nd_region_interleave_set_cookie(nd_region);
        struct nd_label_ent *label_ent;
        struct nd_namespace_pmem *nspm;
@@ -1718,7 +1719,11 @@ struct device *create_namespace_pmem(struct nd_region *nd_region,
        if (__le64_to_cpu(nd_label->isetcookie) != cookie) {
                dev_dbg(&nd_region->dev, "invalid cookie in label: %pUb\n",
                                nd_label->uuid);
-               return ERR_PTR(-EAGAIN);
+               if (__le64_to_cpu(nd_label->isetcookie) != altcookie)
+                       return ERR_PTR(-EAGAIN);
+
+               dev_dbg(&nd_region->dev, "valid altcookie in label: %pUb\n",
+                               nd_label->uuid);
        }
 
        nspm = kzalloc(sizeof(*nspm), GFP_KERNEL);
@@ -1733,9 +1738,14 @@ struct device *create_namespace_pmem(struct nd_region *nd_region,
        res->name = dev_name(&nd_region->dev);
        res->flags = IORESOURCE_MEM;
 
-       for (i = 0; i < nd_region->ndr_mappings; i++)
-               if (!has_uuid_at_pos(nd_region, nd_label->uuid, cookie, i))
-                       break;
+       for (i = 0; i < nd_region->ndr_mappings; i++) {
+               if (has_uuid_at_pos(nd_region, nd_label->uuid, cookie, i))
+                       continue;
+               if (has_uuid_at_pos(nd_region, nd_label->uuid, altcookie, i))
+                       continue;
+               break;
+       }
+
        if (i < nd_region->ndr_mappings) {
                struct nvdimm_drvdata *ndd = to_ndd(&nd_region->mapping[i]);
 

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 35dd75057e1697f2e03de12c62cf3f6cabb69aec..2a99c83aa19f080ec866fc6cb3475c1b256cfc43 100644 (file)
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -328,6 +328,7 @@ struct nd_region *to_nd_region(struct device *dev);
 int nd_region_to_nstype(struct nd_region *nd_region);
 int nd_region_register_namespaces(struct nd_region *nd_region, int *err);
 u64 nd_region_interleave_set_cookie(struct nd_region *nd_region);
+u64 nd_region_interleave_set_altcookie(struct nd_region *nd_region);
 void nvdimm_bus_lock(struct device *dev);
 void nvdimm_bus_unlock(struct device *dev);
 bool is_nvdimm_bus_locked(struct device *dev);

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 7cd705f3247c341160a6b2ad7d1827c1604f34ce..b7cb5066d9613e681af289d6e97459b0d122526f 100644 (file)
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -505,6 +505,15 @@ u64 nd_region_interleave_set_cookie(struct nd_region *nd_region)
        return 0;
 }
 
+u64 nd_region_interleave_set_altcookie(struct nd_region *nd_region)
+{
+       struct nd_interleave_set *nd_set = nd_region->nd_set;
+
+       if (nd_set)
+               return nd_set->altcookie;
+       return 0;
+}
+
 void nd_mapping_free_labels(struct nd_mapping *nd_mapping)
 {
        struct nd_label_ent *label_ent, *e;

diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 8458c5351e562e57ea1161fc5ab234d5e53a47bb..77e7af32543f698d0413286dc8702d7124bcf81b 100644 (file)
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -70,6 +70,8 @@ struct nd_cmd_desc {
 
 struct nd_interleave_set {
        u64 cookie;
+       /* compatibility with initial buggy Linux implementation */
+       u64 altcookie;
 };
 
 struct nd_mapping_desc {